Annette Kurre

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.

It is known that anxiety and depression influence the level of disability experienced by persons with vertigo, dizziness or unsteadiness. Because higher prevalence rates of disabling dizziness have been found in women and some studies reported a higher level of psychiatric distress in female patients our primary aim was to explore whether women and men with vertigo, dizziness or unsteadiness differ regarding self-perceived disability, anxiety and depression. Secondly we planned to investigate the associations between disabling dizziness and anxiety and depression.

The Dizziness Handicap Inventory (DHI) is a validated, self-report questionnaire which is widely used as an outcome measure. Previous studies supported the multidimensionality of the DHI, but not the original subscale structure. The objectives of this survey were to explore the dimensions of the Dizziness Handicap Inventory - German version, and to investigate the associations of the retained factors with items assessing functional disability and the Hospital Anxiety and Depression Scale (HADS). Secondly we aimed to explore the retained factors according to the International Classification of Functioning, Disability and Health (ICF).

To translate the Dizziness Handicap Inventory into German (DHI-G) and investigate reliability, assess the association between selected items of the University of California Los Angeles Dizziness Questionnaire and the DHI-G, and compare the scores of patients and healthy participants. Cross-sectional design. Tertiary center for vertigo, dizziness, or balance disorders. One hundred forty-one patients with vertigo, dizziness, and unsteadiness associated with a vestibular disorder, with a mean age (standard deviation) of 51.5 (13.2) years, and 52 healthy individuals participated. Fourteen patients participated in the cognitive debriefing; 127 patients completed the questionnaires once or twice within 1 week. The DHI-G assesses disability caused by dizziness and unsteadiness; the items of the University of California Los Angeles Dizziness Questionnaire assess dizziness and impact on everyday activities. Internal consistency was estimated using Cronbach alpha, reproducibility by calculating Bland-Altman limits of agreement and intraclass correlation coefficients. Associations were estimated by Spearman correlation coefficients. Patients filled out the DHI-G without problem and found that their self-perceived disabilities were mostly included. Cronbach alpha values for the DHI-G and the functional, physical, and emotional subscales were 0.90, 0.80, 0.71, and 0.82, respectively. The limits of agreement were +/-12.4 points for the total scale (maximum, 100 points). Intraclass correlation coefficients ranged from 0.90 to 0.95. The DHI-G correlated moderately with the question assessing functional disability (0.56) and fairly with the questions quantifying dizziness (0.43, 0.35). The DHI-G discriminated significantly between healthy participants and patients. The DHI-G demonstrated good reliability and is recommended as a measure of disability in patients with dizziness and unsteadiness.