Electrographic Correlates of Plateau Waves in Patients With Leptomeningeal Metastases.

We describe video electroencephalography (video-EEG) correlates of transient neurological attacks due to plateau waves-paroxysmal elevations in intracranial pressure-in patients with leptomeningeal metastases. We identified 3 patients with leptomeningeal metastases, intracranial hypertension, and transient neurological attacks captured on video-EEG without evidence of seizures or epileptiform activity. We identified all clinical events on video and reviewed the corresponding EEG data for evidence of abnormalities. All 3 patients had mild to moderate slowing and 2 had frontal intermittent rhythmic delta activity during background EEG recording. There were 33 clinical events recorded and stereotyped for each patient. All 33 events were associated with an increase in delta range slowing of ≥30% compared to the background. This abnormality started ≤2 minutes before the onset of clinical symptoms and persisted for minutes after clinical resolution. This study is the first to carefully describe the electrographic correlates of transient neurological attacks due to plateau waves in patients with leptomeningeal metastasis. Clinical attacks were consistently associated with a possible EEG signature of diffuse delta range slowing. Future studies can validate the sensitivity and specificity of these EEG changes as a prognostic and/or response biomarker in patients with leptomeningeal metastases with or without intracranial hypertension.