Obstructive sleep apnea is associated with worse cognitive outcomes in acute moderate-to-severe traumatic brain injury: A TBI Model Systems study

Objective: To examine the relationship between polysomnography-classified obstructive sleep apnea (OSA) severity and cognitive performance in acute moderate-to-severe traumatic brain injury (TBI). Method: This was a cross-sectional, secondary analysis leveraging data from a clinical trial (NCT03033901) and TBI Model Systems. Sixty participants (mean age = 50 ± 18y, 72% male, 67% white) with moderate-to-severe TBI from five civilian rehabilitation hospitals were assessed at one-month post-injury. Participants underwent Level 1 polysomnography. OSA severity was classified as mild, moderate, and severe using the Apnea-Hypopnea Index (AHI). Associations between OSA metrics of hypoxemia (nadir and total time spent below 90%) and AHI with cognition were examined. Cognition was assessed with the Brief Test of Adult Cognition by Telephone (BTACT), which is comprised of six subtests assessing verbal memory, attention/working memory, processing speed, language, and executive function. Results: Over three-quarters of this acute TBI sample (76.7%) were diagnosed with OSA (no OSA n = 14; mild OSA n = 19; moderate/severe OSA n = 27). After adjustment for age, gender, and education, those with OSA had worse processing speed, working memory, and executive functioning compared to those without OSA. Compared to those with moderate/severe OSA, those with mild OSA had worse working memory and executive function. Conclusions: OSA is highly prevalent during acute stages of TBI recovery, and even in mild cases is related to poorer cognitive performance, particularly in the domains of attention/working memory and executive functioning. Our results support the incorporation of OSA diagnostic tools and interventions into routine clinical care in rehabilitation settings.