Revisiting the Common Misconceptions About Traumatic Brain Injury Scale (CM-TBI); What Does It Really Measure?

Objective: To examine the factor structure and validity of the 40-item common misconceptions in traumatic brain injury (CM-TBI) scale, and to develop and evaluate additional concussion-focussed items to broaden the instrument's scope.

Method: A purposive sample of 988 participants from across all habitable continents (M age 43, range 16-90 years, 84% female) completed the CM-TBI and 5 additional concussion items at commencement of an online course on TBI.

Results: Item analysis resulted in the removal of 19 items due to ambiguous wording and poor conceptual integrity, and/or low discrimination and low inter-item correlations. An exploratory factor analysis on the remaining 26 items revealed a 3-factor model had best fit, with an additional 8 items removed due to low or cross-loadings, low communalities, and/or low conceptual relevance, resulting in an 18-item revised scale.

Conclusion: There is no psychometric support for the current structure of the CM-TBI. This is likely due to changes in understanding of TBI since the scale's inception, and issues of conceptual ambiguity. It is also proposed that a distinction must be made between knowledge and misconceptions, as these are 2 related but different constructs that are not clearly delineated in the current CM-TBI. Using the revised scale here offers researchers a more modern, focussed, and valid measure, but a new scale to measure knowledge and misconceptions in TBI is urgently needed.