Non-rapid eye movement sleep instability in mild cognitive impairment: a pilot study.
OBJECTIVE
Polysomnographic (PSG) studies in mild cognitive impairment (MCI) are not conclusive and are limited only to conventional sleep parameters. The aim of our study was to evaluate sleep architecture and cyclic alternating pattern (CAP) parameters in subjects with MCI, and to assess their eventual correlation with cognition.


METHODS
Eleven subjects with MCI (mean age 68.5 ± 7.0 years), 11 patients with mild probable Alzheimer's disease (AD; mean age 72.7 ± 5.9 years), referred to the Outpatient Cognitive Disorders Clinic, and 11 cognitively intact healthy elderly individuals (mean age 69.2 ± 12.6 years) underwent ambulatory PSG for the evaluation of nocturnal sleep architecture and CAP parameters.


RESULTS
Rapid eye movement sleep, CAP rate, and CAP slow components (A1 index) were decreased in MCI subjects and to a greater extent in AD patients, compared to cognitively intact controls. AD showed also decreased slow wave sleep (SWS) relative to healthy elderly individuals. MCI nappers showed decreased nocturnal SWS and A1 subtypes compared to non-nappers. Several correlations between sleep variables and neuropsychological tests were found.


CONCLUSIONS
MCI and AD subjects showed a decreased sleep instability correlated with their cognitive decline. Such a decrease may be considered as a potential biomarker of underlying neurodegeneration.
['Maestri|Michelangelo|M|', 'Carnicelli|Luca|L|', 'Tognoni|Gloria|G|', 'Di Coscio|Elisa|E|', 'Giorgi|Filippo Sean|FS|', 'Volpi|Leda|L|', 'Economou|Nicholas-Tiberio|NT|', 'Ktonas|Periklis|P|', 'Ferri|Raffaele|R|', 'Bonuccelli|Ubaldo|U|', 'Bonanni|Enrica|E|']
D000368:Aged D000369:Aged, 80 and over D000544:Alzheimer Disease D016022:Case-Control Studies D060825:Cognitive Dysfunction D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D009483:Neuropsychological Tests D010865:Pilot Projects D017286:Polysomnography D012893:Sleep Wake Disorders D012895:Sleep, REM
Mild cognitive impairment Cyclic alternating pattern Alzheimer's disease Neurodegeneration NREM sleep instability Nap