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

Background The Behavioural Assessment Screening Tool (BAST), which measures self-reported neurobehavioural symptoms experienced by adults with traumatic brain injury (TBI), was specifically developed as a self-reported measure for remote symptom reporting. Our aim was to assess the convergent, discriminant, and known-groups validity of the BAST among community-dwelling adults with TBI. Methods We assessed correlations and group differences with previously validated measures in two existing datasets (n =111, n =134). Other measures were the Patient Health Questionnaire-9 (depression), Generalized Anxiety Disorder-7 (anxiety), Positive and Negative Affect Schedule, Frontal Systems Behavior Scale (Executive Dysfunction, Apathy, Disinhibition), Modified Fatigue Impact Scale, Patient-Reported Outcomes Measurement Information System (Fatigue), Aggression Questionnaire (anger, hostility, physical and verbal aggression), and Alcohol Use Disorders Identification Test (alcohol misuse). Results BAST subscales had stronger correlations with measures of similar (|r |=0.602-0.828, P r |=0.364-0.589, P r |d =1.2-1.9) for known groups with moderate-severe depression, moderate-severe anxiety, fatigue, problematic disinhibited and frontal executive behaviours, and alcohol misuse. Results support the construct validity of the BAST subscales. Conclusion(s) The BAST demonstrated good convergent, discriminant, and known-groups validity, supporting its use for remote self-reported symptom reporting to improve chronic symptom monitoring in community-dwelling adults with TBI.