Insight into the relationship between brain/behavioral speed and variability in patients with minimal hepatic...

Area of Science:

• Neuroscience
• Clinical Neurology
• Cognitive Science

Background:

• Minimal hepatic encephalopathy (MHE) is a subclinical brain dysfunction in liver cirrhosis patients.
• Intra-individual variability (IIV) in reaction times (RTs) and psychomotor slowing are potential MHE markers.
• Behavioral measures alone do not reveal the neural basis of these MHE-related phenomena.

Purpose of the Study:

• To investigate the electrophysiological correlates of psychomotor slowing and increased IIV of RTs in MHE patients.
• To explore the neural underpinnings of cognitive deficits in MHE using event-related potentials (ERPs).

Main Methods:

• Recorded ERPs during a stimulus-response (S-R) conflict task in liver cirrhosis patients (with and without MHE) and healthy controls.
• Utilized a Bayesian approach to estimate single-trial P300 parameters.
• Analyzed the relationship between P300 parameters and RT distributions.

Main Results:

• MHE patients displayed increased P300 latency jitter and reduced single-trial P300 amplitude compared to controls.
• In healthy individuals, P300 parameters correlated with RTs; this linkage was weakened or absent in MHE patients.
• A diminished relationship between P300 parameters and RTs was observed in MHE.

Conclusions:

• The loss of the P300-RT relationship in MHE patients is associated with higher IIV of RTs and psychomotor slowing.
• Investigating single-trial ERP parameters and RT distributions is valuable for understanding brain function in health and disease.