A psychometric evaluation of a new social subscale for the Common Misconceptions about Traumatic Brain Injury (CM-TBI) questionnaire: toward the CM-TBI-II.

OBJECTIVE: Existing TBI misconception measures are critiqued for failing to measure postinjury social experiences. This study developed a social subscale for the Common Misconceptions about TBI (CM-TBI) questionnaire for use in the general public.

METHODS: Seven experts independently review items drawn from the literature. Shortlisted items were administered online to 158 adults (aged ≥18 years; 51% postschool educated; 60% no TBI experience), the CM-TBI, and a measure of construct validity (a published TBI-adaptation of the Community Attitudes Towards the Mentally Ill; CAMI-TBI). One week later, the new items were redeployed ( n  = 46).

RESULTS: Expert review and iterative correlations identified a 10-item social subscale (internal consistency, test-retest reliability, α's>.80). When added to the CM-TBI (ie. CM-TBI-II), the internal consistency was .71. The social subscale was significantly correlated with CAMI-TBI measures (p's <.05, r's > .3). There was no significant difference on the social subscale for education subgroups (school vs post-school, p  = 0.056) or previous TBI experience; but there was a difference for the CM-TBI-II (post-school>school; Cohen's d = 7.83, large effect).

CONCLUSION: This study found strong preliminary psychometric support for a new social subscale, administered as the CM-TBI-II. This subscale shows promise as a measure of misconceptions about social functioning post-TBI. The CM-TBI-II could support evaluations of programs aiming to improve social engagement and community participation for people with TBI.