Evaluation of Thought and Language Functions in Patients with Obstructive Sleep Apnea Syndrome

Objective: Patients with obstructive sleep apnea syndrome (OSAS) could display disorders in cognitive areas including attention, long-term visual and verbal memory, structural abilities, and executive functions. There are contradictory results regarding language ability and psychomotor functions. We evaluated the thought and language functions of patients with OSAS and their relationship with disease severity.
Methods: Patients who applied to the sleep disorders center with a preliminary diagnosis of OSAS were included in the study. According to the polysomnographic (PSG) results, 95 patients diagnosed with OSAS were accepted as the patient group, and 31 patients without OSAS were accepted as the control group. All patients were administered the thought-language index (TLI) by a psychologist. TLI scores were calculated and the differences between patient and control groups were evaluated. It was also examined the relationship between rapid eye movement (REM)-related OSAS and TLI scores.
Results: There was no significant difference between the patient and control groups regarding total TLI score. However, the “poverty of speech” score, which is a subcategory of TLI, was found to be significantly higher in the control group than in the patient group (p=0.266, p=0.025 respectively). No patient scored in the category of thought disorder. There was also no significant relationship between the severity of OSAS and TLI score, poverty of speech, weakening of purpose, and perseveration (p=0.846, p=0.111, p=0.839, p=0.059 respectively). When the patient group was classified as REM-related and non-REM-related OSAS, no significant.
Conclusion: In the evaluation of patients with OSAS through TLI, no impairment was found regarding thought and language functions. The poor performance of individuals who were diagnosed with OSAS were excluded in terms of “poverty of speech” may be related to snoring and accompanying arousal and excessive daytime sleepiness. No negative effect of REM-related OSAS on thought and language functions was detected. Further studies are required to evaluate thought and language functions in patients with OSAS.