Impact of Post-Traumatic Epilepsy on Mental Health and Multidimensional Outcome and Quality of Life: An NIDILRR TBIMS Study

Traumatic brain injury (TBI) and subsequent post-traumatic epilepsy (PTE) often impair daily activities and mental health (MH), which contribute to long-term TBI-related disability. PTE also affects driving capacity, which impacts functional independence, community participation, and satisfaction with life (SWL). However, studies evaluating the collective impact of PTE on multidimensional outcomes are lacking. Thus, we generated a model to investigate how PTE after moderate-to-severe (ms)TBI affects TBI-associated impairments, limits activities and participation, and influences SWL. Of 5108 participants with msTBI enrolled into the National Institute for Disability, Independent Living, and Rehabilitation Research TBI Model Systems between 2010 and 2018 and with seizure-event data available at year-1 post-TBI, 1214 had complete outcome data and 1003 had complete covariate data used for analysis. We constructed a conceptual framework illustrating hypothesized interrelationships between year-1 PTE, driving status, functional independence measure (FIM), depression and anxiety, as well as year-2 participation, and SWL. We performed univariate and multivariable linear and logistic regressions. A covariate-adjusted structural equation model (SEM), using the lavaan package (R), assessed the conceptual framework's suitability in establishing PTE links with outcomes 1-2 years post-injury. Multiple parameters were evaluated to assess SEM fit. Year-1 PTE was correlated with year-1 FIM motor (standardized coefficient, β_std = -0.112, p = 0.007) and showed a trend level association with year-1 FIM cognition (β_std = -0.070, p = 0.079). Individuals with year-1 PTE were less likely to drive independently at year 1 (β_std = -0.148, p < 0.001). In addition, FIM motor (β_std = 0.323, p < 0.001), FIM cognition (β_std = 0.181, p = 0.012), and anxiety (β_std = -0.135, p = 0.024) influenced driving status. FIM cognition was associated with year-1 depression (β_std = 0.386, p < 0.001) and year-1 anxiety (β_std = 0.396, p < 0.001), whereas year-1 FIM motor (β_std = 0.186, p = 0.003), depression (β_std = -0.322, p = 0.011), and driving status (β_std = 0.233, p < 0.001) directly affected year-2 objective life participation metrics. Moreover, year-1 depression (β_std = -0.382, p = 0.001) and year-2 participation (β_std = 0.160, p < 0.001) had direct effects on year-2 SWL. SWL was influenced indirectly by year-1 variables, including functional impairment, anxiety, and driving status-factors that impacted year-2 participation directly or indirectly, and consequently year-2 SWL, forming a complex relationship with year-1 PTE. A sensitivity analysis SEM showed that the number of MH disorders was associated with participation and SWL (p < 0.001), and this combined MH variable was directly related to driving status (p < 0.02). Developing PTE during year-1 after msTBI affects multiple aspects of life. PTE effects extend to motor and cognitive abilities, driving capabilities, and indirectly, to life participation and overall SWL. The implications underscore the crucial need for effective PTE management strategies during the first year post-TBI to minimize the adverse impact on factors influencing multidimensional year-2 participation and SWL outcomes. Addressing transportation barriers is warranted to enhance the well-being of those with PTE and msTBI, emphasizing a holistic approach. Further research is recommended for SEM validation studies, including testing causal inference pathways that might inform future prevention and treatment trials.