Objective: To evaluate the usefulness of polymyographic recording of abnormal muscle activity in differentiating functional from non-functional cervical dystonia.
Background: Differentiating functional cervical dystonia from organic dystonia can be clinically challenging, particularly in patients presenting with atypical postures or tremor. Experts recently highlighted the limited diagnostic accuracy of individual clinical features in functional cervical dystonia1. Neurophysiological techniques such as polymyography may provide objective markers that support the diagnostic process.
Method: We performed polymyographic recordings in 60 patients presenting with cervical dystonia using an eight-channel EMG system (Neuro-MEP-8ch®). Recordings were obtained from relevant cervical muscles during different conditions including rest, voluntary movements, distraction tasks, and passive head movements.
Results: From 60 cases, 15% (n=9) were functional, and 6.7% (n=4) were combined. There was no statistical difference in age, sex, disease duration, tremor presence or frequency between patients with functional and non-functional dystonia.
Several polymyographic features compatible with functional movement disorder were identified. The most frequent finding was tremor distractibility or entrainment (n=8). Additional findings included tremor frequency variability (n=4), distractibility of dystonic muscle activity (n=3), coactivation of antagonist muscles during passive movements (n=3), variability of dystonic posture over time (n=3) and marked fluctuations in dystonia severity (n=2).
Conclusion: Polymyographic assessment may reveal electrophysiological features suggestive of functional etiology in patients presenting with cervical dystonia, especially in tremulous forms. These findings may complement clinical examination and improve diagnostic confidence when distinguishing functional from non-functional cervical dystonia.
References: (1) Baizabal-Carvallo JF, Alonso-Juarez M, Jankovic J. Functional cervical dystonia: diagnostic accuracy of distinct clinical features. J Neurol. 2025 Dec 17;273(1):31. doi: 10.1007/s00415-025-13580-5. PMID: 41405642.
This project was supported by VEGA/1/0514/25 Grant.
To cite this abstract in AMA style:
M. Minar, Z. Kosutzka. Polymyographic Features Suggestive of Functional Etiology in Patients with Cervical Dystonia [abstract]. Mov Disord. 2026; 41 (suppl 1). https://www.mdsabstracts.org/abstract/polymyographic-features-suggestive-of-functional-etiology-in-patients-with-cervical-dystonia/. Accessed October 1, 2026.« Back to 2026 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/polymyographic-features-suggestive-of-functional-etiology-in-patients-with-cervical-dystonia/