Visual attention in cirrhotic patients: a study on covert visual attention orienting.

Attentional dysfunction, which influences overall cognitive productivity, is not well characterized in cirrhotic patients. The aim of this study was to clarify the features of covert visual attention orienting in cirrhotics without overt hepatic encephalopathy. One hundred consecutive cirrhotic patients and 40 controls were enrolled. Visual covert attention orienting was assessed by the Posner test, which evaluates the effect of a cue on visual reaction times. Patients were characterized by the number connection test (NCT) and electroencephalographic (EEG) spectral analysis. The severity of liver disease was graded using standard laboratory parameters and the Child-Pugh's classification. Fifty-five psychometric and EEG evaluations were performed in the follow-up of 17 patients to assess the relationship between the variations of psychometric and neurophysiological findings. NCT and quantified-EEG parameters (altered in 19% and 40% of cirrhotic patients, respectively) were linked to each other and to the severity of liver disease. The Posner test showed a delay of visual reaction times in class B-C cirrhotic patients. Reaction times were correlated with ammonia and EEG parameters. The effect of the cue was higher in cirrhotic patients than in controls, particularly in the invalid position. This study suggests that cirrhotic patients have a reduced activity rate and reduced capacity to disengage attention previously focused on a cue. Such alterations are linked to NCT and EEG findings.