Affected Executive Dysfunction In Patients With Obstructive Sleep Apnea Syndrome

Objective: To explore the differences in sub-domains of executive function between mild-moderate and severe OSAS patients and the effects of continuous positive airway pressure(CPAP) treatment for patients’ executive function. Meantime we investigated the main influencing factors of executive function in OSAS patients.Mmethods: 74 OSAS patients aged between 30 and 60 years were enrolled in the study including 26 patients with mild-moderate OSAS and 48 patients with severe OSAS.All these patients were screened from the Sleep Center of Second Affiliated Hospital of Soochow University from November 2013 to April 2014. All patients were monitored by polysomnography(PSG) and Tested by Stroop Color Word Test(SCWT), Wisconsin Card Sorting Test(WCST), Verbal Fluency Test(VFT), Digit Span Test(DST), Trail Making Test(TMT) at an early visit to evaluate their sleep condition and executive function. 12 patients with severe OSAS were treated by CPAP for three months and retested by neuropsychological tests mentioned above.Results: No significant differences on age, gender, education years, body mass index(BMI), mini-mental state examination(MMSE) scores, and epworth sleeping scale(ESS) scores were found between the two groups. The severe OSAS patients revealed a significantly higher quota in total sleep time(TST), sleep efficiency(SE), time and proportion of non-rapid eye movement sleep(NREMS)1, the time and proportion of NREMS2, longest time for sleep apnea, apnea hypopnea index(AHI), oxygen desaturation index(ODI), proportion of total arousal index(T90%), total arousal index(TAI), respiratory arousal index(RAI), and a significantly lower quota in sleep latency(SL), proportion of slow wave sleep(SWS), lowest oxygen saturation(LSa O2), spontaneous arousal index(SAI).Significantly higher scores of time-consuming of TMT-B, TMT-interference,SCWT-Cand SCWT-interference and the components of WCST, including Ra, Re, Rpe,n Rpe, Rpep were found in severe OSAS group. On the other hand, severe OSAS patientsshowed a significant reduction in correct number of VFT. After CPAP treatment for 3months, 12 severe OSAS patients showed a significantly higher score of SCWT-interference and components of WCST, including Rc, Re, Rpe, Rpep.The spearman correlation analysis revealed a association between sleep parameters and executive function. At sleep parameters about severity, a significant positive correlation was revealed between AHI and time-consuming of TMT-B, TMT-interference,SCWT-C, SCWT-interferenceand socre of WSCT Ra, Re, Rpe. At sleep parameters about hyoxemia, a significant positive correlation was revealed between ODI and time-consuming of TMT-B, TMT-interference, SCWT-B, SCWT-C, SCWT-interference and socre of WSCT Ra, Re, Rpe, n Rpe, Rpep and a significant negative relationship was revealed between ODI and correct number of VFT. A significant positive correlation was revealed between LSa02 and time-consuming of TMT-B, SCWT-B, SCWT-C,SCWT-interference and socre of WSCT Ra, Re, Rpe, Rpep, and a significant negative correlation were revealed between LSa02 and correct number of VFT. A significant positive correlation was revealed between T90% and TMT-B, TMT-interference, SCWT-B,SCWT-C, SCWT-interferenceand socre of WSCT Ra, Re, Rpe, n Rpe, Rpep and a significant negative correlation was revealed between T90% and correct number of VFT.At sleep parameters about sleep structure, a significant positive correlation was revealed between TAI and time-consuming of TMT-B, TMT-interference, SCWT-B, SCWT-C,SCWT-interferenceand socre of WSCT Ra, Re, Rpe, n Rpe. A significant positive correlation was revealed between RAI and time-consuming of TMT-B, TMT-interference,SCWT-B, CWT-C, SCWT-interferenceand socre of WSCT Ra, Re, Rpe, Rpep.a significant positive correlation was revealed between SAI and time-consuming of SCWT-C, SCWT-interference. A significant negative relationship between SWS and SCWT-C, SCWT-interference and socre of WSCT Re, Rpe.Conclusion: Our study identified defected executive function of sub-domains including shifting, inhibition and generativity power and shifting in severe OSAS patients.Executive dysfunction were partly improved after CAPA treatment for 3 months. In addition, correlation analysis between respiratory nocturnal parameters and executive function indicated intermittent hypoxemia and sleep fragmentation largely contribute to executive dysfunction in OSAS patients.