Methods for diagnosing hepatic encephalopathy in patients with cirrhosis: a multidimensional approach

Mini-Mental State Examination in patients with hepatic encephalopathy and liver cirrhosis: a prospective, quantified electroencephalography study

Background

Mini-Mental State Examination (MMSE) is one of the most commonly used methods in the assessment of cognitive mental status. MMSE has been used in hepatology but its usefulness in the evaluation of hepatic encephalopathy (HE) has never been properly assessed. The aim of the study was to investigate the value of MMSE in detection of HE in patients with cirrhosis.

Methods

One hundred and one consecutive patients with liver cirrhosis underwent neurological examination, MMSE and electroencephalography (EEG). Spectral analysis of EEG was done with calculation of mean dominant frequency (MDF) and relative power of delta, theta, alpha and beta rhythms. Minimal HE was diagnosed in patients with normal neurological status and alterations in spectral EEG. Statistical analysis included Fisher’s exact and Anova analysis. Categorical data were compared using Levene’s test for equality of variances. Correlation-coefficient analysis was performed by the Pearson’s r or Z-test, as needed. Tests performance was assessed by the calculating the area under the ROC curve (AUC) and evaluating its difference from reference area (AUC=0.5). A p value <0.05 was considered statistically significant.

Results

Overt HE was identified in 49 (48.5%) and minimal HE in 22 (21.8%) patients. Although there were significant correlations between both severity of liver disease (Child-Pugh classification), overt HE (West-Haven criteria) and various MMSE items, MDF showed no correlation with any of MMSE items as well as MMSE summary score. MMSE (score and items) did not discriminate patients without HE and minimal HE. The only significant differences between patients without HE and with overt HE were seen in respect of MMSE score (p<0.02), orientation to place (p<0.003), repetition (p<0.01) and complex commands-understanding (p<0.02). Test performance analysis has shown that MMSE has no value as a prediction method in determining minimal HE and in respect of overt HE has a sensitivity of 63% and specificity of 52% by a cut-off level at 27.5 points to diagnose overt HE.

Conclusions

In conclusion, although MMSE score and single items are altered in patients with overt HE, MMSE has no value in the assessment of minimal HE. Because MMSE could be impaired in several cognitive dysfunctions, more specific test should be used for measuring HE.

Melatonin secretion and metabolism in patients with hepatic encephalopathy

BACKGROUND AND AIM

The rhythm of melatonin secretion and its blood level changes in cirrhotic patients, but the causes of these alterations have not been sufficiently appreciated. The aim of study was to estimate the dependence between melatonin secretion and metabolism and the severity of hepatic encephalopathy.

METHODS

The study included 75 alcoholic cirrhotic patients (A, B, C) with hepatic insufficiency and 25 healthy subjects (group K). Three groups of patients were identified, 25 patients each, with grade 1, 2, and 3 hepatic encephalopathy according to West-Haven Scale. Immunoenzymatic method was used to measure serum melatonin (at 02:00 h and 09:00 h) level and 6-sulfatoxymelatonin (6-HMS) excretion in the urine (during night and day).

RESULTS

Nocturnal serum melatonin levels (pg/mL) in groups were: K-57.1 ± 11.4, A-38.5 ± 11.2, B-53.4 ± 17.9, C-79.5 ± 27.9 (P < 0.01); whereas diurnal levels were: K-10.9 ± 3.5, A-33.5 ± 12.0, B-53.8 ± 23.1, C-98.5 ± 34.6 (P < 0.01). Similar differences were found in the evaluation of 6-HMS excretion (μg/9 h) in urine at night: group K-23.4 ± 14.4, A-16.6 ± 5.4, B-14.3 ± 6.2 (P < 0.01), C-3.3 ± 1.5 (P < 0.001). Diurnal 6-HMS excretion (μg/15 h) was lower only in group C and it was respectively: K-6.9 ± 3.4, A-7.1 ± 1.7, B-7.6 ± 1.7, C-4.3 ± 2.2 (P < 0.001). Serum ammonia concentrations (μg/dL) were: group K-30.4 ± 8.9, A-51.8 ± 25.4 (P < 0.05), B-73.0 ± 29.8 (P < 0.001), C-107.5 ± 34.8 (P < 0.001). No correlation between melatonin and ammonia levels in all groups was found.

CONCLUSIONS

The elevated melatonin blood levels both at night and day may account for some of the clinical manifestations of hepatic encephalopathy (daytime sleepiness, fatigue).

