Dama dama) are present. The plots were also surveyed in summer for woody plant size structure, stem density and bramble (Rubus fruticosus agg.). Eight plots were re‐scanned twice in winter to compare seasonal VC values and assess scan consistency. Sample plots with higher densities of small stems had significantly reduced VC 1 m from the ground. Other stem size classes, mean percentage bramble cover and understory LAI did not significantly affect VC. There was no difference in VC between summer and winter scans, or between repeated winter scans. The density of small stems influenced viewsheds at deer eye height and may alter behavioural responses to perceived risk. This study demonstrates how TLS technology can be applied to address questions in large herbivore ecology and conservation.There is great potential for the use of terrestrial laser scanning (TLS) to quantify aspects of habitat structure in the study of animal ecology and behaviour. Viewsheds—the area visible from a given position—influence an animal's perception of risk and ability to respond to potential danger. The management and conservation of large herbivores and their habitats can benefit greatly from understanding how vegetation structure shapes viewsheds and influences animal activity patterns and foraging behaviour. This study aimed to identify how woodland understory structure influenced horizontal viewsheds at deer eye height. Mobile TLS was used in August 2020 to quantify horizontal visibility—in the form of Viewshed Coefficients (VC)—and understory leaf area index (LAI) of 71 circular sample plots (15‐m radius) across 10 woodland sites in North Wales (UK) where fallow deer ( Viewsheds (the area visible from a given location) can affect animal responses to danger. This study used mobile terrestrial laser scanning (TLS) to reveal that higher densities of small tree stems reduce viewsheds for deer in woodland environments. We discuss potential implications for deer management and demonstrate how mobile TLS can be applied to study the influence of habitat structure on animal behaviour and ecology. We used mobile TLS to quantify horizontal viewsheds, summarised as Viewshed Coefficients (VC) 1 m above the ground. Woodland structure was assessed by surveying the density of different stem size classes, species composition of woody vegetation (trees and shrubs) and bramble (Rubus fruticosus agg.) cover. The expectation was that higher densities of tree stems of all size classes and higher bramble cover would significantly reduce horizontal visibility as a function of distance from a given point. Leaf area index (LAI) of the understory was also extracted from the TLS data to assess the extent to which leafy foliage influenced horizontal viewsheds. We predicted that higher LAI values would correspond to lower horizontal visibility as a function of distance from a given point. In addition, a subset of plots was scanned in both summer and winter to compare horizontal viewsheds in different seasons. Visibility may be reduced in leaf‐on compared with leaf‐off conditions due to heightened seasonal foliage density from deciduous vegetation. Each winter scan was also repeated to check the consistency of the mobile scanning method. Through this work, we demonstrate how potential sightlines of large herbivores are altered by properties of forest understory structure.Our study aimed to evaluate the extent to which woodland structure influences horizontal visibility at a height relevant to a large herbivore species ‐ fallow deer  were located to capture as much variation as possible in density, structure, size and diversity of the tree and shrub communities within each of the 10 woodland sites Figure . Table 12.2Prunus spinosa), were surveyed as thoroughly as possible.LiDAR scans were conducted with a GeoSLAM  ZEB Revo TLS system to determine the horizontal visibility and LAI in each plot. Previous studies have validated GeoSLAM ZEB devices for use in forest surveys  to compare horizontal visibility in leaf‐off versus leaf‐on seasons. This January sampling period was also used to assess the consistency of the scanner and the data collection methodology by repeating all scans in the eight sampling plots, one directly after the other. The two scans per plot were then compared for significant differences in horizontal visibility.Fraxinus excelsior). To enable measurement of these saplings within a practical timeframe, all ash stems within the ‘Sapling’ and ‘Small’ categories  greater than 0.3 m in height were surveyed in each plot. For each woody plant, the taxon was identified as precisely as possible . For woody stems taller than or equal to breast height (1.3 m), the size class of diameter at breast height (DBH) was determined using a diameter tape . At each of these eight locations, a quadrat was placed on the ground and the number of squares containing bramble foliage and stems was counted from above. These eight counts were averaged to obtain a bramble count value for each plot survey. These two or three values from across the survey years were then averaged to obtain mean percentage bramble cover for each plot.Each plot was surveyed for bramble cover either two or three times across the summers of 2019–2021 using 0.25‐m2.3viewshed3d . The ground points were classified using the classify_ground function (lidR). The topographical slope was removed using the remove_slope function (viewshed3d) to make sure that the effect of vegetation in each plot could be examined independently of slope. Finally, the ground was reconstructed with the optimal resolution to ensure that sightlines did not pass through the forest floor using the reconstruct_ground function (viewshed3d).Point clouds were processed in R version 4.0.3  were used to crop the point cloud to 2 m in height and 15 m in radius, respectively. The data were then filtered to include the z coordinates only, then a leaf area density (LAD) profile was generated for each point cloud at height bands of 0.75, 1.25 and 1.75 m using the LAD function from the lidR package. The LAI for each point cloud was calculated from the LAD profiles for the height range of 0.75–1.5 m using the lai function in the leafR package  values were calculated for each point cloud within the bounds of 0.75–1.5 m in height. Point cloud processing used the same functions as for the Visibility Coefficient estimates, except for the n = 44), combined with the high level of variability among plots in species composition, meant that there were no clear relationships between species and VC that could be demonstrated statistically. While certain species provided a notably strong obstruction of view, such as patches of large Cotoneaster spp. and cherry laurel (Prunus laurocerasus) evergreen shrubs at site BWN, they occupied an insufficient number of plots to test the individual effects of these species. Our analysis therefore focused primarily on the effects of woody plant size, understory LAI and bramble cover on VC. Stem counts within the 15‐m radius plots were converted to stems per hectare for further analysis.The large number of woody plant species across the 10 sites (r = .74). In addition, data exploration using dot plots, histograms and box plots was conducted for each of the fixed effects and the dependent variable (VC) to check whether a normal error structure was appropriate. Based on this data exploration, a log transformation was applied to correct zero‐skewness in the following variables: very large stem density, small stem density, sapling density and mean percentage bramble cover. In addition, all explanatory variables were scaled through z‐scoring to bring them on to comparable scales for analysis. Using the R package lme4  by their propensity to cast shade using values reported by Ellenberg  prior to this paired test to remove the influence of any order effects.The following statistical tests were also conducted on the VC values: (1) point cloud processing was repeated without the slope removal step to assess whether the slope of the ground influenced VC. We compared VC values of point clouds from the same plots with and without ground slope removed using a two‐tailed Wilcoxon signed‐rank test, (2) we used a one‐tailed Wilcoxon signed‐rank test to determine whether there was any significant difference between the VC values of plots surveyed in the summer and winter. A mean value of VC from each of the eight pairs of winter scans was taken, and these were then compared with the eight summer scans from the same plots, and (3) we used a two‐tailed Wilcoxon signed‐rank test to compare same‐day repeat winter scans to assess whether error in the methodology generated differences in VC between scans. Scan pairs were randomised into two groups  had a ΔAIC of 0, while the next top ranked model had a ΔAIC of 5.20. In addition, the top model had an AIC weight of 80%. Given the importance of the top model, the estimates and 95% confidence intervals were examined for each explanatory variable. VC significantly decreased with increasing density of small stems (3.2n = 71) than when the ground slope was included  during point cloud processing. However, the difference was not significant  between point clouds with and without slope included .Mean VC was marginally higher when the ground slope was removed  than in summer scans , but the difference was not significant  between the VCs of winter and summer scans  and group B  were very similar. There was no significant mean difference  between the VCs of scans in groups A and B . This indicates that the walking pattern of the surveyor did not influence the outcome of the viewshed analysis.The mean VC for winter scans in group A , we conducted a post hoc power analysis to gauge the effect size that would be required to generate a significant effect. This was conducted using the pwr.t.test function from the pwr package  and light‐demanding species ash (Fraxinus excelsior) at several study sites  or hornbeam (Carpinus betulus), which cast especially heavy shade  had negligible independent effects on VC. The density of larger tree stems is restricted by their greater resource requirements. In addition, the foliage of larger trees is generally concentrated in the main canopy, above the eye height of terrestrial herbivores. Therefore, they are less likely to significantly hinder viewsheds at 1 m. Canopy trees can influence the understory through shading from dense foliage, which reduces the density of light‐demanding understory vegetation   being killed by human hunters increased with reduced terrain ruggedness and greater distance to bogs and young forests, indicating that hunters mostly killed moose in more easily accessible, open areas ; data curation (lead); formal analysis ; funding acquisition (supporting); investigation (lead); methodology (lead); project administration ; resources (lead); software ; validation (lead); visualization (lead); writing – original draft (lead); writing – review and editing . John R. Healey: Conceptualization (supporting); formal analysis (supporting); funding acquisition (lead); methodology (supporting); resources (supporting); supervision (supporting); writing – review and editing . Markus P. Eichhorn: Conceptualization (supporting); formal analysis (supporting); funding acquisition (lead); methodology (supporting); supervision (supporting); writing – review and editing . Owain Barton: Methodology (supporting); visualization (supporting); writing – review and editing (supporting). Andrew R. Smith: Formal analysis (supporting); methodology (supporting); writing – review and editing (supporting). Graeme Shannon: Conceptualization (supporting); formal analysis ; funding acquisition (lead); methodology (supporting); project administration ; resources (supporting); software ; supervision (lead); visualization (supporting); writing – original draft (supporting); writing – review and editing .The authors declare no conflict of interest.Appendices S1–S7.Click here for additional data file.


