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Critical flicker frequency is diagnostic of minimal hepatic encephalopathy
  1. Serag Esmat1,
  2. Nouman El Garem1,
  3. Hassan Raslan2,
  4. Mohamed Elfekki3,
  5. Gihan A Sleem1
  1. 1Department of Internal Medicine, Cairo University, Cairo, Egypt
  2. 2Department of Internal Medicine, Al Agouza Police Hospital, Giza, Egypt
  3. 3Department of Internal Medicine, Beni Suef University, Beni Suef, Egypt
  1. Correspondence to Serag Esmat, Department of Internal Medicine, Faculty of Medicine, Cairo University, Al-Saray Street, El Manial Cairo, Cairo 11562, Egypt; seragesmat{at}, seragesmat{at}


Minimal hepatic encephalopathy may affect up to 80% of cirrhotic patients, in the absence of overt hepatic encephalopathy. The objective of the study is to evaluate the accuracy of diagnosis of minimal hepatic encephalopathy with critical flicker frequency (CFF). The study was conducted on 180 patients with post hepatitis C liver cirrhosis and on 60 healthy subjects as control. Patients and controls were divided into four groups: group 1 (60), healthy individuals as a control group; group 2 (60), patients with liver cirrhosis (Child class A); group 3 (60), patients with liver cirrhosis (Child class B); and group 4 (60), patients with liver cirrhosis (Child class C). All participants were subjected to estimation of CFF, line drawing test, complete blood picture, liver functions, viral markers, and abdominal ultrasound. CFF detected abnormality in 90% of patients. Accuracy of CFF in differentiation of Child A from normal is 100%, Child B from normal is 100%, Child C from normal is 100%, Child A from Child B is 80%, Child A from Child C is 100% and Child B from Child C is 100%, and it has higher accuracy than line drawing test. CFF is a simple, reliable and accurate method for the diagnosis of minimal hepatic encephalopathy. It is not influenced by the patient level of education.

  • Minimal hepatic encephalopathy
  • hepatic encephalopathy
  • Critical flicker frequency
  • Liver cirrhosis
  • Chronic HCV

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  • Contributors All authors have contributed in this article and are in agreement with the content of the manuscript.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval Review board of the department of internal medicine, Faculty of Medicine, Cairo University.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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