title: Neurocognitive impairment in Chinese patients with obstructive sleep apnoea hypopnoea syndrome.
abstract: OBJECTIVE
  Sleep-disordered breathing is known to be associated with impairment in cognitive function. The aim of this study was to characterize neurocognitive impairment in a cohort of Chinese patients with varying severities of obstructive sleep apnoea hypopnoea syndrome (OSAHS), and to develop a sensitive instrument for routine screening of cognitive impairment.
  
  
  METHODS
  Eligible patients (n = 394) were categorized into a primary snoring group, and mild, moderate and severe OSAHS groups, based on assessment of AHI. The Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE) questionnaires were administered to assess cognitive function, and the correlations between questionnaire scores and clinical and polysomnographic parameters were further evaluated by stepwise multivariate regression.
  
  
  RESULTS
  MoCA scores decreased progressively across the spectrum from primary snoring to severe OSAHS. Importantly, mild neurocognitive impairment as defined by a MoCA score <26 was more common in the moderate (38.6%) and severe (41.4%) OSAHS groups than in the mild OSAHS (25.0%) and primary snoring (15.2%) groups. In contrast, MMSE scores were largely normal and comparable among all four groups. Evaluation of MoCA subdomains further revealed selective reduction in memory/delayed recall, visuospatial and executive function, and attention span in the severe OSAHS group compared with the other groups. Stepwise multivariate regression analysis demonstrated that MoCA scores correlated significantly with lowest oxygen saturation (L-SaO(2) ) and years of education.
  
  
  CONCLUSIONS
  Neurocognitive impairment is common in patients with OSAHS. The MoCA is a brief and sensitive tool for the assessment of cognitive impairment in OSAHS patients, whose performance on the MMSE is in the normal range.
authors.affiliation: Sleep Center, Second Affiliated Hospital of Soochow University, Suzhou, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Chen
authors.forename: Kang-Ping
authors.initials: KP
authors.lastname: Xiong
authors.forename: Juan-Ying
authors.initials: JY
authors.lastname: Huang
authors.forename: Yi-Xin
authors.initials: YX
authors.lastname: Lian
authors.forename: Fa
authors.initials: F
authors.lastname: Jin
authors.forename: Zhen-Hua
authors.initials: ZH
authors.lastname: Li
authors.forename: Min-Yan
authors.initials: MY
authors.lastname: Zhao
authors.forename: Chun-Feng
authors.initials: CF
authors.lastname: Liu
mesh_terms: D000328:Adult; D044466:Asian People / Q000208:ethnology; D002681:China / Q000453:epidemiology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000453:epidemiology* / Q000208:ethnology; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D017286:Polysomnography; D012044:Regression Analysis; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000453:epidemiology* / Q000208:ethnology