From dysphonia to dysphoria: Mokken scaling shows a strong, reliable hierarchy of voice symptoms in the Voice Symptom Scale questionnaire☆

Abstract 

Symptoms of hoarseness (dysphonia) are common and often associated with psychological distress. The Voice Symptom Scale (VoiSS) is a 30-item self-completed questionnaire concerning voice and throat symptoms. Psychometric and clinical studies on the VoiSS show that it has good reliability and validity, and a clear factorial structure. The present article presents a further advance in voice measurement from the patient's point of view. To date, there has been no examination of whether voice-related symptoms form a hierarchy; that is, whether people who suffer voice problems progress through a reliable set of problems from mild to severe. To address this question, the technique of Mokken scaling was applied to the VoiSS in 480 patients with dysphonia. A strong and reliable Mokken scale—a symptom hierarchy—was found, which included 17 of the 30 items. This new information on dysphonia shows that voice symptoms progress from voice-oriented difficulties, through practical problems, to disturbances of social relationships and mood (dysphoria). The results add information about the structured phenomenology of voice problems, further establish the relationship between voice impairment and psychosocial impairment, and suggest practical applications in the assessment of dysphonic voices.

Keywords: Dysphonia, Dysphoria, Mokken scaling, Voice Symptom Scale