Sustained Effect of Botulinum Neurotoxin in Myoclonus Owing to Epilepsia Partialis Continua

Abstract

Background: Epilepsia partialis continua (EPC) is defined as continuous myoclonic jerking of a body part of cortical origin and often resembles a movement disorder. Unfortunately, anti-epileptic therapy is frequently ineffective. Currently, the effect of botulinum neurotoxin (BoNT) therapy in EPC is controversial. Methods: We analyzed case histories, treatment protocols, and video documentation of 5 patients with EPC, who received BoNT therapy in our movement disorders unit. The Unified Myoclonus Rating Scale was used to document treatment effects. Results: In all patients, BoNT treatment significantly reduced severity and frequency of myoclonus and led to pronounced improvement of speech and arm utilization, regardless of etiology or duration of EPC. Conclusion: BoNT represents a safe, effective treatment in EPC, offering long-term abatement of myoclonus. The substantial functional profit may hint at mechanisms beyond local impairment of neuromuscular transmission, such as modulation of maladaptive cortical plasticity, as observed in dystonia and poststroke spasticity.