Diagnosis of sub-clinical hepatic encephalopathy by Neuropsychological Tests (NP-tests)

At present, there are no generally accepted diagnostic criteria or methods for sub-clinical hepatic encephalopathy (SHE) associated with liver cirrhosis. We therefore developed an easily conducted computer-aided quantitative neuropsychological function test system for use in routine medical practice.

The system was used prepare basic values according to age in 542 healthy subjects, and the results were compared with 292 liver cirrhosis patients. The software is composed of eight tests: NCT-A, NCT-B, Figure Design Test, Digit Symbol Test, Block Design Test, and the Reaction Time-A, Reaction Time-B, and Reaction Time-C.

Performance time is approximately 15 to 20 min. There is no need to select a specific test location and it is convenient to use even without a professional examiner. When the top and bottom 10%, which correspond to the outlier values statistically in the healthy subjects, were used as the cutoff values abnormal results were observed in approximately 25% of the liver cirrhosis patients. Moreover, 58% of the patients had abnormal values according to the results of at least one of the tests.

It is expected that this test will be used to further assess the diagnosis and pathology of SHE and that it will be utilized as a routine method of diagnosis.