Dizziness and quality of life in clinic and general population samples of dizzy individuals

The aims were to characterize dizziness in terms of its severity and nature, to describe the limitations experienced by quantifying and establishing dimensions of quality of life, to model the processes and factors involved in the quality of life of dizzy individuals and to develop and assess a dizziness-specific quality of life questionnaire.Questionnaire surveys were carried out in clinic (N=405) and general population (N=55) samples of dizzy individuals. In addition two comparison groups were surveyed: clinic population of facial pain patients and individuals without dizziness in the general population.Characteristics of dizziness in clinic and general population samples are described and compared. Psychometric properties were established for two applied questionnaires: the commonly used Dizziness Handicap Inventory (DHI) and the newly applied quality of life questionnaire, the Functional Limitations Profile (FLP). Both were found to be reliable measures for groups of dizzy individuals. Although there is some support for validity of the DHI, a revised subscale structure is proposed reflecting the intrinsic properties of the items more accurately than the original. The FLP appears to be a valid measure of the quality of life of dizzy individuals.Quality of life was quantified in the four survey groups and comparisons made. A significant reduction in quality of life was found for dizzy individuals, the greatest reduction being for the psychosocial aspects. The limitations reported by dizzy individuals are shown to be specific and different from comparison groups.Factor analysis of FLP responses suggests a three-dimensional model of quality of life consisting of psychological, physical and social well-being, supplemented by a contingent factor representing other health problems. This model underpins the newly developed questionnaire, the Dizziness Impact Profile (DIP), constructed from analysis of item responses on the original FLP. The DIP appears to be valid and reliable based on analysis of the item scores from the FLP, but requires further validation.Increased understanding of dizziness and the limitations in lifestyle experienced by its sufferers and the development of the Dizziness Impact Profile to quantify these in a convenient way is important to meet the needs of dizzy individuals in terms of service provision and planning.