The multifactorial nature of Alzheimer’s disease (AD) has led scientific researchers to focus on the modifiable and treatable risk factors of AD. Sleep fits into this context, given the bidirectional relationship with AD confirmed by several studies over the last years. Sleep disorders appear at an early stage of AD and continue throughout the entire course of the pathology. Specifically, sleep abnormalities, such as more fragmented sleep, increase in time of awakenings, worsening of sleep quality and primary sleep disorders raise with the severity and progression of AD. Intervening on sleep, therefore, means acting both with prevention strategies in the pre-clinical phase and with treatments during the course of the disease. This review explores sleep disturbances in the different stages of AD, starting from the pre-clinical stage. Particular attention is given to the empirical evidence investigating obstructive sleep apnea (OSA) disorder and the mechanisms overlapping and sharing with AD. Next, we discuss sleep-based intervention strategies in the healthy elderly population, mild cognitive impairment (MCI) and AD patients. We mention interventions related to behavioral strategies, combination therapies, and bright light therapy, leaving extensive space for new and raising evidence on continuous positive air pressure (CPAP) treatment effectiveness. Finally, we clarify the role of NREM sleep across the AD trajectory and consider the most recent studies based on the promising results of NREM sleep enhancement, which use innovative experimental designs and techniques. Alzheimer’s disease (AD) affects at least 27 million people, and its occurrence has a dramatic impact on the life of patients and caregivers, in addition to elevated financial costs to society .Sleep disorders and alterations of macro- and microstructural sleep features are common in the elderly population ,3,4. SomIn this light, sleep represents a modifiable and treatable risk factor for AD. The perspectives and methodologies of research on the relationship between sleep and AD have changed over time . In the This review considers, at first, sleep abnormalities and primary sleep disorders, in particular insomnia, sleep breathing disturbances (SBD), circadian rhythm disturbances, and excessive daytime sleepiness (EDS), in qualitative and quantitative terms to provide a comprehensive view of the most recent advances associating poor sleep quality and AD. It contextualizes the main results of these studies in the light of new findings on pathophysiological mechanisms associating sleep with AD. Empirical evidence underlining the well-known relationship between sleep disturbances and AD/MCI condition is also mentioned. Then, it focuses on evidence that encloses sleep and AD along a trajectory, starting from normal aging and crosses the evolution of the disease, providing a comprehensive view of the current state of the art. With this aim, we consider mainly longitudinal studies that investigate sleep pathway in predictive and evolving terms in relation to AD.Furthermore, we emphasize the role of obstructive sleep apnea (OSA) disorder, given the growing evidence of its overlapping and sharing mechanisms with AD. OSA could be viewed as a representative condition of the relationship between sleep and AD due to its main features .Then, we explore sleep-based intervention, considering AD as a continuum that starts from the pre-clinical stage and follows the trajectory of the disease, suggesting that any intervention strategy should be administered as early as possible to achieve effective results to improve patients’ quality of life and slow disease progression.After an update on sleep hygiene-based interventions, combination therapies, and bright light therapy (BLT), we provide a new in-depth look at the continuous positive air pressure (CPAP) as a possible new target therapy, in the light of the close relationship between OSA and AD.Finally, we focus on the current knowledge on the specific role of NREM sleep alterations in the trajectory of AD. We review the most recent studies based on promising results on NREM sleep enhancement as a possible strategy to prevent and/or slow down the AD pathology, using innovative experimental designs and techniques to provide a comprehensive view of the most promising therapeutic approaches.Approximately 60% of AD patients exhibit sleep disturbances that occur from the pre-clinical stages of the disease . Sleep cA high percentage of MCI patients ranging from 8.8% to 45% also suffer from sleep disturbance, similarly but less markedly than AD patients. Many studies found less time spent in REM sleep, a lower amount of SWS in MCI compared to healthy elderly. Furthermore, insomnia, SBD, circadian rhythm disturbances and EDS are also present in MCI patients .About twenty years ago, more in-depth investigations of the relationship between sleep disorders/alterations and cognitive decline began in populations of healthy older adults. The rationale was based on the evidence that sleep disorders occur at very early stages of AD. The limitation of these studies is determined by the fact that most of them were based on subjective assessments of sleep quality provided by patients or caregivers, which are poorly reliable. Objective measures obtained through actigraphy and polysomnography (PSG) allow greater reliability, and their importance, also in the field of dementia, should be carefully considered by the scientific community. The PSG is not commonly included in the clinical assessment of AD patients. On the other hand, PSG studies in AD/MCI are recently growing, allowing a more extensive knowledge about the relationship between sleep alterations and AD pathophysiology see .Insomnia is common in AD and has been extensively studied in relation to cognitive decline in healthy elderly subjects. However, the results are still heterogeneous. A longitudinal study with a 3-year follow-up in an elderly sample showed that self-reported chronic insomnia independently predicted the risk of cognitive decline, but only in men . AnotherAt the same period, a longitudinal study on 2012 healthy elderly with follow-up at 2 and 10 years  showed tGiven the limitations of self-reported measurements regarding sleep quality and quantity, some studies have investigated the relationship between disturbed sleep and cognitive decline using actigraphy as an objective method to investigate sleep. In particular, a longitudinal study  investigRegarding sleep duration, many cross-sectional studies have emphasized a U-shaped relationship between self-reported sleep duration and cognition, as both too long and too short sleep durations were associated with worsening cognitive function ,25.Starting from the above-mentioned associations that link poor sleep quality with AD, investigators have hypothesized several possible mechanisms underlying this relationship, assuming both pathological processes common to sleep and AD and a mutual influence between them. These mechanisms include structural and functional changes in some brain regions related to sleep and cognition , increased neuronal excitability, oxidative stress, abnormal pattern of glucose metabolism, defects in the clearance of toxic substances in the brain , neuronal loss (with particular reference to locus coeruleus noradrenergic neurons).The involvement of DMN in relation to sleep and AD is crucial in light of the new advancement in the pathomechanisms of this relationship. A cross-sectional study, based on MRI , investiIt is interesting to note that fragmentation is one of the main and common characteristics of sleep-related disorders: insomnia, breathing disorders, intra-sleep awakenings, poor sleep quality, EDS, sleep-wake rhythm disorders are based on a fragmented sleep that, as evidenced by many studies carried out with sleep deprivation protocols ,28, haveSleep fragmentation means to interrupt the continuity of regular sleep, and this phenomenon has important implications: decreased slow wave sleep (SWS) and REM sleep, subsequent daytime sleepiness, metabolic changes, increased oxidative stress, increased neuronal and synaptic excitability, misalignment of homeostatic and circadian rhythms. Regarding SWS, its amount represents the best indicator of reduced Aβ levels, suggesting that reduced or fragmented SWS might initially increase soluble Aβ levels and subsequently facilitate the deposition and formation of Aβ plaques in the brain . The cinRecent animal studies have also attributed a role of sleep in the clearance of toxic substances (including Aβ) in the brain by the glymphatic system ,33, a peThe glymphatic system appears to be regulated by the sleep-wake rhythm, since more movement of CSF tracers through brain tissues have been found in sleeping rats than in awake rats . BeneficIn the context of the most common sleep disturbances in healthy elderly, MCI, and AD patients, the issue of changes in circadian rhythms is of particular interest, especially for the successive intervention strategies that are often based on the regulation of sleep-wake rhythms. Empirical evidence shows poor consolidation of rest-activity rhythms, reduced amplitude of circadian rhythms, and misalignment of circadian markers such as body temperature and cortisol levels in AD patients . SpecifiTranah and colleagues  first inA cross-sectional study showed that the MCI group exhibited an advanced timing of onset of melatonin secretion compared with the control group, without differences in the melatonin levels . RegardiConcerning neurotransmitters, it is possible that the noradrenergic system is implicated, particularly with regard to its role in pineal melatonin synthesis . The choGabelle and coworkers  aimed atIn the context of the relationship between sleep abnormalities and AD, OSA needs to be treated in more depth, given the growing amount of new research that closely associates OSA and AD, even hypothesizing possible shared and mutually affecting mechanisms between these two conditions. AD patients are five times more likely to have OSA when compared with controls, and OSA appears in approximately 50% of AD patients . FurtherAD and OSA share several risk factors such as age, gender, cardiovascular comorbidities, and genetic background . In partRecent evidence shows that OSA is associated with a treatable form of dementia known as Idiopathic normal-pressure hydrocephalus (iNPH) characterized by intracranial venous hypertension delaying drainage of CSF into the cerebral venous sinuses . The ratAlso, a number of pathological mechanisms associated with the bidirectional relationship between disturbed sleep and AD seem to be very blatant in the case of OSA. The results of a study evaluating the relationship between EDS and Aβ accumulation  showed tIn this view, OSA seems to involve all (and more) of the above mechanisms regarding the consequences of fragmented or disturbed sleep on the brain. OSA is widely linked to oxidative stress, glucose homeostasis, decreased connectivity in brain areas related to cognition, loss of noradrenergic neurons in the locus coeruleus, deficit in the clearance of toxic substances in the brain, and gray matter abnormalities.Regarding the potential mechanisms that could underlie the relationship between OSA and AD, the work of Yaffe and coworkers  aimed toTherefore, recent studies have investigated the relationship between OSA and AD, trying to correlate Aβ deposition with different levels of OSA severity. A recent study  showed tRecently, the first systematic review by Fiedorczuk and co-workers  reportedDamage produced by oxidative stress is also part of the pathogenesis of cognitive decline associated with both aging and neurodegenerative disorders. In humans, hypoxemia seen in OSA has been associated with a delay in peripheral nerve conduction  and dysfAnother recent review  analyzedObservations