The Age And Education-corrected Number Connection Test And Digit Symbol Test For The Use Of Diagnosis Of Minimal Hepatic Encephalopathy

【OBJECTIVE】: Number connection test (NCT )and digit symbol test (DST) are regarded as common and sensitive psychometric measures for diagnosis of minimal hepatic encephalopathy (MHE), but many studies found that the results of NCT and DST were influenced by age and education. The normal range of NCT and DST was very different in previous studies, Some groups defined the limits of the normal range by studying small control, and didn't correct age and education, or only corrected the age. We will establish the age and education-corrected normative values, try to increase the accuracy of diagnostic of MHE.【METHODS】: In this study the NCT-A and DST were administered to 843 healthy volunteers(age: 16to 65 years,education:1-6to >12y) to analyze the in?uence of age and education. Establish the age and education-corrected, and age and education-independent normative data were applied to 429 patients with liver cirrhosis . The normal values were defined as the mean±2times standard deviation (2SD), MHE was defined as presence of at least one abnormal psychometric test. The liver function was evaluated by Child–Pugh Classification. The differences between age and education-corrected and age and education-independent normative data for the diagnosis of MHE were compared by statistical methods .【RESULTS】: 1. NCT-A and DST were in?uenced by age (standard coefficient 0.405, p = 0.000; standard coefficient -0.527, p = 0.000) and education (standard coefficient -0.347, p = 0.000; standard coefficient 0.405, p = 0.000). 2. 120 patients with liver cirrhosis were diagnosed as MHE (27.97%), 113 of them were NCT abnormal (26.34%), 54 of them were DST abnormal (12.59%), 47 of them were both abnormal (10.96%). The positive patients in Child-A were 21 (19.81%), and Child-B were 46 (23.71%), Child-C were 53 (41.09%),the positive rate of Child-C was greater than Child-B and Child-A (p <0.01), there was no differences between Child-B and Child-A (p> 0.05). 3. Logistic analysis showed that when establish normative data by age and education-corrected, the MHE were only related with liver function (p=0.000), regardless of age (p = 0.328) and educational level (p = 0.563). The MHE of control group were not only in?uenced by the liver function (p = 0.000), but also by age (p= 0.000) and educational level (p = 0.005) .【CONCLUSION】: Establish the age and education-corrected normative data can increase the accuracy of diagnosis of MHE by NCT and DST.