Masticatory performance in patients with myasthenia gravis

Masticatory muscle electromyograms (EMGs) were recorded while patients with bulbar myasthenia gravis chewed artificial food and compared with those of patients with ocular myasthenia gravis, patients in clinical remission who had previously suffered from bulbar myasthenia gravis and healthy individuals. Masticatory performance and EMGs were significantly smaller in the bulbar group. There were no indications of subclinical masticatory muscle weakness in patients with bulbar myasthenia gravis in remission and in patients with ocular myasthenia gravis. Patients with bulbar myasthenia gravis barely compensated for muscular weakness by chewing at a higher percentage of their maximal EMG. These quantitative findings, when combined with subjective reports of masticatory muscle weakness, show that a need to support the jaw is characteristic of patients with bulbar myasthenia gravis who produce low EMG activity.