Melatonin levels in serum and ascitic fluid of patients with hepatic encephalopathy

Cirrhotic patients exhibit disturbed melatonin homeostasis, which may lead to sleep disturbances, but an influence on the hepatic encephalopathy has not been elucidated. Aim. In the present study, the association of melatonin levels in serum and ascitic fluid and ammonia concentration related to the intensity of hepatic encephalopathy (HE) was investigated. Material and Methods. The study included 90 alcoholic patients with hepatic encephalopathy and 30 healthy volunteers (C). Patients were divided in three groups according to 0–4 West-Haven Score: HE₁ (n = 28), HE₂ (n = 30), and HE₃ (n = 32). Melatonin was measured by radioimmune assay. Results. In fasting patients with hepatic encephalopathy we noted higher melatonin serum levels [pg/mL] than in healthy subjects groups: C—11.3 ± 3.9, HE₁ – 34.3 ± 12.2 (P < 0.01), HE₂—54.8 ± 23.9, and HE₃—119.8 ± 96.4 (P < 0.001). No correlation between melatonin and ammonia levels was found. Melatonin was detected in ascetic fluid in 24 patients of group HE₂ and 27 patients of group HE₂ of hepatic encephalopathy. Conclusions. Our results suggest that high blood levels of melatonin in cirrhotic liver patients may account for some of the clinical manifestations of hepatic encephalopathy, for example, daytime sleepiness, fatigue.

Simple tools for complex syndromes: a three-level difficulty test for hepatic encephalopathy

BACKGROUND

Despite the impact of hepatic encephalopathy on quality of life and prognosis, easily administered tests for its diagnosis are still lacking.

AIM

To assess the usefulness of the Scan package, a three-level-difficulty computerised reaction time test, to diagnose varying degrees of hepatic encephalopathy.

METHODS

Sixty-one cirrhotic patients underwent clinical evaluation, paper-and-pencil psychometry and the Scan package; 32 healthy controls served as reference.

RESULTS

Twenty-nine patients were classified as unimpaired, 15 as having minimal and 17 as having overt hepatic encephalopathy. All healthy controls were able to complete the Scan package; in contrast, the number of patients who were able to complete three/two/one part decreased in parallel with the degree of encephalopathy (χ(2)=17, p=0.01). Reaction times in all three parts increased significantly with the severity of encephalopathy. However, the profile of increase was different [group: F(3,77)=26, p<0.0001; test: F(2,154)=277, p<0.0001; group×test: F(6,154)=7, p<0.0001], with different parts being more/less sensitive to varying degrees of encephalopathy.

CONCLUSIONS

The Scan package seems useful for the diagnosis of hepatic encephalopathy and covers a considerable portion of its spectrum of severity.

Neuropsychological tools in hepatology: a survival guide for the clinician

Neuropsychological assessment has three main applications in clinical hepatology: (i) to detect, grade and monitor liver failure-related cognitive alterations in end-stage liver disease (hepatic encephalopathy), (ii) to substantiate complaints of attention or concentration difficulties in patients with non-cirrhotic chronic hepatitis C viral infection, and (iii) to screen patients who are being considered for liver transplantation for early signs of dementia. However, there is limited agreement on how cognitive assessment should be conducted in these patients, and how results should be interpreted and used to implement clinical decisions. In this review, we summarize the available literature on neuropsychological dysfunction in patients with cirrhosis and with chronic hepatitis C viral infection and provide some guidance on how to utilize neuropsychological assessment in practice.

Assessment and usefulness of clinical scales for semiquantification of overt hepatic encephalopathy

Hepatic encephalopathy (HE) represents the effects of liver dysfunction on the brain. When HE is clinically obvious (eg, confusion, poor judgment, personality change), it is termed overt HE. The severity of HE is measured by different methods. Assessing the severity of HE is important for determining patient prognosis and effectiveness of therapy. This article discusses the different methods for grading HE, including clinical rating scales, neuropsychological tests, and neurophysiologic measures.

Assessment of minimal hepatic encephalopathy (with emphasis on computerized psychometric tests)

Minimal hepatic encephalopathy (MHE) is associated with a high risk of development of overt hepatic encephalopathy, impaired quality of life, and driving accidents. The detection of MHE requires specialized testing because it cannot, by definition, be diagnosed on standard clinical examination. Psychometric and neurophysiologic techniques are often used to test for MHE. Paper-pencil psychometric batteries and computerized tests have proved useful in diagnosing MHE and predicting its outcomes. Neurophysiologic tests also provide useful information. The diagnosis of MHE is an important issue for clinicians and patients alike. Testing strategies depend on the normative data available, patient comfort, and local expertise.

