Myokymic discharges in amyotrophic lateral sclerosis (ALS): a rare electrophysiologic finding?

Myokymic discharges (MDs) are uncommonly recognized in amyotrophic lateral sclerosis (ALS). The electrophysiologic findings in 96 ALS patients were retrospectively reviewed. MDs were found in 5.2% of patients, in 0.81% of total muscles examined (8.2% cranial muscles vs. 0.15% limb muscles). The higher frequency of MDs in cranial muscles suggests a difference in the metabolic environment or other mechanism of instability of the anterior horn cells in the brainstem compared to the spinal cord.