Tremor and Myoclonus is Common in Immune-mediated and Hereditary Polyneuropathies

Objective: Our goal was to identify the frequency and types of involuntary movements in immune mediated and hereditary polyneuropathies. Methods: In this prospective study, we included all consecutive patients with immune mediated or hereditary polyneuropathy between January 2017 and November 2019. The presence and type of the involuntary movements were determined by the clinical examination and multichannel surface electromyography. Results: We identified 23 (48.9%) patients with involuntary movements among 47 patients with immune mediated or hereditary polyneuropathy in the study period. All patients with an involuntary movement had postural tremor with accompanying action and/or rest tremor. Short duration and high-amplitude myoclonus was accompanying in 18 (38.3%) patients. The demographic and clinical characteristics and features of nerve conduction studies were similar between patients with and without involuntary movements. Discussion: Tremor and myoclonus were frequent in our cohort. Postural tremor was the most frequent subtype. There was no significant relationship between myoclonus or tremor and clinical/electrophysiological features. Conclusion: For assessing movement disorders in polyneuropathies not only clinical examination, but also electrophysiological studies such as multichannel surface electromyography should be used.