Rifaximin in the treatment of hepatic encephalopathy

Hepatic encephalopathy is a challenging complication in patients with advanced liver disease. It can be defined as a neuropsychiatric syndrome caused by portosystemic venous shunting, ranging from minimal to overt hepatic encephalopathy or coma. Its pathophysiology is still unclear, although increased levels of ammonia play a key role. Diagnosis of hepatic encephalopathy is currently based on specific tests evaluating the neuropsychiatric state of patients and their quality of life; the severity of hepatic encephalopathy is measured by the West Haven criteria. Treatment of hepatic encephalopathy consists of pharmacological and corrective measures, as well as nutritional interventions. Rifaximin received approval for the treatment of hepatic encephalopathy in 2010 because of its few side effects and pharmacological benefits. The aim of this work is to review the use and efficacy of rifaximin both in acute and long-term management of hepatic encephalopathy. Treatment of overt hepatic encephalopathy involves management of the acute episode as well as maintenance of remission in those patients who have previously experienced an episode, in order to improve their quality of life. The positive effect of rifaximin in reducing health care costs is also discussed.

Critical flicker frequency and continuous reaction times for the diagnosis of minimal hepatic encephalopathy: a comparative study of 154 patients with liver disease

Minimal hepatic encephalopathy (MHE) is intermittently present in up to 2/3 of patients with chronic liver disease. It impairs their daily living and can be treated. However, there is no consensus on diagnostic criteria except that psychometric methods are required. We compared two easy-to-perform reproducible bedside methods: the critical flicker frequency (CFF) and continuous reaction times (CRT) tests. A CFF <39 Hz and CRT-index <1.9 (index: the ratio 50/(90 minus 10) percentiles of reaction times) indicates cerebral dysfunction. 154 patients with acute or chronic liver disease with out overt hepatic encephalopathy (HE) underwent both tests at the same occasion. Both tests were abnormal in 20% of the patients and both tests were normal in 40% of the patients. In more than 1/3 the two tests were not in agreement as CFF classified 32% and CRT-index classified 48% of the patients as having MHE (p < 0.005). The two tests were weakly linearly correlated (r(2) = 0.14, p < 0.001) and neither test correlated with the metabolic liver function measured by the Galactose Elimination Capacity (GEC), nor with the blood ammonia concentration. Both tests identified a large fraction of the patients as having MHE and cleared only 40%. The two tests did not show concordant results, likely because they describe different aspects of MHE: the CFF gives a measure of astrocytic metabolic state and hence pathogenic aspects of MHE, whereas the CRT measures a composite key performance, viz. the ability of reacting appropriately to a sensory stimulus. The choice of test depends on the information needed in the clinical and scientific care and study of the patients.

Acetylcholinesterase activity in an experimental rat model of Type C hepatic encephalopathy

Patients with liver malfunction often suffer from hepatic encephalopathy, a neurological complication which can affect attention and cognition. Diverse experimental models have been used to study brain alterations that may be responsible for hepatic encephalopathy symptoms. The aim of the study was to determine whether cognitive impairment found in cirrhosis could be due to disturbance of acetylcholinesterase activity. Acetylcholinesterase activity was assessed in the brains of Wistar rats with thioacetamide-induced cirrhosis. The cirrhotic group displayed up-regulation of acetylcholinesterase levels in the entorrhinal cortex, anterodorsal and anteroventral thalamus and accumbens, whereas down-regulation was found in the CA1, CA3 and dentate gyrus of the hippocampus. Our results indicate that the experimental model of hepatic encephalopathy by chronic administration of thioacetamide presents alterations of acetylcholinesterase activity in brain limbic system regions, which play a role in attention and memory.

Review article: the design of clinical trials in hepatic encephalopathy--an International Society for Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN) consensus statement

BACKGROUND

The clinical classification of hepatic encephalopathy is largely subjective, which has led to difficulties in designing trials in this field.

AIMS

To review the current classification of hepatic encephalopathy and to develop consensus guidelines on the design and conduct of future clinical trials.

METHODS

A round table was convened at the 14th International Society for Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN) meeting. Key discussion points were the nomenclature of hepatic encephalopathy and the selection of patients, standards of care and end-points for assessing the treatment and secondary prevention of hepatic encephalopathy.

