Impairment of response inhibition precedes motor alteration in the early stage of liver cirrhosis

Abnormality in movement initiation may partially explain psychomotor delay of cirrhotic patients, even in the absence of overt hepatic encephalopathy (HE). Therefore, the aim of this study was to determine the mechanisms of psychomotor delay observed in patients with cirrhosis in the absence of overt HE. Fourteen patients with nonalcoholic cirrhosis and 12 healthy matched control subjects underwent the lateralized readiness potential (LRP) measurement elicited by a visuospatial compatibility task (Simon task). Stimulus-triggered LRPonset reflects the time in which response is selected, while response-triggered LRP onset reflects motor execution. Cirrhotic patients showed delayed reaction times (RTs) compared to controls, particularly those with trial-making test A (TMT-A) or electroencephalogram (EEG) alterations. Stimulus-triggered LRP onset was found to be delayedin cirrhotic patients compared to controls, with a significant Group-versus-Condition interaction, showing a reduced cognitive ability to cope with interfering codes, even in patients without minimal HE (MHE). Response-triggered LRP was found to be delayed only in the patients with TMT-A or EEG alterations. In conclusion, cirrhotic patients without overt HE display a psychomotor slowing, depending firstlyon response inhibition and only later accompanied by impaired motor execution.