Short, self-report voice symptom scales: Psychometric characteristics of the Voice Handicap Index-10 and the Vocal Performance Questionnaire IAN J. DEARY, PHD, ALISON WEBB, MSC, KENNETH MACKENZIE, FRCS, JANET A. WILSON, FRCS, and PAUL N. CARDING, PHD, Edinburgh, Scotland, Newcastle-upon-Tyne, United Kingdom, and Glasgow, Scotland OBJECTIVE: Short, self-report symptom question- naires are useful in routine clinical situations for as- sessing the progress of disorders and the influence of interventions. The Voice Handicap Index-10 (VHI-10) and Vocal Performance Questionnaire (VPQ) are brief self-reported assessments of voice pathology, apparently useful in the general voice clinic population. Little is known of the structure or internal consistency of either tool, nor whether they correlate. This study carried out a substantial, sys- tematic evaluation of their performance in the Lar- yngology office setting. STUDY DESIGN AND SETTING: 330 adult (222 women, 108 men) voice clinic attenders completed the VHI and the VPQ. RESULTS: The VHI-10 and VPQ each had a large, single principal component, high in- ternal consistency, and were highly correlated (dis- attenuated r0.91). CONCLUSION: The VHI-10 and the VPQ are similar, short, convenient, internally-consistent, unidimen- sional tools. SIGNIFICANCE: The total VHI-10 or VPQ score is a good overall indicator of the severity of voice dis- orders. (Otolaryngol Head Neck Surg 2004;131: 232-5.) O ne major initiative of contemporary outcomes re- search is the development of patient-centered outcome measures. Patient self-report symptom scales can pro- vide valuable information about functional abilities and quality of life. 1 A number of well established general health quality of life instruments have been developed with strong validity and reliability data. 2 Several dis- ease or condition-specific patient questionnaires have been developed to examine voice-related quality of life. 3,4 However, most of these questionnaires are time consuming to complete (and score) and arguably pro- vide a degree of redundant information. In contrast, brief, concise but clinically-useful self report question- naires are highly attractive in the clinical environment. Short questionnaires have been developed to address specific disorders, e.g. the Voice Outcome Survey is a measure specifically developed for patients with vocal cord paralysis. 5 Similarly, the Voice Related Quality of Life scale focuses on the disability aspects of voice disorders. 6 Two short-form, voice-related scales—the Vocal Handicap Index-10 item questionnaire (VHI-10) 1 and the Vocal Performance Questionnaire (VPQ) 7— have been described. The longer (30 item) versions of the VHI and the VPQ are reliable, valid, and sensitive measures of voice problems. 7-10 Both short-form scales use a single total ‘severity’ score that assumes that all the items contribute to a unidimensional entity. How- ever, there are insufficient psychometric data on either scale to support this assumption. Furthermore, data are required to examine whether these two questionnaires assess similar aspects of what is experienced by a patient with voice disorders. The aims of this study were to examine: 1) whether or not these short scales truly are unidimensional tools, i.e. is the use of a total VHI-10 and/or VPQ score valid?; 2) the internal consistency (a form of reliabili- ty)of both short questionnaires; and 3) the correlation between them. MATERIALS AND METHODS Subjects The sample studied was 330 people (108 men, 222 women) with a primary complaint of dysphonia (hoarseness) who were referred to Otolaryngology out- patient clinics. The mean age of the men was 55.2 years (SD = 15.5 years; range 23-88), and of the women was 48.2 years (SD = 17.5 years; range 17-87). They suf- fered from a wide range of dysphonia diagnoses, with From the Department of Psychology, University of Edinburgh, Edinburgh (Dr. Deary), the Department of Otolaryngology–Head and Neck Surgery, Uni- versity of Newcastle, Freeman Hospital, Newcastle-upon-Tyne (Drs Webb, Wilson, and Carding), and the Department of Otorhinolaryngology and Head and Neck Surgery, Glasgow Royal Infirmary, Glasgow (Dr MacKen- zie). Supported by a Wellcome Trust Health Services Research Grant. Ian Deary is the recipient of a Royal Society-Wolfson Research Merit Award. Reprint requests: Paul Carding, PhD, Professor of Voice Pathology, Depart- ment of Otolaryngology Head and Neck Surgery, University of Newcastle, Freeman Hospital, Newcastle-upon-Tyne NE7 7DN, United Kingdom; e- mail, paul.carding@ncl.ac.uk. 0194-5998/$30.00 Copyright © 2004 by the American Academy of Otolaryngology–Head and Neck Surgery Foundation, Inc. doi:10.1016/j.otohns.2004.02.048 232