RESULTS

It was generally agreed that severity assessment of hepatic encephalopathy in patients with cirrhosis, whether made clinically or more objectively, should be continuous rather than categorical, and a system for assessing the SONIC (Spectrum of Neuro-cognitive Impairment in Cirrhosis) was proposed. Within this system, patients currently classified as having minimal hepatic encephalopathy and Grade I hepatic encephalopathy would be classified as having Covert hepatic encephalopathy, whereas those with apparent clinical abnormalities would continue to be classified as overt hepatic encephalopathy. Some aspects of the terminology require further debate. Consensus was also reached on the patient populations, standards of care and endpoints to assess clinical trial outcomes. However, some compromises had to be made as there is considerable inter- and intravariability in the availability of some of the more objective surrogate performance markers.

CONCLUSIONS

The objectives of the round table were met. Robust, defendable guidelines for the conduct of future studies into hepatic encephalopathy have been provided. Outstanding issues are few and will continue to be discussed.

Mechanisms, diagnosis and management of hepatic encephalopathy

Hepatic encephalopathy (HE) is a serious neuropsychiatric complication of both acute and chronic liver disease. Symptoms of HE can include confusion, disorientation and poor coordination. A general consensus exists that the synergistic effects of excess ammonia and inflammation cause astrocyte swelling and cerebral edema; however, the precise molecular mechanisms that lead to these morphological changes in the brain are unclear. Cerebral edema occurs to some degree in all patients with HE, regardless of its grade, and could underlie the pathogenesis of this disorder. The different grades of HE can be diagnosed by a number of investigations, including neuropsychometric tests (such as the psychometric hepatic encephalopathy score), brain imaging and clinical scales (such as the West Haven criteria). HE is best managed by excluding other possible causes of encephalopathy alongside identifying and the precipitating cause, and confirming the diagnosis by a positive response to empiric treatment. Empiric therapy for HE is largely based on the principle of reducing the production and absorption of ammonia in the gut through administration of pharmacological agents such as rifaximin and lactulose, which are approved by the FDA for the treatment of HE.

Improving the inhibitory control task to detect minimal hepatic encephalopathy

BACKGROUND & AIMS

Quantification of the number of noninhibited responses (lures) in the inhibitory control task (ICT) has been proposed for the diagnosis of minimal hepatic encephalopathy (MHE). We assessed the efficacy of ICT compared with recommended diagnostic standards.

METHODS

We studied patients with cirrhosis and healthy individuals (controls) who underwent the ICT at 2 centers (center A: n=51 patients and 41 controls, center B: n=24 patients and 14 controls). Subjects were evaluated for MHE by psychometric hepatic encephalopathy score (PHES). Patients from center B also were assessed for MHE by critical flicker frequency and spectral electroencephalogram analyses.

RESULTS

Patients with cirrhosis had higher ICT lures (23.2+/-12.8 vs 12.9+/-5.8, respectively, P<.01) and lower ICT target accuracy (0.88+/-0.17 vs 0.96+/-0.03, respectively, P<.01) compared with controls. However, lures were comparable (25.2+/-12.5 vs 21.4+/-13.9, respectively, P=.32) among patients with/without altered PHES (center A). There was a reverse, U-shaped relationship between ICT lure and target accuracy; a variable adjusting lures was devised based on target accuracy (weighted lures at center B). This variable differed between patients with and without MHE. The variable weighted lures was then validated from data collected at center A by receiver operator characteristic curve analysis; it discriminated between patients with and without PHES alterations (area under the curve=0.71+/-0.07). However, target accuracy alone was as effective as a stand-alone variable (area under the curve=0.81+/-0.06).

CONCLUSIONS

The ICT is not useful for the diagnosis of MHE, unless adjusted by target accuracy. Testing inhibition (lures) does not seem to be superior to testing attention (target accuracy) for the detection of MHE.

Review article: the modern management of hepatic encephalopathy

BACKGROUND; Hepatic encephalopathy, both overt and minimal, forms a continuum of cognitive change in cirrhosis. Strategies to diagnose and treat hepatic encephalopathy have evolved considerably.

AIM

To examine the updated diagnostic and treatment strategies for hepatic encephalopathy.

METHODS

Techniques for the clinical, psychometric and neurophysiological evaluation of hepatic encephalopathy are reviewed. The methods reviewed include pure clinical scales (West-Haven), psychometric tests (PSE-syndrome test), neurophysiological tests (EEG, Critical flicker frequency, CFF) and computerized tests (Inhibitory control test, ICT).

