Detection of fasciculations in amyotrophic lateral sclerosis: The optimal ultrasound scan time

INTRODUCTION: This study seeks to elucidate the optimal scan time to detect fasciculations by using ultrasound in the diagnosis of amyotrophic lateral sclerosis (ALS). METHODS: The intervals between fasciculations were recorded from tongue, abdominal, and limb muscles in ALS patients, incorporating assessment of the cumulative probability of 2 fasciculations occurring. RESULTS: From 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. DISCUSSION: A definition of 2 or more fasciculations occurring during a scan time of 60 s reliably allowed detection of fasciculations in ALS. Muscle Nerve, 2017.