regarding the association between OSA and glucose metabolism are of interest because glucose homeostasis and insulin regulation are recognized as risk factors for cognitive decline . In geneOSA also appears to contribute to a reduction of the noradrenergic neuronal population in the locus coeruleus . The locAn interesting work by Bubu and collaborators  examinedThe relationship between OSA and AD has also been recently studied specifically in relation to tau protein levels by considering some regions of interest as highly susceptible to tau accumulation . Results in elderly subjects without cognitive impairment showed that those with witnessed apnea had higher tau levels in the inferior entorhinal and temporal cortex .A cross-sectional study of 2909 cognitively healthy older men  showed tTo date, there are no therapies for the treatment of AD: all clinical interventions are aimed at slowing the disease progression and improving the patients’ quality of life. In view of a neurodegenerative disorder that seems to have a multifactorial nature, researchers are giving growing importance to the identification of risk and modifiable factors for the prevention and treatment of AD and AD-related comorbidities.In recent years, sleep fits very strongly into this context, although sleep-based interventions are still few and poorly structured. This is partially due to the fact that sleep assessment and monitoring are not yet included in the clinical routine related to AD and cognitive impairment, leading to a general underestimation of sleep-related problems in AD patients. Some sleep-related treatments have been studied and found to be effective in both the elderly and patients with cognitive decline and AD.In this section, we summarize the well-known sleep-based intervention strategies concerning the use of sleep hygiene, combined interventions and BLT. Then, we focus on Continuous Positive Air Pressure (CPAP), highlighting the concept that each of these interventions should be administered early to prevent or slow down as much as possible the course of AD. A summary of the main results of sleep-based intervention strategies is reported in In AD patients, given the risk of possible adverse effects of sedative medications, behavioral strategies are often recommended. These strategies are based on sleep hygiene rules or combine a series of behavior designed to improve sleep quality and cognition. In general, sleep hygiene rules include regularity in bedtimes, limiting naps during the day, avoiding excitatory substances such as alcohol, nicotine, and caffeine, maintaining a room temperature that is not too hot or too cold, and reducing light and noise in the environment . BehavioFor example, the effects of behavioral strategies have been studied in the elderly population. Some studies have observed that combining certain behavioral strategies positively affected disturbed sleep in elderly populations. One study had combined social activities and low-intensity physical activity, showing an increase in SWS after two weeks of treatment . An inteOne study evaluated the effectiveness of a 4-week “Sleep Intervention Program” that included sleep compression, modified stimulus control, and sleep hygiene compared with a 4-week control intervention among healthy older adults . Those wThe issue concerning the possible beneficial effect of these interventions on cognition remains open. There are emerging and encouraging results from studies conducted on MCI patients. A 24-week structured limbs exercise program was administered to MCI patients . It resuBright light therapy (BLT) is a non invasive treatment based on the assumption that many individuals with sleep disorders have a disrupted sleep-wake cycle. This is related to age-dependent functional changes and to degeneration associated with the central nervous system, with particular reference to the supra-chiasmatic nucleus in the hypothalamus , as specA recent study  evaluateAnother recent study  analyzedA possible alternative to BLT is blue-enriched lighting, which provides high circadian stimulation during the day. It is based on new technologies in light-emitting-diode (LED), which provides blue-enhanced light at high intensity during the day and low intensity at night. This line of research is very recent and, therefore, still needs much experimental confirmation. At present, results are not homogeneous. Figueiro and colleagues  demonstrn = 46) [Recently, a research group performed two studies based on the effectiveness of a tailored lighting intervention in patients with AD and related dementias ,91. The n = 46) . The taiIn the second study, the investigators administered the same all-day lighting intervention to 47 AD and related dementias patients for 25 weeks to assess its long-term impact on sleep, mood, and behavior . The resAlthough in the present review we do not discuss the effects of drugs or supplements for the treatment of sleep disorders in AD, it is useful to mention the important advances in research on the role of melatonin and melatonin receptor agonist in the prevention of sleep disturbances. A recent review focused on the role of melatonin as a therapeutic mediator for sleep disorders and possible delirium—typical of advanced AD stages—in intensive care unit (ICU) . Sleep lAs previously described, one of the most promising target of non-pharmacological strategies for AD from the early stages of the disease comes from recent studies that have analyzed the relationship between OSA and AD. Beyond the presence of cognitive impairment, CPAP is the elective treatment for OSA, given the numerous empirical confirmations of the effectiveness of this therapy on sleep, behavior, cognition, mood and daytime sleepiness of OSA patients. In recent years, there has been a robust increase in the number of works that have investigated the efficacy of CPAP in relation to AD, with the aim to improve patient’s quality of life and possibly slowing the progression of neurodegenerative processes in cognitively healthy elderly OSA or pre-clinical stages of AD.n = 52) [The effects of CPAP on cognitive functioning were investigated in patients with mild to moderate AD (n = 52) . The comn = 52) . Althougn = 52) showed a lower percentage of N1 and a higher percentage of N2. In the paired analysis, three weeks of CPAP led to a significant decrease in the number of intra-sleep awakenings, percentage of stage 1, arousal and increased stage 3. Therefore, the effectiveness of CPAP was visible immediately after a single night with a sleep deepening. Improvements were maintained for three weeks in the follow-up evaluation. The same authors developed an experimental protocol that involved alternating CPAP treatment and placebo in AD patients with OSA, examining the effects of 3 weeks of CPAP followed by three weeks of placebo followed by other three weeks of CPAP . After aThe presence of OSA in a high percentage of AD patients also leads to the idea that breathing disorders during sleep, aggravating several conditions related to AD risk factors, could be associated with an earlier onset of cognitive decline. In this regard, a paper by Osorio et al.  showed tThe work of Liguori and collaborators  was the The effects of CPAP on sleep were reviewed by Brillante and coworkers  with theThe ability of CPAP to slow down the process of cognitive decline has also been investigated in another work . As exprA general examination of the literature regarding the effects of CPAP on non-demented OSA individuals reveals that the effectiveness of CPAP is related to cognition, such as memory, verbal fluency, executive functions, decreased sleep destruction and, in particular, alertness ,101. FurAn interesting multicenter study called The Apnea Positive Pressure Long-term Efficacy Study (APPLES) evaluated the neurocognitive effects of CPAP on OSA patients by comparing active treatment with a sham condition . ResultsImprovement in daytime sleepiness was also observed by Rosenzweig and coworkers  that comSeveral studies assessed the effect of CPAP on cognitive task-related local brain activity using fMRI. A longitudinal study  conducteInterestingly, the brain of OSA patients seems to behave in a similar way to that of elderly subjects or with AD: in fact, the pattern of over-recruitment of brain regions to support an adequate level of cognitive performance is similar ,106. ThiHowever, the results are not homogeneous. As an example, in another work 27 untreated patients with severe OSA and 24 control subjects underwent MRI at baseline and after six months of continuous CPAP treatment . No modiFurther specific studies are still needed to determine the real effectiveness of CPAP, especially in healthy elderly with cardiovascular comorbidities and in patients with other risk factors for AD, to try to include the monitoring of OSA patients and provide adequate intervention even in the preventive phase of cognitive decline.In the last decades, the technological enhancement of research methodologies widely contributed to the characterization of the sleep alterations in the AD trajectory from the pre-clinical stage to the full-blown expression of the disease and the elucidation of their possible role in the progression of the neurodegenerative process. In this vein, studies focused on the EEG hallmarks of NREM sleep in healthy aging, MCI, and AD have had a strong impact.It is well-known that several NREM sleep EEG oscillations have an active role in memory processes and plastic mechanisms . In partHealthy aging is characterized by an alteration of both slow waves and sleep spindles, more pronounced in the frontal areas, in terms of reduced density, incidence and amplitude ,119,120.AD pathology is associated with a further, progressive, and regionally-specific disruption of NREM sleep electrophysiology compared to healthy aging . Beyond It is worth noting that a recent study  has beenOverall, these results highlight that (a) healthy aging is characterized by a disruption of several NREM sleep hallmarks; (b) such NREM deterioration is progressively greater and locally-specific with the development of the AD pathology; (c) the alteration of NREM oscillations is associated with the level of cognitive decline; (d) early disruption of different NREM sleep oscillations, even during the pre-clinical stage of AD, can predict the development of the neurodegenerative process; (e) a complex relationship characterizes inter-dependent wakefulness and sleep electrophysiological modifications in AD and MCI. It is worth noting that many investigations also found macro- and microstructural modifications of REM sleep in AD/MCI ,139,140.The reviewed findings raise the possibility that NREM sleep alterations may represent not only a marker of AD but also a risk factor of its evolution. Hence, a specific mechanistic relation may link the alteration of NREM sleep oscillatory events and the pathophysiology of AD. In line with this hypothesis, many animal and human researches have been designed to describe the possible relation between NREM sleep disruption and early markers of AD. Starting from the notion that Aβ and tau pathology start their accumulation before the appearance of the cognitive impairment associated with AD , the resIn a pioneering study, Kang and co-workers  showed iIn this context, the existence of a specific relation between NREM sleep alterations and AD pathology has received strong empirical support. Mice overexpressing Aβ protein exhibited reduced and more fragmented NREM sleep ,144. ManOverall, cross-sectional studies, sleep deprivation/disruption protocols, and longitudinal evaluations support the notion of a mechanistic link between NREM sleep impairment and AD pathology, with wider evidence about SWA and Aβ burden. In this vein, an extensively accepted hypothesis concerns the existence of a bidirectional relation between these