Evaluation of excessive daytime sleepiness and cognitive functions in patients with obstructive sleep apnea syndrome

Aim: To determine the prevalence of obstructive sleep apnea syndrome with excessive daytime sleepiness and cognitive impairment in patients presenting to Sleep Disorders Laboratory of Dicle University Medical Faculty Hospital. İn addition to demonstrate the relationship between factors such as severity of obstructive sleep apnea syndrome, nocturnal hypoxia, age, gender and comorbidity with daytime sleepiness and cognitive impairment in these patients. Material and Method: This was a prospective study. All Patients who were admitted into Sleep Disorders Laboratory of our hospital between 07.01.2019 to 09.30.2019 and accepted to participate were included in the study. Patients with under the age of eighteen, patients who have not educated for at least 5 years, PSG diagnosed with central sleep apnea syndrome and upper respiratory resistance syndrome, with malignancy of any system, hypoxemia due to any additional disease, patients with diagnosed psychiatric disorders, patients who use medication for psychiatric illness, patients with alcohol or drug addiction, unstable cardiovasculer diseases, patients who have suffered a cerebrovascular accident, patients with hypothyroidism were not included in the research group. A detailed history was taken from our patients who would be subject to polysomnography test on the day of the procedure. The resting blood pressures were measured two times in mm-Hg with 5-minute intervals from the patients, and the arithmetic mean of these systolic and diastolic blood pressures were taken as basis. The waist circumference and the neck circumference of the patients were measured in centimeters and the weight of the patients was measured in kilograms. Excessive daytime sleepiness (EDS) levels of the patients were evaluated using 'Epworth Sleepiness Scale' and cognitive performance using 'Standardized Mini Mental Test'.According to the results of polsomnography test, patients were grouped into four different categories as per Apnea-Hypopnea Index (AHI) which were simple snoring (AHI<5/h), Mild Sleep Apnea (AHİ;5-15/h), Moderate Sleep Apnea (AHİ:15-30/h) and Severe Sleep Apnea (AHİ>30/h) respectively. SPSS 18 program was used to calculate the statistical data. Statistical significance was accepted as p <0.05. Results: Of the patients included in the study, 97 (% 87,4) were male and 14(%12,6) were female. Among all patients, 103 patients were evaluated as OSAS and the frequency of OSAS was % 92,7'in our study. 8 (% 7,2) of our patients were evaluated as simple snoring, 34 (%30,6) were mild OSAS, 23 (% 20,7) were moderate OSAS and 46 (% 41,4) were severe OSAS. Among all patients, Excessive daytime sleepiness(EDS) was detected in 40 (%36) patients. Obesity was found to be statistically significantly higher in patients with EDS. In 37 (92.5%) of patients with EDS OSAS was detected, 13 (35%, 1) of these patients had mild OSAS, 5 (13.5%) of moderate OSAS, 19 (51.3%) severe OSAS was detected. However, the presence and severity of OSAS did not show a statistically significant difference in the group with and without GAUH. As a result of the Standardized Mini Mental Test (SMMT) applied to the participants, 26 (23.4%) of the participants had mild cognitive impairment, while 85 (76.6%) had no cognitive impairment. The effect of female gender, primary school graduation, obesity, DM, cardiovascular disease, hypertension and antihypertensive drug use on SMMT score was found statistically significant. Of the 26 patients with mild cognitive impairment, 25 were found to have OSAS, 1 (3.8%) of them were observed simple snoring, 6 (23.1%) of them were mild OSAS, 6 (23.1%) of them were moderate OSAS, 13 (50%) of them were severe OSAS. While SMMT score was normal in 33 (71.7%) of 46 patients who participated in our study and found severe OSAS, 13 (28.2%) patients in this group had mild cognitive impairment. Age, waist circumference, BMI, systolic TA, oxygen desaturation index and desaturation (SO2 <90%) residence time were higher in the group with cognitive dysfunction, and the difference was statistically significant. Conclusion: We have found that OSAS is responsible for deficiencies in cognitive functions, which include attention, memory, and executive functions. These findings are consistent with the relevant international literature. The most important limitations of the study are the absence of a healthy control group besides patients with OSAS and the low number of patients in different OSAS groups. We think that studies with more patients and control groups will clearly reveal neurodegenerative efficacy and will open a field for sleep medicine and preventive health service.