title: Prevalence and etiology of false normal aEEG recordings in neonatal hypoxic-ischaemic encephalopathy.
abstract: BACKGROUND
  Amplitude-integrated electroencephalography (aEEG) is a useful tool to determine the severity of neonatal hypoxic-ischemic encephalopathy (HIE). Our aim was to assess the prevalence and study the origin of false normal aEEG recordings based on 85 aEEG recordings registered before six hours of age.
  
  
  METHODS
  Raw EEG recordings were reevaluated retrospectively with Fourier analysis to identify and describe the frequency patterns of the raw EEG signal, in cases with inconsistent aEEG recordings and clinical symptoms. Power spectral density curves, power (P) and median frequency (MF) were determined using the raw EEG. In 7 patients non-depolarizing muscle relaxant (NDMR) exposure was found. The EEG sections were analyzed and compared before and after NDMR administration.
  
  
  RESULTS
  The reevaluation found that the aEEG was truly normal in 4 neonates. In 3 neonates, high voltage electrocardiographic (ECG) artifacts were found with flat trace on raw EEG. High frequency component (HFC) was found as a cause of normal appearing aEEG in 10 neonates. HFC disappeared while P and MF decreased significantly upon NDMR administration in each observed case.
  
  
  CONCLUSIONS
  Occurrence of false normal aEEG background pattern is relatively high in neonates with HIE and hypothermia. High frequency EEG artifacts suggestive of shivering were found to be the most common cause of false normal aEEG in hypothermic neonates while high voltage ECG artifacts are less common.
authors.affiliation: First Department of Pediatrics, Semmelweis University, Budapest, Bókay u, 53-54, H-1083, Hungary. marics.gabor@gmail.com.
authors.forename: Gábor
authors.initials: G
authors.lastname: Marics
authors.forename: Anna
authors.initials: A
authors.lastname: Csekő
authors.forename: Barna
authors.initials: B
authors.lastname: Vásárhelyi
authors.forename: Dávid
authors.initials: D
authors.lastname: Zakariás
authors.forename: György
authors.initials: G
authors.lastname: Schuster
authors.forename: Miklós
authors.initials: M
authors.lastname: Szabó
mesh_terms: D016477:Artifacts; D001238:Asphyxia Neonatorum / Q000150:complications / Q000503:physiopathology* / Q000628:therapy; D004569:Electroencephalography / Q000187:drug effects / Q000379:methods; D005188:False Negative Reactions; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D007036:Hypothermia, Induced / Q000009:adverse effects; D020925:Hypoxia-Ischemia, Brain / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy; D007231:Infant, Newborn; D008297:Male; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology; D012189:Retrospective Studies; D012640:Seizures / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D012768:Shivering; D059629:Signal-To-Noise Ratio
chemical_list: D003473:Neuromuscular Nondepolarizing Agents