Abnormal theta-band rhythm: EEG abnormality as potential biomarkers for disease severity in pediatric anti-NMDAR
Yumie Tamura1,2, Mitsumasa Fukuda1, Akihiko Ishiyama1
1Department of Neuropediatrics, Tokyo Metropolitan Neurological Hospital, Japan.
Insights
Pediatric anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis requires early treatment. This study found abnormal theta-band rhythms on electroencephalogram (EEG) may indicate severe NMDAR encephalitis in children, aiding early diagnosis.
Area of Science:
- Pediatric Neurology
- Neuroimmunology
- Clinical Electrophysiology
Background:
- Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a severe autoimmune condition in children.
- Early immunosuppressive therapy is crucial, often preceding definitive antibody confirmation.
- Electroencephalogram (EEG) patterns in pediatric NMDAR encephalitis are not well-characterized, unlike in adults.
Purpose of the Study:
- To investigate electroencephalogram (EEG) characteristics in children with anti-NMDAR encephalitis.
- To identify potential EEG biomarkers associated with disease severity.
- To aid clinicians in the early identification of severe pediatric anti-NMDAR encephalitis cases for prompt intervention.
Main Methods:
- Retrospective case series of six pediatric patients (ages 1-13) with anti-NMDAR encephalitis.
- Clinical severity assessed using the Clinical Assessment Scale in Autoimmune Encephalitis (CASE).
- Acute-phase EEG recordings (long-term video and conventional) were analyzed for specific patterns and recovery times.
Main Results:
- No patients exhibited normal posterior-dominant rhythm; only one showed extreme delta brushes (EDBs).
- Three patients with higher CASE scores (≥15) displayed abnormal theta-band rhythms during non-REM sleep.
- These severe cases also demonstrated prolonged EEG recovery times.
Conclusions:
- Abnormal theta-band rhythms during non-REM sleep may serve as an acute-phase EEG biomarker for severe anti-NMDAR encephalitis in children.
- Findings suggest EEG can provide valuable insights into disease severity, complementing clinical assessments.
- Early identification of severe cases through EEG biomarkers can facilitate timely and effective treatment.
Abstract:
Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis in children often requires early immunosuppressive therapy before antibody detection. While various electroencephalogram (EEG) patterns, including extreme delta brushes (EDBs), have been reported in adults, pediatric EEG characteristics remain understudied. This study aims to assist clinicians in identifying severe cases early, potentially improving treatment outcomes through prompt intervention. This retrospective case series examined EEG features influenced by disease severity in children with anti-NMDAR encephalitis. We evaluated six children (1-13 years old; four females, two males) treated at Tokyo Metropolitan Neurological Hospital from January 2007 to January 2023. The severity of autoimmune encephalitis in our patients was assessed using the Clinical Assessment Scale in Autoimmune Encephalitis (CASE). The literature proposes a severity classification for the CASE score, wherein scores of 0-8 points are categorized as mild, 9-18 points as moderate, and 19-27 points as severe. In our patients, CASE scores ranged from 4 to 25 (median:19). We reviewed acute-phase EEG recordings, including 13 long-term videos and 58 conventional recordings. None of the patients maintained a normal posterior-dominant rhythm, and only one exhibited EDBs. Notably, three patients with higher CASE scores (≥15) displayed abnormal theta-band rhythm during non-REM sleep and prolonged EEG recovery times. Our findings suggest that abnormal theta-band rhythms may serve as a potential acute-phase EEG biomarker for severe anti-NMDAR encephalitis in children.
