B – 46 The moderating role of insomnia on the relationship between TBI incidence and cognitive dysfunction

Abstract Objective Although insomnia is common among Traumatic Brain Injury (TBI) patients, its relationship to executive function is not well understood. We examined the potential moderating role of insomnia on executive dysfunction among TBI patients and controls. Method We utilized data from the Federal Interagency Traumatic Brain Injury Research (FITBIR) System. Data from TBI patients (n=1,587) and controls (n=478) were extracted. Included participants were adults who had a data collection point one year after recruitment from an Emergency Room setting; they were primarily Male (65.57%), White (76.90%), and had a mean age of 40.75 years (SD=16.77). Multiple linear regressions were run to examine the relationships between insomnia (measured by the Insomnia Severity Index; ISI), TBI incidence, and executive function (measured by the Trail-Making Test; TMT), while controlling for relevant demographic covariates. Results There was a two-way interaction between insomnia symptoms and TBI incidence (B=-0.08, p< 0.01), such that TBI patients had a more negative relationship between insomnia and executive function than the controls; the main effect of insomnia remained significant (B=-0.06, p< 0.001), while the effect of TBI incidence did not (B=-0.19, p=0.54). Demographic correlates were significant predictors of executive dysfunction, with older, non-White, Hispanic, and lower-education individuals performing worse on executive function measures. Conclusion In our study, insomnia exacerbated the discrepancy between TBI patients and controls at high levels of insomnia, with TBI patients performing significantly worse at an executive function task. Insomnia could be a valuable treatment target in improving quality of life among this population. More research is needed to understand associated demographic characteristics.