Factor analysis and correlation between Dizziness Handicap Inventory and Dizziness Characteristics and Impact on Quality of Life scales.

In order to assess the different dimensions of disability and handicap analyzed in the Dizziness Handicap Inventory (DHI) and Dizziness Characteristics and Impact on Quality of Life (UCLA-DQ) questionnaires a factor analysis study was done. The instruments used were the corresponding transculturally adapted versions of the originals into Spanish. The study included 337 patients with dizziness, independent of location and etiology, who were able to respond to all the items in the questionnaires given before vestibular testing. Factor analysis was used to determine the structure of both scales; a principal components analysis with orthogonal rotation (Varimax) was conducted on data collected from the patients. A three-factor solution was obtained in the DHI and a two-factor solution for the UCLA-DQ. The factors obtained from the DHI were related to vestibular handicap, vestibular disability and visuo-vestibular disability; the factors from the UCLA-DQ were related to frequency and severity of dizziness. There was no coincidence between the items in each of the factor obtained in the DHI questionnaire and the items in the subscales provided in the original version. The main relation between factors was found between vestibular handicap and frequency. The DHI and UCLA-DQ questionnaires are multidimensional questionnaires for the assessment of the impact of dizziness and provide a model for vestibular disability and handicap.