The fMRI Study of Working Memory in Patients with Minimal Hepatic Encephalopathy

Objective To explore the neural basis of spatial working memory impairment in mild hepatic encephalopathy using ethology and BOLD.Materials and Methods 12 patients with mild hepatic encephalopathy and 12 normal controls were matched for brain fMRI scanning of n back task.AFNI software was used to analyze fMRI data.Results(1) In the n back task,the accuracy of patients with mild hepatic encephalopathy was lower than that of the control group and the average response time was also significantly prolonged,which had significant differences(P0.001).(2)fMRI study showed that the neural network of bilateral prefrontal cortex(PFC),bilateral premotor area(PreMA),supplementary motor area(SMA) and bilateral parietal area(PA) were activated in n back task.Quantitative analysis of regions of interests found that all of working memory related brain regions had memory load related load effect in the control group,but only PreMA and PA showed the load effect in patients with mild hepatic encephalopathy.(3) Intergroup analysis showed the activation intensity of working memory related brain regions of patients with mild hepatic encephalopathy were lower than that of the control group in three different memory loads.Conclusion Patients with mild hepatic encephalopathy have impairment in spatial working memory,and the weakened function of bilateral PFC,PreMA,SMA,and bilateral PA may be one of the neural mechanisms.