To describe the process of implementing a Youth Participatory Action Research (YPAR) project at a continuation high school (CHS) and share the results of a youth‐designed research project that explores barriers to high school completion.YPAR was implemented across three cohorts at a CHS in the central coast of California from 2019 to 2022. Student survey respondents were enrolled CHS students between March and April 2021.A modified YPAR curriculum integrating research methodology and social justice topics was used to guide student‐led research that resulted in a cross‐sectional survey.Field notes maintained by the first author documented the process of implementing YPAR including the curriculum, conversations, and research decisions and procedures. A student‐designed survey disseminated to all enrolled students resulted in 76 (66%) participant responses. The survey included 18 close‐ended questions and three narrative responses.This study details how YPAR methodologies can be translated to a high school credit recovery program. For example, student cohorts were needed to maintain continuity over time. A student‐designed survey revealed that 72% of student respondents reported taking care of family members and illuminated high rates of depression symptoms.This study offers a detailed description of how we implemented YPAR at a credit recovery program and provides student‐driven perspectives on educational reform and evaluation. This project addresses the implementation and challenges of using YPAR to engage youth in transformational resistance to rapidly study and improve CHS' policy and practice. CHS have fulfilled multiple roles, including citizenship training, vocational advising, and preventing dropout.California is the most diverse state in terms of socioeconomics, household composition, and cultural identity.CHS are responsive to California's compulsory education laws that require that students between the ages of 6 and 18 years to attend public school, with the exception of students enrolled in private education. CHS welcome students who are at least 16 and “at‐risk” of not graduating.CHS are governed by national and state legislation that centers accountability by measuring student or teacher success and identifying low‐performing schools. For example, the Every Student Succeeds Act (ESSA)1.1Critical Race Theory (CRT), which has been a cornerstone of education activism and reform since the turn of the Century, posits that race, ethnicity, and social class affect school experiences and performance for youth of color.CRT also provides a framework for understanding disengagement from the student perspective. Solorzano and Delgado BernalCHS are in a unique position to serve Black and Latiné youth because these students are overrepresented in their ranks and may have non‐traditional academic needs resulting from high residential mobility, lower socio‐economic status, and foster care system involvement.1.2Youth Participatory Action Research (YPAR) is a youth engaged iteration of Participatory Action Research (PAR), includes the same values as PAR, and can be used to address inequities in education and support positive youth development.YPAR includes youth researchers in every phase of research,1.3n = 2) YPAR studies involved continuation or alternative high schools.One systematic analysis reporting on YPAR research in schools identified 38 studies with a majority (71%) of studies being conducted within urban school settings, 21% in suburban settings, and the remainder (8%) in multiple school‐based settings or rural settings.1.4To address the shortcomings in the literature and in practice, we undertook a study to detail the process of implementing YPAR across three cohorts of youth co‐researchers within a CHS in California. We used YPAR to uncover youth perspectives about school reform practices in the context of low attendance and graduation rates. Similar to Solorzano and Delgado Bernal,22.1The school district initiated the university—school research collaboration. The participating CHS was eligible for CSI because its graduation rates were below the state target. The CHS in 2020 had an enrollment of 113 students of whom 93% were Latiné, 90.3% were classified as “socioeconomically disadvantaged,” and 19.5% were classified as “English Learners.”2.2The research team included members of the author team: a graduate student researcher (NL), three youth co‐researchers  and a faculty research supervisor (JS). Decision‐making was shared among the graduate student researcher and the co‐researchers. The graduate student researcher is a first‐generation college graduate, Latina, and from a low‐resourced community; she is a doctoral student in school psychology and has received mental health training under the supervision of licensed school and clinical psychologists. The faculty research supervisor is trained as a school psychologist and conducts research on systems change to support vulnerable populations; she has a longstanding partnership with the school district and was the principal investigator for the research.Since youth at the continuation of high school are highly mobile, it was common for the number of youth co‐researchers to fluctuate throughout the year. Youth co‐researchers were first identified by school staff and provided with information about days and times of the regular YPAR sessions. Following the initial staff recommendation, youth who were interested attended a YPAR session or information session prior to deciding if they wanted to continue as a YPAR member. Demographics of youth co‐researchers were not collected. Instead, conversations about immigration status, families, and connections to geographic location were discussed as a way to center youths' conceptions of their identities.2.3Through the YPAR process between Spring 2020 and Fall 2022, student co‐researchers developed and implemented a mixed methods approach to identify and describe the underlying reasons for low school attendance to understand factors that may contribute to low graduation rates. In response to the challenge conducting YPAR with a highly mobile student population , three groups of youth co‐researchers (Cohorts 1–3) participated. Each cohort was in place for 3–10 months, with an overlap for a few members to ensure continuity. Notably, the three cohorts of YPAR implementation were all affected by the COVID‐19 school closures and distance learning. The graduate student researcher adapted curriculum implementation and YPAR sessions to online Zoom sessions as necessary and awaited school approval for in‐person implementation when available.The graduate student researcher adapted two YPAR curriculaSince this YPAR project was carried out across three cohorts, Cohorts 2 and 3 were tasked to carry out Cohort 1's selected research methodology and to expand implementation. Two students from Cohort 1 returned for Cohort 2 and shared with Cohort 2 their experience in YPAR and the survey results. Cohort 2 also decided which survey variables to focus on based on their interest and frequency among student respondents. Cohort 2 developed focus group questions intended to explore student mental health and its effects on attendance and high school completion and began discussing possible methods for implementation in year 3. The graduate student researcher and a continuing co‐researcher from Cohort 2 shared the project with Cohort 3. Cohort 3 prepared to implement the focus groups and continued to workshop the focus group questions designed by Cohort 2.During Cohort 3, the school was transitioning back to in‐person classes after COVID‐19 school closures, and they did not implement the focus groups because of the school's focus on crisis response and more urgent student supports during this time. The graduate student researcher adjusted and supported the school and the students through other avenues . In addition, the sustainability of YPAR curricula, with modifications to support use by CHS students, was planned with school administration for a time when they would have the bandwidth to offer teacher‐led YPAR embedded in the leadership curriculum.2.4Through conversations facilitated and documented by the graduate student researcher, youth co‐researchers in Cohort 1 decided to develop a survey asking about mental health (anxiety and depression), substance use, family responsibility , safety, and transportation. In addition, some questions were specifically tailored to the students' experiences during COVID‐19 because the survey was fielded as students were returning to in‐person classes after attending school virtually for a year due to COVID‐19 school closures.As co‐researchers were interested in exploring mental health symptom presentation for anxiety and depression, the graduate student researcher engaged with the co‐researchers about existing validated mental health questionnaires while also weighing student co‐researchers' priority of keeping the survey under 20 questions. The YPAR team decided to incorporate the Patient Health Questionnaire‐2 (PHQ‐2) and the Generalized Anxiety Disorder 2‐item (GAD‐2)2.5The student‐designed survey was administered between March 31 and April 9, 2021. All student survey participants were recruited from the participating CHS. A total of 108 students, which was the total enrollment at the time, were invited to complete or opt out of the survey. Parents were notified and provided with a copy of the survey via the online parent portal. Parents had the opportunity to opt for their student out of participating. Demographic variables were not collected to maintain anonymity. The survey was disseminated through the web‐based survey platform Google forms. Data were downloaded to Excel and uploaded into SPSS Version 27 for descriptive analysis.2.6Field notes maintained by the first author documented the process of implementing YPAR including the curriculum, conversations, and research decisions and procedures. The first author was an active participant in the YPAR process and completed field notes during and after YPAR sessions with youth co‐researchers to provide contextual information for informal conversations, research decisions, suggested adjustments from youth co‐researchers, and the general process of YPAR. Field notes were not formally analyzed but were used to inform the iterative process of participatory research and gather quotes on informal conversations with youth co‐researchers.2.7The University of California, Santa Barbara institutional review board (IRB) reviewed and approved this study.33.1Table As explained above, cohorts were essential in ensuring continuity of research efforts developed by the YPAR team. The cohorts provided meaningful input throughout the process and took part in discussions and planning. The team engaged in critical reflection, proposed solutions, and acted with urgency for change.3.2A total of 72 (66%) students responded to the survey. A summary of key findings is reported in Table One of the final questions on the survey was open‐ended and asked students to share their reasons for not attending school. Responses included: “I get really bad anxiety and I feel like something is on my chest making it hard for me to breathe and also makes me feel noxious,” “Sometimes my anxiety gets really high and I literally cannot for the life of me show up to school like that,” “sick, doctors appointment, family problems,” “Lack of motivation I guess,” and “Very little sleep, anxiety, etc.”3.3They shouldn't be asking those straight A students, who have privilege, about how the school is working for them or how it can be better. It works for them. If they want to know how to make schools better, they should ask us. Students here who have been pushed to the back