Initial development of the lewy body dementia – domain rating scale: a disease-specific outcome measure

Lewy body dementia (LBD) lacks a validated, disease-specific outcome measure, limiting clinical trials and the development of disease-modifying therapies. We developed the Lewy Body Dementia–Domain Rating Scale (LBD-DRS), an LBD-specific instrument assessing symptom severity and functional impact across cognitive, neuropsychiatric, motor, autonomic and somatic, and sleep-wake domains, alongside activities of daily living and overall impact, to be completed by interviewing the patient and an informant. A three-round international Delphi process (consensus ≥ 75%) was conducted with LBD experts, and a workshop with people with LBD and carers provided complementary feedback. Response rates were 93% (R1, n = 41/44), 74% (R2, n = 35/47), and 69% (R3, n = 42/61). Consensus was reached on the need for an LBD-specific scale (98%), inclusion of the five symptom domains (95%), and the suitability of the final prototype for cognitive pretesting (93%). The LBD-DRS is, to our knowledge, the first consensus-derived, multi-domain composite measure of symptom severity and functional impact developed specifically for LBD. It is ready for cognitive pretesting and formal clinimetric evaluation.