phenomena: NREM sleep alterations, particularly concerning SWA, would be associated with greater expression of AD pathology, which in turn induces a further impairment in NREM sleep oscillations ,171. AccBeyond SWA, the possible relation between sleep spindle deterioration and markers of AD pathology has also been investigated. A recent study showed that impaired SO-spindle coupling in older adults predicted a greater tau burden in the medial temporal lobe . InteresAccording to Mander , the avaThe hypothesis of a bidirectional influence between NREM sleep alterations and AD pathological components implies that therapeutic strategies aimed to improve NREM sleep may represent innovative solutions to contrast the development of AD. According to the proposed literature, the rationale would be that the improvement of NREM sleep oscillations should promote Aβ clearance, decreasing neurotoxic waste accumulation and oxidative stress, and thus improving memory performance . ConsistA first hypothetical objective of NREM sleep enhancement would be the prevention of AD pathology. The strategic modulation of local sleep oscillations may be used in healthy aging and in the pre-clinical stage of AD to reinforce the protective role of NREM sleep against the pathological markers of AD, thus preventing the neurodegenerative process. On the other hand, the enhancement of specific sleep oscillations may potentially have a role in the treatment of full-blown AD, slowing down the progression of the neurodegeneration through the contrast of the vicious cycle between NREM alterations and AD expression.Beyond pharmacological treatments, several non-invasive techniques have recently demonstrated their ability to modulate the human EEG oscillations during sleep with beneficial effects on memory ,174. ThePromising findings came from research on transcranial current stimulation (tCS) protocols, a group of brain stimulation techniques designed to non-invasively affect cerebral physiology and cognitive processes . Such meThe first study in this field used a bi-frontal oscillating anodal transcranial direct current stimulation (tDCS) protocol in the slow oscillations (SOs) frequency  applied during nocturnal NREM sleep in healthy elderly adults . The autPartially consistent results have been found by Ladenbauer and coworkers . Indeed,The same stimulation protocol has been used in healthy elderly during the first NREM period of night sleep . CompareOnly one study assessed the effect of so-tDCS compared to sham during a daytime nap in subjects with aMCI . ConsistOverall, results about the administration of so-tDCS during sleep in healthy elderly and subjects with MCI to promote NREM sleep oscillations and memory consolidation appear promising, albeit not uniform. Beyond several methodological differences between the reviewed studies that may have affected the results , it should be noted that the active stimulation had a negative influence on sleep architecture in both studies that found no differences or detrimental effects on memory performance compared to sham ,196. TheAnother approach for the modulation of NREM sleep oscillations to enhance cognitive functioning is represented by auditory stimulation. The delivery of specific types of acoustic stimuli during sleep can affect NREM oscillations ,199,200.In the first study, Papalambros and coworkers  assessedIn contrast with these encouraging results, Schneider and coworkers  recentlyFinally, only one study assessed the effects of acoustic stimulation phase-locked to the upstate of the sleep slow waves in a small sample of aMCI patients, compared to a sham condition . The autTaken together, the few studies on phase-locked loop acoustic stimulation in the elderly to modulate sleep physiology and enhance memory reveal encouraging but heterogeneous results. Interestingly, recent findings suggest that closed-loop auditory stimulation applied to enhance SOs may be more effective during specific phase windows, which would be different in younger and older adults . In thisThe proposed application of strategies to enhance NREM sleep oscillations with the aim to prevent or slow down AD pathology has a solid scientific background, and findings in this field appear promising. However, we are far from the possibility to employ these strategies in a clinical context. The number of studies is still scarce, and results are heterogeneous. Moreover, beyond specific methodological points, partially explaining such outcome variability that should be controlled in future studies , severalConcerning the possibility to use these strategies in healthy subjects to prevent AD development, the observation of their ability to enhance NREM oscillations and memory after one night does not constitute sufficient evidence. Indeed, their long-term influence on sleep physiology and memory and their direct efficacy in preventing AD symptoms are still unknown. A ceiling effect associated with prolonged stimulation is conceivable. For these reasons, the efficacy of these methods during extended periods of time needs to be tested. The same issue can be raised concerning the possibility to use these techniques to slow down the neurodegenerative process in full-blown AD. Moreover, studies on the direct application of these strategies in AD patients are still missing. A further effort is needed to provide concrete evidence about the efficacy of these strategies along the different stages of the AD trajectory.It is worth noting that the reviewed strategies  are not the only techniques to modulate NREM sleep electrophysiology. Indeed, we considered only those methods with consolidated literature in young adults and several available results in the aging population. However, other strategies may be of potential interest in this field. Transcranial magnetic stimulation (TMS) applied during sleep can modulate SWA when applied in healthy young adults . HoweverThe development of early intervention strategies aimed to reduce AD risk and slow down the neurodegenerative process represents a great challenge in current research and clinic. In this field, the agreement about the view of sleep as a crucial target for therapeutic intervention is progressively growing, thanks to a large number of studies pointing to (a) the existence of strong and progressive sleep alterations in the AD pathology, (b) the predictive role of early sleep dysfunctions on subsequent cognitive decline, (c) the bidirectional relationship between sleep alterations (particularly concerning NREM sleep oscillations) and AD ,142. Acc


Early-life experiences influence a broad spectrum of behaviors throughout the lifespan that contribute to resilience or vulnerability to mental health disorders. Yet, how emotionally salient experiences early in life are encoded, stored, and processed and the mechanisms by which they influence future behaviors remain poorly understood. The paraventricular nucleus of the thalamus (PVT) is a key structure in modulating positive and negative experiences and behaviors in adults. However, little is known of the PVT’s role in encoding and integrating emotionally salient experiences that occur during neonatal, infancy, and childhood periods. In this review, we (1) describe the functions and connections of the PVT and its regulation of behavior, (2) introduce novel technical approaches to elucidating the role of the PVT in mediating enduring changes in adult behaviors resulting from early-life experiences, and (3) conclude that PVT neurons of neonatal rodents are engaged by both positive and negative emotionally salient experiences, and their activation may enduringly govern future behavior-modulating PVT activity during emotionally salient contexts. Positive and negative experiences during sensitive developmental periods influence brain maturation to induce lasting alterations to cognitive and emotional behaviors . Indeed,The PVT has emerged as an important node in the limbic/reward system and within circuits that control appetitive/approach and aversive/avoidance behaviors  and is iThe PVT is heterogenous in its afferent and efferent projections and functional output of these projections . PVT proThe PVT receives input from a wide variety of cortical and subcortical areas involved in reward and stress-related behaviors . GlutamaThe PVT contributes to regulating responses to stress. Acute stressors, such as foot shock , immobilappetitive experiences. It is activated by initial exposure to a variety of drugs of abuse  is more densely expressed in the pPVT . ApproxiCorticotropin-releasing hormone receptor type 1 (CRHR1) and type 2 (CRHR2), which regulate behavioral, autonomic, endocrine, and immune responses to stress, are also expressed in the PVT . Their lEach of these neuromodulators or receptors contribute to particular functional or behavioral niches occupied by the PVT, including those related to drug-seeking, approach and avoidance behaviors, and responses to stress. Consequently, they likely contribute to the PVT’s roles in responses to remote emotionally salient experiences as well.Both positive and negative early life experiences exert enduring consequences on motivated behaviors as well as on responses to stress later in life . More spMany of the adult behaviors associated with early life experiences involve the functions of the PVT, indicating a possible role for this region in contributing to the observed deficits. For example, anhedonia, the reduced ability to experience pleasure derived from otherwise enjoyable activities, is a predictive sign of depression, schizophrenia, and substance use disorders . AnhedonIn addition to disruptions in reward circuit function, ELA also induces perturbations in fear memory and expression, including enhanced freezing behavior in both auditory and contextual fear conditioning paradigms . CircuitIndeed, as the PVT plays a crucial role in influencing behavior in response to remote emotionally salient events, might it contribute to the effects of experiences as remote as those early in life? Our group finds that a week of recurrent bouts of augmented maternal care during early postnatal development increased c-Fos expression in the PVT relative to that of pups reared in control conditions . This acThe development of preclinical models of positive and negative early life experience provides researchers the opportunity to understand complex neural mechanisms using approaches that are not possible in humans. Numerous paradigms have been used to generate stress or adversity during sensitive developmental periods. These models generally result in perturbation of the functions of the reward circuit, leading to deficits in reward-seeking behaviors  and, in One such experimental model of ELA is the long-established recurrent maternal separation model, in which pups are separated from the dam daily for prolonged periods . More reExperimental approaches have also been applied for generating positive early-life experiences. Again, because the key source of environmental signals to neonatal rodents (and humans) is the parent, these paradigms have aimed to manipulate maternal caring behaviors. The neonatal handling procedure involves removing the dam for 15 minutes daily, leading to barrages of maternal care upon her return to the cage . Adult mImportantly, the paradigms described above allow for creating a suite of early-life experiences, setting the stage for dissection of the specific neural circuitries and cell populations involved in the resulting behavioral changes - including the role of the PVT.Current approaches for uncovering the role of the PVT in encoding early-life experiences and mediating their behavioral consequences involve the use of the targeted recombination of active populations (TRAP) technique. This method allows for permanent access to neuronal ensembles activated during a specific experience, enabling