Downbeat Nystagmus as a Manifestation of Myoclonic Status Epilepticus in a Patient With Anoxic Brain Injury.

BACKGROUND/PURPOSE: Downbeat nystagmus (DBN) is an uncommon finding in comatose patients, especially as a manifestation of epileptiform activity. We report a 59-year-old man who developed DBN in the context of myoclonic status epilepticus following anoxic brain injury secondary to cardiac arrest. The DBN was phase-locked with generalized periodic epileptiform discharges (GPDs) on electroencephalography (EEG) and resolved with pharmacologic burst suppression. CONCLUSION: This case suggests a potential link between DBN and cortical epileptiform activity, which we hypothesize may be due to bilateral cortical hyperexcitability and cerebellar disinhibition. The presence of DBN in this setting may indicate a poor prognosis.