Abstracts

Rationale: Autonomic seizures are a type of focal seizure, with varied clinical symptoms that can include alterations in cardiovascular, gastrointestinal, sudomotor, vasomotor, or thermoregulatory functions. These are thought to be mediated by activation of the central autonomic network and have been associated with seizures originating from multiple regions including the anterior cingulate cortex, anterior insula, hypothalamus, amygdala, and hippocampus. Piloerection (“goosebumps”) is commonly seen in conjunction with other clinical features but is an uncommon principal ictal manifestation. We present a unique case of a 21-year-old male with drug-resistant focal epilepsy (DRE), with seizures consisting of bilateral piloerection and/or chills followed by coughing, who underwent stereo electroencephalography (sEEG) monitoring and cortical stimulation. Spontaneous seizures were recorded from the right amygdala/hippocampus. Cortical stimulation of the right amygdala and hippocampus elicited piloerection, supporting this region as the likely epileptogenic zone.

Methods: Seven sEEG electrodes, each with 10 contacts, were targeted to portions of the anterior cingulate gyrus, anterior insula, posterior insula, amygdala, hippocampal head, and hippocampal tail. Cortical stimulation occurred 4 days following sEEG electrode implantation and 15 hours after the last spontaneous seizure had occurred. At the time of the stimulation, the patient was taking levetiracetam, oxcarbazepine, and zonisamide. Cortical stimulation was performed using a current stimulator starting at 50 Hz for 4 seconds and 1 mA. The current was increased in 1-2 mA increments until either a clinical response occurred, an afterdischarge occurred, or 7 mA was reached. Settings of 1 Hz for 20 seconds were used in the mesial temporal structures as well.

Results: During the period of intracranial monitoring, 11 typical seizures with "goosebumps" or "chills" followed by coughing were recorded. Electrographically, the first EEG change (low voltage fast activity) was in the right amygdala/hippocampus. During cortical stimulation, brief typical sensations of a "chills", "goosebumps", and a difficult-to-describe sensation ("pre-aura") were elicited through stimulation of the amygdala (at 50 Hz) and hippocampal head (at both 1 Hz and 50 Hz). The posterior insula, middle temporal gyrus, precentral gyrus, and hippocampal tail were also stimulated without triggering these sensations.

Conclusions: Our case highlights a rare form of autonomic seizures with piloerection and chills as cardinal features, originating from the right amygdala and hippocampus. sEEG confirmed seizure onset in these regions, and cortical stimulation reliably reproduced symptoms. This work reinforces the role of mesial temporal structures, particularly the amygdala and hippocampus, in autonomic seizure semiology. The findings contribute to the growing body of literature on the symptomatogenic zones of autonomic seizures, enhancing our understanding of their neuroanatomical basis and providing clinically actionable information for pre-surgical evaluation and potential resection planning in DRE.

Funding: N/A