of the class and end up at a CHS.Evidence from this study suggests that school systems can learn from including youth as key stakeholders in educational reform. A student shared their frustration about the school board's request for student input from other schools and reflected on which students' input was valued.School‐level changes resulted from YPAR as well. In Fall 2021, the school received Model CHS recognition from the CDE. Achieving this award signals a dramatic change from the CSI eligible status that initially prompted the collaborative agreement that began this work. The YPAR research team was involved in providing letters of recommendation and interviews for the award. The implementation of YPAR was highlighted as an example of a comprehensive service for students who are “at‐risk.” Additional outcomes included the creation of intentional youth spaces in response to co‐researchers' expressed need for a room to unwind. In Fall 2021, the school converted a classroom into a room with couches and tables for students to use as needed.why these things are happening”), their connection to other students , and the group rapport . In addition, several YPAR student co‐researchers were recommended and attended the California Association of Student Councils (CASC) as a leadership opportunity. One YPAR student presented at the 2020 National Association for School Psychologists conference. Several YPAR students were nominated for and supported to obtain local, state, and national scholarships. In addition, throughout the process, the graduate research assistant supported students with scholarship applications, provided crisis support, trained the CHS alumni to become mentors for current students, and spoke at a local school board meeting to advocate for the community image of the continuation school students.Participants of YPAR engaged in several transformational experiences as a result of skills they developed during YPAR. Gathered from informal conversations and YPAR sessions with youth co‐researchers, student feedback often suggested that they valued the YPAR content  endorsed missing school to support family members such as taking care of siblings, accompanying family members to appointments, or supporting parents struggling with substance use disorders. Previous research has underscored that students who attend alternative education programs often face challenges that their traditional high school peers may not, for example potential involvement in the foster care system and experiencing lower socioeconomic status.One of the main goals for student researchers was to better understand their peers' mental health concerns. In the present study, 30.5% of student respondents met screening‐criteria for GAD, similar to other research studies that also used the GAD‐2 as a screening tool for adolescents.4.4Evidence from this study suggests that school systems can learn from including youth voices as key stakeholders in educational reform. Specifically, CHS are in a unique position to support students who have been failed by the school system and therefore should be at the forefront of educational reform. This research is consistent with literature that emphasizes that “vulnerable” youth are crucial and should be providing input for shaping and reforming educational policy and practice.4.5Although this project was intended to highlight the process of YPAR within a specific CHS, there are limitations and challenges the authors found notable. Generalizability is limited given that this study was conducted in California and state education laws differ, namely compulsory education that largely affects the study participants and youth co‐researchers. In addition, demographics of this CHS may not be representative of other CHS or alternative education systems and therefore, there may be additional considerations in a different social context. Youth co‐researchers were students who were identified as “at‐risk” of not graduating at 16 years of age, which in some states, would allow them to cease their public education if they chose. Additionally, findings from the student‐designed survey were limited to questions considered and asked by the graduate student researcher and youth co‐researchers, so were unable to identify other reasons for disengagement.5This project contributes to the limited literature of YPAR implementation within CHS, offering an example of YPAR implementation across three academic years with highly mobile youth, and provides insight into barriers to school attendance. Student co‐researchers demonstrated the critical need to engage youth who have historically been failed by the US education system in order to implement educational reform that serves all students.This project was funded by a grant from the California Department of Education from the Comprehensive Support and Improvement Funding. The first author is a recipient of a fellowship from the Robert Wood Johnson Foundation Health Policy Research Scholars Program.Appendix S1. Supporting informationClick here for additional data file.


To describe how veterinarians utilise and perform urinalyses for dogs and cats.A survey, developed and distributed through the Veterinary Information Network, enlisted veterinarians who perform urinalyses for dogs and cats. Participants were directed to question banks based on whether urinalyses were performed in‐house, by an outside diagnostic laboratory, or using an in‐house automated instrument. Participants using multiple methods were directed to questions that related to the chosen methods.A total of 1059 predominantly first‐opinion clinicians from the USA and Canada completed the survey. Participants performed urinalyses much less frequently than blood work during a routine examination. The most common factors preventing participants from performing a urinalysis with blood work included clients' financial constraints, difficulty obtaining urine and lack of perceived diagnostic need. The most common reasons for submission to a diagnostic laboratory included efficiency, more trusted results and convenience. Speed of obtaining results was the most common reason for performing urinalyses in‐house. Of the participants who performed in‐house urinalyses, fewer always performed a manual sediment examination (79%) as compared with urine‐specific gravity (99%) and manual dipstick (87%).This survey documents that urinalysis is often not used in senior patients as recommended by recent clinical guidelines for dogs and cats which can result in decreased diagnosis and impaired management of subclinical disease. There is significant variability in urinalysis methods despite veterinary guidelines promoting standardisation, and this could lead to inaccurate results. Veterinarians commonly perform urinalyses during the evaluation of their patients. It constitutes the third arm of the minimum database, along with a complete blood count (CBC) and chemistry panel. Routine urinalysis allows veterinarians to gain information about renal glomerular and tubular function, lower urinary system health and other body systems Fry . Urine‐set al. et al. et al. et al. et al. et al. et al. As perceptions of the roles of companion animals in society change, clients and veterinarians alike increasingly prioritise prevention and early diagnosis of diseases. Recently, canine life stages guidelines have been established by the American Animal Hospital Association (AAHA) for primary care diagnostics and treatments to help veterinarians optimise medical practices , casts, crystals and infectious organisms. Recently, automated urine dipstick readers and urine sediment analysers have been developed to perform urinalyses in‐house more efficiently and consistently , sent to an outside diagnostic laboratory (outside lab), in‐house using an automated dipstick reader (dipstick reader), and/or in‐house using an automated sediment analyser . Based on this question, the participants were given a select question bank that applied to each of the methodologies they selected. For example, if a participant only performed urinalyses using outside labs, then they were directed to an applicable question bank. However, if a participant used both outside labs and in‐house exams, then the participant answered two question banks that included questions about both.Participants that performed in‐house exams were asked several questions regarding how urinalyses are performed, by whom, their reasons for performing urinalyses in‐house rather than sending samples to outside labs, and whether they have considered using an in‐house automated analyser. Questions for participants that sent urinalyses to outside labs included how they store the urine, factors that determine why they send urinalyses to laboratories rather than performing them in‐house, what component of the urinalysis is the main limiting factor for performing urinalyses in‐house, and if they would consider using an automated in‐house instrument, if available. Disease entities that may have driven the selection of measured urine components were not queried in the study. Veterinarians who reported using an in‐house dipstick reader and/or sediment analyser were asked which type of analyser they use along with questions regarding sample preparation and storage. Participants using sediment analysers were asked questions focused on if and when they send samples to outside labs or perform in‐house exams instead of, or in addition to, the sediment analyser. Additionally, participants in this group were asked how often they review images generated by the analyser and what prompts them to review images or send them to a clinical pathologist for review.Descriptive statistics were performed in this study to evaluate the different facets of the data generated from the survey. The participants were divided into categories depending on the method of urinalyses performed. The data were reported as percentages and medians. Figures were generated using Microsoft Excel.This study was performed as a collaboration between Texas A&M University and Veterinary Information Network. The study was deemed not to be human research and was therefore exempted from IRB approval.A total of 1182 participants filled out the online survey between September and October 2019. Thirty participants who did not complete the survey were excluded. Seven participants who completed the survey were excluded because they reported they do not see patients directly and/or do not perform urinalyses for dogs or cats. Eighty‐six participants (7.5%) were from countries other than the USA or Canada or did not state their country and were excluded. Of the remaining 1059 participants, 918 were from the USA (87%) and 141 were from Canada (13%)  reported that they do not perform a urinalysis with every/almost every CBC or chemistry profile, most commonly because of financial constraints (n=452), because they do not think the urinalysis is warranted (n=386), and/or difficulty obtaining urine (n=372). This contrasts to 89% of respondents (945 of 1059) who stated that they would perform a urinalysis when the patient has indications for urine testing. The most common reasons for not testing in this situation are difficulty obtaining urine (n=93) and financial constraints (n=60).The number of participants that often or always perform urinalyses with CBC and chemistry panels varied widely based on the age of the patients Table . For patThe majority of participants indicated that they perform urinalyses by multiple methods with most performing in‐house exams, followed by using outside labs Table . The uriversus outside labs) were the ability to obtain rapid results (n=680), having the required equipment (n=305), availability of trained staff (n=323) and