Design & Participants
Data from two prospective psychometric studies were combined for these analyses. The first study cohort comprised n=110 community-dwelling adults with a >3-month history of complicated mild to severe TBI; the second study cohort comprised n=135 community-dwelling adults with a >3-month history of mild to severe TBI. Detailed methods for the parent studies have been previously published [19,21]. Briefly, participants were recruited through research registries, past participation in TBI-related studies, and through community organizations serving persons with TBI.
Ethics approval and consent to participate.
All participants provided informed consent and all procedures were approved by the University of Pittsburgh Institutional Review Board and the University of Texas Southwestern Medical Center Institutional Review Board and performed in accordance with relevant guidelines and regulations.
Primary Measure: Behavioral Assessment Screening Tool (BAST)
Previous studies report details about the development and psychometric evaluation of the BAST [18–21]. Briefly, the BAST is a multidimensional self-reported neurobehavioral symptom measure assessing frequency of experiencing a symptom or behavior over the past two weeks, ranging from never to very often. The BAST subscales cover five domains: Negative Affect, Fatigue, Executive Dysfunction, Substance Use, and Impulsivity.
Measures for Convergent, Discriminant, and Known Groups Validity
Participants in the first cohort completed all questionnaires remotely using paper-pencil forms, then returned completed measures via mail in prepaid and addressed envelopes. Participants in the second cohort completed all questionnaires electronically via REDCap™. Table 2 summarizes all measures collected for the current analyses, including validated measures of positive and negative affect, depression, anxiety, fatigue, aggression, alcohol misuse, and dysregulated behavior.
To characterize known-groups for depression and anxiety, we classified individuals based on a cut-off score of >10 on the Patient Health Questionnaire and on the Generalized Anxiety Disorder-7 to indicate moderate-severe depressive and anxiety symptoms, respectively [22,23]. To characterize known-groups for probable alcohol misuse (only in cohort 2), we classified males with AUDIT scores >7 and females with AUDIT scores >5 as being indicative of problematic drinking, based on established cut-off scores [24]. To characterize known-groups for fatigue, we classified individuals based on established cut-off scores for PROMIS Fatigue 7-item short form equivalent to a t-score <60 (<23 raw score) vs >60 ( >23 raw score) in the second cohort [25]. To characterize known-groups for impulsivity and for executive dysfunction, we classified individuals based on established cut-off scores for FrSBe Disinhibition and Executive Function subscales (t-scores <65 vs >65) in the first cohort [26].
Data analysis
We examined descriptive statistics, including frequencies and percentages for demographic characteristics and means and standard deviations for clinical characteristics of the sample. We evaluated convergent and discriminant validity evidence for the BAST subscales using Spearman correlation coefficients examining hypothesized correlations patterns (see Table 1). A pattern of stronger correlations supported between BAST subscales and measures of similar constructs and weaker correlations between BAST subscales and measures of dissimilar constructs would support our hypotheses for convergent and discriminant validity [27].
To examine known-groups validity, we examined differences in BAST subscale scores between those with and without moderate-severe depressive symptoms, moderate-severe anxiety symptoms, clinically significant fatigue, and alcohol abuse using t-tests and Cohen’s d effect sizes. Given the number of analyses, we set a conservative threshold of p<.001 for statistical significance. All statistical analyses were conducted using SPSSv26 for Windows.