Introduction:  Traumatic brain injuries (TBIs) are associated with several negative outcomes, such as cognitive deficits, vision deficits, mood disorders, and risk for increased substance use. The purpose of this study was to assess the long term impact of TBI in patients who were assessed with an objective measure of physiologic brain function serially after injury. 

Method: 4 metrics, Box Score, Right Area Median, Left Area Median, and Conjugate Box Score, from a passive automated eye tracking task were compared to a psychological outcome measure in order to determine the relationship between oculomotor dysfunction and psychological outcome six months after injury. Fourteen head-injured subjects were recruited from a Level 1 trauma center and compared to 58 healthy controls. The TBI cohort was assessed at the initial and six month time points. The Sports Concussion Assessment Tool-3 (SCAT-3) measured cognitive deficits (SAC) and symptoms of mood disorders (SSS). The Medical, Socioeconomic, and Lifestyle Questionnaire (MSL) was used to assess substance use and psychiatric history. 

Results: At the time of injury, TBI subjects in comparison to controls, were more likely to have a previous psychiatric history (38.4% vs 23%) and have worse cognition (SAC p=.005), tracking metrics (Box Score p=0.05; Conjugate Box Score p=.00368), and mood (SSS p=<.001). Alcohol and drug use increased in the TBI group from 23% to 31% and 0% to 8%, respectively from the initial to the six month time points. However, controls reported drinking more alcohol and using more drugs (87%; 17%) in comparison to the TBI subjects (23%; 0%). Psychological problems still persisted long term as individuals with TBI, compared to controls, still had symptoms of mood (p=.003291) but not cognitive dysfunction (p=.443) or visual deficits (Box Score p=0.994; Conjugate Box Score p=.0.5687; Right Area Median p=.0.9037; Left Area Median p=0.8588 six months from the time of injury. Initial eye tracking metrics were not able to predict long term symptoms of mood, but significantly predicted long term deficits in cognition (p=.00806).

Conclusion: Overall, the results show that there are differences in controls and TBI subjects at time of injury.  Subjects seem to recover at the six month time point, with regards to cognition, vision, and mood, but not substance use.  Eye tracking metrics predict impaired cognition at 6 months.  Limitations include the small number of subjects participating in long term follow up.

Psychological Effects of Traumatic Brain Injury Measured after Objective, Diagnostic Assessment of Physiologic Disruption at Multiple Time Points