The Effect of Induced Hyperammonaemia on Sleep and Melanopsin-mediated Pupillary Light Response in Patients With Liver Cirrhosis

Inclusion Criteria: * Patients with a clinical diagnosis of Child Pugh Class A or B cirrhosis * Written informed consent * \>20 and \<80 years of age Exclusion Criteria: * Misuse of alcohol in the preceding 6 months, * Episodes of hepatic decompensation leading to in-patient admissions during the previous month * History or clinical signs of overt HE or severe sleep-wake disturbances * On anti-HE treatment (lactulose, rifaximin, Hepa-Merz, Generaid, Bramino) * History of significant head injury * Neurological/psychiatric comorbidity needing medical treatment * Taking neuroactive medication/medication known to affect sleep * Travel across more than two time zones in the preceding 3 months * Shift work in the preceding 5 years * Contraindications for arterial puncture (negative collateral circulation test, wrist infection or vascular abnormalities).