Abnormalities of the Bereitschaftspotential and MRI pallidal signal in non-encephalopathic cirrhotic patients.

In cirrhotic patients, even in the non-encephalopathic state, MRI may show an increased signal in globus pallidus in T1-weighted sequences, the clinical significance of which is still poorly characterized. A dysfunction of the motor circuit of the basal ganglia might be predicted if the increased MRI signal expressed alterations in the globus pallidus activity. We compared the Bereitschaftspotential (BP) in 15 non-encephalopathic cirrhotic patients and 15 age-matched controls and found that the amplitude of the early component and the peak negativity of the BP before the electromyogram onset were significantly reduced in the patient group. The intensity of the pallidal signal was related to the plasma ammonia level but the amplitudes of the BP were not related to the pallidal signal or to ammonia. These findings indicate that a defective activity of the cortical areas implicated in the preparation of movement, not specifically related to the pallidal signal, can be present in cirrhotic patients, even in the non-encephalopathic state.