assessment of the role of these neurons in reward and stress-related behaviors later in life . FurtherThere is a strong association between early-life experiences and subsequent resilience or vulnerability to emotional disorders. Many of these disorders are characterized by disruptions in behaviors related to reward-seeking, fear expression, and stress responses . The PVTCK wrote an initial draft. All authors conceived the manuscript, refined the manuscript, and approved the submitted version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Despite that it is commonly accepted that migraine is a disorder of the nervous system with a prominent genetic basis, it is comorbid with a plethora of medical conditions. Several studies have found bidirectional comorbidity between migraine and different disorders including neurological, psychiatric, cardio- and cerebrovascular, gastrointestinal, metaboloendocrine, and immunological conditions. Each of these has its own genetic load and shares some common characteristics with migraine. The bidirectional mechanisms that are likely to underlie this extensive comorbidity between migraine and other diseases are manifold. Comorbid pathologies can induce and promote thalamocortical network dysexcitability, multi-organ transient or persistent pro-inflammatory state, and disproportionate energetic needs in a variable combination, which in turn may be causative mechanisms of the activation of an ample defensive system with includes the trigeminovascular system in conjunction with the neuroendocrine hypothalamic system. This strategy is designed to maintain brain homeostasis by regulating homeostatic needs, such as normal subcortico-cortical excitability, energy balance, osmoregulation, and emotional response. In this light, the treatment of migraine should always involves a multidisciplinary approach, aimed at identifying and, if necessary, eliminating possible risk and comorbidity factors. It is commonly accepted that migraine is a pathology of the nervous system. For many years, attention has been focused on the predominant role of the brainstem in the genesis of migraine attacks and, probably, in its recurrence  and the consequent triggering of the so-called peripheral sensitization  could be a marker of endothelial dysfunction, linking vascular disease to migraine ], a meta-analysis of susceptibility genes for migraine identified enrichment for genes expressed in vascular and smooth muscle tissues, consistent with a vascular involvement , and NO] released by sympathetic, parasympathetic, and sensory neurons and in smaller arterioles in response to the neuronal firing  to milder ischemic conditions.In summary, when investigating the case of the migraine–stroke connection, we should look for a criminal conspiracy where all the suspects of the neuro-vascular-endothelial unit have a guilty role.Metabolic diseases, like diabetes and obesity, as well as endocrine diseases are highly prevalent conditions in the general population. Recently, several studies showed the presence of a complex and intriguing comorbidity between migraine and these disorders, suggesting new pathogenetic mechanisms for migraine.Insulin resistance (IR) is a condition characterized by a subnormal physiological response to normal insulin concentrations, with increased quantities of insulin produced to maintain adequate intracellular glucose concentrations. Metabolic syndrome (MetS) is a syndrome characterized by a cluster of metabolic abnormalities including hyperglycemia, hypertension, dyslipidemia, abdominal obesity, and a pro-inflammatory state. These two medical conditions are interrelated and share common underlying mediators and pathways.p = 0.032), and the risk for MetS increases significantly in patients with CM and medication-overuse headache  ]. Furthermore, the authors found a linear decrease in the prevalence of active migraine during the 24 years before a diagnosis of T2DM . In underweight individuals, the pooled risk of migraine was marginally increased by 13%  between endometriosis and migraine and suggested a role for genes involved in interleukin-1 receptor binding, focal adhesion-PI3K-Akt-mTOR-signaling, mitogen-activated protein kinase (MAPK), and tumor necrosis factor-alpha (TNF-α) signaling in the association between these two traits -PET and the level of functional cortical activity with evoked potentials showed a low metabolism of the cortical areas and high functional activity in migraineurs compared with healthy subjects , which occurred in 66.1% of the cases; the highest occurrence was of migraine (32.9% of the patients), followed by tension-type headaches (TTHs) (9.2%). Yet other studies have reported a significant association with headaches, particularly migraine-type headaches, being linked to the frequency of seizures  pathways are involved. Moreover, given the complexity of the networks involved, it is likely that the cortical projections of headache pain are widespread, also involving the areas belonging to neurolimbic network  and not just the primary sensory-sensitive areas. This is the reason why we could consider most cases of IEH as autonomic seizures  and panic disorder (PD) , whose presence might influence migraine response to treatment, in both the short and long run . PTSD occurs with a higher prevalence in people suffering from CM (43%) than those with EM (9%) . It develops from prolonged interpersonal traumatic experiences without the opportunity to avoid them. Along with typical PTSD clinical dimensions, cPTSD has “disturbances in self-organization” . This syndrome has a higher level of depression and dissociation and is more associated with medical diseases  [World Health Organization (WHO), Data on the co-presence of migraine and substance use disorder (SUD) are slightly controversial. For instance, previous evidence suggests a lower prevalence of alcohol consumption/addiction among patients with migraine. This is possible since wine, beers, or spirits are commonly perceived as easy triggers for headache attacks  axis was found in both disorders  encompassing a region of the gene KIAA0564  over the left dorsolateral pre-frontal cortex (l-DLPFC)  dysfunction, like genetic abnormalities of voltage-gated sodium channels  the risk of incidence of only one of the two conditions   in patients with narcolepsy    than do non-migraineurs  is independently related to CM, with a higher prevalence than patients with EM (53.9 vs. 44.6%) , researchers observed that the more severe the gastroesophageal reflux disease (GERD), the more prevalent is migraineur and non-migraineur headache  is a genetically based autoimmune systemic disorder triggered by gluten  ingestion and characterized by GI and non-GI symptoms, including migraine  and migraine are often comorbid, and researchers observed that the longer the history and severity of migraine, the higher the risk of being affected by IBS , in both adults , the production of inflammatory cytokines, and dysbiosis, that is, a microbial imbalance or maladaptation.During embryogenesis, the ENS develops simultaneously with the CNS, and they are connected by the modulation of the vagal nerve. Therefore, although it is unclear if the correlation between migraine and gastric digestive symptoms is due to a primary neurologic or gastric issue, gastric symptoms can be regarded as part of the spectrum of dysautonomia dysfunctions related to a migraine attack. To support this hypothesis, the entity of gastroparesis is related to the severity of migraine intensity , or systemic disorders, like systemic lupus erythematosus (SLE). It is not clear whether the headache, and specifically migraine, is a direct, specific manifestation of disease and its activity or it is only a concomitant disorder; and, most importantly, it is a matter of debate if headache and in particular migraine can predispose some patients to the subsequent development of an autoimmune disorder.Several studies assessed migraine prevalence in MS patients, which varies consistently among studies, ranging from 19.8 to 78%  included lupus headache as a descriptor, defined as a severe, persistent headache with often migraine-like features and unresponsive to analgesic treatment  and beta2GPI antibody positivity other than Raynaud's phenomenon in two  criteria and, in general, managed according to the available treatment guidelines.A variety of dated studies investigated the association between antiphospholipid syndrome (APS) and migraine, reporting a migraine prevalence ranging from 0 to 30%  than in normal subjects  seems to be more prevalent in migraineurs than in non-migraineurs (Kalaydjian and Merikangas, Several studies have investigated this association between migraine and atopic diseases in both adult and child populations. In particular, a relationship between asthma and migraine-type headaches has been reported especially in females as well as a greater prevalence of hay fever, rhinitis, and dermatitis in migraineurs than in healthy non-atopic controls (Mortimer et al., Dysfunction of the immunological system can be the common pathophysiological link between migraine and immunological diseases. Indeed, some immunological dysfunction has been suggested to play a role in migraine pathogenesis (Kemper et al., In pSS patients, pro-inflammation-mediated mechanisms and endothelial dysfunctions of the cerebral microcirculation could account for the comorbidity with migraine and Raynaud's phenomenon (Morreale et al., de novo or an exacerbation of a preexisting migraine is the location of MS lesions in strategic sites of the nociceptive pathways involved in the processing of head pain in migraine, such as midbrain/periaqueductal gray matter areas (Gee et al., One of the possible explanations of the occurrence of migraine The association between RA and SLE and migraine has been related to a shared dysfunction of the serotonergic system (Zeller et al., An increased production of platelet-activating factor and the release of vasoactive neuropeptides can play a role both in asthma pathogenesis (Wasserman, A good clinical history and neurological examination are sufficient to make a diagnosis of migraine and to evaluate the association with other medical conditions Evans, . NowadaySince the late 1980s, MRI studies have disclosed the presence of small, punctuate, regions of high-signal intensity involving the deep or periventricular WM in patients with migraine (Hougaard et al., The imaging features of WMHs of migraine patients may resemble the WM lesions seen in patients with inflammatory diseases, like MS, representing a diagnostic challenge. The presence of cortical lesions or more than three periventricular lesions or the identification of an intralesional vein may provide important pieces of information in the diagnostic work-up of migraine patients with WMHs, being highly specific for MS (Absinta et al., Much attention has been paid to the differential diagnostics between the migraine aura, especially when presenting as negative scotoma, and the acute ischemic stroke. In fact, on admission to the emergency room, 1 to 41% of patients presenting with stroke-like symptoms are events that mimic a stroke but are not caused by an ischemic brain event (Merino et al., in vivo, Li and colleagues (Li et al., Over the last decades, the use of neuroimaging techniques has improved our understanding of the pathophysiology of migraine and provided new insights into the mechanisms underpinning comorbid conditions (Messina R. et al., Recent imaging evidence has shown common functional and structural imaging patterns in migraine and RLS, supporting shared pathophysiological mechanisms between these two conditions. Abnormalities of dopaminergic neurons, such as the substantia nigra, and volumetric alterations of the middle frontal gyrus have been demonstrated in patients with comorbid migraine and RLS (Yang