Temporal Lobe Epilepsy Associated With Glutamic Acid Decarboxylase Antibodies
Anna Rada, Lea Marie Reisch, Anne Hagemann, Friedrich G. Woermann, Christian G. Bien
Abstract
BACKGROUND AND OBJECTIVES: Epilepsy associated with glutamic acid decarboxylase antibodies (GAD-abs) often presents as temporal lobe epilepsy (TLE). However, detailed data on this condition are lacking. The aim of this study was to demonstrate that TLE with GAD-abs (GAD-TLE) is distinct from other forms of TLE and to describe the subgroup of patients with epilepsy and GAD-abs but no evidence of TLE. METHODS: Inpatients from 2011 to 2022 with high serum GAD-abs (≥1:80, confirmed by a cell-based assay and typical staining pattern on a tissue-based assay) were included. The control group comprised patients with mesial TLE (EMU-mTLE) with hippocampal sclerosis or nonlesional epilepsy diagnosed on the epilepsy monitoring unit (EMU) and having negative results on a broad panel of neural antibodies. Data were retrospectively collected from first admission (visit 1 [V1]) and most recent follow-up (visit 2 [V2]). Parameters included demographic data, comorbidities, seizure characteristics, electroencephalography findings, MRI results, verbal memory performance, GAD-ab titers (V1), therapies, seizure and memory outcomes, and occupational status (V2). RESULTS: = 0.04). Verbal memory remained stable, and occupational status was unchanged. Ten GAD-ab-positive cases without evidence of TLE were identified, including 3 with generalized features. DISCUSSION: Epilepsy associated with GAD-abs predominantly manifests as TLE and as such is an epilepsy syndrome (GAD-TLE). In comparison with EMU-confirmed patients with mTLE without GAD-abs, the seizure outcome is inferior but the neuropsychological performance is usually normal and remains stable. A subset of patients with epilepsy with high-titer GAD-abs do not have TLE, some presenting with generalized features.