P067 Stage dependent alteration of cortical excitability in patients with hepatic encephalopathy

Abstract

Altered cortical excitability is supposed to play a relevant role in the pathophysiology of hepatic encephalopathy (HE). However, most data is based on animal studies and only limited data of patients with HE is available. We therefore investigated cortical excitability in HE-patients at different disease stages using transcranial magnetic stimulation. In eleven patients with HE stage 1, ten patients with HE stage 2 and ten age matched healthy control subjects several measures for cortical excitability of the primary motor cortex, i. e. motor threshold, motor evoked potential recruitment curve (MEP-RC), short interval intracortical inhibition (SICI), long interval intracortical inhibition, intracortical facilitation and short interval intracortical facilitation were compared. The critical flicker frequency (CFF) was also measured as one marker of disease severity. In HE-patients the slope of the MEP-RC was shallower compared to healthy controls. Moreover SICI was significantly reduced in HE stage 2 patients compared to healthy controls and a relevant correlation between SICI and CFF was found. No differences were found in the other measures. Our results suggest a disease stage dependent alteration of motor cortical and corticospinal excitability in patients with HE.