Evaluation of the executive functions of the brain in adult patients with obstructive sleep apnea syndrome

Abstract

Introduction: Patients with obstructive sleep apnea syndrome (OSAS) frequently display impairments in executive functions attributed to fragmented sleep architecture and desaturation. Aims: To assess executive functions in patients with OSAS. Methods: 205 OSAS patients and 40 healthy controls were included in the study. The OSAS severity was measured using the apnea-hypopnea index (AHI) by polysomnography, and was defined as mild AHI (5–15 events·h–1), moderate (AHI 15–30 events·h–1) and severe (AHI >30 events·h–1). The Verdal Fluency Test (Semantic, Phomenic) was used to assess the verbal/executive control ability. Their executive function was also evaluated by Trail Making Test A and B for measuring divided and selective attention, respectively, Stroop Color and Word Test for assessing selective attention and cognitive flexibility and IOWA gambling task for assessing real-life decision making. Results: OSAS patients and healthy controls were matched for age (53±10 vs. 49±14 years, respectively) and body mass index (42±4 vs. 40±4 years, respectively). OSAS patients had significantly lower scores on the Verdal Fluency Test Semantic [43±17 vs. 52±16, p=0.003), Verdal Fluency Test Phomenic (29±13 vs. 36±12, p=0.003), Trail Making Test A [29±13 vs. 36±12, p=0.003), Stroop Color Test (89±11 vs. 95±9,5, p>0.001), Stroop Color and Word Test (53±20 vs. 61±10, p>0.001) and IOWA gambling task (16±23 vs. 29±20, p>0.001) compared to controls. Impaired executive functions were associated with more severe OSAS. No significant difference was detected in Trail Making Test B between two groups (p=0.053). Conclusions: We found impaired executive functioning in OSAS patients.