Abstract: Objective Obstructive sleep apnea syndrome (OSAS) is known to be associated with impairment in cognitive function. The aim of this study is to develop a sensitive screening tool to detect mild cognitive impairment (MCI) among Chinese patients with OSAS. Methods There were totally 51 0SAS patients (OSAS group) and 35 primary snoring peoples (control group) included in our study. All of them were monitored by polysomnography (PSG), administered by the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) questionnaires to assess their sleep condition and cognitive function. Results Compared with control group, the score of MoCA in OSAS group was 21.1±3.0, strikingly lower than the control group 25.0±2.0（P＜0.01）,the score of MMSE in OSAS group and control group were 27.8±1.8 and 28.1±1.7,the difference were of no significance. Conclusions The MoCA is a brief and sensitive tool for the assessment of MCI in OSAS patients, whose performance on the MMSE is in the normal range.

Key words: Obstructive sleep apnea syndrome mild cognitiveimpairment Neuropsychological test