The PSE (Portosystemic Encephalopathy) syndrome test is available, but its use in everyday clinical practice is limited. Originally a battery of roughly 30 paper-and-pencil cognitive tests, the PSE test has largely been replaced by a streamlined version called the PHES (Psychometric Hepatic Encephalopathy Score) and by newer digital alternatives that are faster and easier to administer. Whether you can access it depends on your medical center and the tools your hepatologist or gastroenterologist uses.
What the PSE Test Is and Why It Matters
The PSE test was designed to detect a condition called minimal hepatic encephalopathy (MHE), a subtle form of cognitive impairment caused by liver disease. When the liver can’t filter toxins properly, those toxins reach the brain and affect thinking speed, coordination, and concentration. The tricky part is that minimal hepatic encephalopathy often has no obvious symptoms. People may feel mentally foggy or have slower reaction times without realizing something measurable is wrong.
An estimated 50% to 80% of people with cirrhosis develop some degree of minimal hepatic encephalopathy. Its presence signals a worse prognosis and reduced survival, which is why screening matters even when symptoms seem mild or absent. In 1998, an international working group endorsed the PSE test as the gold standard for diagnosing this condition. That designation has since shifted to the shorter PHES version, which pulls five specific subtests from the original PSE battery.
The PHES: The Version Most Clinics Use
The PHES takes five tests from the larger PSE battery and combines their results into a single score. Those five tests are:
- Number Connection Test A: measures how quickly you can connect numbered dots in order
- Number Connection Test B: a more complex version that alternates between numbers and letters
- Digit Symbol Test: assesses processing speed by matching symbols to numbers
- Serial Dotting Test: evaluates motor speed and accuracy
- Line Tracing Test: tests hand-eye coordination by having you trace a path without crossing boundaries
All five are paper-and-pencil tasks that evaluate cognitive processing speed, psychomotor coordination, and visual-motor skills. They’re relatively simple to take and don’t require blood draws or imaging. The combined score is compared against normative data adjusted for factors like age and education level. A score at or below a certain threshold (typically negative 4 or negative 5 points) indicates minimal hepatic encephalopathy. In validation studies, the PHES showed 100% specificity, meaning it very rarely flags someone who doesn’t actually have the condition, though its sensitivity was around 66%, so it can miss some cases.
The PHES is currently considered the gold standard for diagnosing minimal hepatic encephalopathy and is still actively used in clinical research. A version 2.0 was released in 2020.
Why It’s Not Widely Used in Routine Care
Despite being effective, the PSE/PHES battery faces practical barriers. Screening for minimal hepatic encephalopathy is frequently overlooked in routine practice because of the time the test requires, the cost of testing, and the limited availability of testing materials at many facilities. The test also needs to be administered by an experienced examiner, which adds a layer of logistics that some clinics can’t support.
Joint guidelines from the American Association for the Study of Liver Diseases (AASLD) and the European Association for the Study of the Liver (EASL) acknowledge this reality. Rather than recommending universal screening for every cirrhosis patient, these guidelines suggest a targeted approach: test the patients who would benefit most, particularly those reporting reduced quality of life, cognitive complaints from family members, or whose jobs involve public safety (such as driving).
Digital Alternatives That Are Easier to Access
If your doctor doesn’t offer the paper-based PHES, several digital tests serve a similar purpose and are gaining traction in clinical settings.
The most prominent is the EncephalApp Stroop test, a smartphone application developed in 2013 specifically to screen for minimal hepatic encephalopathy. It measures psychomotor speed and cognitive flexibility by asking you to identify colors on a screen while ignoring conflicting text. It takes only a few minutes and can be administered in a regular office visit. A newer version called QuickStroop can be completed in about one minute with similar accuracy.
Other digital options include the continuous reaction time test, the inhibitory control test, and the SCAN test. Each approaches cognitive screening slightly differently, but all aim to catch the same underlying problem: toxin-related brain impairment from liver disease. The inhibitory control test, for example, showed 79% sensitivity in one study, higher than the PHES, though with lower specificity at 66%.
How to Get Tested
If you have cirrhosis and are concerned about cognitive changes, the first step is raising the issue with your hepatologist or gastroenterologist. Many doctors won’t screen for minimal hepatic encephalopathy unless you bring it up, since it’s not yet part of standard checkups for liver disease at most centers. Mention specific symptoms: difficulty concentrating, slower reaction times, trouble with tasks that used to be easy, or concerns raised by family members.
Your doctor may have the PHES available on-site, or they may use the EncephalApp Stroop test as a quicker alternative. Larger academic medical centers and specialized liver clinics are more likely to offer formal psychometric testing. The PHES itself is a low-cost tool since it only requires printed test sheets and a stopwatch, but availability still varies widely by location and practice.
If testing confirms minimal hepatic encephalopathy, treatment can improve cognitive function and quality of life. Early detection also helps identify patients at higher risk for more severe episodes of hepatic encephalopathy down the line, which makes screening genuinely useful even when symptoms feel manageable.