ABSTRACT
Leigh's disease is an unusual, multifocal, relapsing-remitting disorder of the central nervous system, that usually affects children but may affect adults. The lesions in Leigh's disease characteristically occur in the upper brainstem at the meso-diencephalic junction. The authors report an adult patient with Leigh's disease whose principal neurologic abnormality was a persistent, primary-position, seesaw nystagmus associated with a paroxysmal ocular tilt reaction. Both seesaw nystagmus and ocular tilt reaction typically occur in patients with meso-diencephalic lesions. These observations draw attention to the importance of considering Leigh's disease in the differential diagnosis of adults as well as of children presenting with seesaw nystagmus or a paroxysmal ocular tilt reaction.