Brain Injury Screening Tool (BIST): Test-retest Reliability in a Community Adult Sample
OBJECTIVE: To determine the test-retest reliability of the Brain Injury Screening Tool (BIST), which was designed to support the initial assessment of mild traumatic brain injury (mTBI) across a variety of contexts, including primary and secondary care. DESIGN: Test-retest design over a 2-week period. SETTING: Community based. PARTICIPANTS: Sixty-eight adults (aged 18-58 years) who had not experienced an mTBI within the last 5 years and completed the BIST on two different occasions. MEASURES: Participants were invited to complete the 15-item BIST symptom scale and the Depression, Anxiety and Stress Scale (DASS-21) online at two time-points (baseline and 2 weeks later). To account for large variations in mood affecting symptom reporting, change scores on the subscales of the DASS-21 were calculated, and outliers were removed from the analysis. RESULTS: The BIST total symptom score and subscale scores (physical-emotional, cognitive and vestibular) demonstrated moderate to good test-retest reliability with intraclass correlation coefficients ranging between 0.51 and 0.83. There were no meaningful differences between symptom reporting on the total scale or subscales of the BIST between time1 and time2 at the p<0.05 level when calculated using related samples Wilcoxon signed-rank tests. CONCLUSION: The BIST showed evidence of good stability of symptom reporting within a non-injured, community adult sample. This increases confidence that changes observed in symptom reporting in an injured sample are related to actual symptom change rather than measurement error and supports the use of the symptom scale to monitor recovery over time. Further research is needed to explore reliability of the BIST within those aged <16 years.