Diurnal changes of critical flicker frequency in patients with liver cirrhosis and their relationship with sleep disturbances

Sleep disturbances in chronic liver disease

Sleep disturbances are common in chronic liver disease and significantly impact patient outcomes and quality of life. The severity and nature of sleep disturbances vary by liver disease etiology and severity. While there is ongoing research into the association between liver disease and sleep-wake dysfunction, the underlying pathophysiology varies and, in many cases, is poorly understood. Liver disease is associated with alterations in thermoregulation, inflammation, and physical activity, and is associated with disease-specific complications, such as HE, that may directly affect sleep. In this article, we review the relevant pathophysiologic processes, disease-specific sleep-wake disturbances, and clinical management of CLD-associated sleep-wake disturbances.

Psychometric methods for diagnosing and monitoring minimal hepatic encephalopathy -current validation level and practical use

Hepatic encephalopathy (HE) is cerebral dysfunction caused by liver failure and inflicts 30-40% of patients with liver cirrhosis during their disease course. Clinically manifest HE is often preceded by minimal HE (MHE) - a clinically undetectable cognitive disturbance closely associated with loss of quality of life. Accordingly, detecting and treating MHE improve the patients' daily functioning and prevent HE-related hospital admissions. The scope of this review article is to create an overview of the validation level and usage of psychometric tests used to detect MHE: Portosystemic hepatic encephalopathy test, continuous reaction time test, Stroop EncephalApp, animal naming test, critical flicker frequency test, and inhibitory control test. Our work is aimed at the clinician or scientist who is about to decide on which psychometric test would fit best in their clinic, cohort, or study. First, we outline psychometric test validation obstacles and requirements. Then, we systematically approach the literature on each test and select well-conducted studies to answer the following questions:• Which percentage of patients with cirrhosis does the test deem as having MHE?• Is the test able to predict clinically manifest HE?• Is there a well-known test-retest variation and inter-observer variation?• Is the test able to detect a treatment response?• Is the test result affected by age, educational level, gender, or comorbidities?

Critical Flicker Fusion Frequency: A Narrative Review

This review presents the current knowledge of the usage of critical flicker fusion frequency (CFF) in human and animal model studies. CFF has a wide application in different fields, especially as an indicator of cortical arousal and visual processing. In medicine, CFF may be helpful for diagnostic purposes, for example in epilepsy or minimal hepatic encephalopathy. Given the environmental studies and a limited number of other methods, it is applicable in diving and hyperbaric medicine. Current research also shows the relationship between CFF and other electrophysiological methods, such as electroencephalography. The human eye can detect flicker at 50-90 Hz but reports are showing the possibility to distinguish between steady and modulated light up to 500 Hz. Future research with the use of CFF is needed to better understand its utility and application.

Sleep disorder in patients with chronic liver disease: a narrative review

Sleep disturbance is a common feature of chronic liver disease (CLD) with impact on health-related quality of life; 60-80% of patients with CLD report subjective poor sleep; frequent presentations of sleep disturbance include insomnia, reduced sleep efficiency, increased sleep latency, reduced time in rapid eye movement (REM) sleep, restless leg syndrome and excessive daytime sleepiness (EDS). Key contributors to sleep disturbance include hepatic encephalopathy (HE) and circadian rhythm imbalance due to altered melatonin metabolism. Specific conditions causing CLD, such as non-alcoholic fatty liver disease (NAFLD), chronic viral hepatitis and primary biliary cholangitis (PBC) result in different types of sleep disturbance, and the treatment of these conditions can often also lead to sleep disturbance. There are currently limited management options for sleep disturbance in CLD. Obstructive sleep apnoea (OSA) is a common condition that causes chronic intermittent hypoxia due to airway collapse during sleep. This chronic intermittent hypoxia appears to contribute to the development of NAFLD. The presence of reactive oxygen species and the overexpression of hypoxia inducible factor 1-alpha secondary to hypoxia may be responsible for the second 'hit' of the 'two-hit' hypothesis of NAFLD. Treatment of the intermittent hypoxia with continuous positive airway pressure therapy has limited efficacy against liver dysfunction. There remain many outstanding areas of investigation in the management of sleep disturbance in CLD, and of liver dysfunction in OSA.