et al., It has been suggested that increased neuronal excitability and CSD might play a role in the comorbidity between migraine and epilepsy (Nye and Thadani, It is clear from the amount of studies reviewed here that migraine disorders are comorbid with a plethora of pathologies, not only of the CNS see . This reOverall, we can argue that the bidirectional mechanisms that are likely to underlie this extensive comorbidity between migraine and other medical manifestations are manifold . GeneticThe variable combination of thalamocortical network dysexcitability, of multi-organ transient or persistent pro-inflammatory state, and disproportionate energetic needs induced and promoted by the additive comorbid pathologies, may be causative mechanistic factors of the activation of an ample and diffuse defensive system that includes the trigeminovascular system in conjunction with the neuroendocrine hypothalamic system. The latter, through vagal and spinal extrinsic primary afferent neurons, is involved in coordinating appropriate behavioral responses to aversive and threatening stimuli (Grafe et al., Some studies pointed out the headache clinical features and response to acute and preventive treatment can have only minor differences in the two sexes (Vetvik and MacGregor, Overall, all this implies that the treatment of migraine should always involve a multidisciplinary approach, aimed at identifying and, if necessary, eliminating possible risk and comorbidity factors. This necessarily means that action should be taken as early as possible in life, both as children and as adults when migraine is still episodic. This is to avoid the evolution toward first a chronic form and then toward pharmacological resistance. This educational-behavioral process not only could favor the response to drugs for the attack and prophylaxis but could also allow the therapy to be better tailored to the individual patient.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.CA and GC contributed to the discussion of content, review, and/or editing of the manuscript before submission. All authors researched data for and participated in the writing of the article and proofread the final manuscript before submission.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Primary progressive aphasia (PPA) is a neurodegenerative disorder characterized by a gradual, insidious and progressive loss of language abilities, with naming difficulties being an early and persistent impairment common to all three variants. In the absence of effective pharmacological treatments and given the progressive nature of the disorder, in the past few decades, many studies have investigated the effectiveness of language training to minimize the functional impact of word-finding difficulties in daily life.We review language treatments most commonly used in clinical practice among patients with different variants of PPA, with a focus on the enhancement of spoken and written naming abilities. Generalization of gains to the ability to name untrained stimuli or to other language abilities and the maintenance of these results over time are also discussed. Forty-eight studies were included in this literature review, identifying four main types of language treatment: a) lexical retrieval treatment, b) phonological and/or orthographic treatment, c) semantic treatment, and d) a multimodality approach treatment. Overall, language training is able to induce immediate improvements of naming abilities in all variants of PPA. Moreover, despite the large variability among results, generalization and long-term effects can be recorded after the training. The reviewed studies also suggest that one factor that determines the choice of a particular approach is the compromised components of the lexical/semantic processing system.The majority of studies have demonstrated improvements of naming abilities following language treatments. Given the progressive nature of PPA, it is essential to apply language treatment in the early stages of the disease. Originally described as a nosological entity, primary progressive aphasia (PPA) is now considered a neurological syndrome characterized by a variety of clinical symptoms with different degrees of severity, including speech and language impairment due to the degeneration of language networks , 2. The For a diagnosis of PPA, language impairment should be the most prominent deficit, at least for the first 2 years of symptom onset, without other cognitive and behavioural disorders , 6, 7. MInterest in PPAs has grown rapidly over the years . Recent The nf/avPPA has main clinical features of agrammatism in language production and/or effortful halting speech . As an iThe svPPA is clinically characterized by a slow loss of semantic knowledge , anomia,The l/phvPPA has core features of deficits in word retrieval and sentence repetition . l/phvPPAlthough a detailed description of the distinctive features of PPA variants has been outlined, some patients show an aphasic syndrome that cannot be classified into any of the three variants . A minorIn a substantial number of patients with PPA, the disease arises at middle age and has a devastating effect on their quality of life . MoreoveIn the absence of effective pharmacological therapies to improve or stabilize the cognitive-linguistic deficits, there has been an increased interest in language training interventions to minimize the functional impact of communication difficulties in daily life and remediate language deficits in PPAs , 19, 20.With the progress in the diagnosis of PPA, an important aspect for obtaining satisfactory results is to apply an impairment-based approach that focuses on the particular language deficits of a patient . SeveralIt is important to note that the use of the same type of language training in patients with similar clinical features may often lead to different results , 25, 30.Naming difficulty is one of the first symptoms of PPA , 17, 32.Word-finding difficulties recorded in the three variants of PPA involve different linguistic processes, leading to substantial differences in the type of errors made by patients with PPA –35. The In PPA, the neural degeneration process can affect these language-related cortical regions differently, implying clinical and anatomical heterogeneity among the three variants , 37, 38.For nf/avPPA, in which imaging studies have highlighted the involvement of the left posterior frontal and insular regions, patients have been reported to have naming deficits specifically during the naming of actions rather than of objects , 40. In All of this evidence converges on the assumption that the anatomical differences underlying naming impairments in PPA reflect the involvement of separate word-finding operations, which, in turn, leads to different error types in naming tasks.Several studies have demonstrated effectiveness of intervention approaches in improving naming difficulties in PPAs , 55–60, Due to the impact of language impairments on daily life activities, several studies have investigated the effectiveness of different speech-language therapies in providing word relearning interventions, strategies and aids for adequate communication and support, and providing education for caregivers , 63, 64.In the following sections, we will discuss the immediate benefits of language training on the measures of oral and written naming outcomes, the possible generalization to other tasks, and maintenance over time for each variant of PPA.“ AND ”.We searched the Medline (PubMed) database for literature containing the following terms: We reviewed all titles and abstracts and examined all relevant original research articles  original research; (b) conducted on patients with PPA; (c) comprising only behavioural language intervention and no combined interventions; (d) providing at least one oral or written naming outcome measure; and (e) published before 15 January 2021. Furthermore, animal studies, reports of secondary data such as meta-analyses, reviews or letters and study protocols were excluded. Full-texts of the remaining studies were read before their exclusion or inclusion. References of the included studies were also screened to identify possible additional sources. Only English-language articles were included. Finally, 48 studies published between 2001 and 2020 were included in this literature review  lexical retrieval treatment; (b) phonological and/or orthographic treatment; (c) semantic treatment; and (d) multimodality approach treatment Table .Lexical retrieval treatment is the most common intervention performed in people with PPA to treat progressive word-finding difficulties . This trSome treatment techniques have been identified as lexical retrieval treatment, such as cueing hierarchies, lexical retrieval in context, and repetition and/or reading in the presence of a picture (RRIPP) .The complete cueing hierarchy is based on the principles of the Lexical Retrieval Cascade Treatment. This intervention starts with semantic self-cueing techniques  and progresses with orthographic and phonemic self-cues  and repetition of the target word , 84. Hown = 8) evaluated the effects of language training on naming nouns; only one focused on verbs, two investigated the naming accuracy for both nouns and verbs, and the other two studies evaluated the effects of language training on nouns, verbs and adjectives. Interestingly, all of the studies on lexical retrieval treatment assessed the long-term effects of the treatment with follow-up assessments (2–84 weeks).In this review, 13 studies investigated the effectiveness of lexical retrieval treatment on naming abilities in a total of 73 patients with PPA . Specifically, 12 studies assessed the oral naming performance using trained and untrained whole-word accuracy as measures, whereas only one study investigated both oral and written naming abilities using trained and untrained whole-word accuracy and letter accuracy, respectively. Most of the studies  compared the efficacy of orthographic and phonological treatments in a total of 79 participants with a diagnosis of PPA . Specifically, one study investigated oral naming performance to measure trained and untrained whole-word accuracy; one assessed oral naming performance to measure only untrained whole-word accuracy; one study assessed written naming performance as the primary outcome measure for the trained and untrained phoneme-grapheme and phoneme-word correspondences (letter accuracy); and the other five studies investigated both oral and written naming abilities using trained and untrained whole-word accuracy and letter accuracy/whole-word accuracy, respectively. All studies have evaluated the effects of language training on the naming of nouns. Interestingly, only two studies assessed the long-term effects (32–144 weeks).Of the eight studies that investigated the effectiveness of phonological and/or orthographic treatment in a total of 85 patients with PPA , two studies examined the effectiveness of phonological treatment alone on naming abilities in a total of 5 patients with PPA , one study focused on the effects of orthographic treatment alone in a patient with l/phvPPA, while most studies (n = 5) included participants with different PPA subtypes [Below, we will detail the evidence of gains obtained for oral and written naming abilities by application of phonological and/or orthographic treatment on different variants of PPA. Specifically, among the eight studies identified, one reported evidence only in subjects with a diagnosis of nf/avPPA  and two subtypes , 86, 88 The study of Louis et al.  was the Applying a phonological cueing hierarchy treatment in two individuals with PPA, one with l/phvPPA and one with svPPA, Newhart et al.  showed aIn contrast, the study of Tsapkini and Hillis  applied In a subsequent study, Meyer et al.  proposedIn subsequent studies, the same