Pervasive TBI and Inhibitory Control in a Male New Zealand Prison Population

Objective: Traumatic brain injury (TBI) is disproportionately prevalent in incarcerated populations, yet the potential impact on cognitive functioning remains underexplored. This study examined the relationship between TBI history and cognitive performance in a male prison population.

Method: Sixty-three participants from Tongariro Prison completed a comprehensive neuropsychological assessment including measures of executive function, memory, processing speed, and perceptual reasoning, with embedded performance validity metrics. TBI history was assessed using the Ohio State University TBI Identification Method (OSU-TBI ID), premorbid function was assessed using the Speed and Capacity of Language Processing (SCOLP) Spot-the-Word task, mood was assessed using the Depression, Anxiety and Stress Scales (DASS-21), and alcohol and substance use were measured using the Alcohol, Smoking and Substance Involvement Screening Test (ASSIST). Regression analyses explored the relationship between TBI history and cognitive functioning, controlling for premorbid function, mood, alcohol and substance use, and ethnicity.

Results: Contrary to hypotheses, TBI frequency and severity were not associated with poorer cognitive performance in this population. However, a self-reported history of pervasive TBI—defined as repeated head impacts over a narrow time frame—was significantly associated with reduced performance on the Color–Word Interference Test (CWIT) inhibition task, indicating links to greater cognitive disinhibition.

Conclusions: Findings suggest that experiencing at least one period of pervasive TBI may be associated with an impact on inhibition (but not other aspects of executive functioning) in men in prison. These results underscore the importance of nuanced TBI history assessment and highlight inhibition as a potential target for rehabilitation in incarcerated individuals exposed to repetitive head trauma.