Cognitive impairment in patients with traumatic brain injury and obstructive sleep apnea

Objective: To examine the impact of comorbid obstructive sleep apnea (OSA) on the cognitive functioning of traumatic brain injury (TBI) patients. Design: A case-control study. Neuropsychologic test performances of TBI patients with OSA were compared with those who did not have OSA. The diagnosis of OSA was based on standard criteria using nocturnal polysomnography. Setting: Three academic medical centers with level I trauma centers, accredited sleep disorders centers, and rehabilitation medicine programs. Participants: Thirty-five TBI patients who were part of a project that assessed the effect of sleep disorders in a larger sample of consecutively recruited TBI patients. There were 19 patients with TBI and OSA. They were compared with 16 TBI patients without OSA who were comparable in terms of age, education, severity of injury (when available), time postinjury, and Glasgow Coma Scale scores (when available). Interventions: Not applicable. Main Outcome Measures: The Psychomotor Vigilance Test, Rey Complex Figure Test, Rey Auditory Verbal Learning Test, digit span test from the Wechsler Memory Scale-Revised, and finger-tapping test. Results: The TBI patients with OSA performed significantly worse than the non-sleep disordered TBI patients on verbal and visual delayed-recall measures. The groups performed comparably on motor, visual construction, and attention tests. The TBI patients with OSA made more attention lapses (reaction times >= 500ms), but showed comparable fastest and slowest reaction times on a measure of sustained attention. Conclusions: OSA is associated with more impairment of sustained attention and memory in TBI patients. It is possible that early identification and treatment of OSA may improve cognitive, and thus potentially functional, outcomes of TBI patients with this disease.