Needle electromyography of bulbar muscles in patients with amyotrophic lateral sclerosis evidence of subclinical involvement

To determine if quantitative motor unit action potential (MUAP) analysis and peak ratio interference pattern analysis of the fifth, seventh, and eleventh cranial nerve innervated muscles are helpful in the assessment of subclinical bulbar involvement in ALS. With both electromyographic (EMG) techniques, electrical activity was recorded via needle electrodes from the right frontalis, masseter, and sternocleidomastoideus muscles of nine ALS patients without clinical bulbar signs (Frenchay score >85%) aged 40 to 87 years; 21 healthy subjects aged 27 to 74 years; and five ALS patients with clinical bulbar signs (Frenchay score