XI

The Xerostomia Inventory (XI) is an 11-item self-report questionnaire designed to measure subjective perception of dry mouth (xerostomia). Developed by Thomson and colleagues in 1999, it has become the standard validated instrument for assessing dry mouth severity in clinical practice and research. The XI captures both the frequency and severity of oral dryness symptoms and their impact on daily functioning, distinguishing symptomatic xerostomia from objective salivary gland dysfunction.