Development of the Persian version of the Vertigo Symptom Scale: Validity and reliability

Vertigo Symptom Scale (VSS) is a proper instrument for assessing the patient status, clarifying the symptoms, and examining the relative impact of the vertigo and anxiety on reported handicap. Our aim is the translation and cross-cultural adaptation of the VSS into Persian language (VSS-P) and investigating its validity and reliability in patients with peripheral vestibular disorders.

VSS was translated into Persian. Cross-cultural adaptation was carried out on 101 patients with peripheral vestibular disorders and 34 participants with no history of vertigo. They completed the Persian versions of VSS, dizziness handicap inventory (DHI), and Beck anxiety inventory (BAI). Internal, discriminant, and convergent validities, internal consistency, and test-retest reliability were determined.

The VSS-P showed good face validity. Internal validity was confirmed and demonstrated the presence of two vertigo (VSS-VER) and autonomic-anxiety (VSS-AA) subscales. Significant difference between the median scores for patient and healthy groups was reported in discriminate validity (P <0.001). Convergent validity revealed high correlation between both BAI and DHI with VSS-P. There was a high test-retest reliability; with intraclass correlation coefficient of 0.89, 0.86, and 0.91 for VSS-AA, VER, and VSS-P, respectively. The internal consistency was good with Cronbach's alpha 0.90 for VER subscale, 0.86 for VSS-AA subscale, and 0.92 for the overall VSS-P.

The Persian version of the VSS could be used clinically as a valid and reliable tool. Thus, it is a key instrument to focus on the symptoms associated with dizziness.