Objective:

NA

Background:

Somatosensory evoked epilepsy is a rare form of reflex epilepsy, and its relation to glutamic acid decarboxylase (GAD) 65 antibody remains unknown. Prior studies have demonstrated an association between musicogenic reflex epilepsy with GAD65 antibodies, and these seizures are often resistant to antiseizure medications (ASMs). Here we present an unusual case of tactile stimulus-induced reflex seizures in a patient with GAD65 antibody associated autoimmune epilepsy, who sustained more than 50% seizure reduction after intravenous immunoglobulin (IVIG) treatment.

Design/Methods:

NA

Results:

A 59-year-old female presented to clinic for a 6-year history of seizures. She reported two different seizure semiologies. The first type were focal aware seizures, with electric tingling sensation of the right arm followed by involuntary motor movement that were triggered by touching her right arm. The second type were focal seizures with impaired awareness characterized as right scalp numbness, dysarthria, and staring. MRI scan of her brain was normal. Video electroencephalogram (EEG) recording captured her typical right sensorimotor evoked seizures which originated at the left central region, as well as seizures arising from the left frontal/anterior temporal and right temporal regions. Her neurological exams demonstrated slowly progressive cerebellar ataxia. Her autoimmune encephalitis testing revealed positive GAD65 antibody in the serum (2130 nmol/L) and cerebrospinal fluid (1.02 nmol/L). She has tried several ASMs and is currently taking lacosamide, clobazam, zonisamide, and pregabalin. Although GAD65-related autoimmune epilepsy has been known to be poorly responsive to ASMs and moderately responsive to IVIG, her seizure burden was significantly reduced after starting IVIG. Her seizure frequency was decreased from 10 per day to 5 per month. 

Conclusions:

To our knowledge, this is the first case of somatosensory evoked epilepsy in a patient with GAD65 associated autoimmune epilepsy. Immunotherapy may play a role in these patients who are medically-refractory. Surgery may be additionally considered in select cases.