The performance of critical flicker frequency on determining of neurocognitive function loss in severe obstructive sleep apnea syndrome

This study aimed to compare the critical flicker frequency (CFF) and the mail-in cognitive function screening ınstrument (MCFSI) tests' effectiveness in diagnosing neurocognitive function losses in patients having severe obstructive sleep apnea syndrome (OSAS). A total of 85 subjects (47 patients with a diagnosis of severe OSAS and 38 healthy controls) were included into the study. MCFSI scores greater than or equal to five and CFF scores less than 39 Hz were considered abnormal. Demographic and polysomnographic parameters of patients with OSAS were studied, and correlations between the MCFSI, CFF scores and Epworth Sleepiness Scale (ESS) scores were analysed. The mean age of the patients was 49.6 ± 12.0 years. In the OSAS group, the CFF score was found to be low when compared with the control group, while the MCFSI score was found to be high. Pathological CFF scores (<39) were found in 13 patients (27.7%) in the OSAS group, while pathological MCFSI scores (≥5) were found in 19 patients (40.4%). CFF scores were found to be low in only 26% of the patients with OSAS who were found to have high MCFSI scores. MCFSI scores were high in only 38% of the patients with OSAS who were found to have low CFF scores. There was a significant correlation between ESS and CFF scores. In conclusion, the usefulness of the CFF test in determining cognitive function loss in patients with OSAS needs to be demonstrated via studies which utilize a larger sample size.

Increased serum interleukin-6, not minimal hepatic encephalopathy, predicts poor sleep quality in nonalcoholic cirrhotic patients

BACKGROUND

Sleep-wake disturbances are common in patients with cirrhosis and have a considerable effect on health-related quality of life; however, the underlying mechanism behind the phenomenon is unclear. Cytokines are involved in the mediation of signalling pathways regulating fibrogenesis, leading to cirrhosis. In addition, increased cytokines could contribute to sleep disturbances.

AIM

To determine the relationship between pro-inflammatory cytokines and sleep disturbance in cirrhotic patients.

METHODS

Ninety-eight nonalcoholic cirrhotic patients without overt hepatic encephalopathy were enrolled in this cross-sectional study. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality. The Psychometric Hepatic Encephalopathy Score (PHES) was used to examine cognitive performance and define minimal hepatic encephalopathy (MHE). The Hospital Anxiety and Depression Scale (HADS) was used to evaluate the mood status of the patients. Pro-inflammatory cytokines that include interleukin 6 (IL-6) and tumour necrosis factor-α, as well as HBV-DNA or HCV-RNA levels were determined in patients.

RESULTS

A total of 56 (57%) cirrhotic patients were identified as 'poor' sleepers (PSQI > 5). After multivariate analysis, IL-6 (P = 0.001) and HADS scores (P = 0.002) were found to be independent predictive factors of poor sleep quality. No significant relationships were observed between the sleep indices and the presence of MHE. HCV-RNA, but not HBV-DNA, viraemia was associated with sleep disturbance in cirrhotic patients.

CONCLUSIONS

Sleep disturbance is found commonly in cirrhotic patients and a high serum IL-6 level is predictive of poor sleep quality. Minimal hepatic encephalopathy by itself may not contribute to sleep dysfunction in cirrhotic patients.

Glucose fluctuations reduce quality of sleep and of life in patients with liver cirrhosis

BACKGROUND

Sleep disturbance and decreased health-related quality of life (HRQOL) are significant complaints in patients with liver cirrhosis. Although the etiology of these complications is unclear, we propose that glucose intolerance may be a predisposing factor. Therefore, our aim was to investigate the relationship between glucose intolerance and these complications.

METHODS

We assessed continuous glucose monitoring in 43 patients with chronic liver disease. Among these patients, 36 completed the Pittsburgh Sleep Quality Index (PSQI), the 36-Item Short-form Health Survey (SF-36), and the Neuropsychological Test (NPT). We also assessed the change in glucose fluctuations between preoperative periods and 1 year after liver transplantation in 13 patients.

RESULTS

Standard deviation (SD) of blood glucose was 24.15 ± 13.52. SD values correlated to glucose metabolism measures, including HbA1c and glycoalbumin. SD values also correlated to markers of liver fibrosis, including type IV collagen. Twenty-one patients (58.3 %) were classified as "poor" sleepers, with a global PSQI score ≥6. Glucose fluctuations correlated with the global PSQI score (r = 0.456, p = 0.008) and the SF-36 score (r = 0.434, p = 0.013). Multivariate regression analysis identified SD values as an independent risk factor for sleep disturbance (r = 0.12, p = 0.039) and decreased HRQOL (r = -0.32, p = 0.024). SD values did not correlate with the NPT. SD values were also improved in 11 (84.6 %) patients 1 year after liver transplantation.

CONCLUSION

Abnormal glucose fluctuations are a risk factor for sleep disturbance and decrease of HRQOL in patients with cirrhosis.