Spatio-temporal decomposition of the electroencephalogram in patients with cirrhosis

Abstract

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. 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. 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). Analysis of the EEG utilising SEDACA provides significantly more diagnostic information on the neuropsychiatric status of patients with cirrhosis than obtained conventionally.