economics (n=263). Of 141 participants who chose “other” reasons, 75 explained that they believe the results are more accurate when done in‐house due to time delays causing artefacts with submission to outside labs, with crystal formation being a common concern.Of the participants that use both in‐house exams and outside labs, the median percentage of time that they perform in‐house exams was 50% (range: 1 to 99%). For all participants that perform in‐house exams (n=728), common reasons for performing urinalyses in‐house  always measure the USG when doing a urinalysis. Approximately 95% (694 of 728) of participants use a refractometer for USG measurement, whereas 0.1% (1 of 728) use urine dipstick alone and 4.4% (32 of 728) use both the urine dipstick and refractometer Table , despiteOf the time categories provided, a plurality of participants indicated that manual sediment examination takes between 6 and 10 minutes to prepare and perform Fig. . PracticMost participants that perform in‐house exams without sediment analysers complete both the dipstick and sediment evaluations within 30 minutes of collection Fig . Few parFor participants that perform in‐house exams with or without sediment analysers, 84% of respondents centrifuge <3 mL or 3 to 6 mL of urine . Additional information regarding how participants perform urinalyses are presented in Table Of the participants who only perform in‐house exams, 35% (86 of 246) have considered obtaining a sediment analyser. Reasons for not obtaining a sediment analyser are described in Fig. Eighty‐nine percent (108 of 121) of participants that use outside labs store the urine in the refrigerator before collection by the courier. For these participants, the most common factors that contribute to sending urinalyses to outside labs are efficiency (105 of 121), trusted/reliable results (81 of 121), lack of expertise in urinalysis and/or sediment examination (79 of 121), and convenience (78 of 121). When asked which component of the urinalysis is the main limiting factor for performing urinalyses in‐house, 54 participants chose the sediment examination, two participants chose urine dipstick testing, and none chose USG. The time to analysis for outside diagnostic laboratories was not included in the survey.Of participants who exclusively send urinalyses to outside labs, 28% (34 of 121) stated they would use a sediment analyser if one was available and 32% (39 of 121) stated they would not; 36% (44 of 121) of participants stated that they would consider using a sediment analyser. Participants indicated cost, accuracy and personnel time were the major deciding factors.Approximately one‐third of participants indicated that they use either dipstick readers, sediment analysers or both. However, only 7% of participants selected that they perform urinalyses exclusively using these methods Table . Of the e.g. culture or urine protein‐to‐creatinine ratio).Of the participants who use sediment analysers, 89% (285 of 319) use the IDEXX™ SediVue™, whereas 8% (27 of 319) use the Abaxis™ VetScan™ Sediment Analyser, with the remaining participants being unaware of the brand they use. Of the participants who use sediment analysers, approximately two‐thirds also submit urine to outside labs. The most common factors leading to submission of urine to outside labs despite having a sediment analyser include the need for additional expertise for interpretation and unexpected/uncertain/confusing results from the automated analyser Fig. . Anotherversus 24% (59 of 251) reporting that they often or always do this. The most common reasons for performing in‐house exams with a sediment analyser are described in Fig. Eighty‐four percent (269 of 319) of participants who use sediment analysers indicated that they perform an automated sediment analysis on 90 to 100% of urine samples that undergo urine dipstick testing. Eighty percent (256 of 319) of participants stated that they perform the automated sediment evaluation within 30 minutes of urine collection. Twenty‐six participants indicated that they sometimes refrigerate samples before using the sediment analyser, and 18 (69%) run the urine sediment immediately or within 10 minutes of removal from the refrigerator. Of the participants who use sediment analysers, 79% (251 of 319) perform a manual sediment examination as a follow‐up or substitute for the sediment analysers, although 76% (191 of 251) of these respondents indicated that they rarely or sometimes do Of the participants who use sediment analysers, approximately 74% (236 of 319) reported often or always reviewing images selected by the analyser. The factors that prompt participants to review images included suspected bacteria (n=100); an unclassified crystal (n=68), cell (n=63) or cast (n=47); unknown material (n=58); confirmation of cells (n=52), casts (n=42) or the report in general (n=52); and/or the opportunity to learn (n=50). Most participants reported never (247 of 319) or rarely (n=62) sending images to a clinical pathologist for review.et al. et al. Our survey of first‐opinion small animal clinicians revealed that urinalyses are commonly excluded as part of the minimum database, even for older patients. Furthermore, participants who perform in‐house urinalyses omit examination of the urine sediment more often than other components of the urinalysis. Our survey suggests that clinicians in first‐opinion practice underutilize urinalyses in older patients. The results of our study also demonstrate the variability and lack of standardisation of urinalysis techniques in veterinary clinics despite published clinical guidelines . The strengths and weaknesses of sending urinalyses to outside labs are largely opposite of performing urinalyses in‐house. Some strengths of sending to outside labs include time efficiency and more trusted results due to more expertise with urine sediment examinations, whereas weaknesses of this method include increased costs and delayed analysis and results, which can affect clinical application.Over 60% of veterinarians use multiple methods for performing urinalyses. Different strengths and weaknesses of each modality impacted veterinarians' decisions about which method to use. Strengths of in‐house manual examinations include faster and low‐cost results with fewer artefacts of time‐delayed samples, whereas weaknesses include the time it takes to perform this test and potential inaccuracies. In 30% of practices, veterinarians are the only personnel performing the urine sediment examinations. Even when other technical staff are utilised, veterinarians perform urine sediment examinations an average of one of three of the time. Given the average time of 6 to 10 minutes to prepare and perform urine sediment examinations, procedure time might limit veterinarians and technicians from performing urinalyses in‐house, or it might lead to incomplete analyses, with omission of the most time‐consuming component  than participants using in‐house exams (69%). The American Society of Veterinary Clinical Pathologists (ASVCP) quality assurance guidelines state that urinalyses should ideally be performed within 30 minutes of collection  are stable for a maximum of 4 hours in the refrigerator . In addition, the present study found that 67% of participants that send urinalyses to outside labs did so because of the lack of expertise in performing urinalyses and/or sediment examination. Automated sediment analysers might allow participants to gain familiarity and experience with sediment examinations by reviewing the images provided, as supported by the participants who indicated that reviewing the images provides them with an opportunity to learn. Over time, this could allow veterinarians to feel more confident and educated about performing urine sediment examinations. However, there was some concern among participants about the accuracy of these analysers, and more studies are needed to determine the role of these new analysers in veterinary medicine.Manual dipstick examinations were not considered the main limiting component for most participants. Moreover, the use of dipstick readers did not appear to increase the percentage of dipstick analyses performed within 30 minutes when compared to manual dipstick analysis  . Based on our survey, some of the more variable practices involved urine sediment preparation. Almost half of the participants use less than 3 mL of urine to prepare the urine sediment despite the recommendation that a standard volume of at least 3 to 5 mL be centrifuged . Time to analysis after shipment to outside laboratories was also not queried but can significantly change the quality of the result. In addition, during data analysis and review of responses, some participants appeared to confuse automated urinalysis instruments and manual urinalysis examinations. When identified, these participants were excluded from analysis for the questions related to methodology. Because of the automated nature of the survey, computerised code was used to direct participants to specific question banks, and that is a potential source for error. There were eight participants who were funnelled to the wrong category as an error of the online survey protocol; these participants were excluded for the related questions. No other obvious discrepancies were identified on visual inspection of the data. Furthermore, given the large number of respondents, a minor number of participants being misdirected would likely have little or no impact on our findings.The present study has some potential limitations, inherent with being a survey‐based study. Although a large number of participants were recruited for this study, the recruitment process involved veterinarians who are members of Veterinary Information Network, and this might introduce selection bias. Another potential limitation is that manual dipstick and sediment evaluations were included in the same category, which could have affected responses for manual sediment examinations, such as how often a sediment examination is performed. Other factors affecting the frequency of sediment examination could also have influenced participant responses if participants completed the survey considering patients in which a particular situation warranted a focused urine evaluation ; data curation ; formal analysis (lead); methodology ; writing – original draft (lead); writing – review and editing . Johanna Heseltine: Conceptualization (lead); data curation (supporting); formal analysis ; methodology ; project administration ; supervision ; writing – original draft (supporting); writing – review and editing . Mark Rishniw: Data curation (lead); formal analysis ; methodology (lead); project administration (supporting); resources (lead); software (lead); writing – review and editing . Mary Nabity: Conceptualization ; data curation (supporting); formal analysis ; methodology ; project administration ; supervision ; writing – original draft (supporting); writing – review and editing .Appendix S1. Survey: urinalysis in veterinary practice.Click here for additional data file.Fig S1. Percentage of surveyed participants based on the amount of time urine is stored before examination when using manual dipstick, manual sediment, or automated sediment analyser for canine and feline urinalysesClick here for additional data file.Table S1. Number of surveyed participants and number of canine and feline urinalyses performed weekly by urinalysis methodology. The shaded areas indicate the methodologies used by that participant groupClick here for additional data file.Table S2. In‐house urinalysis methodology for all participants that selected “in‐house manual exam” on a survey regarding canine and feline urinalysesClick here for additional data file.


