A Systematic Review of the Neuropsychological Sequelae of People Diagnosed with Anti N-Methyl-D-Aspartate Receptor Encephalitis in the Acute and Chronic Phases.

OBJECTIVE: A systematic review was conducted to investigate the emerging cognitive profile for people diagnosed with anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis.

METHOD: Ten papers met the review criteria including five neuropsychological case studies and five case series; three of the 10 studies used matched controls. The cognitive functioning of 54 participants (46 female: eight male) was studied. Paper quality assessment was undertaken and outcomes summarized. Neuropsychological results during the acute phase (≤12 months) and chronic phase (>12 months) were extracted and a narrative review of the papers' findings undertaken.

RESULTS: A range of neuropsychological test batteries were used across the studies, administered between one and four times. The review revealed difficulties with memory, particularly delayed verbal memory, and executive functioning. This may be consistent with the role of NMDA receptors in the limbic system, specifically the hippocampus, which are thought to be essential to aspects of learning and memory.

CONCLUSIONS: To date, there is a paucity of high quality neuropsychological and psychological research concerning the impact of anti-NMDAR encephalitis on cognitive function and psychosocial wellbeing, both of adults and particularly of those under 18 years. Significant limitations of the literature reviewed include lack of attention to pre-morbid functioning, insufficient rationale for neuropsychological battery choice, use of samples of convenience, and limited translation of neuropsychological findings into rehabilitation. Limitations of this review include exclusive focus on an adult population and the necessity of a narrative review given the methodological diversity in studies making up the evidence base.