title: Value of the critical flicker frequency in patients with minimal hepatic encephalopathy.
abstract: Minimal hepatic encephalopathy (MHE) is mainly diagnosed using psychometric tests such as the psychometric hepatic encephalopathy score (PHES). Despite the clinical and social relevance of MHE, psychometric testing is not widespread in routine clinical care. We assessed the usefulness of the critical flicker frequency (CFF), for the diagnosis of MHE and for the prediction of the development of overt episodes of HE. The normal range of PHES in the Spanish population was evaluated in a control group. Subsequently, 114 patients with cirrhosis and 103 healthy controls underwent both PHES and CFF tests. A diagnosis of MHE was made when the PHES was lower than -4 points. Patients were followed-up every 6 months for a total of 1 year. CFF did not correlate with age, education, or sex in the control group. The mean CFF was significantly lower in patients with MHE versus non-MHE or controls. Mean CFF correlated with individual psychometric tests as well as PHES (r = 0.54; P < 0.001). CFF <38 Hz was predictive of further bouts of overt HE (log-rank: 14.2; P < 0.001). There was a weak correlation between mean CFF and Child-Pugh score but not with model for end-stage liver disease score. In multivariate analysis using Cox regression, CFF together with Child-Pugh score was independently associated with the development of overt HE.
  
  
  CONCLUSIONS
  CFF is a simple, reliable, and accurate method for the diagnosis of MHE. It is not influenced by age or education and could predict the development of overt HE.
authors: Unit for the Clinical Management of Digestive Diseases, Hospital Universitario de Valme, Sevilla, Spain. mromerog@supercable.es
authors: Manuel
authors: M
authors: Romero-Gómez
authors: Juan
authors: J
authors: Córdoba
authors: Rodrigo
authors: R
authors: Jover
authors: Juan A
authors: JA
authors: del Olmo
authors: Marta
authors: M
authors: Ramírez
authors: Ramón
authors: R
authors: Rey
authors: Enrique
authors: E
authors: de Madaria
authors: Carmina
authors: C
authors: Montoliu
authors: David
authors: D
authors: Nuñez
authors: Montse
authors: M
authors: Flavia
authors: Luis
authors: L
authors: Compañy
authors: José M
authors: JM
authors: Rodrigo
authors: Vicente
authors: V
authors: Felipo
mesh_terms: D000368:Aged; D005260:Female; D005425:Flicker Fusion; D006501:Hepatic Encephalopathy / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D015995:Prevalence; D012306:Risk