We examine the test accuracy of the Development and Well‐Being Assessment (DAWBA) eating disorder screening items to explore whether the increased eating difficulties detected in the English National Mental Health of Children and Young People (MHCYP) Surveys 2021 reflect an increased population prevalence.Study 1 calculated sensitivity, specificity, and positive and negative predictive values from responses to the DAWBA screening items from 4057 11–19‐year‐olds and their parents, in the 2017 MHCYP survey. Study 2 applied the positive predictive value to data from 1844 11–19‐year‐olds responding to the 2021 follow‐up to estimate the prevalence of eating disorders in England compared to 2017 prevalence.Parental report most accurately predicted an eating disorder . Sensitivity increased when parent and child answers were combined, and with a higher threshold (of two) for children. The prevalence of eating disorders in 2021 was 1% in 17–19‐year‐olds, and .6% in 11–16‐year‐olds—similar to the prevalence reported in 2017 . However, estimates for boys (.2%–.4%) and young men (.0%–.4%) increased.out eating disorders, particularly when parents or carers screen negative, but are relatively poor at predicting who will have a disorder. Data from both parents and children and applying a higher cut point improves accuracy but at the expense of more missed cases.We found tentative evidence of increased population prevalence of eating disorders, particularly among young men. Despite this, the DAWBA screening items are useful for ruling The prevalence of eating disorders did not markedly change from 2017 to 2021, but we found tentative evidence of an increase, particularly among young men. This is despite larger increases in problematic eating, which need further investigation. The DAWBA screen is best suited to ruling out eating disorders which limits its clinical applications as it would provide many false positives requiring further assessment. Study 2 then applied the Positive Predictive Values (PPV) generated from Study 1 to estimate the prevalence of eating disorders in 2021 compared to that in 2017.We examined the diagnostic accuracy of the DAWBA screening questions, with the aim of estimating the prevalence of eating disorders from the 2021 follow‐up data. Our objective was to provide empirical context to better assess the extent to which increased clinical demand is being driven by increased population prevalence and to examine the impact of COVID‐19 .Diagnostic accuracy would not differ between the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM‐5)  and the Health Research Authority Confidentiality Advisory Group (16/CAG/0016). The follow‐up surveys were approved by the Office for National Statistics Ethical Committee, and our analysis by the University of Cambridge Psychology Research Ethics Committee (PRE.2020.145).2.2The 2017 MHCYP survey involved a stratified probability sample of 9117 children and young people aged 2–19 years living in England drawn from the NHS Patient Register. More detail about the sampling approach and sample are available in the NHS Digital report  applies questions to identify those with no problems to proceed directly to the next module, reducing participant burden. Those who screened positive are asked more detailed structured questions that relate directly to the diagnostic criteria, while semi‐structured probes explore the experience of these difficulties , which involved data from a community sample of 500 young people and their parents  as it is normally applied or (ii) set at two positive items for both parents and young people. We assessed the diagnostic accuracy of (1) these two different thresholds, 2) ICD‐10 and DSM‐5 criteria, and (3) individual responses versus combined responses from the parent and child or young person (where available). The components of diagnostic accuracy are defined in Figure  ICD‐10 aThe 2017 MHCYP routed all children and parents who screened negative through to the next module, which led to zero false negatives. A study designed to establish test accuracy would collect data on some screen negatives but because this was a survey that was not designed to do that, we applied false negative rates from a previous validation study of the DAWBA screen based on the 2004 BCAMHS   = 1.3). The text below, therefore, refers to DSM‐5 diagnoses unless otherwise specified.Table specific in parents: 93.7 (95% CI: 92.8–94.6) for parents of 11–16‐year‐olds, and 92.7% (95% CI: 89.8–95.1) for parents of 17–19‐year‐olds, and highly sensitive in children and young people at 100%.Using the standard threshold, the screening questions were highly Table 3.1.2Table Compared with Table Parental report was highly specific for both age groups and both diagnostic classifications, but sensitivity estimates were imprecise and lower for 11–16‐year‐olds than 17–19‐year‐olds. Applying the false negative rate greatly reduced the sensitivity of the screening questions across all informants. Sensitivity was higher when parent and child answers were combined, and even higher when the threshold for children was two or more compared to parents as single informants  as well as qualitative data to assign diagnoses if clinical impairment was evident, even if DSM‐5 and ICD‐10 diagnostic criteria were not met, with only one additional eating disorder emerging in this fashion. Thus, despite the limitations of the DAWBA screen, the very high NPV gives us confidence that those screening negative in the 2017 and 2021 MHCYP surveys are unlikely to have an eating disorder. The 2021 follow‐up had to be brief and online, but our work supports the need for inclusion of the full DAWBA in a future baseline population survey with a refreshed and representative sample. Repeating the DAWBA in a larger sample would also provide data on trends in eating disorders, allowing the longer‐term impacts of COVID‐19 on eating behaviors to be better examined.This is the first study to examine the diagnostic accuracy of the DAWBA screening questions in parents and young people, and the only population‐based study to estimate population prevalence of eating disorders before and after the pandemic. It benefits from a large, representative population sample. Nevertheless, the data were not originally collected with the intention of conducting a diagnostic accuracy study, and the present findings must be interpreted with limitations in mind. The full DAWBA was not applied to participants who screened negative in 2017, which deprived Study 1 of a true false‐negative rate, necessitating assumptions based on a smaller pilot sample. The “true” false negative rate in the general population of children and young people, however, is likely to fall between our two estimates (0%–2.4%) using this tool.Further research should analyze the results from the full DAWBA on a large sample of participants who screen negative to ensure more precise estimates. Sensitivity analyses with different assumptions could bolster these results, but the raw data are yet to be made available from NHS Digital.5The DAWBA eating disorder screen shows strong NPV and, particularly when used with parents or carers, could be highly useful at ruling out (if negative) and also ruling in (if positive) an eating disorder in clinical practice. While parental report alone provides the highest diagnostic accuracy, our findings also highlight the importance of speaking to both parents and children during assessment and using clinical judgment to balance the evidence when their accounts conflict. Finally, we found tentative evidence of a modest increase in eating disorders at population level.Tamsin Newlove‐Delgado: Resources; writing – original draft; writing – review and editing. Sally McManus: Data curation; project administration. Frances Mathews: Writing – review and editing. Suzanne Hill: Data curation; project administration. Katharine Sadler: Data curation; methodology. Tamsin J Ford: Conceptualization; funding acquisition; supervision; writing – original draft; writing – review and editing.Tracking the impact of COVID‐19 on national longitudinal probability sample MR/V027751/1. All research at the Department of Psychiatry in the University of Cambridge was supported by the NIHR Cambridge Biomedical Research Centre (BRC‐1215‐20014) and NIHR Applied Research Centre. Tamsin Newlove Delgado was supported by an NIHR Advanced Fellowship (NIHR 300056). The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.The original survey was commissioned by the Department of Health for England and delivered by a consortium including the National Centre of Social Research (NatCen), Office for National Statistics (ONS), and the universities of Cambridge and Exeter. The UKRI funded the wave 2 follow up and the current analysis: The authors declare no conflict of interest.Data S1 The full DAWBA eating disorders module,Click here for additional data file.Data S2 DSM‐5 and ICD‐10 criteria for eating disordersClick here for additional data file.


