Objective: The goal of this study is to characterize severity and variability of symptoms in people with segmental, multifocal, or generalized isolated dystonia. Standardized data will contribute to an improved understanding of clinical features of this population and provide insight into performance of clinical rating scales to support future planned interventional studies.

Background: There are currently no approved oral pharmacologic agents for isolated dystonia. Botulinum toxins (BoNTs) are the only approved products in the US; however, these are approved solely for focal cervical dystonia or blepharospasm and provide only symptomatic relief. Furthermore, existing databases are predominantly comprised of focal dystonia patients, with a paucity of data in other subtypes.

Method: People with isolated dystonia were enrolled into two cohorts: segmental/multifocal or generalized. At the first visit, a detailed medical and treatment history was obtained, and clinical rating scales were performed: Burke-Fahn-Marsden (BFM) Dystonia Rating Scale and Clinical Global Impression of Severity (CGI-S). At the second visit, these rating scales were repeated, and intercurrent health-related events were captured.

Results: From April 2025-February 2026, 104 individuals were enrolled at 22 movement disorder sites in the US, with 94 participants having at least one study visit. Mean age was 53.7 years, 74.5% female. Mean time from symptom onset to diagnosis was 6.3 years. The most-reported non-dystonia disorders were anxiety (38.3%) and depression (16.0%). After BoNTs (73.4%), the most commonly prescribed medications, by class, were anxiolytics (44.7%), lipid lowering (29.8%), antidepressants and muscle relaxants (25.5% each). At visit 1, mean CGI-S score was 3.9 (SD 0.8), mean BFM severity score (not using the weight factor) was 20.4 (SD 15.2), and mean BFM disability score was 2.9 (SD 3.6).

Conclusion: This study demonstrated high off-label medication use. Additionally, these data suggest a clear need for additional treatment options given persistent severity despite concomitant therapy. Results from this study will help in planning an interventional drug study, specifically development of entry criteria (eg, minimum severity scores in order to detect treatment effect) and ensuring training on scales that may not be commonly used in clinical practice but capture aspects of dystonia that most impact patients.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/an-observational-study-of-segmental-and-generalized-isolated-dystonia-to-inform-development-of-new-drug-therapies/