AUDITORY EVENT-RELATED CEREBRAL POTENTIALS (P300) IN HEPATIC-ENCEPHALOPATHY - TOPOGRAPHIC DISTRIBUTION AND CORRELATION WITH CLINICAL AND PSYCHOMETRIC ASSESSMENT

Background/Aims: Early cognitive disturbances in patients with cirrhos is (Ci) are difficult to assess. Therefore, we evaluated the role of t opographic auditory evoked cerebral potentials (P300-EP). Methodology: Prospective longitudinal study. Setting: Tertiary clinical care insti tution. Participants: 45 patients with cirrhosis were compared to 22 h ealthy subjects. Main Outcome Measures: Hepatic Encephalopathy (HE) wa s assessed using the clinical grading, standardized psychometric tests , and auditory evoked P300-EP by multichannel EEG recordings. Results: In the patients, the mean P300 peak latency teas significantly increa sed (386.7+/-26.7 versus 318.6+/-22.2 ms in controls, p<0.00001). Even in patients with cirrhosis but no HE (n=18) the P300 peak latency was abnormally prolonged (>384 ms) in 8 cases (44%). In addition, P180 pe ak latency was significantly longer in patients with liver cirrhosis a s compared to controls (p=0.021). The maximal P300 amplitude was signi ficantly lowered in patients with liver cirrhosis in the frontocentral and central cortical regions (FZ: p<0.008; Cz: p<0.04). Liver functio n and etiology of liver disease were not related to the increased peak latencies of the P300 and P180 peaks. Conclusions: P300-EP is a sensi tive measure to defect functional cognitive impairment in cirrhotic pa tients with subclinical HE and clinically apparent HE. Typical changes include latency prolongation and decreased central peak amplitude. So me 40% of patients with no clinical evidence of HE and normal psychome tric tests show abnormal results during P300 testing, which is likely to reflect early impairment of cognitive function. Auditory evoked P30 0 potentials are more sensitive than psychometric testing alone.