The Xerostomia Inventory: a multi-item approach to measuring dry mouth

Abstract

Objective: To develop a valid multi-item method of measuring the symptoms of xerostomia which includes the wide range of xerostomia symptoms in a single quantitative measure. Design: A combination of qualitative and quantitative approaches. Setting A cohort study in South Australia. Participants: Older people aged 65 years or more who were taking part in the South Australian Dental Longitudinal Study. Measures: Xerostomia symptoms were evaluated using a multi-item inventory format and, for comparison pulposes, a standard single dry-mouth question. Resting whole-salivary flow rate was estimated using the 'spit' method. Results: Xerostomia and flow-rate data were available for 636 individuals. Factor analysis revealed the presence of a discrete xerostomia dimension, represented by l1 items whose responses were summated to give a single Xerostomia Inventory (XI) scale score. This had a very low correlation with resting flow rate but a much stronger, positive correlation with the standard dry-mouth question responses. Conclusions: The XI shows adequate content and concurrent validity, and appears to be a promising advance on previous approaches to xerostomia symptomatology although further testing is required.