Motor unit changes in thoracic paraspinal muscles in amyotrophic lateral sclerosis.

In 38 amyotrophic lateral sclerosis (ALS) patients and 28 controls, we performed motor unit potential (MUP) analysis in the C-6 and T-5 paraspinal and biceps muscles. In ALS cases, we found similar abnormalities in MUPs in paraspinal and limb muscles. Fasciculation potentials (FPs) were more frequent in biceps than in paraspinal muscles, but fibrillation potentials and positive sharp waves (fibs-sw) were equally frequent in all three muscles. These results confirm the value of paraspinal MUP analysis in the diagnosis of ALS.