Arch Clin Neuropsychol. 2023 Oct 8:acad067.018. doi: 10.1093/arclin/acad067.018. Online ahead of print.
OBJECTIVE: Evaluate if traumatic brain injury (TBI) characteristics, age of injury, or recency of injury is related to course of neurocognitive decline in aging and/or increases conversion rates to mild cognitive impairment (MCI) or all-cause dementia later in life.
METHODS: Data were obtained from the National Alzheimer’s Coordinating Center for participants 50-85 years old with 3 to 5 visits from 2015-2022. Groups were stratified by: 1) self-reported TBI history (No TBI [n = 2382], Single TBI without loss of consciousness [LOC; n = 102], Single TBI w/LOC [n = 228], Multiple TBI without LOC [n = 36], and Multiple TBI w/LOC [n = 115]), 2) age of most recent TBI (No TBI [n = 2382], TBI = 65 years old [n = 76]), and 3) recency of TBI (no TBI [n = 2382], 15 years ago [n = 301]). Mixed linear models compared normed neuropsychological composite trajectories (executive functioning/attention/speed, language, memory, and overall), co-varying for age, gender, education, apolipoprotein E4 status, and baseline diagnosis (normal aging n = 1720, MCI n = 749, or dementia n = 417). Logistic binary regression examined MCI/dementia conversion rates.
RESULTS: Longitudinal neurocognitive trajectories in composite measures were similar among TBI groups (example figure below). Specific TBI history, age of injury, or recency of injury did not impact neurocognitive trajectories or conversion rates to MCI or dementia (all p’s > 0.01).
CONCLUSIONS: TBI history, regardless of injury characteristics, age, or recency, did not worsen neurocognitive decline or MCI/dementia conversion. The mechanism and factors that increase dementia risk after TBI are unclear. Additional longitudinal research in carefully designed longitudinal cohorts is needed.