The era of next‐generation sequencing has increased the pace of gene discovery in the field of pediatric movement disorders. Following the identification of novel disease‐causing genes, several studies have aimed to link the molecular and clinical aspects of these disorders. This perspective presents the developing stories of several childhood‐onset movement disorders, including paroxysmal kinesigenic dyskinesia, myoclonus‐dystonia syndrome, and other monogenic dystonias. These stories illustrate how gene discovery helps focus the research efforts of scientists trying to understand the mechanisms of disease. The genetic diagnosis of these clinical syndromes also helps clarify the associated phenotypic spectra and aids the search for additional disease‐causing genes. Collectively, the findings of previous studies have led to increased recognition of the role of the cerebellum in the physiology and pathophysiology of motor control—a common theme in many pediatric movement disorders. To fully exploit the genetic information garnered in the clinical and research arenas, it is crucial that corresponding multi‐omics analyses and functional studies also be performed at scale. Hopefully, these integrated efforts will provide us with a more comprehensive understanding of the genetic and neurobiological bases of movement disorders in childhood. The pace of gene discovery in the field of pediatric movement disorders has skyrocketed in the next‐generation sequencing era. With the identification of novel disease‐causing genes, a flurry of investigations aiming to link the molecular and clinical aspects has often followed. Here, this process is exemplified by the developing stories of paroxysmal kinesigenic dyskinesia and myoclonus‐dystonia syndrome. Dystonia is defined as involuntary muscle contractions affecting one or more body parts, thereby causing twisting movements or abnormal postures. Several disorders featuring early‐onset dystonia are known to be genetically determined. These dystonia syndromes can be classified based on their associated features; isolated dystonia refers to conditions in which dystonia is the sole movement disorder phenotype, whereas combined dystonia denotes conditions in which dystonia co‐exists with other involuntary movements (such as myoclonus). In addition, some dystonia syndromes are paroxysmal in nature; that is, they are characterized by episodic occurrences of involuntary movements. This Perspective focuses on selected conditions representing paroxysmal and combined dystonias; namely, paroxysmal kinesigenic dyskinesia (PKD) and myoclonus‐dystonia syndrome (MDS). In addition, isolated dystonias will also be discussed briefly. This review is not intended to be exhaustive; rather, it aims to showcase the winding road from gene discovery to mechanistic insights in this field. Taken together, these developing stories demonstrate how gene discovery inspires and anchors the efforts of basic and clinical investigations, which in turn help delineate the phenotypic spectra and pathophysiological mechanisms of pediatric movement disorders.Movement disorders in childhood comprise a wide range of etiologically and clinically heterogeneous conditions that are often difficult to diagnose and treat. Investigations of pediatric movement disorders require a multidisciplinary approach that includes various modalities of neuroimaging, electrophysiology, and genetic and metabolic evaluations. With the advent of next‐generation sequencing (NGS) technologies, the list of causative genes for pediatric movement disorders has expanded rapidly. As such, genetic testing has become increasingly important in the evaluation of children and adolescents with movement disorders.1, 222.1 PKD is the most common form of paroxysmal dyskinesia, and it is usually kinesigenic . This readily recognizable clinical picture of PKD, along with its exquisite responsiveness to low‐dose sodium channel blockers, has been delineated several decades ago. However, the electrophysiological underpinnings of PKD were a subject of debate. PKD is sometimes associated with a family or personal history of self‐limited infantile seizures, and this condition is known as PKD with infantile convulsions . At the turn of the century, linkage analysis was used to map the locus for these conditions to the pericentromeric region of chromosome 16; subsequently, similar results have been reported by multiple research groups. Despite extensive attempts to identify the causative gene following the identification of the locus, the gene responsible for PKD—the proline‐rich transmembrane protein 2 gene (PRRT2)—was first identified in 2011 through exome sequencing.PRRT2 was subsequently confirmed as a major causative gene of PKD in multiple clinical cohorts of different racioethnic backgrounds, and it was also found to be associated with a variety of other neurological conditions, including epilepsy, migraine, and episodic ataxia. Moreover, PRRT2‐associated phenotypic heterogeneity was reported even within families.Paroxysmal dyskinesia is characterized by brief episodic attacks of dystonia and/or choreoathetotic movements. Both familial and sporadic cases have been identified, with most patients showing onset during childhood. Paroxysmal dyskinesia takes several forms that are named after their respective triggering factors and are assigned individual codes in the Online Mendelian Inheritance in Man (OMIM) database. These include PKD (OMIM #128200), paroxysmal non‐kinesigenic dyskinesia , and paroxysmal exercise‐induced dyskinesia .6 PKD 2.2PRRT2 was identified as the causative gene for PKD, very little was known about its functions at the cellular and neural circuit levels. In vitro studies have reported that disease‐causing mutations result in decreased or absent protein expression. However, cells co‐transfected with mutant and wild‐type PRRT2 did not show evidence of a dominant‐negative effect, which suggested haploinsufficiency as the pathogenic mechanism. This view was further supported by the identification of 16p11.2 microdeletions involving PRRT2 in some patients. However, not every mutant transcript is subject to nonsense‐mediated decay, and the PRRT2 protein is known to oligomerize, suggesting that the dominant‐negative effect may play a pathogenic role for some variants. Interestingly, the penetrance for paroxysmal movement disorder appears to be lower in cases with 16p11.2 deletions, which is a relatively common form of microdeletion syndrome associated with a variety of neurodevelopmental disorders. It remains to be clarified whether this is due to incomplete characterization of the associated phenotypic features, or if the contiguous gene(s) has epistatic or other disease‐modifying effects.At the time when echanism.23 Thi This makes them suitable models for investigating the mechanisms of these disorders. The various presynaptic functions of PRRT2 have been better understood in recent years. First, PRRT2 interacts with several presynaptic proteins involved in the synaptic vesicle cycle—notably SNAP‐25 and vesicle‐associated membrane protein 2 —to regulate the release of neurotransmitters. Notably, mutations in SNAP25 and VAMP2 are associated with neurodevelopmental disorders with dystonia. Second, PRRT2 interacts directly with P/Q‐type calcium channels (encoded by CACNA1A), and both PRRT2 and CACNA1A are heavily expressed in the cerebellum. PRRT2 deficiency leads to decreased membrane targeting of P/Q‐type calcium channels, thus reducing the presynaptic calcium influx currents mediated by these channels. Therefore, the significant overlap between PRRT2‐ and CACNA1A‐related neurological phenotypes—including paroxysmal dyskinesia, episodic ataxia, hemiplegic migraine, and epilepsy—is likely non‐fortuitous. Third, proteomic studies showed that the α3 subunit of Na+/K+‐ATPase (encoded by ATP1A3) is one of the major binding partners of PRRT2.ATP1A3 is associated with a wide spectrum of neurological phenotypes (which are sometimes complicated), and both PRRT2 and ATP1A3 mutations are implicated in distinct forms of paroxysmal dyskinesia and epilepsy. The phenotypic similarities suggest that the interference of their interactions may be related to the pathogenesis of these disorders.In line with findings from human patients, rodent models of PRRT2 deficiency also exhibit paroxysmal movement disorder phenotypes.30 Thi Proteomic studies show that PRRT2 may act as an AMPA receptor accessory protein, suggesting that it is involved in postsynaptic function. Further research is needed to elucidate the role of PRRT2 in this aspect. In addition, PRRT2 may also act at extra‐synaptic sites by negatively modulating neuronal voltage‐gated sodium channels, including Nav1.6 (encoded by SCN8A). In this regard, it is interesting to note that a specific form of SCN8A mutation (c.4447G>A), which presumably causes a slight gain of function, may also manifest as PKD/IC. Both PRRT2‐ and SCN8A‐related PKD are responsive to therapy with sodium channel blockers. However, the paroxysmal electroencephalographic changes recorded during dyskinetic attacks suggest that SCN8A‐related PKD could be epileptic in nature  and multitude of interacting partners of PRRT2 indicate that it is a multifunctional or multitasking molecule. Therefore, ule cells41—and2.3PRRT2 is the only gene that has consistently been found to be related to PKD. Variants of several other genes  have been suggested to be responsible for a few cases of PKD. However, the genetic etiology of a significant fraction of patients with PRRT2‐negative familial or sporadic PKD remains to be identified, suggesting the presence of other causative gene(s). Whole exome sequencing studies have recently revealed that TMEM151A variants are responsible for PKD in three dominantly‐inherited families and in several sporadic cases.TMEM151A‐related PKD resembles the phenotype associated with PRRT2, although subtle differences between them have been noted . A common homozygous haplotype mapped to the chromosomal region 16p12‐11.2 was found to co‐segregate with the disease status. This locus overlapped with the previously identified PKD/IC locus, leading to the speculation that a common causative gene underlies these seemingly similar neurological phenotypes. Due to the presence of multiple loops of consanguinity in the pedigree, the critical region was initially analyzed using a recessive consanguineous model; however, the results did not yield any potentially disease‐causing homozygous variants in a consistent manner. In a study that assumed a recessive model that included compound heterozygous mutations, the researchers identified TBC1D24—rather than PRRT2—as the causative gene for the disorder. In retrospect, the constellation of neurological phenotypes described by Guerrini et al. is distinct from that of PRRT2‐related disorders, and their inheritance pattern is also different. However, given that the genes implicated in movement disorders often have incomplete penetrance and variable expressivity, the distinction between different genetically‐defined clinical entities could only be appreciated in hindsight.The search for genes associated with paroxysmal dyskinesia has provided insights into the #608105).51 A cPNKD (formerly known as MR‐1), is homologous to the hydroxyacylglutathione hydrolase (HAGH) gene, with their protein products sharing b‐lactamase domains. HAGH detoxifies methylglyoxal, which is a compound present in coffee and alcohol and produced as a by‐product of oxidative stress. Therefore, it was once speculated that PNKD and HAGH have similar enzymatic activities. Although this possibility was refuted in later experiments, PNKD may still have alternative catalytic functions related to potential triggering factors. Interestingly, tottering mice—generated through a loss‐of‐function mutation of Cacna1a , whose heterozygous loss‐of‐function mutations segregate with MDS.SGCE‐related MDS is typically inherited from the father, and there is a marked difference in the penetrance depending on the parental origin of the disease allele. This finding led to the speculation of a maternal imprinting