German version of the Chedoke McMaster arm and hand activity inventory (CAHAI-G): intra-rater reliability and responsiveness.

Background: The English version of the Chedoke Arm and Hand Activity Inventory is a validated, upper-limb measure with the purpose of assessing functional recovery of the arm and hand after a stroke. A German translation and cross-cultural adaptation was recently produced and demonstrated high validity, inter-rater reliability and internal consistency. As a follow-up, the present study evaluated the intra-rater reliability and responsiveness of the CAHAI-G for the long and all shortened versions.

Methods: The CAHAI-G and the Action Research Arm Test were assessed on three different measurement events: upon entry (ME1), two to 3 days after entry (ME2), and after three to 4 weeks (ME3). For the intra-rater reliability analysis, the ME1 CAHAI assessments were recorded on video and rated by three therapists to obtain the intraclass coefficients (ICC). The data of all three MEs were analysed in a group of stroke inpatients for the evaluation of responsiveness. To test for responsiveness, the CAHAI-G change data were compared to concurrent instruments: The Global Rating of Change-questionnaire and the Global Rating of Concept-questionnaire. Both served as external criteria. For all CAHAI-G versions (7, 8, 9 or 13 items), the same analysis procedures for the evaluation of the responsiveness parameter were performed.

Results: In total, 27 patients (9 females, age 63 ± 13.7) were enrolled in the study. The ICCs for the intra-rater reliability were calculated to be between 0.988 and 0.998 for all CAHAI versions. Responsiveness parameters were as follows from CAHAI-G 7 to 13: Minimal Detectable Change (MDC 5.3, 6.0, 6.1, 8.2; Pearson's correlation coefficients CAHAI-Gs with ARAT 0.365, 0.409, 0.500, 0.597. The Area und Under the Curve and the Minimal Clinical Important Difference values for all CAHAI-G versions and the three external criteria ranged between 0.483 to 0.603 and 2.5 to 9.0, respectively.

Conclusion: In addition to the high validity, inter-rater reliability and internal consistency, the CAHAI-G revealed high intra-rater reliability. The data also suggest an adequate responsiveness of the CAHAI-G versions 9 and 13.