Research Letter: Impact of Obstructive Sleep Apnea Disease Duration on Neuropsychological Functioning after Traumatic Brain Injury: A Veterans Affairs TBI Model Systems Study

Objective: To examine the relationship between obstructive sleep apnea (OSA) disease duration and cognitive functioning in those with a history of traumatic brain injury (TBI). We hypothesized that longer OSA duration would predict poorer cognitive performance. Setting: Inpatient brain injury units at a Veterans Affairs (VA) Polytrauma Rehabilitation Center. Participants: Participants in the VA TBI Model Systems multicenter longitudinal study who enrolled in a modular substudy (April 15, 2018, to January 15, 2021) examining cognition following TBI. All participants had received inpatient rehabilitation for TBI and reported a diagnosis of OSA (n = 89, mean age = 40.8 years, 97% male, 81% White). Reported duration of OSA ranged from 2 to 7 years (mean = 4.2; SD = 3.9). Design: Retrospective analysis of prospective cohort, cross-sectional. Main Measures: Brief Test of Adult Cognition by Telephone (BTACT). Results: Controlling for age, education, and time to follow commands, OSA disease duration was negatively associated with delayed verbal memory (R²Δ = 0.053, F_(1,84)= 5.479, P =.022). Performance in other cognitive domains was not significantly associated with OSA disease duration. Conclusion: This study provides preliminary evidence that longer duration of OSA (ie, time since diagnosis) has a negative impact on verbal memory in those with a history of hospitalized TBI. This finding extends the literature (which focused on the general population) on the cognitive impact of OSA and is consistent with hypothesized mechanisms such as hippocampal damage and secondary impact of fatigue. Findings suggest that early OSA identification and treatment may be prudent for persons with TBI.