authors , 72 applPhonological and orthographic treatments are frequently used in the rehabilitation of speech disorders in PPA patients. All works examined, except for the study by Louis et al. , describLikewise, all studies that assessed written naming performance for trained items showed positive posttreatment effects of both procedures, although larger effects were generally observed using orthographic treatment , 87, 88.The application of semantic treatment has been widely investigated to treat anomia in patients with PPA . Semantin = 22) examined the effects of semantic treatment training on the naming of only nouns, while one focused on the naming of nouns and verbs. In addition, more than half of the studies on semantic treatment (n = 15) assessed the long-term effects of the treatment with follow-ups (1–28 weeks).In this literature review, 23 studies have investigated the effectiveness of semantic treatment on oral and written naming abilities in a total of 66 patients with PPA . Specifically, 22 studies focused on oral naming performance, measuring the whole-word accuracy of items. Nineteen of these studies investigated the effects of the treatment on both trained and untrained items; one assessed the naming accuracy of only trained stimuli, while two studies examined only the naming accuracy of untrained items. Most studies  and l/phvPPA (n = 2). In this study, the use of SFA therapy induced preservation of naming ability for trained items for up to 96 weeks, in comparison to a decline for untrained items.Finally, Flurie et al.  evaluateThe study of Beeson et al.  applied The effects of semantic treatment on naming abilities have important clinical implications, especially in the treatment of anomia related to a neurodegenerative deficit in the semantic system. Although most of the studies have applied semantic treatment in subjects with svPPA and only a few investigated the effects on nf/avPPA  and l/phSome studies investigating naming treatment in PPA have combined impairment-based approaches with functional approaches (communication skills training) to improve communicative independence in these patients. These multimodality approaches often include counselling and education on the use of strategies for patients’ caregivers –109.Training involves the use of several language exercises (restorative treatments) and provides a series of strategies to help the patient express desired content (compensatory treatments). Specifically, restorative treatments are impairment-based and include tasks aimed at treating specific language deficits, such as lexical retrieval, object definition and use, and apraxia of speech. Differently, compensatory treatments involve tasks focused on developing communication strategies, such as sentence production, conversation practice, word writing, use of an Alternative and Augmentative Communication devices and role-playing, in order to increase and facilitate the individual’s participation in daily life activities , 119.This type of rehabilitative approach is frequently addressed to patients not distinguished by clinical variants , 109 sinn = 53) were not classified into a specific subtype of PPA.Four studies that used multimodality approaches in a total of 54 patients with PPA were identified in our literature review. Only one of these patients received a diagnosis of nf/avPPA, while the others .Below, we will detail the evidence from the four studies.In addition to the widely described benefits for a variety of language measures and quality of life in chronic aphasia , FarrajoMoreover, Rogalski et al.  used a nAnother innovative anomia treatment combines restorative and compensatory approaches to improve deficits and develop communication strategies to facilitate daily life activities of patients, as has been described by Cadório et al. . This stRecently, Rebstock et al.  investigAs shown by the above studies, the application of the multimodality approach in patients with PPA does not provide clear-cut results, perhaps due to the variability of the treatments applied and/or the heterogeneity of clinical profiles of participants. In this regard, only two studies have reported an improvement in the naming of trained items after multimodality stimulation treatment , 107. LiThis review provides a broad overview of the effectiveness of language treatments in improving oral and written naming in PPA patients. Specifically, we describe the results arising from the application of these interventions for each variant of PPA in terms of immediate benefits on naming abilities, generalization and long-term maintenance.Treatment of anomia can be approached with various types of integrative interventions. One well-investigated form of language intervention for PPA is lexical retrieval treatment . Severalvia telerehabilitation). Some studies included in the present review have highlighted the positive effects of telerehabilitation-based language treatment in PPA, which is a treatment modality that could also be useful to promote delivery of medical care during a large-scale epidemic, such as the coronavirus disease COVID-19 pandemic [Regardless of the variant of PPA, all types of language treatment seem to show significant immediate posttreatment gains in oral and/or written naming for trained items, with no significant differences among types of word class treated or among the modalities of administration of the intervention (e.g., at-home, face-to-face by clinicians or pandemic .Regarding the immediate benefits for naming in PPA, interventions to rehabilitate anomia deficits are useful in patients with a speech disorder caused by a neurodegenerative disease.Another crucial issue involves the generalization of treatment benefits to untrained stimuli, one of the more important issues in rehabilitation. Although the underlying causes of anomia are different, with the gradual loss of semantic knowledge in svPPA and the alteration of phonological processing in l/phvPPA, lexical retrieval training seems to be able to achieve generalized benefits to untrained stimuli in both variants , 83, 84.With respect to the possibility of eliciting generalization to other language tasks by applying language training in PPA, this result has been recorded after the application of phonological or orthographic treatment in patients with a diagnosis of svPPA and l/phvPPA –72, 87 aRegarding the long-term maintenance of effects, lexical retrieval treatment , 76–84 aMultimodality approaches have been less studied. Current evidence shows that this rehabilitation strategy has slight effects on naming, generalization and long-term measures, probably due to the variability of the treatments applied and/or the heterogeneity of the clinical profile of the samples –109.Current research suggests that pathophysiologically targeted language treatment may be more successful than a “one size fits all” approach . SimilarAs recently reported, native language is relevant on the phenotype and clinical presentation of PPA , 127. ThSubstantial evidence has supported that language treatment should begin as early as possible to maintain the naming abilities .Although the results of the present review are of considerable interest, it is important to note some limitations. First, the included studies had methodological differences, such as heterogeneity of language treatments, differences in the sample size and variability in the outcome measures used.Although the studies reviewed here focused on the enhancement of spoken and written naming abilities, the selected studies have assessed naming of nouns, verbs or adjectives, emphasizing the issue of selecting the most suitable outcome measurements on the basis of the language profile of the recruited PPA sample. Moreover, these studies recruited patients at different disease severity status. Taken together, these differences make it difficult to compare the results of the studies and to draw a clear-cut conclusion.Moreover, most of the studies reviewed here employed case series with a pre-post design, while only one study was a controlled clinical trial. The results of randomized controlled trials will hopefully provide better information to guide future direction in rehabilitation. Furthermore, generalization of effects to untrained items and to other language tasks and the long-term maintenance of effects were not analysed in most of the included studies. These limitations imply the need for further research to investigate the effectiveness of different types of treatment in patients with PPA.patients. In addition, innovative approaches, such as combination of non-invasive brain stimulation techniques with speech-language therapy, have shown promising results in facilitating naming abilities in PPA [Currently there are no curative treatments available for PPA. Although there are no clear guidelines for language treatment , a numbes in PPA , 17, 21.Our review indicates that language treatments aimed for progressive naming difficulties appear to be an excellent opportunity for intervention and should be viewed as a necessary component of care for individuals with PPA. Larger and more extensive clinical studies applying language training, alone or in combination with neuromodulation , 21, 131A multidisciplinary, person- and goal-centered approach is desirable, which highlights the importance of collaboration among professionals of different backgrounds in the field of PPA, with the overall aim of maintaining daily life functioning by improving the efficiency of treatment and patient care , 23. Yet


In the United States (U.S.), the expansion of the use of fentanyl drugs was accompanied by increased numbers of individuals who suffer from fentanyl use disorder , there has been a rise in opioid-related overdose deaths, sparked by the use of fentanyl CDC, . In whatAfrican American patients who meet the diagnostic criteria for FUD and also suffer from other medical illnesses could be at high risk of fentanyl-induced death (Hser et al., Patients suffering from SARS have respiratory complications (Li and Ma, According to COVID-19 mortality records from the National Vital Statistics System, African Americans showed disproportionately higher percentage of COVID-19-related death CDC, . In WashThe rise in fentanyl overdose deaths in African American communities is alarming and suggests that new strategies tailored to mitigate the problem in this population are needed. We recommend the expansion of awareness programs about the risks of fentanyl in the drug supply, the expansion of naloxone distribution for overdose reversal, and increased access to drug treatment programs. We believe that multi-level teams should include community leaders, policy makers, government agencies, educators, prevention specialists, and treatment and recovery providers are needed to develop tailored intervention strategies targeted toward the treatment barriers that are prevalent in African American communities. Furthermore, following long periods of abstinence, recent inmates and patients being treated for an opioid use disorder might benefit from overdose prevention educational programs and take-home naloxone for themselves and others who might be witnesses to an overdose episode (McDonald and Strang, There is a need to address the health inequities in the African American community. The reasons for these disparities have thought to include long-standing systemic health and social inequities, as well as, the structural racism, which if not addressed, may subsequently elevate COVID-19 death rates in other states with large populations of African Americans. We recommend programs tailored to expand COVID-19 vaccination in these marginalized communities to mitigate the risk of dying from COVID-19. These should include the placement of large movable vehicles within communities with poor public transportation.To conclude, we