Table 2.

Diagnostic tools for the diagnosis of minimal hepatic encephalopathy

Test type	Test approach to differentiate MHE form unimpaired subjects
Formal neuropsychological; Assessment	No standard battery for MHE has been designed, but could include test of attention, executive function, psychomotor ability, and speed information processing to evaluate cognition, and mental activity.
Neuropsychological	EEG: Detect changes in cortical cerebral activity; Evoked potentials: Measurement of firing patterns of single cells or cell clusters.
Computerised	SCAN test: Measures speed and accuracy to perform a digit recognition memory task of increasing complexity; CFF: Degree of vigilance; CRT: Relies on the repeated registration of the motor reaction time to auditory stimuli. Measures the stability of the reaction time; Stroop test: Evaluates psychomotor speed and cognitive flexibility; ICT: Test of response inhibition and working memory.
Imaging	MRI: Through mean kurtosis values, evaluates six regions of interest, and amplitude of low frequency fluctuation values, which correlate with PHES values.
Short neuropsychological batteries	PHES: Evaluates cognitive/psychomotor processing speed and visuomotor coordination (NCT-A, NCT-B, SDT, LTT, DST); ANT: Cognitive function related to prefrontal anterior/cortex cortical areas.

ANT: Animal naming test; CFF: Critical flicker frequency; CRT: Continuous reaction time; DST: Digit symbol test; EEG: Electroencephalogram; ICT: Inhibitory control test; LTT: Line tracing test; MHE: Minimal hepatic encephalopathy; MRI: Magnetic resonance imaging; NCT-A: Number connection test A; NCT-B: Number connection test B; PHES: Psychometric hepatic encephalopathy score; SDT: Serial dotting test.