Objective: We evaluated the presence of these features across a set of 12 cervical muscles predominantly associated with abnormal posturing in CD using a multi-muscle surface electromyography (sEMG) recording paradigm.

Background: Cervical dystonia (CD) is characterised by involuntary contractions of neck muscles leading to abnormal head postures and movements. Neurophysiological markers of dystonia include abnormal muscle co-contraction and altered intermuscular coupling.

Method: Recordings were obtained in four CD patients, during baseline rest (60 s, seated) and during a cyclic head rotation task (60 s). Intermuscular coherence (IMC) was estimated across all 66 muscle pairs. Peak frequency and coupling range were identified across the 3–35 Hz spectrum and averaged across muscle pairs and participants. Beyond this, the directionality of intermuscular coupling was assessed using a multivariate autoregressive model (MVAR), allowing for the identification of distinct coupling components: ipsilateral, bilateral, and adjacent cervical muscles.

Results: At rest, CD patients demonstrated peak IMC at 8 Hz (range 3–10 Hz). During cyclic rotation, the coupling range shifted upward (6.5–15.5 Hz), extending into the beta band. Partial Directed Coherence derived from MVAR coefficient, revealed directionality between bilateral muscle pairs, ipsilateral adjacent and ipsilateral remote muscle pairs across each participant.

Conclusion: Multi-muscle sEMG analysis demonstrates task-dependent changes in IMC in CD. Increased coupling within the beta frequency range during movement may reflect abnormal neural drive across cervical muscles. This approach may provide a quantitative neurophysiological marker of dystonic muscle activation and contribute to the objective characterisation of CD.

« Back to 2026 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/evaluation-of-electromyographic-measures-of-cervical-dystonia-using-a-12-muscle-recording-paradigm/