# Convergent, discriminant, and known groups validity of the Behavioral Assessment Screening Tool (BAST) in chronic traumatic brain injury

## TL;DR

The BAST is a self-report tool that effectively measures neurobehavioral symptoms in adults with chronic traumatic brain injury.

## Contribution

The study provides evidence for the BAST's convergent and discriminant validity in community-dwelling adults with chronic TBI.

## Key findings

- BAST subscales showed strong correlations with similar constructs and weak correlations with dissimilar ones.
- Significant group differences were found in BAST scores for individuals with depression, anxiety, fatigue, and alcohol misuse.
- The BAST supports its use in mobile health platforms for monitoring chronic TBI symptoms.

## Abstract

The Behavioral Assessment Screening Tool (BAST) measures self-reported neurobehavioral symptoms commonly experienced by adults with traumatic brain injury (TBI). To assess the convergent, discriminant, and known-groups validity of the BAST among community-dwelling adults with chronic traumatic brain injury (TBI), we conducted correlation analyses and tests of group differences with previously validated symptom measures in two samples (n = 111, n = 134). Measures used for comparison were: Patient Health Questionnaire (depression), Generalized Anxiety Disorder-7 (anxiety), Positive and Negative Affect Schedule, Frontal Systems Behavior Scale (Executive Dysfunction, Apathy, Disinhibition), Modified Fatigue Impact Scale, PROMIS Fatigue, Aggression Questionnaire (anger, hostility, physical and verbal aggression), and Alcohol Use Disorders Test (alcohol misuse). BAST subscales had stronger correlations with measures of similar (|r|=.602-.828, p < .001) and related (|r|>.30, p < .001) constructs and weaker correlations (|r|<.300) with measures of dissimilar/unrelated constructs, supporting hypotheses of convergent and discriminant validity, respectively. Statistically significant group differences (p’s < .001) in BAST subscales were found, with large effect sizes (Cohen’s d = 1.2–1.9), for known-groups with moderate-severe depression, moderate-severe anxiety, clinically significant fatigue, problematic disinhibited and frontal-executive behaviors, and alcohol use.

Results support the convergent and discriminant validity of the BAST subscales. The BAST was specifically developed as a self-reported measure for remote symptom reporting, supporting its incorporation into mobile health platforms to improve chronic symptom monitoring in community-dwelling adults with TBI. With further validation research, the BAST could be used for early identification of persons with TBI who could benefit from intervention.