Analysis of critical flicker frequency threshold in hepatic encephalopathy: dynamics and cortical activations
Critical flicker frequency (CFF) is a reproducible determination for quantification of the severity of hepatic encephalopathy (HE) in cirrhotic patients. It is not affected appreciably by training. CFFs change consistently in parallel with the evolution of HE after transjugular intrahepatic portal-systemic stent (TIPSS) placement. CFF determination is suitable for monitoring fluctuations in the severity of HE in response to precipitating factors or therapeutical intervention. A correlation between CFF threshold and impairment of attentional-executive and decision-making cortical networks, demonstrated by event-related functional magnet resonance imaging (efMRI), was found in minimal HE (mHE) and overt HE. The activated brain areas during CFF threshold detection correspond to the activated cortical networks described previously in positron emission tomography (PET) studies of cirrhotic patients with HE. Standardized CFF detection was found to be a sensitive, reproducible and objective determination for quantifying the short and long-term evolution of mHE and overt HE.
KeywordsHepatic Encephalopathy Cirrhotic Patient Minimal Hepatic Encephalopathy Critical Flicker Frequency Activate Brain Area
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