Abstract
The purpose of this cross-sectional validation study was to evaluate the clinical utility of the DHI-CA by (1) examining its dimensionality using exploratory factor analysis (EFA) and (2) calibrating DHI-CA items (using the multidimensional Rasch model) to obtain item difficulty levels. A retrospective chart review was conducted for 132 patients between the ages of 8 and 18 years (mean age = 15.3 ± 2.1 years) from a multidisciplinary post-concussion management tertiary center. Data were extracted on age, sex, and DHI-CA. EFA revealed that 12 out of 25 items did not fit in the subscale that they were originally described under, indicating poor dimensionality. Calibration of items on the Wright Maps revealed that 50% of the items pooled in the lower difficulty level, indicating a potential ceiling effect. Corrected item-rest correlations for the physical, emotional, walking/mobility, and community participation ranged from 0.44-0.66, 0.27-0.61, 0.54-0.57, and 0.32-0.69 (p < 0.001), respectively. The clinical utility of the DHI-CA was found to be questionable due to the presence of double-barreled items and the ceiling effect. Clinicians must supplement data from the DHI-CA with other measures and patient interviews to make informed clinical decisions specific to the post-concussion population until new, robust, and valid measures are developed.