Delineation of the Clinical Features and Treatment Response of Oromandibular Dystonia: A Multicenter Summary of 2,057 Cases

Objective To better characterize oromandibular dystonia (OMD) to facilitate early diagnosis and test the hypothesis that botulinum toxin treatment alleviates symptoms, regardless of etiology, to provide guidance on treatment strategies. Methods To better characterize this condition we utilize a three-pronged approach. First, we provide a comprehensive summary of the world’s literature encompassing 1157 cases in 27 separate manuscripts. Next, we describe the clinical features of 727 OMD subjects enrolled by the Dystonia Coalition (DC), an international multicenter database. Finally, we provide details of the treatment approach and response from two expert centers where large numbers of OMD patients are followed. Cases from expert centers were utilized to analyze whether response to botulinum toxin varied by etiology of OMD. Results In all cohorts, typical age at onset was in the 50s and approximately 70 % of cases were female. Although the literature OMD more commonly described as a focal dystonia, analysis of the DC database revealed it more commonly appears as part of a segmental dystonia. Expert center review of 173 cases revealed botulinum toxin injections improved symptom severity by more than 50% in approximately 78% of subjects. Among the patients at expert centers, analysis revealed that treatment response did not vary by etiology. Conclusions Botulinum toxin injections are an effective treatment for OMD, regardless of etiology. By providing a more comprehensive description of OMD and the therapeutic efficacy of botulinum toxin for this type of dystonia, we hope to improve clinical recognition to aid in timely diagnosis and inform treatment strategies. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was supported in part by the Dystonia Medical Research Fellowship Award and in part by grants to the DC a consortium of the Rare Diseases Clinical Research Network (RDCRN) that is supported by U54 TR001456 from the Office of Rare Diseases Research (ORDR) at the National Center for Advancing Clinical and Translational Studies (NCATS) and U54 NS065701 and U54 NS116025 from the National Institute for Neurological Diseases and Stroke (NINDS). The Sartain Lanier Family Foundation as well as the Jean and Paul Amos Parkinsons Disease and Movement Disorders Program Endowment also provided support for this study. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Emory University Institutional Review Board, the Icahn School of Medicine, and the DC steering committee approved all procedures involving human subjects. All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes The data utilized from the Dystonia Coalition database is openly available by request.