Spectral versus visual EEG analysis in mild hepatic encephalopathy

Objective: Spectral EEG analysis has been claimed to reduce subjective vari ability in EEG assessment of hepatic encephalopathy and to allow the detect ion of mild encephalopathy. Method: To test such assumptions, 43 digital EEG were recorded in 32 cirrho tics without overt encephalopathy or with grade 1 overt encephalopathy; 7 p atients were re-tested (2-5 times) in their follow up. All patients underwe nt psychometric assessment. Nineteen controls were considered. EEG were bli ndly evaluated by two electroencephalographers and by spectral EEG analysis performed according to 3 different techniques. Results: The reliability of the classification based on spectral analysis ( biparietal technique) was higher than that based on a three-degree qualitat ive visual reading (concordance/discordance = 58/4 versus 46/16 P < 0.01) a nd comparable with that of semiquantitative visual assessment based on post erior basic rhythm (concordance/discordance = 55/7 P = 0.5). The accuracy o f spectral EEG analysis was higher than that of qualitative visual EEG read ings alone (90 versus 75%) and comparable to semi-quantitative visual asses sment (87%), however, statistical significance was not reached. In the foll ow-up, the variations of theta and delta relative power were found to be si gnificantly correlated with psychometric variations. Conclusions: In conclusion, spectral EEG analysis may improve the assessmen t of mild hepatic encephalopathy by decreasing interoperator variability an d providing reliable parameters correlated with mental status. (C) 1999 Els evier Science Ireland Ltd. All rights reserved.