Movement disorders phenomenology in focal motor seizures

Introduction: Although focal motor seizures may resemble one or more movement disorders their phenomenology and prevalence remain uncertain. Methods: To examine the extent to which focal motor seizures can present with a phenomenology fulfilling diagnostic criteria for movement disorders, 100 consecutive patients with focal motor seizures were rated by movement disorders experts, epileptologists, and general neurologists. Results: A focal motor seizure phenomenologically manifested as a defined movement disorder in 29% of the patients from a consecutive video-EEG documented cohort as per consensus among experts: myoclonus and dystonia (10 and 9 cases, respectively) were the most common movement disorders, followed by chorea (4), stereotypies (3) myoclonus-dystonia (2), and tremor (1). Conclusions: Movement disorders and focal motor epilepsy share overlapping movement phenomenology.