Table 3.
Summary of the most widely diagnostic tools used for MHE diagnosis
| Test | Tested domain | Copyright | Dedicated (Europe-Asia/ USA) | Time required for administration and interpretation (min) | Comments |
|---|---|---|---|---|---|
| NCT-A | Psychomotor speed | Yes | No/No | 1–2 | Poor specificity |
| NCT-B | Psychomotor speed, set shifting and divided attention | Yes | No/No | 1–3 | Poor specificity |
| BDT | Visuospatial reasoning, praxis and psychomotor speed | Yes | No/Yes | 10–20 | It can be used for dementia testing as well |
| DST | Psychomotor speed and attention | Yes | No/Yes | 4 | Tends to be very sensitive and is an early indicator |
| LTT | Psychomotor speed and visuomotor ability | Yes | No/Yes | 2–4 | Outcomes are errors and time; tests balance between speed and accuracy |
| SDT | Psychomotor speed | Yes | No/es | 1–2 | Only tests psychomotor speed but has a higher sensitivity than DST |
| PHES | Psychomotor speed, set shifting, attention, visual perception, visuospatial orientation and visuomotor ability | Yes | No/Not for all tests | 15 | Inexpensive, easy to administer, good external validity, prognostic value (predictive of survival and OHE development); performance influenced by age and educational level |
| R-BANS | Verbal/visual/working memory; visuospatial, language and psychomotor speed | Yes | No/Yes | 25–35 | Primarily studied in dementia and brain injury. Limited HE experience |
| ANT | Semantic fluency test and verbal retrieval and recall | No | No | 1 | Simple to administer; good sensitivity for screening of MHE; prognostic value (predictive of survival and OHE development); easy tool for caregivers for identify mental status alterations; useful for illiterate patients |
| ICT | Response inhibition, working memory, vigilance and attention | Yes | No/No | 15–20 | Need highly functional patients and familiarity with computers |
| SCAN test | Working memory, vigilance and attention | Yes | No/No | 15–20 | Prognostic value (predictive of mortality) |
| CRT | Motor reaction speed, sustained attention and inhibitory control | NA | NA | 10 | Not affected by age and educational level; no learning effect; simple software are required |
| Stroop Test | Psychomotor speed, cognitive flexibility, executive control and functioning of anterior attention system | No | NA | 5 | Simple to explain, administer and interpret; good sensitivity for screening of MHE; highly accessible by web (available in app-form); influenced by age, educational level and training |
| CFF | Measure of visual temporal resolution | NA | NA | 10 | Simple to administer and interpret; prognostic value (predictive of survival and OHE development); partially influenced by training, setting and etiology; requires specialized equipment |
| EEG | Generalized brain activity | No | Yes/Yes | 10–15 | Can be performed in comatose patients; alterations not specific for HE |
| VEPs | Interval between visual stimulus and activity | No | Yes/Yes | May vary | Highly variable and poor overall results |
| BAEPs | Response in brain cortex after auditory click stimuli | No | Yes/Yes | May vary | Inconsistent response with HE testing/prognostication |
| P300 Cognitive evoked potentials | An infrequent stimulus embedded in irrelevant stimuli is studied | No | Yes/Yes | Different ranges | Correlates with severity of hepatic encephalopathy (high latency and low amplitude of P300 waves) |
ANT: animal naming test; BAEPs: brainstem auditory evoked potentials; BDT: block design test; CFF: critical flicker frequency; CRT: continuous reaction time; DST: digit symbol test; EEG: electroencephalogram; ICT: inhibitory control test; LTT: line tracing test; NCT-A: number connection test A; NCT-B: number connection test B; PHES: psychometric hepatic encephalopathy score; SDT: serial dotting test; VEPs: visual evoked potentials.