Category: Rating Scales
Objective: To provide an overview of psychosis rating scales validated in specific neurodegenerative disease populations and compare psychometric characteristics of the validated psychosis scales.
Background: Psychosis is a common and complex non-motor symptom (NMS) across various neurodegenerative disorders such as Parkinson’s disease (PD), Alzheimer’s disease (AD), dementia with Lewy bodies (DLB), Corticobasal degeneration (CBD), Progressive Supranuclear Palsy (PSP), and Multisystem Atrophy (MSA). Although several scales are used to rate psychosis in neurodegenerative diseases, no gold standard currently exists. We systematically reviewed the validation studies of scales that are used to assess psychosis in neurodegenerative diseases.
Method: A systematic review of literature was conducted of articles published between 1806 to April 2019 with pertinent databases individually searched. Original validation studies of all scales used to assess psychosis in PD, AD, DLB, CBD, PSP and MSA were retrieved. Four primary outcome measures were collected and analyzed; internal consistency, interrater reliability, test-retest reliability, and validity. We also estimated which scales were most commonly used to assess psychosis in PD, AD and DLB.
Results: 56 studies were included in the review. Of these, 33 assessed the validity of a scale by comparing it against a reference standard. Test-retest reliability, internal consistency, and interrater reliability were evaluated by 23, 29 and 28 studies respectively. Psychometric properties of the scales were found to be inconsistent across these studies. Overall, validation studies exist for 32 different scales. No scale was found to be validated specifically for MSA, CBD, PSP or DLB. The NPI was the most frequently utilised scale in AD, PD and DLB studies, even though it has only been validated in AD patients.
Conclusion: Disease-specific psychosis rating scales in PD, DLB, CBD, PSP, and MSA are sorely lacking and represent a key unmet need.
To cite this abstract in AMA style:
P.S Malhotra, Y.M Wan, E.K Tan. A Systematic Review of the Psychometric Properties of Psychosis Rating Scales in Neurodegenerative Conditions [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/a-systematic-review-of-the-psychometric-properties-of-psychosis-rating-scales-in-neurodegenerative-conditions/. Accessed June 15, 2025.« Back to MDS Virtual Congress 2020
MDS Abstracts - https://www.mdsabstracts.org/abstract/a-systematic-review-of-the-psychometric-properties-of-psychosis-rating-scales-in-neurodegenerative-conditions/