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Published on: November 13, 2016
Cerebral functional activity and connectivity changes in anti-N-methyl-D-aspartate receptor encephalitis: A
Luhui Cai1, Yanli Liang1, Huanjian Huang1
1Department of Neurology, The First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
Background:
Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis showing severe neuropsychiatric symptoms is the most common type of autoimmune encephalitis. However, the corresponding standard clinical magnetic resonance imaging (MRI) presents normal or atypical in the majority of patients with anti-NMDAR encephalitis. Here, this study aimed to investigate the alterations in brain functional activity in patients with anti-NMDAR encephalitis and whether these alterations contributed to cognition and mood disorders.
Methods:
Seventeen patients with anti-NMDAR encephalitis and eighteen gender, age and education-matched healthy controls were recruited. All participants underwent neuropsychological tests (including Montreal Cognitive Assessment (MoCA), Hamilton Anxiety Scale (HAMA), and Hamilton Depression Scale (HAMD24)) and resting-state functional MRI. MRI data was firstly analyzed by amplitude of low-frequency fluctuation (ALFF), and brain regions with altered ALFF between groups were selected as regions of interest for the further functional connectivity (FC) analysis. Correlation analyses were performed to investigate the associations between brain dysfunction and neuropsychological performance.
Results:
Relative to the healthy controls, patients with anti-NMDAR encephalitis performed inferiorly in the MoCA score, and showed anxiety and depression disorders with higher HAMA and HAMD24 scores (all p < 0.05). In the brain functional activity analysis, the patients showed decreased ALFF values in the bilateral posterior cingulate gyrus, left precuneus, and bilateral cerebellum (false- discovery- rate corrected, p < 0.05). Furthermore, relative to the control group, the patients showed significantly increased FC between the left posterior cingulate cortex (PCC) and the bilateral lingual gyrus, right calcarine, right cuneus, also between the right PCC and the right fusiform gyrus, bilateral lingual gyrus, left calcarine, left cuneus, and right posterior central gyrus (false- discovery- rate corrected, p < 0.05). FC strength between the left posterior cingulate gyrus and right cuneus, and between the right posterior cingulate gyrus and left cuneus were both positively correlated with MoCA memory scores (r = 0.485, p = 0.048; r = 0.550, p = 0.022).
Conclusion:
The present study highlight that decreased spontaneous neural activities and abnormal FC exhibited in the patients with anti-NMDAR encephalitis, which may participate in the process of cognition and emotion deficits. These results may help to elucidate the clinical radiological contradictions in anti-NMDAR encephalitis and contribute to deeper understanding of the pathophysiological mechanism of the disease.
Insights
Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis patients exhibit reduced brain activity and altered functional connectivity, correlating with cognitive and mood impairments. These findings help explain clinical-radiological discrepancies in NMDAR encephalitis.
Area of Science:
- Neuroscience
- Immunology
- Radiology
Background:
- Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a common autoimmune disorder causing severe neuropsychiatric symptoms.
- Standard MRI often shows normal or atypical findings in affected patients.
- Investigating brain functional activity is crucial for understanding disease mechanisms.
Purpose of the Study:
- To investigate alterations in brain functional activity in anti-NMDAR encephalitis patients.
- To determine if these alterations correlate with cognitive and mood disorders.
Main Methods:
- Recruited 17 anti-NMDAR encephalitis patients and 18 healthy controls.
- Administered neuropsychological tests (MoCA, HAMA, HAMD24) and resting-state functional MRI.
- Analyzed amplitude of low-frequency fluctuation (ALFF) and functional connectivity (FC), correlating with clinical scores.
Main Results:
- Patients showed lower MoCA scores and higher anxiety/depression scores than controls.
- Decreased ALFF was observed in the posterior cingulate gyrus, precuneus, and cerebellum.
- Increased FC was found between the posterior cingulate cortex and other brain regions, correlating with memory performance.
Conclusions:
- Patients with anti-NMDAR encephalitis exhibit decreased spontaneous neural activity and abnormal functional connectivity.
- These neural alterations may contribute to cognitive and emotional deficits.
- Findings offer insights into the pathophysiological mechanisms and clinical-radiological paradoxes in anti-NMDAR encephalitis.
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