RESULTS

Clinical scales are limited, whereas psychometric tests (specifically PSE-syndrome test), CFF and ICT can be used to diagnose minimal hepatic encephalopathy. However, there is no single test that can capture the entire spectrum of cognitive impairment. Treatment options and goals depend on the acuity of hepatic encephalopathy. In-patient management should concentrate on supportive care, precipitating factor reversal and lactulose and/or rifaximin therapy. Out-patient therapy should aim to prevent recurrences, and both lactulose and rifaximin have evidence to support their use.

CONCLUSIONS

Diagnostic techniques for hepatic encephalopathy range from simple scales to sophisticated tools. Treatment options depend on the stage of hepatic encephalopathy. The future challenge is to evaluate cognitive function as a continuum with clinically relevant outcomes and to develop well-tolerated and inexpensive treatments for hepatic encephalopathy.

Associative learning deficit in two experimental models of hepatic encephalopathy

People with hepatic insufficiency can develop hepatic encephalopathy (HE), a complex neuropsychological syndrome covering a wide range of neurological and cognitive and motor alterations. The cognitive deficits include disturbances in intellectual functions such as memory and learning. In spite of its high prevalence in western societies, the causes of HE have not yet been clearly established. For this reason, experimental models of HE are used to study this condition. In this work, two experimental models were used, one Type B HE (portacaval shunt) and the other Type C HE (cirrhosis by intoxication with thioacetamide), to evaluate its effect on two tasks of associative learning: two-way active avoidance and step-through passive avoidance. The results show an impediment both in acquisition and retention of active avoidance in both models of HE. However, in passive avoidance, only the rats with portacaval shunt presented a memory deficit for the aversive event. In our opinion, these results can be explained by alterations in the neurotransmission system presented by animals with hepatic insufficiency, which are mainly caused by a rise in cerebral histamine and a dysfunction of the glutamatergic system.

Type and etiology of liver cirrhosis are not related to the presence of hepatic encephalopathy or health-related quality of life: a cross-sectional study

BACKGROUND

Hepatic encephalopathy has a negative impact on health-related quality of life (QoL) in liver cirrhosis. There are scarce and conflicting data on whether type or etiology of liver cirrhosis could be related to hepatic encephalopathy in patients with cirrhosis. We aimed to determine the impact of cirrhosis etiology on hepatic encephalopathy and whether hepatic encephalopathy affects health-related QoL among patients with cirrhosis of different etiologies.

METHODS

A total of 156 cirrhotic patients were prospectively evaluated for the presence of hepatic encephalopathy according to the West-Haven criteria as well as by means of two psychometric tests. Patients with cryptogenic cirrhosis or cirrhosis due to mixed hepatocellular/cholestatic etiologies were excluded. Fasting plasma glucose levels were also measured. QoL was evaluated by means of a validated questionnaire (SF-36).

RESULTS

Diabetes mellitus was more common in patients with hepatocellular cirrhosis compared to those with cholestatic cirrhosis but the two groups did not differ in cirrhosis severity or the prevalence of hepatic encephalopathy (p > 0.05). The groups of patients with cirrhosis due to alcohol, hepatitis C, or cholestatic liver disease did not differ in severity of liver cirrhosis or the prevalence of hepatic encephalopathy (p > 0.05). Patients with cirrhosis of different etiologies did not differ in any SF-36 domain (p > 0.05). In multivariate analysis, performance at neuropsychological testing was independently related only to age, diabetes mellitus, and the Child-Pugh score whereas the SF-36 physical component summary only to the Child-Pugh score and hepatic encephalopathy.

CONCLUSION

Cirrhosis etiology does not seem to be related to hepatic encephalopathy or health-related QoL. Cognitive impairment is associated mainly with age, liver disease severity and diabetes mellitus.

Introduction to the Hepatic Encephalopathy Scoring Algorithm (HESA)

A primary obstacle to early diagnosis and treatment of hepatic encephalopathy (HE) is the lack of a well-validated, standardized assessment method. The purpose of this study was to present preliminary validity data on a new method of grading HE, the Hepatic Encephalopathy Scoring Algorithm (HESA), which combines clinical impressions with neuropsychological performances to characterize HE. Participants were 49 inpatients admitted for complications of end stage liver disease. Each participant's level of HE was graded using HESA and the West Haven Criteria (WHC) by independent raters blinded to each other's rating. A moderately strong association was found between the two grading methods (r = 0.60), and individual HESA clinical and neuropsychological indicators were good discriminators among grades. The results also suggest HESA may be more sensitive to mental status impairment in the middle grades of HE than WHC. These findings suggest HESA holds promise as a multi-method approach to grading all levels of HE.