mechanism. It was subsequently confirmed that the maternally‐derived allele of SGCE is silenced by promoter methylation and that the imprinting pattern is maintained in the human brain.Myoclonus‐dystonia syndrome  is characterized by dystonia and myoclonic jerks mainly involving the neck, trunk, and upper limbs. The myoclonus is generally more prominent and predominant over the dystonia. Other characteristic—but not universal—features of MDS include psychiatric disturbance and alcohol responsiveness. This constellation of clinical features has been noted for several decades.62 The Different isoforms have also been identified in pre‐ and postsynaptic compartments. This multitude of isoforms suggests the complex roles of SGCE in neuronal biology, and a variety of cellular processes—such as calcium homeostasis, membrane stabilization, and cell cycle control—have been implicated in its functioning. Despite these findings, the relevance of these isoforms to the pathogenesis of MDS remains obscure. SGCE is highly expressed in the cerebellum in mice and humans. Neuroimaging studies have also pointed to a phenotype‐related metabolic change in the parasagittal cerebellum in individuals with SGCE mutations. Eyeblink conditioning (a paradigm of cerebellar‐dependent associative learning) is impaired in patients with SGCE‐related MDS, but not in those with isolated dystonia. In this paradigm, alcohol negatively affects performance in healthy individuals and improves it in patients with SGCE‐related MDS. Taken together, the molecular, anatomic, and functional data converge on the pivotal role of the cerebellum in the pathogenesis of MDS. However, a study reported that cerebellar Purkinje cell‐specific Sgce‐knockout mice did not exhibit the cardinal features of MDS, suggesting the involvement of other brain regions. In contrast, adult mice with acute cerebellar Sgce knockdown showed the salient features of MDS, including myoclonus, dystonia, and alcohol responsiveness. This discrepancy suggests the existence of some compensatory mechanisms in the previous model.Multiple isoforms of SGCE, including a brain‐specific one (exon 11b), are expressed in humans.70 Dif3.2SGCE mutations have been found in only roughly one‐third to half of all patients with MDS, suggesting the presence of additional causative genes for this condition. An investigation of a dominantly‐inherited British pedigree with eight affected subjects yielded a novel causative gene, potassium channel tetramerization domain‐containing 17 (KCTD17). This was achieved through linkage analysis coupled with exome sequencing (a common strategy used in the NGS era) to identify novel dystonia‐causing genes. The role of KCTD17 in MDS was further corroborated by two independent reports of cases with de novo splice‐site mutations in this gene. However, KCTD17‐related MDS differs from that caused by SGCE mutations. Specifically, the dystonia is predominant and progressive in KCTD17‐related MDS, whereas it is usually non‐progressive in SGCE‐related MDS .79 ThiCACNA1B) or are pending replication and validation . Other genes, such as SCN8A, are associated with myoclonus and dystonia in some cases; however, their overall presentations do not fit the typical clinical picture of MDS. Although some researchers have considered SCN8A to be a candidate gene for MDS, deleterious variants of this gene have not been found to date.In the past decade, several other genes have also been reported to be causative of MDS, although they were either challenged by later studies .84 OthKCNN2 as another causative gene. After excluding the established genetic causes of MDS (SGCE and KCTD17) and several other potentially related genes (including SCN8A and RELN), a heterozygous missense variant of KCNN2 was found to segregate with disease status. This variant results in the substitution of an amino acid residue that is evolutionarily conserved. A sporadic case of MDS with de novo mutation of KCNN2 has also been reported.KCNN2 encodes the SK2 subunit of the small‐conductance calcium‐activated potassium (SK) channel, which mediates repolarizing/hyperpolarizing currents in some neurons in the central nervous system.KCNN2 is highly expressed in the cerebellum, and some patients harboring KCNN2 variants exhibit cerebellar eye signs or cerebellar ataxia. Collectively, the discovery of KCNN2‐related MDS reinforces the view that the cerebellum is involved in the pathogenesis of MDS. Various Kcnn2 rodent models have been in use since before human mutations were identified. The Trdk rat is dominantly transmitted and mimics essential tremor in humans; the frissonnant mouse is recessively inherited, and this was previously characterized as a model of Parkinsonism. Re‐examining these mutant animals may help explain the phenotypes of the disorder and their neurobiological bases in light of the findings from human patients.A recent study analyzed a three‐generation pedigree with dominantly inherited MDS and identified ive gene.86 Aft44.1 Nevertheless, one of the converging themes in PKD and MDS , which is the prototypical and most common form of early‐onset isolated dystonia. Altered cerebellar synaptogenesis and cerebellar microstructural defects (particularly those involving Purkinje cells) have also been observed in mouse models of DYT1 dystonia. Interestingly, torsinA—the protein product of TOR1A—modulates the degradation of misfolded epsilon‐sarcoglycan, suggesting a potential pathophysiological connection between DYT1 dystonia and SGCE‐related MDS. The tottering mice (harboring a Cacna1a mutation) exhibit paroxysmal dystonia that is associated with electrophysiological activities presumably generated within the cerebellar cortex, and the ablation of cerebellar Purkinje cells in these mice results in the disappearance of dystonia. Taken together, these findings lend further credence to the role of the cerebellum in genetic movement disorders. In contrast, a recent study investigated the expression and co‐expression of dystonia‐associated genes and found that they were enriched in the basal ganglia, and not in the cerebellum. However, it should be noted that the study used primarily adult‐derived data for analysis. As such, the discrepancy seems to suggest that in some genetic movement disorders, the cerebellum may play a more pivotal role in children than in adults.The localization of pertinent neural substrates and circuits is a classical subject of interest in clinical neurology. Pediatric movement disorders, and especially hyperkinetic involuntary movements, were traditionally viewed as disorders involving mainly the basal ganglia circuitry.93 Nev For instance, a proof‐of‐concept trial  of cerebellar TMS showed promising results in patients with PRRT2‐related PKD, corroborating the pivotal role of the cerebellum in this condition. Collectively, the mechanistic insights inspired by genetic discoveries in pediatric movement disorders reinforce the notion that questions about motor control should be reframed to consider the basal ganglia–cerebellar–cerebral cortical network as a whole.Identifying the neural circuits or substrates involved in a particular movement disorder not only improves our mechanistic understanding of these disorders, but may also inform targeted interrogation and the rational design of therapeutic trials with deep brain stimulation (DBS) or transcranial magnetic stimulation (TMS).103 Fo4.2PRRT2‐related PKD and SGCE‐related MDS, are associated with electrophysiological abnormalities. A recent study demonstrated that mice with PRRT2 deletion in cerebellar granule cells are susceptible to the occurrence of a slowly propagating wave of depolarization in the cerebellar cortex (including granule cells and Purkinje cells). This wave precedes the aberrant outputs of deep cerebellar nuclei that are time‐locked to paroxysmal dyskinetic attacks. The spreading depolarization in the cerebellar cortex is reminiscent of an electrophysiologically similar phenomenon in the cerebral cortex known as cortical spreading depression (CSD), which is a slowly propagating wave of neuronal and glial depolarization followed by sustained underactivity. Although CSD is the putative electrophysiological process responsible for the generation of migraine aura, patients with PRRT2‐related PKD also often report auras (or a sense of impending attacks) prior to dyskinetic events. Moreover, migraine is one of the PRRT2‐related phenotypes, even though PRRT2 variants are considered to be risk‐modifying rather than disease‐causing for migraine. Altered functions of several interacting partners of PRRT2—such as the α3 isoform of Na+/K+‐ATPase (encoded by Atp1a3) and the CaV2.1 calcium channel (encoded by Cacna1a)—have been associated with changes in the susceptibility to spreading depolarization in various brain regions. As reviewed earlier , variant‐level functional assessments have now become more tractable.Phenotypic variability is common in monogenic movement disorders in childhood. Moreover, various forms of involuntary movements often occur in combination and/or are embedded in more complex neurological scenarios, which may encompass epilepsy, neurodevelopmental disorders, and psychiatric disturbances.112 ItPRRT2‐ and SGCE‐related disorders. It is possible that other genetic factors also modify the expression of phenotypic features. The roles of nearby genes are particularly intriguing, as movement disorders seem to be less reported in conditions involving both causative and contiguous genes . More research is needed to clarify whether modifier genes really exist, or whether involuntary movements were just overlooked because of more complicated clinical pictures. An aspirational goal envisaged for human genomics states that by 2030, ‘the clinical relevance of all encountered genomic variants will be readily predictable.’ However, the incomplete penetrance and variable expressivity of many dystonia‐related genes make this a formidable goal in the field of pediatric movement disorders.Even if variant‐level functional characterization is achieved, patients with the same genetic variants could still have disparate manifestations. For example, marked intrafamilial phenotypic variability has been reported in isorders.115 It by inserting the endophenotype in between the genetic etiology and phenomenological classification, so that the diverse relationships between genes and phenotypes can be better appreciated. Moreover, the incorporation of endophenotypes—be it electroencephalographic signatures or other characteristics—highlights the complex pathophysiological processes linking genotypes and phenotypes. For example, both PRRT2 and SCN8A mutations may present with paroxysmal dyskinesia, albeit through different mechanisms  in this field, suggesting the convergence of several pathogenetic pathways. Therefore, the transdiagnostic approach can provide an inroad into this body of knowledge. This can be achieved by using the electrophysiological characteristics of these disorders . The discovery of these novel genes would only mark the end of the initial stages of our collective efforts in understanding the genetic bases of these movement disorders. As exemplified by the developing stories of PKD and MDS, gene discovery often helps anchor subsequent basic and clinical studies, which in turn elucidate the pathophysiology of respective clinical phenomena in more detail . The iterative use of reverse genetics and forward genetics in human and animal models not only yields insights into disease mechanisms, but also facilitates the discovery of novel disease‐causing or disease‐predisposing genes. Ultimately, this strategy can help refine our understanding of the genetic landscape and pathophysiology of pediatric movement disorders.Thanks to advances in NGS technologies, the past decade has witnessed an acceleration in the pace of discovery of novel genes pertinent to pediatric movement disorders Table3. IndeThe author declares no conflict of interest.The peer review history for this article is available in the Supplementary Information: Record of Transparent Peer ReviewClick here for additional data file.


