Validation of the German version of the Vertigo Symptom Scale (VSS) in patients with organic or somatoform dizziness and healthy controls

Objective The objective of this study was to validate the German version of the Vertigo Symptom Scale (VSS) and to determine its ability to differentiate the type, frequency, and severity of balance disorders. The scale (34 items) was designed by Yardley and coworkers and has been already validated in its English and Spanish versions. Methods 98 patients with organic vertigo syndromes, 90 patients with somatoform (psychogenic) dizziness and 56 healthy controls were evaluated with the VSS and additional standardized questionnaires regarding distress (SCL-90R), quality of life (SF-36), anxiety and depression (HADS). In order to differentiate organic from somatoform dizziness all patients underwent detailed clinical neurological and vestibular neurophysiological testing. Results The two identified subscales 'vertigo and related symptoms' (VER) and 'somatic anxiety and autonomic arousal'(AA) had good internal consistencies (Cronbach's alpha: VER 0.79; AA 0.89). Test-retest correlations were r = 0.75 for VER and r = 0.75 for AA. VER could discriminate well between dizziness patients and healthy controls. AA discriminated moderately between somatoform and organic dizziness. We found close relations between the AA scale and different measures of emotional distress. Correlations between VER and measures of emotional distress were weaker. Conclusion The German version of the VSS has good reliability and validity in the detection of different vertigo syndromes. Measurement of anxiety symptoms can be helpful to identify patients with somatoform dizziness.