A factor analytic study of the dizziness handicap inventory: does it assess phobic avoidance in vestibular referrals?

Panic disorder and agoraphobia have been associated with increased functional disability in individuals who have vestibular problems. The Dizziness Handicap Inventory (DHI), a 25-item self-report questionnaire with three rationally derived subscales, was designed to measure functional, emotional, and physical disability associated with vestibular disturbance. Despite the apparent usefulness of the DHI, there have been few studies of its psychometric properties. The primary purpose of the present study was to assess the factor structure of the DHI. A principal components analysis with oblique rotation was conducted on data collected from 95 patients referred to a tertiary-care vestibular disorders clinic for assessment of vestibular disturbance. Both 2-factor and 3-factor solutions are reported. The 2-factor solution was indicative of General Functional Limitations and Postural Difficulties. In the 3-factor solution, General Functional Limitations was split into factors indicative of Disability in Activities of Daily Living and Phobic Avoidance, while the Postural Difficulties factor remained stable. We also characterized the 3-factor solution by assessing the correlation of factor scores with measures of vestibular symptoms, mood, and anxiety. The general pattern of results does not support the validity of the original subscale structure of the DHI. Implications for revising the DHI to provide a more comprehensive and factorially valid assessment of disability associated with vestibular disturbance are discussed.