Responsive neurostimulation for focal motor status epilepticus

Abstract

No clear evidence-based treatment paradigm currently exists for refractory and super-refractory status epilepticus, which can result in significant mortality and morbidity. While patients are typically treated with antiepileptic drugs and anesthetics, neurosurgical neuromodulation techniques can also be considered. We present a novel case in which responsive neurostimulation was used to effectively treat a patient who had developed super-refractory status epilepticus, later consistent with epilepsia partialis continua, that was refractory to antiepileptic drugs, immunomodulatory therapies, and transcranial magnetic stimulation. This case demonstrates how regional therapy provided by responsive neurostimulation can be effective in treating super-refractory status epilepticus through neuromodulation of seizure networks.

Figure 1

Color‐coded tracking of antiepileptic medication administration, anesthetic infusions, immunomodulatory medications, and additional therapies used in the patient's treatment. RNS stimulation was started on HD75. LAC, lacosamide; LVT, levetiracetam; LOR, lorazepam; PHT, phenytoin (or fosphenytoin); VPA, valproate; PHB, phenobarbital; CBZ, clobazam; OXC, oxcarbazepine; DZP, diazepam; BVT, brivaracetam; GBP, gabapentin; Methylpred, methylprednisolone; TMS, transcranial magnetic stimulation; HD, hospital day.

Figure 2

(A) Example of lateralized periodic discharges in the right posterior quadrant in a bipolar montage. Low frequency filter: 1 Hz, High frequency filter: 70 Hz, Notch: 60 Hz, sampling frequency: 512 Hz. Blue tracing demonstrates eye movements, and red tracing is concurrent ECG. (B) Two sets of MRIs, top row obtained on hospital day 1, with FLAIR, DWI, and ADC sequences (left to right). Bottom row obtained on hospital day 58. These demonstrate hyperintensity over the right occipital and parietal lobes. (C) Two PET scans, top image obtained on hospital day 29, bottom image obtained on hospital day 47. While top image demonstrates global hypometabolism in the bilateral parietal and occipital lobes, the bottom image suggests hypermetabolism in the right parietal and occipital lobes.

Figure 3

(A) 3D reconstruction of strip and depth electrodes implanted. The first column shows strip electrodes: RPM, right parietal mesial (green). RPA, right parietal anterior (blue); RPL, right parietal lateral (red); ROM, right occipital mesial (cyan); ROP, right occipital posterior (yellow); ROL, right occipital lateral (magenta). The second column shows depth electrodes: RSMA, right supplementary motor area (yellow); RFS, right frontal superior (green); RFI, right frontal inferior (blue); RPT, right parietal (cyan); ROS, right occipital superior (black); ROI, right occipital inferior (orange); RPO, right parietal‐occipital (red); RCM, right centromedian thalamic nucleus (magenta). The third column shows the relation between strip electrode coverage (blue) and depth electrode coverage (green). (B) One seizure pattern seen with invasive monitoring, primarily involving the right parietal mesial strip (sRPM) on contacts 4–6. Low‐frequency filter: 0.5 Hz, High‐frequency filter: 70 Hz, Notch: 60 Hz, sampling frequency: 512 Hz. (C) Second seizure pattern seen with invasive monitoring, primarily involving the right occipital posterior strip (sROP) on contacts 1–3, as well as the right occipital inferior depth on contacts 7–10. (dROI) Low‐frequency filter: 0.5 Hz, High‐frequency filter: 70 Hz, Notch: 60 Hz, sampling frequency: 512 Hz.

Figure 4

(A) 3D reconstruction of RNS strip electrodes on the cortical surface. Green electrode, AOcc, corresponds to the anterior occipital strip. Blue electrode, POcc, corresponds to the posterior occipital strip. (B) Coronal (left) and sagittal (right) views of RNS strip electrodes co‐registered onto PET brain scan obtained on hospital day 57. Blue box corresponds to the location of the anterior occipital strip, and green box corresponds to the location of the posterior occipital strip. (C) Demonstration of an event captured by the responsive neurostimulation device in bipolar montage, seen primarily on the posterior occipital strip, contacts 1–2. AOcc, anterior occipital strip; POcc, posterior occipital strip. Tracing obtained from the Patient Data Management System associated with the responsive neurostimulation device. (D) Overall trend of long events (>40 sec in length) detected by the responsive neurostimulation device. Bars demonstrate daily event totals. RNS, responsive neurostimulation.