Premature cognitive decline in specific domains found in young veterans with mTBI coincide with elder normative scores and advanced-age subjects with early-stage Parkinson's disease

PLoS One. 2021 Nov 17;16(11):e0258851. doi: 10.1371/journal.pone.0258851. eCollection 2021.

Abstract

Importance: Epidemiologists report a 56% increased risk of veterans with (+) mild traumatic brain injury (mTBI) developing Parkinson's disease (PD) within 12-years post-injury. The most relevant contributors to this high risk of PD in veterans (+) mTBI is unknown. As cognitive problems often precede PD diagnosis, identifying specific domains most involved with mTBI-related PD onset is critical.

Objectives: To discern which cognitive domains underlie the mTBI-PD risk relationship proposed in epidemiology studies.

Design and setting: This exploratory match-controlled, cross-sectional study was conducted in a medical school laboratory from 2017-2020.

Participants: Age- and IQ-matched veterans with (+) and without mTBI, non-veteran healthy controls, and IQ-matched non-demented early-stage PD were compared. Chronic neurological, unremitted/debilitating diseases, disorders, dementia, and substance use among others were excluded.

Exposure: Veterans were or were not exposed to non-penetrating combat-related mTBI occurring within the past 7-years. No other groups had recent military service or mTBI.

Main outcomes / measures: Cognitive flexibility, attention, memory, visuospatial ability, and verbal fluency were examined with well-known standardized neuropsychological assessments.

Results: Out of 200 volunteers, 114 provided evaluable data. Groups significantly differed on cognitive tests [F (21,299) = 3.09, p<0.0001]. Post hoc tests showed veterans (+) mTBI performed significantly worse than matched-control groups on four out of eight cognitive tests (range: p = .009 to .049), and more often than not performed comparably to early-stage PD (range: p = .749 to .140).

Conclusions and relevance: We found subtle, premature cognitive decline occurring in very specific cognitive domains in veterans (+) mTBI that would typically be overlooked in a clinic setting, This result potentially puts them at-risk for continual cognitive decline that may portend to the eventual onset of PD or some other neurodegenerative disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Brain Concussion / psychology*
  • Cognitive Dysfunction / etiology*
  • Depression / psychology
  • Humans
  • Middle Aged
  • Parkinson Disease / psychology*
  • Stress Disorders, Post-Traumatic / psychology
  • Veterans / psychology*

Grants and funding

VAN was the Principal Investigator funded, in part, by the Graham and Caroline Holloway Family Foundation, the JES Edwards Foundation under Grant # RP20007, and the Institute for Translational Research (formerly the Center for Alzheimer’s and Neurodegenerative Disease Research) at UNT Health Science Center under Grant # RI10024. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.