Long-term outcomes in temporal lobe epilepsy with glutamate decarboxylase antibodies

Objective: To assess the long-term outcomes of patients with temporal lobe epilepsy and CSF anti-glutamate decarboxylase antibodies (GAD65-Abs). Methods: We retrospectively analyzed the clinical records of 35 patients with temporal lobe epilepsy and CSF GAD65-Abs, collected from January 1993 to December 2016 and assessed cognitive impairment and seizure activity at last visit. Cognitive impairment was considered significant if impacting on daily life activities. Immunohistochemistry on rat brain slices and ELISA were used for antibody detection and titration. Results: Median age was 30 years (range 2–63), 32/35 (91%) patients were female, and median follow-up was 68 months (range 7–232). At presentation, 20 patients had isolated temporal lobe epilepsy and 15 patients had other limbic symptoms, including anterograde amnesia (n = 10) and behavioral disturbances (n = 5). Progressive clinical deterioration over follow-up was reported in 28/35 patients (80%), including gradual increase of memory impairment (n = 25), and apparition of behavioral disturbances (n = 4) or mood disorders (n = 18). At last follow-up, 24/35 (69%) patients had cognitive disturbances with an impact on patient’s daily life activities, and 28/35 (80%) still had active seizures. Conclusion: Most patients with temporal lobe epilepsy and CSF GAD65-Abs develop a chronic disease with progressive cognitive impairment and refractory epilepsy regardless of the presence of additional limbic symptoms at onset.