Translation and validation of the vertigo symptom scale into German: A cultural adaption to a wider German-speaking population

BACKGROUND Dizziness and comorbid anxiety may cause severe disability of patients with vestibulopathy, but can be addressed effectively with rehabilitation. For an individually adapted treatment, a structured assessment is needed. The Vertigo Symptom Scale (VSS) with two subscales assessing vertigo symptoms (VSS-VER) and associated symptoms (VSS-AA) might be used for this purpose. As there was no validated VSS available in German, the aim of the study was the translation and cross-cultural adaptation in German (VSS-G) and the investigation of its reliability, internal and external validity. METHODS The VSS was translated into German according to recognized guidelines. Psychometric properties were tested on 52 healthy controls and 202 participants with vestibulopathy. Internal validity and reliability were investigated with factor analysis, Cronbach's α and ICC estimations. Discriminant validity was analysed with the Mann-Whitney-U-Test between patients and controls and the ROC-Curve. Convergent validity was estimated with the correlation with the Hospital Anxiety Subscale (HADS-A), Dizziness Handicap Inventory (DHI) and frequency of dizziness. RESULTS Internal validity: factor analysis confirmed the structure of two subscales. Reliability: VSS-G: α = 0.904 and ICC (CI) =0.926 (0.826, 0.965). Discriminant validity: VSS-VER differentiate patients and controls ROC (CI) =0.99 (0.98, 1.00). Convergent validity: VSS-G correlates with DHI (r = 0.554) and frequency (T = 0.317). HADS-A correlates with VSS-AA (r = 0.452) but not with VSS-VER (r = 0.186). CONCLUSIONS The VSS-G showed satisfactory psychometric properties to assess the severity of vertigo or vertigo-related symptoms. The VSS-VER can differentiate between healthy subjects and patients with vestibular disorders. The VSS-AA showed some screening properties with high sensitivity for patients with abnormal anxiety.