The Development of a New Computer-Adaptive Test to Evaluate Strain in Caregivers of Individuals With TBI: TBI-CareQOL Caregiver Strain

Objective: To develop a new measure of caregiver strain for use in caregivers of individuals with traumatic brain injury (TBI), Traumatic Brain Injury Caregiver Quality of Life (TBI-CareQOL) Caregiver Strain. Design: Qualitative data, literature reviews, and cross-sectional survey study. Setting: Three TBI Model Systems rehabilitation hospitals, an academic medical center, and a military medical treatment facility. Participants: Caregivers (N=560) of civilians (n=344) or service members/veterans (SMVs) with TBI (n=216). Interventions: Not applicable. Main Outcome Measure: TBI-CareQOL Caregiver Strain Item Bank. Results: Exploratory and confirmatory factor analyses, a graded response model (GRM) and differential item functioning supported the retention of 33 items in the final measure. GRM calibration data was used to inform the selection of a 6-item static short form, and to program the TBI-CareQOL Caregiver Strain computer-adaptive test (CAT). CAT simulation analyses indicated a 0.97 correlation between the CAT scores and the full item-bank. Three-week test-retest reliability was strong (r=0.83). Conclusions: The new TBI-CareQOL Caregiver Strain CAT and corresponding 6-item short form were developed using established rigorous measurement development standards; this is the first self-reported measure developed to evaluate caregiver strain in caregivers of individuals with TBI.