[Oculomotor forms of myasthenia].

The diagnostic difficulty in purely oculo-motor forms of myasthenia can be due to the lack of fluctuation in symptoms, the occurrence of complete spontaneous remissions, lasting several months or years, the absence of a decremental response in muscle potentials as evidenced by classical repetitive stimulation of the motor nerve, and negative responses to pharmacological testing. Thus, several investigative procedures have been developed to aid in the diagnosis of questionable cases. These include electromyography of proximal muscles and single fiber recordings, the dosage of acetylcholine receptors antibodies (specificity of nearly 100 %), and histological examination of neuro-muscular junction (invariably finding specific lesions of motor end plates).