Abstract

IntroductionThis study seeks to elucidate the optimal scan time to detect fasciculations by using ultrasound in the diagnosis of amyotrophic lateral sclerosis (ALS). MethodsThe intervals between fasciculations were recorded from tongue, abdominal, and limb muscles in ALS patients, incorporating assessment of the cumulative probability of 2 fasciculations occurring. ResultsFrom prospective studies of 228 muscles from 19 ALS patients, fasciculations were detectable in 68% of patients. The longest interfasciculation interval recorded was 81.4 s in the hand muscle. The cumulative probability of 2 fasciculations occurring was calculated as 0.9 in all muscles during a period of 60 s. DiscussionA definition of 2 or more fasciculations occurring during a scan time of 60 s reliably allowed detection of fasciculations in ALS. Muscle Nerve, 2017