Test-retest Reliability of the Brain Injury Screening Tool (BIST)
The Brain Injury Screening Tool was developed to provide clinicians with a brief tool to assess mild traumatic brain injuries and guide clinical care pathway decisions in both primary and secondary care. However, there is a need to ensure that the BIST is stable, and that any changes in responses over time are due to recovery, and not due to changes in how people respond to questions in the BIST (test-retest reliability). The aim of this study was to test the responses of a sample of healthy people on two separate occasions to determine the stability of responses, whilst controlling for the potential influence of mood.
A sample of sixty-eight (68) adults aged between 18 and 58 years completed the 15-item BIST symptom scale on two different occasions (baseline and two weeks later) in addition to the Depression, Anxiety and Stress Scale (DASS-21). At the initial assessment, data was also collected regarding the participants’ age, gender, income, ethnicity, and health comorbidities in order to assess whether such sociodemographic factors influence symptom reporting or not. The results of the study indicated that both the BIST symptom score and the BIST subscale scores exhibited moderate to good test re-test reliability with Intraclass Correlation Coefficients (ICC) ranging between 0.51 and 0.83. Wilcoxon Signed Ranks Tests found no significant differences in symptom reporting on the BIST total scale or the BIST subscales between the two time points at the p<0.05 level.
The evidence of moderate to good test-retest reliability in a healthy sample demonstrated here increases confidence that any changes in symptom reporting in mild traumatic brain injury patients using the BIST tool are more likely to reflect real symptom change, rather than measurement error. This study supports the use of the BIST as a symptom scale to monitor recovery in patients in both primary and secondary care, however, further research needs to be conducted to explore symptom reporting and reliability of the BIST in those under the age of 16 years.