Abstract: Objective  Patients with obstructive sleep apnea syndrome (OSAS) usually complain of daytime hypersomnia and decrease in cognitive function, which affects the quality of their work and life. The reason why the cognitive function of OSAS patients decreased remains controversial. The aim of this study is to evaluate the impairment and the main influencing factors of cognitive function in OSAS. Methods  There were totally 50 OSAS patients (OSAS group) and 25 volunteers (control group) included in our study. All of them were monitored by polysomnography (PSG) and tested by Continuous Performance Test (CPT), n-back test and Stroop Color?Word Test (CWT) to evaluate their sleep condition and cognitive function. Results  No significant difference was found between the two groups in total sleep time and sleep efficiency (P > 0.05, for all). Compared with control group, OSAS group had significant increased time of non-rapid eye movement (NREM) sleep stage Ⅰ and stage Ⅱ, significant decreased time of stage Ⅲ (P < 0.05, for all), while no significant difference in rapid eye movement (REM) sleep. The arousal index (AI) of the OSAS group was significantly higher than control group (P < 0.05). Patients in OSAS group had significantly lower scores in the cognitive function tests (P < 0.01), which showed the ability of attention, response, memory, discernibility and performance were injured. The damage had no significant connection with the severity of the apnea hyponea index (AHI) and hypoxia (P > 0.05, for all), while had significant connection with AI and NREM Ⅲ (P < 0.05, for all). The rate of OSAS patients who underwent nasal continuous positive airway pressure (nCPAP) treatment was very low, only 8% (4/50). Conclusion  The abnormality of OSAS patients' sleep structure is characterized with sleep fragmentation and decrease of NREM Ⅲ, which may be the main factors of cognitive impairment. Exploration of treatment methods targeted on regulating the effected hormones and receptors is meaningful.

Key words: Sleep apnea, obstructive, Cognition disorders, Neuropsychological test, Polysomnography

摘要： 目的 探讨阻塞性睡眠呼吸暂停综合征（OSAS）对认知功能的影响，以及不同睡眠结构异常与认知损害的关联性。方法 采用夜间多导睡眠图以及持续性操作、倒数n 项和Stroop 色词测验，对50 例阻塞性睡眠呼吸暂停综合征患者和25 例健康志愿者进行夜间睡眠监测和认知功能评价。结果 OSAS 组患者睡眠时间和睡眠效率基本正常（均P > 0.05），但非快速眼动睡眠期Ⅰ和Ⅱ期睡眠时间延长、Ⅲ期睡眠时间缩短、微觉醒指数增加，与正常对照组比较差异有统计学意义（均P < 0.05）。OSAS 组患者各项认知功能评分均低于正常对照组（P < 0.01），表现为注意力、反应力、记忆力、干扰分辨能力和执行能力损害，但其损害程度与阻塞性睡眠呼吸暂停严重程度和低氧程度不相关（均P > 0.05），仅与微觉醒指数和深睡眠时间相关。阻塞性睡眠呼吸暂停综合征患者接受夜间经鼻持续气道正压通气治疗的比例极低，仅为8%（4/50）。结论 阻塞性睡眠呼吸暂停综合征患者睡眠结构紊乱主要表现为睡眠片段化和深睡眠减少，可能为认知损害的主要原因。寻找针对睡眠结构紊乱所致激素及其受体水平失调的治疗方法具有临床意义。

关键词: 睡眠呼吸暂停, 阻塞性, 认知障碍, 神经心理学测验, 多道睡眠描记术