Intra and Inter-Rater Reliability and Convergent Validity of FIT-HaNSA in Individuals with Grade П Whiplash Associated Disorder

BACKGROUND: Whiplash-Associated Disorders (WAD) are common following a motor vehicle accident. The Functional Impairment Test - Hand, and Neck/Shoulder/Arm (FIT-HaNSA) assesses upper extremity physical performance. It has been validated in patients with shoulder pathology but not in those with WAD. OBJECTIVES: Establish the Intra and inter-rater reliability and the known-group and construct validity of the FIT-HaNSA in patients with Grade II WAD (WAD2). METHODS: Twenty-five patients with WAD2 and 41 healthy controls were recruited. Numeric Pain Rating Scale (NPRS), Neck Disability Index (NDI), Disabilities of the Arm, Shoulder and Hand (DASH), cervical range of motion (CROM), and FIT-HaNSA were completed at two sessions conducted 2 to 7 days apart by two raters. Intraclass correlation coefficients (ICC) were used to describe Intra and inter-rater reliability. Spearman rank correlation coefficients (ρ) were used to quantify the associations between scores of the FIT-HaNSA and other measures in the WAD2 group (convergent construct validity). RESULTS: The Intra and inter-ICCs for the FIT-HaNSA scores ranged from 0.88 to 0.89 in the control group and 0.78 to 0.85 in the WAD2 group. Statistically significant differences in FIT-HaNSA performance between the two groups suggested known group construct validity (P < 0.001). The correlations between the NPRS, NDI, DASH, CROM and FIT-HaNSA were generally poor (ρ < 0.4). CONCLUSION: The study results indicate that the total FIT-HaNSA score has good Intra and inter-rater reliability and the construct validity in WAD2 and healthy controls.