Neurological and cognitive outcomes after antibody‐negative autoimmune encephalitis in children

Abstract

AIMTo characterize the neurological and cognitive outcomes in children with antibody‐negative autoimmune encephalitis (Ab‐negative AE).METHODA cohort of children presenting to our institution over a 10‐year period with autoimmune encephalitis was identified by structured retrospective review of medical records. Clinical features at presentation and final follow‐up were recorded. Neuropsychological testing was performed in a subset of patients. Outcomes after Ab‐negative AE were compared with outcomes after N‐methyl‐D‐aspartate receptor antibody encephalitis (NMDARE).RESULTSForty‐four patients (26 females, 18 males, median age 9y 2mo [interquartile range 4y 5mo–11y 8mo], 23 with NMDARE) with a diagnosis of autoimmune encephalitis were included. Postencephalitic epilepsy was more frequent after Ab‐negative AE compared to NMDARE (61% vs 14%, p=0.002). Cognitive testing was performed in a subset of patients (n=21; Ab‐negative AE=11, NMDARE=10). Full‐scale IQ was lower after Ab‐negative AE than NMDARE (mean IQ 75 vs 92, p=0.02), primarily because of reduced verbal comprehension index (80 vs 98, p=0.01) and working memory index (77 vs 95, p=0.09). The cognitive function most commonly impaired was executive function (80% [8/10] vs 22% [2/9]).INTERPRETATIONAb‐negative AE was associated with poorer cognitive outcomes than NMDARE at 1‐year follow‐up. Further studies are required to evaluate if immunotherapy can be optimized to improve outcome.