Cutaneous and systemic signs of acute and chronic arsenic poisoning may be vague. Thus, an awareness of these signs is crucial to prevent late or missed diagnoses. This is especially true in non‐endemic countries where individuals may present decades after exposure, or may still be ingesting arsenic via a non‐classical exposure. Existing literature emphasizes several well‐known cutaneous presentations of arsenic toxicity while ignoring the complete clinical spectrum, including several rare tumours of relevance to the dermatologist. This study aims to review the existing literature on dermatological presentations of arsenic toxicity and their management in adults. This article reviews the clinical spectrum of malignant and non‐malignant presentations of chronic arsenic toxicity. This is secondary to its effect of inhibiting enzymes of the Krebs cycle that subsequently impairs oxidative phosphorylation.Cutaneous presentations of arsenic toxicity have been widely reported in literature. Clinical suspicion of chronic arsenic exposure may involve the presence of multifocal non‐melanocytic skin cancers such as basal cell carcinomas (BCC), squamous cell carcinoma (SCC) and in‐situ SCC  in sun‐exposed and sun‐protected skin.33.1A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. A search of EMBASE via OVID and Medline via OVID database for articles from 1946 to August 2020 for terms in abstracts, titles, all fields and subject headings. No language, date or other limits were applied. Full search strategies are given in Table 3.2The protocol was registered with the international prospective register of systematic reviews (PROSPERO), in accordance with PRISMA guidelines (PROSPERO CRD42020203145). Candidate studies were selected by two independent authors (Dr GT and Dr JE) on Covidence on basis of titles and abstracts, then were obtained and read in full. The exclusion criteria were as follows: full‐text article inaccessible; animal‐based study; in vitro study; focussed on arsenic as a therapeutic treatment; non‐dermatological focus; uncertain causality or other causal of cutaneous presentation; non‐primary research article. Paediatric cases were initially part of the inclusion criteria for PROSPERO however was later in the exclusion criteria as authors agreed for the population study to focus on adults. The two authors agreed on the final selection of studies and discrepancies were solved by discussion.3.3Data were collected through Microsoft Excel to capture data items and for data synthesis on the following: study design, recruitment method, sample size, types of exposure, country of exposure, non‐malignant and malignant cutaneous presentations reported as well as treatments. Each study was assigned a level of evidence according to the 2011 Oxford Centre for Evidence‐Based Medicine levels of evidence guidelines. Assessment of risk of bias for each selected study was performed by Dr GT and Dr JE according to the JBI checklist for bias for the corresponding study types and consensus was reached through discussion.3.4Descriptive statistical analysis summarizing the consensus response for checklist questions for each study type was conducted. As identified studies were heterogeneous, meta‐analysis could not be conducted. A narrative synthesis was used as pooling of data is not possible due to the various modalities, presentations, treatment options and permutation of findings of arsenic toxicity reported in current literature. The criteria used by authors of this review to associate clinical features with arsenic toxicity in selected articles was if cutaneous presentations mentioned in case reports and case series were also identified in case‐control, retrospective and cross‐sectional studies. Associations were made based on the clinical presentations and the history provided in the articles suggestive of arsenic exposure or if there were also quantitative measurement of arsenic levels in suspected source or samples from patients. The criteria to consider treatment as potential management for dermatological presentations of suspected arsenic toxicity was if treatment was mentioned to be used in at least three case reports, or was mentioned in case reports and its use was also identified in other case series or retrospective studies.44.1n = 59), case‐control studies (n = 2), cross‐sectional studies (n = 9) and cohort studies (n = 2). Figure The search methods described identified a total of 15 721 articles from Embase and Medline through OVID, published from 1946 to 25 August 2020. After 10 703 duplicate records were removed, articles were screened based on title, abstract and full text as needed to determine eligibility. Retrieved studies were composed of 72 articles selected for review with case reports or series  may be used in individuals with acute arsenic toxicity.4.3Multiple studies selected in this review strongly supports that keratoses, hyper‐ and hypopigmentation can be arsenic‐induced. Hyperpigmentation and hypopigmentation may be generalized or occur as localized patches; a ‘raindrop’ pattern of distribution was commonly reported in exposures to contaminated groundwater and medications.Keratoses were the second most commonly reported presentation of chronic arsenic poisoning and may occur in isolation or accompanying pigmentary changes.Nail changes were noted in seven studies consisting of case reports, retrospective cohort and cross‐sectional studies.4.4Whilst chronic arsenic exposure may be associated with BCC, SCC and BD, there may be rare associated malignancies to consider Figure . Five stOther rare cutaneous tumours were identified in case reports of suspected arsenic exposure but not in other selected articles with higher level of evidence. Cases included reports of porocarcinoma, dermatofibrosarcoma protuberans, hidradenocarcinoma and epithelioid malignant peripheral nerve sheath tumour (EMPNST).4.5Multiple studies have demonstrated that eliminating arsenic exposure is strongly associated with preventing further cutaneous manifestations.Multiple studies of variable level of evidence suggests that standard management of keratinocyte carcinomas may still be effective in those with chronic arsenicism. These included: topical 5‐fluorouracil, imiquimod, cryotherapy, Mohs micrographic surgery, and conventional excision with/without skin graft.5This systematic review aimed to identify cutaneous manifestations of arsenic toxicity and its management in adults as well as to critically appraise current literature. There were variable cutaneous presentations in those with acute arsenic toxicity, thus making it challenging to identify associated link. Common cutaneous manifestations that were strongly associated with chronic arsenic toxicity include hyperpigmentation, hypopigmentation and keratosis and are often present in addition to keratinocyte neoplasms as highlighted in extensive studies consisting of case reports, retrospective and cross‐sectional studies of large sample population size.Although rare tumours were reported in case reports, their association with arsenic exposure remains inconclusive. Individuals with these rare carcinomas had a history of previous arsenic exposure, but causation could not be proven and some case reports did not have objective measurements such as arsenic levels in sources or samples obtained from those affected to confirm their suspicion based on history. Further reports may be limited by the rarity of these carcinomas, and conducting studies of higher level of evidence is not ethically possible.Avoiding further exposure is a common management of chronic arsenic toxicity in several studies. Low level evidence studies suggest that chelation therapy including dimercaprol, sodium dimercaptosulfonate and D‐penicillamine may be potential treatments.Challenges to identify causation between arsenic exposure and cutaneous manifestations are due to how individuals were exposed to arsenic. Individuals diagnosed in developed nations may have been environmentally exposed in endemic countries at a younger age.Diagnoses of arsenic toxicity are likely to be supported if mode of exposure is through ingestion of traditional and Western medicines, as cutaneous presentations may manifest acutely with other systemic symptoms due to incorrect compounding.There are various methods to estimate arsenic levels in various samples. Currently, the ‘gold standard’ is atomic absorption spectrometry due to its high specificity and sensitivity compared to other methods.The strength of this systematic review is that selected studies also had wide representation of timespan (1953–2019) and representation of developed and developing countries where cases are reported in regards to type of exposure, which is particularly important for those affected by environmental or occupational exposure. There are also several limitations to the review. Multiple low level of evidence studies reported dermatological findings but its link with suspected arsenic exposure were only inferred based on history. Subsequently, the majority of these studies lack causal relationships but there were stronger associations in higher level of evidence studies. This also extends to management strategies where treatments for some clinical presentations were reported, but the evidence for its efficacy in context of suspected arsenic toxicity may be low due to lack of reporting in interventional studies or high level of evidence articles.6There is a broad spectrum of dermatological findings for acute and chronic arsenic toxicity reported in current literature. Common stigmata of chronic arsenic toxicity including keratoses and pigmentary changes, as well as potential concurrent keratinocyte tumours. However, uncommon manifestations reported are only inferred based on history to be weakly associated with arsenic exposure due to multiple low‐level evidence studies identified, and treatment efficacy reported are not supported by studies of higher level of evidence.All authors involved in this work have no conflicts of interest to disclose.Gia Toan Tang: Data curation ; Formal analysis ; Investigation ; Methodology ; Software ; Visualization ; Writing – original draft ; Writing – review & editing . Joshua Elakis: Formal analysis ; Investigation ; Methodology ; Supervision ; Writing – original draft ; Writing – review & editing . Laura Scardamaglia: Conceptualization ; Methodology ; Supervision ; Writing – review & editing .Not applicable.Supporting Information S1Click here for additional data file.