The Brain Injury Screening Tool (BIST): Tool development, factor structure and validity

Abstract

Currently health care pathways (the combination and order of services that a patient receives to manage their injury) following a mild traumatic brain injury vary considerably. Some clinicians lack confidence in injury recognition, management and knowing when to refer. A clinical expert group developed the Brain Injury Screening Tool (BIST) to provide guidance on health care pathways based on clinical indicators of poor recovery. The tool aims to facilitate access to specialist services (if required) to improve longer term prognosis. The tool was developed using a three-step process including: 1) domain mapping; 2) item development and 3) item testing and review. An online retrospective survey of 114 adults (>16 years) who had experienced a mild brain injury in the past 10 years was used to determine the initial psychometric properties of the 15-item symptom scale of the BIST. Participants were randomised to complete the BIST and one of two existing symptom scales; the Rivermead Post-concussion Symptom Questionnaire (RPQ) or the Sports Concussion Assessment Test (SCAT-5) symptom scale to determine concurrent validity. Participant responses to the BIST symptom scale items were used to determine scale reliability using Cronbach’s alpha. A principal components analysis explored the underlying factor structure. Spearman’s correlation coefficients determined concurrent validity with the RPQ and SCAT-5 symptom scales. The 15 items were found to require a reading age of 6–8 years old using readability statistics. High concurrent validity was shown against the RPQ (r = 0.91) and SCAT-5 (r = 0.90). The BIST total symptom scale (α = 0.94) and the three factors identified demonstrated excellent internal consistency: physical/emotional (α = 0.90), cognitive (α = 0.92) and vestibular-ocular (α = 0.80). This study provides evidence to support the utility, internal consistency, factor structure and concurrent validity of the BIST. Further research is warranted to determine the utility of the BIST scoring criteria and responsiveness to change in patients.

Rasch Analysis of The Brain Injury Screening Tool (BIST) in Mild Traumatic Brain Injury

“…The process of tool development is described elsewhere. [15] The BIST consists of two components. The rst component comprises of eight questions used to determine if a patient is at 'high risk'.…”

“…The BIST has been found to have good scale reliability and concurrent validity with other symptom measures such as the SCAT-5 and RPQ. [15] Factor analysis previously provided support for use of a total score and three component scores (physical/emotional, cognitive and vestibular-ocular). [15] Rasch Analysis Rasch analysis provides a robust measurement paradigm for evaluation of person reported outcome measures.…”

“…[15] Factor analysis previously provided support for use of a total score and three component scores (physical/emotional, cognitive and vestibular-ocular). [15] Rasch Analysis Rasch analysis provides a robust measurement paradigm for evaluation of person reported outcome measures. The Rasch model proposes that the probability of a person endorsing to a particular item or item response is in uenced by the person's ability (in this case level of symptom severity reported by a person) and the level of di culty of item (in this case level of symptom severity expressed by the item).…”

“…Neither of these tools have been designed to directly inform clinical pathway decision making. [13,14] To support a more consistent health care management pathway for mTBI and to support the implementation of clinical guidelines for mTBIs, the Brain Injury Screening Tool (BIST) tool was developed by a multidisciplinary working group [15] in order to support the health care decision making process at the rst medical contact after injury. The BIST was designed to be brief, able to be completed by any health professional at the rst point of medical contact, without the need for speci c training.…”

“…The BIST tool has previously been found to have good readability (estimated reading age of 6-8years), ease of completion, good scale reliability, concurrent validity and a three factor underlying structure, with support for use of a total scale score. [15] Rasch analysis builds estimates of true intervals of item di culty and person ability and transforms ordinal scales into interval measures that may be used in parametric statistical analyses and clinical decision making. For example, calculating individual change scores requires subtraction and this is only legitimate with a unidimensional interval scale such as Rasch provides.…”