Detection of minimal hepatic encephalopathy: Normalization and optimization of the Psychometric Hepatic Encephalopathy Score. A neuropsychological and quantified EEG study☆

Background/Aims

Psychometric Hepatic Encephalopathy Score (PHES) and EEG are used to detect minimal hepatic encephalopathy (MHE). We aimed at standardizing PHES in Italy and comparing Italian, German and Spanish norms in EEG characterized cirrhotic patients.

Methods

PHES was standardized on 228 normal individuals. Repeatability was studied in 128 individuals. One hundred patients with liver cirrhosis underwent EEG and PHES which was computed on the Spanish, German and the Italian norms.

Results

Age and education levels were predictors of psychometric tests; therefore, adjusted Z scores were calculated. Practice effect (p<0.01) was detected. In the patients, the Italian norms were closer to the Spanish norms (difference −0.14±1.32, p=0.29) than to the Germans ones (difference 1.97±2.07, p<0.001). The PHES calculated on the Italian norms was correlated with the EEG mean dominant frequency more closely than the ones calculated on the German and Spanish norms (r=0.38, r=0.31, r=0.33, respectively – p<0.01). The detection of MHE on the basis of PHES and EEG showed limited agreement (73%, Cohen’s K=0.32).

Conclusions

(i) Valid norms for PHES were produced, (ii) clues for the use of common norms in Latin Countries were found, (iii) different findings between PHES and EEG possibly reflect various features of MHE.

Abbreviations: PHES, psychometric hepatic encephalopathy score, EEG, electroencephalogram, MHE, minimal hepatic encephalopathy, LTT, line trait test, DST, digit symbol test, TMT-A, trial making test, subtype A, TMT-B, trial making test, subtype B, SDT, serial dotting test, MDF, mean dominant frequency, MZPS, mean Z psychometric score, ROC, receiving operating characteristic curve, HE, hepatic encephalopathy

Keywords: Minimal hepatic encephalopathy, Mild cognitive impairment, Psychometric tests, Spectral EEG, Liver cirrhosis