title: Diurnal changes of critical flicker frequency in patients with liver cirrhosis and their relationship with sleep disturbances.
abstract: BACKGROUND
  We aimed to measure the diurnal changes of critical flicker frequency in healthy subjects and cirrhotic patients and to investigate their relationship with sleep disturbance.
  
  
  METHODS
  Cirrhotic patients and healthy volunteers were included. All groups completed the Pittsburgh Sleep Quality Index and a simple sleep questionnaire. Sleep disturbance was defined as a Pittsburgh Sleep Quality Index score of >5. Critical flicker frequency was measured twice a day to detect diurnal abnormalities.
  
  
  RESULTS
  Overall, 59 cirrhotic patients (54.2% males, Mean Age 59 ± 11 years) and 18 controls (39.9% males, Mean Age 58 ± 9 years) were included. Sleep disturbances were more common in cirrhotics (66.1%) than controls (38.9%, p<0.05). In cirrhotics, the critical flicker frequency was not related to decompensation. The nocturnal values were higher than the morning values in cirrhotics (64.4%), but not in controls (p<0.0001). Additionally, sleep disturbances were more common in cirrhotics who had higher nocturnal values (p<0.05).
  
  
  CONCLUSIONS
  Changes in the diurnal critical flicker frequency were observed in cirrhotics but not in controls. Sleep disturbances in cirrhotics appear to be associated with deviations of the diurnal rhythm of critical flicker frequency rather than with clinical parameters such as the clinical stages of cirrhosis and the Model For End-Stage Liver Disease and Child-Pugh scores.
authors.affiliation: Ege University School of Medicine, Department of Gastroenterology, Izmir, Turkey. Electronic address: gencogencdal@yahoo.co.uk.
authors.forename: Genco
authors.initials: G
authors.lastname: Gencdal
authors.affiliation: Ege University School of Medicine, Department of Gastroenterology, Izmir, Turkey.
authors.forename: Fulya
authors.initials: F
authors.lastname: Gunsar
authors.affiliation: Ege University School of Medicine, Department of Gastroenterology, Izmir, Turkey.
authors.forename: Cenk Emre
authors.initials: CE
authors.lastname: Meral
authors.affiliation: Ege University School of Medicine, Department of Gastroenterology, Izmir, Turkey.
authors.forename: Esin
authors.initials: E
authors.lastname: Salman
authors.affiliation: Ege University School of Medicine, Department of Gastroenterology, Izmir, Turkey.
authors.forename: Berna
authors.initials: B
authors.lastname: Gürsel
authors.affiliation: Ege University School of Medicine, Department of Gastroenterology, Izmir, Turkey.
authors.forename: Nevin
authors.initials: N
authors.lastname: Oruç
authors.affiliation: Ege University School of Medicine, Department of Gastroenterology, Izmir, Turkey.
authors.forename: Zeki
authors.initials: Z
authors.lastname: Karasu
authors.affiliation: Ege University School of Medicine, Department of Gastroenterology, Izmir, Turkey.
authors.forename: Galip
authors.initials: G
authors.lastname: Ersoz
authors.affiliation: Ege University School of Medicine, Department of Gastroenterology, Izmir, Turkey.
authors.forename: Ulus S
authors.initials: US
authors.lastname: Akarca
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002940:Circadian Rhythm; D005260:Female; D006501:Hepatic Encephalopathy / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012893:Sleep Wake Disorders / Q000175:diagnosis / Q000209:etiology*; D011795:Surveys and Questionnaires; D014851:Wakefulness / Q000502:physiology*; D055815:Young Adult
keywords: Cirrhosis; Critical flicker frequency; Sleep disturbances