A Clinical Study Of Cognitive Dysfunction In Sleep Apnea Syndrome

Objective: To investigate cognitive function in patients with sleep apnea syndyome and explore how sleep apnea syndrome affects cognitive function Methods: Two groups, SAS patient group (n=32) and control group (n=29), were administered polysomnograph(PSG), electroencephalography(EEG), brain electrical activity mapping(BEAM), auditory evoked event-related potential (ERP) brainstem auditory evoked potentials (BAEP) .All the people were also inspected neuropsychological examination ,contain Simple Wechsler Adult Intelligence Scale (WAIS) and Simple Wechsler Adult Memory Scale(WAMS). Then we can use the date to have the comparative and correlative study . The results were analyzed with t test and spearmans rank correlationResults: There have significantly performance change between the patients and the controls in many neuropsychological. The memory score on 8 subtest as 1→100, 100 → 1,picture memory ,visual reknown , visual regeneration , comprehensive memory ,associated memory , memory digital and the Memory quotient(MQ) of SAS patients were significant lower than that of control group (P <0.05). The intelligence score on picture fill, picture arrange ,VIQ ,PIQ ,FIQ were also significant lower than that of control group (P <0.05).The SAS patients differentiate significantly from control subjects on several parameters. longer latencies (Fz, Cz, Pz) of N2, P3 waves .but no significant differences were seen in P3 amplitude between the two groups. The power in alpha of BEAM was decrease in SAS patients, but the power in deta and theta were increase. There have prolonger potentials latency of Ⅲ, Ⅳ, Ⅴ waves in SAS patients of BAEP to compare with the controls .The interpeak latency of Ⅰ-Ⅴ, Ⅲ-Ⅴ were also prolonged in SAS groups . There have significant difference on RDI, mean Sao2, lowest Sao2, slow wave sleep , REM sleep duration in SAS patients of PSG and EEG monitor to compare with the controls.Through the comparison of neuropsychological inspection and electroneurophysiological examination ,we can find that the latencies of P300 was significantly positively correlated with the RDI (r=0.718, P =0.009),negatively correlated with mean Sa02(r=-0.692, P =0.038),lowest Sao2(r=-0.751, P =0.018),slow wave sleep(r=0.683, P =0.029), REM sleep duration(r=-0.631, P =0.034), The potentials latency of V wave was positively correlated with RDI(r=0.735, P =0.022), negatively correlated with mean Sao2, (r=-0.697, P =0.027), The interpeak latency of I -VJII-V have negative relationship with IQ. Patient's performance on the visual regeneration test was significantly associated with slow wave sleep duration (r=0.653, P =0.041), and that on the picture arrangement was significantly associated with REM sleep duration (r=0.527, P =0.038). IQ and MQ was positively correlated with slowest Sao2,mean Sao2.slow waves sleep .REM sleep duration.Conclusions: SAS patients can induce cognitive impairment. Nocturnal hypoxaemia and sleep architectur change may play an important role in the cognitive impairment.