title: Spatio-temporal decomposition of the electroencephalogram in patients with cirrhosis.
abstract: OBJECTIVE
  Slowing of the electroencephalogram (EEG) is a recognised feature of hepatic encephalopathy but its diagnostic sensitivity is indeterminate. Recent advances in EEG analysis should provide better quantifiable/more informative data. The aim of this study was to isolate and determine the scalp distribution of the posterior basic rhythm, in patients with cirrhosis, using a technique for spatio-temporal decomposition (SEDACA) of the EEG.
  
  
  METHODS
  One hundred and ten patients with cirrhosis, classified, using clinical and psychometric criteria, as neuropsychiatrically unimpaired or as having minimal/overt hepatic encephalopathy were studied. Eyes-closed, awake EEGs were obtained and subjected to standard spectral analysis and spatio-temporal decomposition. Control data were obtained from 26 reference EEGs.
  
  
  RESULTS
  The error in the estimate of the SEDACA-derived mean dominant frequency was lower than for the standard EEG derivation (P<0.00001). The SEDACA-derived spectral estimates correlated better with neuropsychiatric status and allowed differentiation of the patients with minimal hepatic encephalopathy from the reference population. The SEDACA-derived spatial information showed an anteriorization of the posterior basic rhythm, which became more prominent as the degree of neuropsychiatric impairment increased (P=0.00052).
  
  
  CONCLUSIONS
  Analysis of the EEG utilising SEDACA provides significantly more diagnostic information on the neuropsychiatric status of patients with cirrhosis than obtained conventionally.
authors.affiliation: The UCL Institute of Hepatology, Department of Medicine, Hampstead Campus, Royal Free & University College Medical School, University College London, Rowland Hill Street, London NW3 2PF, UK.
authors.forename: Sara
authors.initials: S
authors.lastname: Montagnese
authors.forename: Clive
authors.initials: C
authors.lastname: Jackson
authors.forename: Marsha Y
authors.initials: MY
authors.lastname: Morgan
mesh_terms: D000328:Adult; D000368:Aged; D004569:Electroencephalography; D004594:Electrophysiology; D005260:Female; D006501:Hepatic Encephalopathy / Q000175:diagnosis / Q000209:etiology* / Q000523:psychology*; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications* / Q000523:psychology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011594:Psychometrics; D012680:Sensitivity and Specificity; D013037:Spatial Behavior