recommend that more studies be conducted to identify health inequities that exist in African American communities as far as opioid prevention, interventions, and treatment resources are concerned. The under-representation of African Americans in medical research is a major impediment in addressing the various health disparities in fentanyl and COVID-19-related deaths in these communities. Erosion of trust due to past unethical clinical trials/research studies conducted on African Americans (Scharff et al., CB drafted and conceptualized the manuscript. JC reviewed and edited the contents of the paper. Both authors approved the final draft of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Transcriptomes and DNA methylation of colon cancer at the single-cell level are used to identify marker genes and improve diagnoses and therapies. Seven colon cancer subtypes are recognized based on the single-cell RNA sequence, and the differentially expressed genes regulated by dysregulated methylation are identified as marker genes for different types of colon cancer. Compared with normal colon cells, marker genes of different types show very obvious specificity, especially upregulated genes in tumors. Functional enrichment analysis for marker genes indicates a possible relation between colon cancer and nervous system disease, moreover, the weak immune system is verified in colon cancer. The heightened expression of markers and the reduction of methylation in colon cancer promote tumor development in an extensive mechanism so that there is no biological process that can be enriched in different types. Colorectal cancer is the most common gastrointestinal tumor with high appearance, recurrence, and death. Up to 70% occurs in the colon, and according to the statistics of 36 cancers in 185 countries in 2018, colorectal cancer resulted in 881,000 deaths, of which over 550,000 cases were due to colon cancer. In addition, more than 1,000,000 new colon cancer patients were confirmed during that year, justifying why the screening and treatment of colon cancer are hot issues worldwide . With thGDNF .The data used in this research are from a previous study  and are Colon cancer cells which possess transcriptomes with methyl-omics and normal cells are selected for further analysis. The genes expressed in all cells are reserved in the analysis for RNA, in contrast, because of the poor quality of methylation sequencing, the genes methylated in over 50% of normal cells and cancer cells are reserved for further methylation analysis. The downloaded transcriptomes are normalized to FPKM or TPM, so the data are renormalized, and the expression level of each gene is represented uniformly by the expression level of each gene taking up the percentage of the average expression level of all genes in the cell. The DNA methylation level is represented by the average methylation level of CpG loci in the promoter region.p-value <0.01 [Wilcox test  . The R pBased on the Seurat R package, principle component analysis (PCA) of colon cancer cell transcriptomes is performed and the top five principle components are picked for later t-distributed stochastic neighbor embedding (t-SNE) . A totalThe Wilcox test and fold change test are carried out between the 607 colon cancer cells and 20 normal cells with transcriptomes. In total, 331 differentially expressed genes are identified, 146 of which are upregulated in colon cancer . To remoAt the same time, functional enrichment analysis indicates the genes of upregulated expression in colon cancer cells are enriched in a variety of biological processes, besides this, these processes are very different between subtypes. The findings above verify the diversities between subtypes and the different mechanisms of colon cancer development in subtypes ; Table 2p-value of the Wilcox test and the absolute value of difference between normal cells and colon cancer cells are verified. Overall, 1,523 genes of upregulated methylation and 4,584 genes of downregulated methylation are identified . In addition, the intra-tumor heterogeneity of colon cancer is more reflected in upregulated expressed genes. Clinically, this finding provides possible targeted therapeutic approaches for colon cancer patients. However, the small number of cells and the high intra-tumor heterogeneity mean that the findings need to be verified in larger cohorts.


In the past decade(s), fluorescence microscopy and laser scanning confocal microscopy (LSCM) have been widely employed to investigate biological and biomimetic systems for pharmaceutical applications, to determine the localization of drugs in tissues or entire organisms or the extent of their cellular uptake (in vitro). However, the diffraction limit of light, which limits the resolution to hundreds of nanometers, has for long time restricted the extent and quality of information and insight achievable through these techniques. The advent of super-resolution microscopic techniques, recognized with the 2014 Nobel prize in Chemistry, revolutionized the field thanks to the possibility to achieve nanometric resolution, i.e., the typical scale length of chemical and biological phenomena. Since then, fluorescence microscopy-related techniques have acquired renewed interest for the scientific community, both from the perspective of instrument/techniques development and from the perspective of the advanced scientific applications. In this contribution we will review the application of these techniques to the field of drug delivery, discussing how the latest advancements of static and dynamic methodologies have tremendously expanded the experimental opportunities for the characterization of drug delivery systems and for the understanding of their behaviour in biologically relevant environments. The development of nanomaterials for the delivery and controlled release of drugs to a selected, specific biological target has been, for many years, one of the core areas of nanomedicine research. Indeed, the design and preparation of smart nanocarriers—with encoded targeting and/or controlled release abilities, multifunctional therapeutic or combined therapeutic/diagnostic properties, and responsivity to diverse stimuli—have reached, over the years, unpredictable achievements . SignifiIn this framework, fluorescence microscopy and laser scanning confocal microscopy (LSCM) are key experimental techniques to unravel the behavior of nanomaterials designed for pharmaceutical applications in biological environments ,11,12,13In addition, aside from imaging techniques, which provide the ability to unravel the localization of DDSs in complex environments, several fluorescence microscopy-related techniques have been developed and refined over the years, thus allowing for informational gain related to the dynamics of DDSs . Fluorescence recovery after photobleaching (FRAP), fluorescence correlation spectroscopy (FCS), and particle tracking (PT) can provide  information on the dynamics of DDSs, or on the modification of the typical dynamics of biological environments in response to the interaction with a DDS. Crucial information on DDS characteristics and behaviors in a complex biological environment can be obtained through these techniques, as the internalization mode of a nanocarrier inside a cell lumen , its adhesion to a biological interface, and its interaction with relevant biomolecules present within biological fluids ,15,16,17Despite the extensive application of LSCM in the characterization of biological systems and nanostructured DDSs, a clear limitation is represented by the achievable spatial resolution, which is far from that of electron microscopes. Indeed, typical sizes of nanostructured DDSs are within the range of a few–a few tens or hundreds of nanometers, which are also the typical length scales of DDS interactions with the surrounding environment, while the resolution limits of LSCM are 200–300 nm in the xy plane and 500–700 nm in the axial direction . Due to this inherent physical limit imposed by the diffraction limit of light, the information obtained through LSCM on the characteristics of nanostructured DDSs, as well as on their impact on subcellular processes or interaction with biological interfaces, is limited.In recent years, different methods have been developed to break the physical diffraction limit of light, approaching the typical nanometric resolution of electron microscopy. From the recognition of the potential groundbreaking impact of super-resolution imaging, with the 2014 Nobel prize in Chemistry, different nanoscopy techniques have been implemented on commercial microscopes, and are constantly refined to expand their applicability. Driven by this new hype around super-resolution microscopy, a general renewed interest has grown on advanced fluorescence microscopy techniques, which now offer multiple options and new opportunities for the characterization of nanostructured objects as DDSs, and of their behaviors  in biological environments, on a nanometric length scale.In this review, we summarize the major recent advancements of fluorescence microscopy-related techniques, in view of their impact in the field of drug delivery. Specifically, in The main application of advanced fluorescence microscopy-based techniques to the investigation of DDSs is the determination of the localization of DDSs in vitro and in vivo, which is a key issue, for instance, to: (i) understand the behavior of DDSs with biological interfaces/barriers and in biological media; (ii) evaluate the degree of cell uptake and understand cell uptake routes in vitro; and (iii) determine the extent of DDS accumulation in selected tissues. In these respects, the main advantage represented by super-resolution techniques is the possibility to accurately determine the localization of DDSs in complex biological samples. Clearly, together with opportunities, several challenges arise. To mention a few: some super-resolution techniques necessitate the use of powerful laser sources , which on one hand requires a tailored design of optimized photostable fluorescent probes, while on the other hand, might determine the photodamage and phototoxicity of biological samples in cases of long exposure ; biologiIn the latest years, the advent of super-resolution microscopy (SRM) has represented a game-changer in the characterization of the behavior of DDSs in biological systems—and more in general, in biomedical research—holding the promise to combine the inherent advantages of confocal microscopy  with an extremely high resolution, thus approaching the limits of electron microscopy. A thorough description of the different SRM techniques is beyond the scope of this review ; STED imaging, first conceptualized in 1994 by Hell et al. , enablesA different approach to achieving the super-resolution adopted in super-resolved, single-molecule localization microscopy is based on the localization of the fluorophores’ position under diffraction limit accuracy, which is completed by determining the centroid of the emitting spot. In particular, as briefly schematized in ®) targeting cancer cell surface biomarkers) on functionalized liposomes [From an applicative perspective, all SRM techniques represent powerful tools in cellular biology and pharmaceutical application. Each of the techniques provides direct visualization of engineered DDSs in vitro and in vivo in cells, tissues, and living organisms, and thus, direct proof of their efficacy in reaching their biological target. However, they can also represent valuable tools in characterizing complex, nanostructured DDSs; complementing the structural, colloidal, and interfacial information obtained through common characterization techniques applied to nanomaterials—such as scattering , surface techniques , and electron microscopy. For instance, STORM microscopy has been recently applied to investigate the formation