Minimal hepatic encephalopathy: longitudinal effects of liver transplantation.

Background: The long-term effects of liver transplantation (LT) on minimal hepatic encephalopathy are poorly documented.
Objective: To assess the cognitive performance of patients with cirrhosis and without overt encephalopathy, before and after LT.
Design: Longitudinal study comparing cognitive performance of patients with cirrhosis before LT and 6 to 18 months after LT, with matched control patients.
Setting: University medical center.
Results: Six months after LT, patients had improved their performance in visuospatial and selective attention, visuospatial short-term and long-term memory, and language tasks. After 18 months, a further improvement was found for selective attention and verbal short-term memory, while no other cognitive functions varied over time.
Conclusions: The present findings confirm preliminary studies showing that LT improves cognitive functions in patients with cirrhosis. The cognitive improvement is not generalized, but appears prominent in attention and memory and, once achieved, remains stable. Rates of recovery differ, being early for some functions and later for others.