Abstracts

Rationale: Eating epilepsy (EE) is a rare type of reflex epilepsy in which seizures are induced by the smell of food or by the process of eating food. Patients with this seizure type make up 0.5-1.0 per thousand of all patients with epilepsy. Methods: We report the case of a 58 year-old male found to have a right mesial temporal lobe tumor who presented with olfactory hallucinations and feelings of a strong urge to sneeze triggered by the smell of food and eating meals. He was admitted to our Epilepsy Monitoring Unit for pre-surgical evaluation six months after presentation and had lost 30 pounds because of food avoidance. Results: During four day Video-EEG (VEEG) Monitoring, multiple habitual simple partial seizures were captured with onset in the anterior right temporal lobe. Seizures were reliably provoked by the smell of food. 3T MRI demonstrated a right mesial temporal lobe tumor with mass effect on the hippocampus, right cerebral peduncle and suprasellar cistern. MEG showed the main cluster of activity in the right temporal lobe posterior and superior to the tumor and the focal EEG abnormalities. The patient experienced one of his habitual seizures during the MEG that localized in the same area as the main cluster of MEG IIEDs. Neuropsychological testing was consistent with right temporal focus. Prior to surgery, the patient was treated with levetiracetam and carbamazepine, but continued to have 3-6 seizures per day. Conclusions: EE is typically localization related, and most commonly consists of complex partial seizures with onset in the inferomesial temporal lobe. Infrequently, EE presents as simple partial seizures with onset localized to the suprasylvian region often induced by somatosensory stimuli. Literature review reveals that PET imaging in patients with right mesial temporal lobe epilepsy (MTLE) compared with left MTLE and healthy controls have varied olfactory stimuli perception due to limbic dysfunction. fMRI studies of odorant activation support this finding. Furthermore, MEG imaging shows that olfactory processing varies based on the strength of the odorant. Weak stimuli more commonly activate the right hemisphere whereas strong stimuli lateralize to the left. This case provides unique insight into pathways of olfactory stimuli processing and suggests the relation of right temporal lobe lesions in triggering abnormal activation in these regions leading to seizure activity.