Cognitive deficits following anti-NMDA receptor encephalitis

Abstract

Background: Anti-NMDA receptor (NMDAR) encephalitis is a recently characterised autoimmune disorder mainly affecting young women. Although the clinical features of the acute disease are well characterised, cognitive long-term outcome has not been examined in detail.

Methods: The authors investigated cognitive performance in nine patients with proven anti-NMDAR encephalitis after recovery from the acute disease period (median 43 months after disease onset, range 23 to 69). Patients underwent a comprehensive neuropsychological assessment, including memory tasks that have previously been shown to be sensitive for hippocampal dysfunction.

Results: Substantial persistent cognitive impairments were observed in eight out of nine patients that mainly consisted of deficits in executive functions and memory. The severity of these deficits varied inter-individually. Patients with early immunotherapy performed significantly better. The most severe deficits were observed with inefficient or delayed initial treatment.

Conclusion: Our results suggest that cognitive deficits constitute a major long-term morbidity of anti-NMDAR encephalitis. These deficits relate to the distribution of NMDARs in the human brain and their functional role in normal cognition. Good cognitive long-term outcome may depend on early and aggressive treatment.

Figure 1

Results of the delayed match-to-sample tasks. Average performance of the control group (mean±SEM, dashed black line) and individual performance of the patients (dark grey) in per cent as a function of the delay. The light grey shaded area depicts the range of two SDs below and above the control group’s performance. Note the impaired performance of patients for the memory delay of 5000 ms in the location (four patients) and in the association task (five patients).