Caloric-induced nystagmus with isoelectric electroencephalogram

Caloric vestibular testing induced nystagmus in a patient with an isoelectric electroencephalogram after cardiopulmonary arrest. This has been demonstrated previously in patients in a chronic persistent vegetative state with intact brainstem reflexes, but never in a patient with an isoelectric electroencephalogram. Animal studies indicate that the quick phase of nystagmus and horizontal saccades are generated in the paramedian pontine reticular formation. The present case supports the conclusion that caloric-induced nystagmus originates in the brainstem in rudimentary form.