Audiometric and tympanometric monitoring of a disease affecting nerve-muscle transmission.

Audiometric and tympanometric tests were used to identify patients with myasthenia gravis, a disease characterized by skeletal muscle weakness. Middle ear muscle reflexes in untreated myasthenics were found to be typically depressed or absent. Hearing was abnormally sensitive for some frequencies and middle ear pressures were often negative. Following drug administration, patients who were responding well to medication had more sensitive reflex thresholds, less sensitive hearing, and were able to equalize middle ear pressures. Tympanometric measurements have proved to be of value in the diagnosis of myasthenia and in monitoring the effects of therapy.