Introduction Patients with cirrhosis have significantly disturbed sleep–wake behaviour. However, the cause of these disturbances is uncertain and their relationship to hepatic encephalopathy (HE) is debated. Sleep is regulated by circadian and homeostatic processes; circadian abnormalities, while present in these patients, do not correlate with the observed disturbances in sleep–wake behaviour (Montagnese et al, 2010). Homeostatic sleep mechanisms are difficult to access; the possibility that homeostatic control is disturbed in these patients has not been systematically studied. Sleep-spindles, which are a feature of the sleep electroencephalogram (EEG), are generated by thalamo-cortical oscillatory networks and are a surrogate marker for homeostatic sleep processes. The same oscillatory networks have been implicated in the pathogenesis of HE.
Aim To examine homeostatic sleep mechanisms in patients with cirrhosis and to determine the relationship between sleep abnormalities and HE.
Method 39 patients with cirrhosis (24 men; 15 woman; mean (range) age 60 (37–85) years) were classified using clinical, psychometric and electrophysiological variables as neuropsychiatrically unimpaired (n=20), or as having minimal (n=6) or overt (n=13) HE. The reference population comprised 50 healthy individuals (26 men; 24 woman; age 55 (41–65) years. Sleep–wake behaviour was characterised using validated questionnaires. Sleep deprived EEGs were obtained in 14 patients (unimpaired (n=5), minimal (n=3) and overt (n=6) HE). The reference population comprised 26 healthy individuals (15 men; 11 woman; age 49 (39–59) years). The EEG was band-pass filtered (12.75–15.0 Hz) and the envelop of the sleep spindles obtained using the Hilbert transform. A threshold was identified which allowed the maximal rate of spindle occurrence to be defined. Variables were compared between patients and controls and in patients by degree of neuropsychiatric impairment.
Results Patients with overt HE were significantly more likely to report night-time sleep disturbances and day-time napping than the control subject and unimpaired patients (p<0.05).
The rate of sleep-spindle occurrence was significantly greater in the EEGs of patients with overt HE than in control subjects and unimpaired patients (59.2±3.8 vs 52.4±2.8, p<0.001 and 53.9±1.5, p<0.005).
Conclusion Sleep–wake disturbances were prevalent in the patients with cirrhosis and increased with the degree of neuropsychiatric impairment. Significant abnormalities were observed in the sleep EEGs in patients with overt HE. Thus, abnormalities in cerebral oscillatory networks may underlie both the sleep disturbances and the neuropsychiatric abnormalities observed in patient with cirrhosis
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.