Determination of Turkish norms of psychometric tests for diagnosing minimal hepatic encephalopathy and proposal of a high sensitive screening test battery

Abstract

Background: Psychometric hepatic encephalopathy score (PHES) needs local standardization.

Aims: This study aimed at standardizing PHES for Turkish patients and compare them with German norms; to determine minimal hepatic encephalopathy (mHE) prevalence with two different methods [PHES battery and Critical Flicker Frequency (CFF)] and to assess whether sub-tests of the battery can be used for screening for mHE.

Methods: Healthy volunteers (n = 816; 400 male) and cirrhotics (n = 124; 58 male) were included. For mHE diagnosis PHES score threshold was set at ≤ - 5 points and that of CFF at < 39 Hz. For comparing German and Turkish norms, datasets were combined. Multiple backward procedure was applied to assess effects of age, sex and education on single tests of the battery. Receiver operating characteristic (ROC) curves were created for assessing diagnostic capabilities of subtests of the battery.

Results: PHES norms for Turks were developed. MHE prevalence in compensated cirrhotics was 29.8% and 27.4% with PHES and CFF tests, respectively, with low compatibility (kappa coefficient 0.389); mHE prevalence decreased to 16% when both tests were combined. Turks performed worse vs Germans in the digit symbol (DS) and serial dotting (SD) subtests but performed better in other subtests. In ROC analyzes of subtests, the combination of DS + SD tests achieved an AUROC of 0.974 versus PHES.

Conclusions: Use of two methods for diagnosing mHE is important for research purposes. From a clinical perspective, sensitivity with acceptable specificity may suffice for screening instruments for mHE. Combined use of DS and SD subtests of the PHES battery appears suitable for this purpose.

Keywords: Cirrhosis; Critical flicker frequency; Minimal hepatic encephalopathy; Portosystemic hepatic encephalopathy score; Turkish norms.