Do quantified sleep architecture abnormalities underlie cognitive disturbances in amnestic mild cognitive impairment?. (September 2019)

• Record Type: Journal Article
• Authors: Menon, Ramshekhar N.; Radhakrishnan, Ashalatha; Sreedharan, Sapna Erat; Sarma, P. Sankara; Kumari, R. Sheela; Kesavadas, C.; Sasi, Deepak; Lekha, V.S.; Justus, Sunitha; Unnikrishnan, J.P.
• Is Part Of: Journal of clinical neuroscience. Volume 67(2019)
• Page Start: 85
• Page End: 92
• Publication Date: 2019-09
• Subjects: aMCI amnestic mild cognitive impairment -- CNHC cognitively normal healthy controls -- AD dementia due to Alzheimer's disease -- PSG polysomnography -- MRI magnetic resonance imaging -- DTI diffusion tensor imaging -- MRS MR spectroscopy -- MMSE mini-mental status examination -- ACE Addenbrooke's Cognitive Examination battery -- RAVLT Rey Auditory Verbal Learning Test -- HADS Hospital Anxiety Depression Scale -- NINCDS–ADRDA National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association -- AHI apnea + hypopnea index -- OSA obstructive sleep apnea -- PLMI periodic limb movement index -- SWS slow wave sleep -- REM rapid eye movement sleep -- CPAP continuous positive airway pressure -- SBD sleep-disordered breathing disturbance -- FA fractional anisotropy -- MD mean diffusivity; Polysomnography -- Mild cognitive impairment -- Sleep -- Neuropsychology -- Neuroimaging; Brain -- Surgery -- Periodicals; Neurosciences -- Periodicals; Nervous system -- Surgery -- Periodicals; Brain -- surgery -- Periodicals; Neurosurgical Procedures -- Periodicals; Neurosciences -- Periodicals; Electronic journals; 616.8
• DOI: 10.1016/j.jocn.2019.06.014
• Languages: English
• ISSNs: 0967-5868

Abstract

Highlights: No significant differences between stable MCI and controls on PSG abnormalities. Correlation between sleep efficiency with associative learning; REM sleep with recall scores. Negative correlation between apnea-hypopnea index with visual memory test scores. Longitudinal cognitive trends in MCI independent of sleep scores. Abstract: The study was designed to gauge association between occult sleep-related breathing disturbances and sleep architecture changes on cognitive trajectories in subjects with amnestic mild cognitive impairment (aMCI) relative to cognitively normal healthy controls, phenotyped by neuroimaging. Subjects with aMCI and normal cognition were prospectively recruited. Following standardized neuropsychological and sleep questionnaire assessment they underwent a single overnight polysomnography (PSG); multimodality MRI was used to ascertain age-corrected radiological differences between the 2 groups. The aMCI cohort was followed up longitudinally with serial cognitive assessments for the next 3 years. Thirty seven subjects with aMCI and 24 control subjects consented for evaluation. Although occult moderate to severe obstructive sleep apnea (OSA) was more prevalent in aMCI (43.6%) as opposed to controls (22.7%); higher median apnea-hypopnea index (AHI = 11.5) and total apnea-hypopnea time (26.6 min) were also noted in aMCI relative to controls (6.6 and 11.4 min respectively), the differences were not statistically significant. In the aMCI group, better sleep efficiency, longer duration of REM sleep correlated with higher associative learning, free-recall/recognition memory performance. Higher AHI had negative correlation with visual memory scores. However longitudinal cognitive trends in the aMCI group over 3 years reflected relative stability (only 5% progressed to AD) notwithstanding imaging differences from controls and appeared to be independent of sleep parameters. The study concluded that despite associations between sleep efficiency, REM sleep and sleep-related breathing variables with neuropsychological test-scores in aMCI, these appear to be comorbidities rather than causative factors for the degree of cognitive impairment or its longitudinal trajectory.