Abstracts

Rationale:
Rasmussen’s Encephalitis (RE)  is a progressive neurologic disorder characterized by drug-resistant focal seizures including epilepsia partialis continua (EPC), unilateral hemispheric brain atrophy, and progressive hemiplegia. Histopathology typically shows T-cell-predominant encephalitis with activated microglia forming nodules and reactive astrogliosis.  The goal of treatment is to decrease seizure frequency and severity and improve functional outcome.  While many studies have reported on the natural history, pathology, imaging, and scalp EEG findings in RE, not much is known about the intracranial EEG.  Here we report an adult patient with RE who underwent stereoelectroencephalography (SEEG) and cortical stimulation.
Method:
  We discuss an adult with RE who underwent stereoelectroencephalography (SEEG), cortical stimulation, and brain biopsy. 
Results:
Patient is a 53-year old right handed female with migraines, prior right cerebellar infarct, and medically-refractory focal epilepsy since age 46. Semiology consisted of left face twitching with retained awareness that often progressed to EPC.  A short course of high dose solumedrol was of no benefit.  She declined other immunotherapy.  MRIs showed progressive right hemispheric atrophy and numerous abnormalities in the right frontal, temporal, occipital, and parietal lobes as well as the insula.  There was also a focus of susceptibility on the gradient echo sequence in the right inferior temporal gyrus concerning for neurocysticercosis.  Prior scalp EEGs revealed right temporal epileptiform discharges, right temporal seizures, and right lateralized rhythmic delta activity (LRDA). Repeat Phase I in February 2020 revealed nearly continuous right central epileptiform discharges and LPDs plus EPC emanating from the right central region causing left facial twitching.  She underwent Phase II in March 2020 to determine whether the most bothersome seizure focus was amenable to resection and to optimize lead placement for neocortical regional responsive neurostimulation. In the OR, she had a right parietal biopsy as well as 14 depth electrodes placed in her right hemisphere including the anterior insula, middle insula, posterior insula, anterior frontal operculum, posterior frontal operculum, parietal operculum, inferior frontal lobe, motor cortex (face area), motor cortex (hand area), medial frontal lobe, parietal primary sensory cortex, medial parietal lobe, anterior cingulate, middle cingulate, posterior cingulate, amygdala, and right lateral parietal lobe. Interictal findings included independent spikes with overriding high-frequency oscillations (HFOs) in the right anterior insula, parietal primary sensory cortex, anterior frontal operculum, hand motor cortex, posterior insula, posterior frontal operculum, parietal operculum, face motor cortex, middle cingulate, and middle insula (Fig 1).   ictal findings included electrographic seizures from the right parietal operculum, posterior insula, middle insula, and posterior frontal operculum. Additionally, there were frequent seizures with left facial twitching that correlated with motor cortex spiking.    Cortical stimulation of her medial frontal cortex caused left hand stiffening/curling similar to her seizures. Stimulation of her posterior frontal operculum and her right motor face caused left face twitching.   Pathology revealed perivascular chronic inflammation with T-cell-predominant infiltrates around the blood vessels (Fig 2).
Conclusion:
Intracranial recordings from patients with RE may be useful in understanding the disease course, progression, and the pathologic networks involved. These discoveries may lead to more targeted treatments including neurostimulation.
Funding:
:None