of the protein corona coating silica nanoparticles, allowing for the quantification of the dynamic inhomogeneities in the protein corona layer  and thusiposomes , showingAside from these examples where SRM is applied to characterize the DDSs themselves, the key contribution of SRM to drug delivery research is represented by the possibility to achieve a direct visualization and the sub-diffraction, nanometric localization of DDSs in biological environments. In this respect, a general issue in SRM is in the choice of suitable fluorescent probes to appropriately label both the nanocarriers/active principles and cellular/subcellular compartments. This issue also applies to fluorescence microscopy; however, in super-resolution techniques, the photophysical properties of the dyes, such as photostability, brightness, and the ability to control the ON/OFF switch of excited states, are determinant factors in the formation of super-resolved images, themselves. Therefore, in the latest years, researchers have focused on synthesizing/developing suitable fluorescent probes, especially for the appropriate labeling of complex cellular environments ,43,44,45A relevant contribution of super-resolution microscopy to drug delivery research is the potential ability to localize a DDS inside cells with high spatial resolution, thus allowing not only for the evaluation of its cell uptake and cell uptake extent, but also its proximity to—and, therefore, its interaction with—specific cellular compartments. In this respect, super-resolution techniques have been applied to understand the endocytic pathways of nanocarriers. For instance, the internalization of cancer-derived exosomes in HeLa cells was detected using PALM/STORM imaging, by revealing the colocalization inside lysosomes , while tSuper-resolution techniques have also been successfully applied to the investigation of the interaction between nanocarriers and DDSs with relevant biological barriers, such as the dermal barrier and the blood–brain barrier. Specifically, Brewer et al. , by applAs already mentioned in the Concerning thin samples, total internal reflection fluorescence (TIRF) microscopy is characterized by a relatively simple experimental setup—allowing for thin samples to reach a high resolution close to that of STED while applying a localized illumination with minimum time and light power exposure—making it particularly suitable for live-cell imaging. As briefly schematized in Concerning thick samples, LSCM and super-resolution microscopies are generally limited to 60–80 µm of depth. Thick samples, as tissue slices, can be investigated through light-sheet-based fluorescent microscopy (LSFM) . The LSFAs reviewed in the previous section, thanks to the advancements of fluorescence microscopy, it is now possible to determine the localization of drug delivery with nanometric resolution. This undoubtedly represents an opportunity to understand the fate of DDSs in living organisms. Another opportunity offered by fluorescence microscopy and laser scanning confocal microscopy-related techniques is to determine not only the localization of nanosystems or drug delivery systems but also their dynamics. Techniques such as particle tracking (PT), fluorescence correlation spectroscopy (FCS), and fluorescence recovery after photobleaching (FRAP), which basic principles are summarized in We consider three main fluorescence microscopy-related techniques as possible options to investigate drug delivery systems from different perspectives. Particle tracking (PT), fluorescence recovery after photobleaching (FRAP), and fluorescence correlation spectroscopy (FCS) are characterized by two main differences: (i) they monitor dynamics and diffusion in different ways  is related to purely Brownian motion, where if the dependence of the MSD on time is tα with α < 1, then subdiffusive/cage/crowding effects occur, whereas with α > 1, active transport effects are present [The PT technique is based on the acquisition/analysis of multiple images of fluorescently labeled diffusing species, which are then analyzed to determine the trajectories of each diffusing species, and therefore analyze their dynamic behavior. In particular, by evaluating the displacement between the particle positions, it is possible to calculate the mean squared displacement (MSD) of particles linked to their diffusion coefficient. The dependence of the MSD on time provides information about the diffusion modes of the particles. A linear dependence of the MSD on time  inside the sample through the employment of a high-intensity laser beam. A series of images is then acquired at normal illumination intensity to monitor the rate and extent of fluorescence intensity recovery inside the ROI. Specifically, from the rate of fluorescence intensity recovery (which is due to the replacement of the photobleached fluorescent dyes with active fluorescent species diffusing from the neighboring areas), the diffusion coefficient of the fluorescent species can be inferred; from the percentage of recovery compared to the theoretical fluorescence recovery, the mobile fraction of the probe is discriminated from the immobile fraction  . The expIn the latest years, fluorescence microscopy-related techniques have exhibited continuous developments and progresses, both from technical and applicative perspectives, holding the promise to provide unprecedented tools for drug delivery research. In this review, we have revised the major fluorescence microscopy-related experimental techniques available for the characterization of drug delivery systems from static and dynamic points of view in different media, with a particular focus on the investigation within biological environments and in vivo. Indeed, the opportunities provided by fluorescence microscopy-related techniques to disentangle scientific issues typical of drug delivery research  are countless and exponentially growing, allowing for the expectation that in the next few years the development of completely new tools and protocols will truly advance drug delivery research.


Reactive arthritis (ReA) is defined as arthritis that arises after infection, where pathogens cannot grow in the affected joints. Formerly, the clinical triad of postinfectious arthritis, urethritis, and conjunctivitis was called Reiter's syndrome; however, these clinical signs only represented a subset of patients with ReA. Due to the great diversity of its manifestations, its diagnosis is a challenge and can be overlooked in clinical practice. Additionally, it is associated with a variety of extra-articular manifestations that may be present either in the acute or chronic phase of the disease. Despite the cardinal clinical presentation characteristics of ReA, no case has been described in the literature that is diagnosed by the presence of classic extra-articular manifestations without objective joint involvement after COVID-19 infection. This report describes the case of a female patient in her third decade of life with an unusual presentation of ReA and focuses on her extra-articular manifestations. Chlamydia trachomatis, Yersinia, Salmonella, Shigella, and Campylobacter [Chlamydia psittaci, Chlamydia pneumoniae, Staphylococcus aureus, and Streptococcus pneumoniae, or by viral infections (such as COVID-19) have been associated with certain cases of ReA [The term "reactive arthritis" (ReA) was introduced in 1969 as an arthritis occurring shortly after or during an infection that did not occur in the joint itself but in other parts of the body without identification of the microorganism in the joint tissue [lobacter . Formerllobacter . Also, bs of ReA . The diss of ReA . Due to s of ReA . It shous of ReA . DespiteA 30-year-old female patient from Maracaibo (Venezuela) with a history of severe respiratory infection by COVID-19 for four months presented with clinical symptoms of six days consisting of odynophagia associated with anosmia, dysgeusia, bilateral conjunctival injection, fever of 38.5 degrees Celsius, and dyspnea. She had a report of a positive antigen test and biochemical markers of poor prognosis as evident by lymphopenia, and increased lactic dehydrogenase, C-reactive protein, transaminases, and D-dimer. She received treatment with dexamethasone according to the RECOVERY study protocol for mild oxygenation disorder for four days without progression to pulmonary phase IIB and was discharged at that time. She presented again two months later due to decreased visual acuity and bilateral ocular pain of left predominance of one month associated with the appearance of painful oral aphthous ulcers involving the lips, palate, and tongue Figures .Additionally, skin lesions with psoriasiform characteristics were documented on the soles of the feet with changes suggestive of subungual hyperkeratosis in the nails and dactylitis of the fourth toe of the left foot Figures , 4. During the course of both hospitalizations, the presence of monoarthritis or oligoarthritis, inflammatory lumbar pain, or enthesitis was not established. She mentioned that she received outpatient treatment with nystatin, clotrimazole, itraconazole, fluconazole, and prednisolone, reporting partial improvement only with the latter at a dose of 15mg per day. On review by systems, she reported the appearance of painful ulcers on the labia majora associated with occasional vaginal discharge, and therefore the assessment was complemented with a smear of vaginal discharge with no signs suggestive of infection and on gynecological assessment with no clinical changes suggestive of cervicitis  B27 and B15 positivity, which could imply a risk in the development of true chronic spondyloarthritis, present features of other spondyloarthritis such as psoriatic arthritis, or represent a risk factor for the genesis of extra-articular manifestations of ReA. A better understanding of the immune alterations that accompany SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) infection may represent a useful opportunity to further investigate the immunopathogenic mechanisms capable of promoting the development of extra-articular manifestations in ReA. According to current knowledge of immunopathogenesis, blocking the IL-17 pathway could be a promising therapeutic alternative in these cases.


During epidemic and non-epidemic seasons, the Kwara North, Nigeria, has consistently reported high incidence rates for meningitis, a disease which mostly affects older members of the community. Limited studies have investigated the nexus between climate change-meningitis and socio-cultural factors influencing the management and control of meningitis among the older adults. This study explored the lived experiences of older individuals with meningitis and relationships with their caregivers in Kaiama Local Government area of Kwara state, Nigeria. 15 participants, 6 men and 9 women, aged 65+ years were purposively selected, and in-depth interviews were conducted. Results indicated that most of the older adults believed that the disease is caused by spiritual or supernatural forces , and the treatment and management, using orthodox medicine of it has been hampered by certain socio-cultural beliefs. Due to beliefs about contagion, older adults are mostly left on their own, with adult children occasionally visiting their parents to provide care only to return to their own homes. Also, children visit with traditional healers who perform rites of purification and give older adults concoctions to use. The study concluded that meningitis is one of the leading causes of untimely death of some older adults in the study communities and it has been worsened by some socio-cultural practices. Based on this conclusion, the study recommended massive enlightenment of the general public about best practices in the treatment and management of the disease among the older members of the study communities.