Horizontal nystagmus with velocity-increasing waveforms in delayed post-hypoxic leukoencephalopathy: a case report

Abnormal eye movements in unconscious patients serve as crucial diagnostic instruments, offering insights into the function of the central nervous system. Understanding these movements can aid in diagnosing the cause of unconsciousness, localizing brain lesions, and predicting outcomes. We report a patient who presented with spontaneous horizontal nystagmus unaffected by light in delayed post-hypoxic encephalopathy. Video-oculography showed exponentially increasing slow phases, with an amplitude ranging from 3° to 9° and a frequency of 0.5 Hz. Based on the results of oculography and neuroimaging, persistent horizontal nystagmus in our patient may be ascribed to an unstable neural integrator, possibly caused by disrupted cerebellar feedback mechanisms for horizontal gaze holding.