Ocular myasthenia mimicking a one-and-a-half syndrome

A 52-year-old patient developed an eye movement disorder first resembling a left internuclear ophthalmoplegia and subsequently a "one-and-a-half syndr ome" as the presenting symptoms of ocular myasthenia gravis. No accompanyin g myasthenic features were present except for the fluctuation in the amplit ude of dissociated nystagmus. This patient shows that an oculomotor disorde r considered a typical pontine lesion may instead be caused by myasthenia g ravis, even in the absence of other clinical and electrophysiologic feature s of neuromuscular deficit.