title: Extreme delta brush: a unique EEG pattern in adults with anti-NMDA receptor encephalitis.
abstract: OBJECTIVE
  To determine continuous EEG (cEEG) patterns that may be unique to anti-NMDA receptor (NMDAR) encephalitis in a series of adult patients with this disorder.
  
  
  METHODS
  We evaluated the clinical and EEG data of 23 hospitalized adult patients with anti-NMDAR encephalitis who underwent cEEG monitoring between January 2005 and February 2011 at 2 large academic medical centers.
  
  
  RESULTS
  Twenty-three patients with anti-NMDAR encephalitis underwent a median of 7 (range 1-123) days of cEEG monitoring. The median length of hospitalization was 44 (range 2-200) days. Personality or behavioral changes (100%), movement disorders (82.6%), and seizures (78.3%) were the most common symptoms. Seven of 23 patients (30.4%) had a unique electrographic pattern, which we named "extreme delta brush" because of its resemblance to waveforms seen in premature infants. The presence of extreme delta brush was associated with a more prolonged hospitalization (mean 128.3 ± 47.5 vs 43.2 ± 39.0 days, p = 0.008) and increased days of cEEG monitoring (mean 27.6 ± 42.3 vs 6.2 ± 5.6 days, p = 0.012). The modified Rankin Scale score showed a trend toward worse scores in patients with the extreme delta brush pattern (mean 4.0 ± 0.8 vs 3.1 ± 1.1, p = 0.089).
  
  
  CONCLUSIONS
  Extreme delta brush is a novel EEG finding seen in many patients with anti-NMDAR encephalitis. The presence of this pattern is associated with a more prolonged illness. Although the specificity of this pattern is unclear, its presence should raise consideration of this syndrome.
authors.affiliation: PENN Epilepsy Center, Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, USA. sarah.schmitt@uphs.upenn.edu
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Schmitt
authors.forename: Kimberly
authors.initials: K
authors.lastname: Pargeon
authors.forename: Eric S
authors.initials: ES
authors.lastname: Frechette
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Hirsch
authors.forename: Josep
authors.initials: J
authors.lastname: Dalmau
authors.forename: Daniel
authors.initials: D
authors.lastname: Friedman
mesh_terms: D000293:Adolescent; D000328:Adult; D060426:Anti-N-Methyl-D-Aspartate Receptor Encephalitis / Q000503:physiopathology*; D058256:Brain Waves / Q000502:physiology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000503:physiopathology; D010551:Personality / Q000502:physiology; D012640:Seizures / Q000503:physiopathology