Cross-cultural adaptation and validation of the German version of the I-HaND^© scale

Peripheral nerve injuries may cause severe functional impairment. The Impact of Hand Nerve Disorders (I-HaND) Scale is a validated tool for measuring pain and function but was previously only available in English. This study aimed to translate, adapt, and validate a German version of the I-HaND.

Following internationally accepted guidelines for cross-cultural adaptation, the I-HaND was forward- and back-translated by certified medical translators. Cognitive interviews with 20 native German-speaking patients ensured clarity and cultural relevance. The final version was administered to 120 patients with upper extremity nerve injuries. Construct validity was tested by correlation with the short Michigan Hand Questionnaire (sMHQ) and internal consistency with Cronbach's alpha. Confirmatory factor analysis was used to evaluate one- and two-factor models.

The German I-HaND showed excellent internal consistency (Cronbach's α = 0.96) and strong negative correlation with the sMHQ (r = -0.90, p < 0.001). Confirmatory factor analysis supported a two-factor model (pain and motor function), although fit indices did not reach optimal thresholds. Cognitive testing confirmed excellent comprehensibility and patient acceptance (median completion time 6 min). No missing data were observed.

The German I-HaND is a valid, reliable, and culturally adapted instrument for assessing pain and function in patients with peripheral nerve injuries. It enables consistent outcome measurement.

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