Session Information
Date: Wednesday, June 22, 2016
Session Title: Neurophysiology (non-PD)
Session Time: 12:00pm-1:30pm
Location: Exhibit Hall located in Hall B, Level 2
Objective: To evaluate cortical excitability in patients with hepatic encephalopathy (HE) using transcranial magnetic stimulation (TMS).
Background: HE is a neuropsychiatric disorder manifesting with movement disorders by means of negative myoclonus and ataxia as well as cognitive dysfunction, confusion or impaired consciousness. Altered cortical excitability, in particular an increase in GABAergic tone, has been proposed to play a relevant role in the pathophysiology of HE. However, most data are based on animal studies and show incongruent results depending on the type of experimental HE, investigated brain region and grade of HE. We therefore investigated cortical excitability, GABAergic and glutamatergic neurotransmission in HE patients at different disease stages using TMS.
Methods: In ten patients with HE stage 2, eleven patients with HE stage 1, four patients with minimal HE and ten age matched healthy control subjects several measures for cortical excitability of the primary motor cortex (M1), 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.
Results: In HE-patients the slope of the MEP-RC was significantly 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.
Conclusions: To our knowledge, this is the first description on cortical excitability and neurotransmission in patients with HE. Although the overall corticospinal excitability was reduced, GABAergic inhibition of M1 was also reduced depending on disease stage. Our results support the notion of region specific alteration of GABAergic neurotransmission with reduced GABAergic tone in M1 in patients with HE.
Part of the work was presented at the ECCN 2015 in Brno.
To cite this abstract in AMA style:
S.J. Groiss, M. Butz, T. Baumgarten, N.D. Füllenbach, D. Häussinger, A. Schnitzler. Stage dependent alteration of cortical excitability in patients with hepatic encephalopathy [abstract]. Mov Disord. 2016; 31 (suppl 2). https://www.mdsabstracts.org/abstract/stage-dependent-alteration-of-cortical-excitability-in-patients-with-hepatic-encephalopathy/. Accessed May 24, 2025.« Back to 2016 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/stage-dependent-alteration-of-cortical-excitability-in-patients-with-hepatic-encephalopathy/