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

Objective To develop a valid multi-item method of measuring the symptoms of xerostomia which includes the wide range of xerostomia symptoms in a singl e quantitative measure. Design A combination of qualitative and quantitativ e 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 usin g a multi-item inventory format and, for comparison purposes, a standard si ngle dry-mouth question. Resting whole-salivary flow rate was estimated usi ng the 'spit' method. Results Xerostomia and flow-rate data were available for 636 individuals. Factor analysis revealed the presence of a discrete xe rostomia dimension, represented by 11 items whose responses were summated t o give a single Xerostomia Inventory (XI) scale score. This had a very low correlation with resting flow rate but a much stronger, positive correlatio n with the standard dry-mouth question responses. Conclusions The XI shows adequate content and concurrent validity, and appears to be a promising adv ance on previous approaches to xerostomia symptomatology although further t esting is required.