P257 Smell triggered seizure in a patient with temporal lobe epilepsy

Introduction Among the reflex seizures, those triggered by smell are very rarely reported. We aimed to present a patient with temporal lobe epilepsy (TLE), who experienced a video-EEG recorded seizure while smelling ylang-ylang extract during a study protocol. Patient and methods The patient is a 34-year-old woman with drug-resistant TLE, which had started when she was 9 years old. Her MRI revealed left mesial temporal lobe sclerosis. She had 1–5 focal seizures impairing awareness per month. Stress and sadness were the only reported seizure triggers. During her routine pre-surgical evaluation, a standardized video-EEG study protocol was also applied after taking her consent. Baseline, hyperventilation, intermittent photic stimulation and olfactory stimulations (OS) were performed with a published standard protocol. One ml of odorant solution of ylan-ylang extract was dropped on a cotton ball, and was applied to the middle of both nostrils during 3 min. This activation was repeated twice and followed by 15 min of resting records (post-OS1 and post-OS2). We investigated modulation of epileptiform discharges by OS by counting the interictal spikes. However, a focal seizure has occurred in the first minute of smelling. After 5 months, video-EEG with the same protocol was repeated and increase in spike counts during post-OS periods was documented. Moreover, she was found to have hypo-osmia with Sniffin Sticks test, despite she had no complaints. Conclusion Our results suggested that olfactory stimulation may trigger reflex seizures and increase interictal spikes in some patients with TLE.