Malnutrition and diabetes mellitus are related to hepatic encephalopathy in patients with liver cirrhosis

BACKGROUND/AIMS

Studies on animal models of hepatic encephalopathy (HE) suggest that poor nutritional status may facilitate the development of HE. Insulin resistance and diabetes mellitus have recently been reported to affect cognition in patients with hepatitis C cirrhosis awaiting liver transplantation. Our aim was to investigate the effects of malnutrition and diabetes mellitus on HE in unselected patients with liver cirrhosis.

METHODS

A total of 128 consecutive cirrhotic patients were prospectively evaluated for the presence of HE according to the West-Haven criteria as well as by means of two psychometric tests and fasting plasma ammonium ion concentrations. Nutritional status was assessed by anthropometry and estimation of recent weight change. Fasting plasma glucose was measured, and in a subgroup of 84 patients fasting serum insulin and insulin resistance were also determined.

RESULTS

Fifty-one (40%) cirrhotics were malnourished, 33 (26%) had diabetes and 42 (34%) had HE. Patients with vs. without malnutrition had more frequently HE (46 vs. 27%; P=0.031) but did not differ in age, aetiology or severity of liver cirrhosis (P>0.1). Multivariate analysis showed that the time needed to perform number connection test A was independently correlated to age, the Child-Pugh score, diabetes and malnutrition (P<0.05 for all). Plasma ammonium ion levels were related to insulin resistance (r=0.42, P<0.001) and muscle mass (r=0.28, P=0.003).

CONCLUSION

Malnutrition and diabetes mellitus seem to be related to HE in patients with liver cirrhosis. Nutritional status and insulin resistance might be implicated in the pathogenesis of HE.

Spatial memory alterations in three models of hepatic encephalopathy

A behavioural evaluation was carried out on three chronic models of hepatic encephalopathy: two models of type B HE, portacaval shunt (PCS) and portal hypertension (PH) and one of type C HE with cirrhosis and portal hypertension from thioacetamide intoxication (TAA). The tasks selected cover a wide range of behaviours related to: locomotion (rotarod-accelerod test), anxiety (open field and elevated plus maze) and memory (Morris water maze). The results indicate that neither locomotor activity nor anxiety was affected in our models, in comparison with their respective controls. However, this is not the case for the mnesic tasks. Hence, the PCS and TAA groups displayed a severe alteration in spatial reference memory and cannot correctly perform the Morris maze task, while this alteration is less severe in the PH group. On the contrary, the PH group revealed a deficit in spatial working memory, like the TAA group, but this does not occur in subjects with PCS. These results reveal a double dissociation in spatial reference memory and spatial working memory between the PCS and PH groups, which would be of great interest to study about cerebral causes and substrates of the alterations accompanying HE.

Renal function and cognitive impairment in patients with liver cirrhosis

OBJECTIVE

Cognitive impairment is a common problem in patients with liver cirrhosis. Its pathogenesis is multifactorial and ammonia is considered to play a central role. Renal function has been shown to be important for ammonia metabolism in cirrhosis. Although renal dysfunction is common in cirrhotic patients, its effect on cognitive function is largely unexplored.

MATERIAL AND METHODS

A total of 128 consecutive cirrhotic patients were prospectively evaluated for the presence of cognitive dysfunction according to the West-Haven criteria and by means of two psychometric tests. Serum creatinine, sodium and potassium as well as plasma ammonia concentrations were assessed. Glomerular filtration rate was also measured by (51)Cr- EDTA clearance in a subgroup of patients.

RESULTS

Forty-one patients (32%) were found to have cognitive dysfunction (clinical evaluation and/or psychometric tests). Sixteen patients (13%) found with serum creatinine levels above reference values had cognitive dysfunction more frequently than patients with creatinine within the normal range (69% versus 31%; p = 0.001), but did not differ in aetiology or severity of cirrhosis (p >0.1). Patients with loop diuretics versus without did not differ in creatinine values (p >0.1). Multivariate analysis showed that cognitive dysfunction was related to hospital admission at inclusion in the study, international normalized ratio and serum creatinine (p <0.05 for all), but not to potassium or sodium levels. Plasma ammonia concentration was related to serum creatinine (r = 0.26, p = 0.004) and the glomerular filtration rate (r = -0.44, p = 0.023).

CONCLUSIONS

Renal dysfunction seems to be related to cognitive impairment in patients with liver cirrhosis and might be implicated in the pathogenesis of hepatic encephalopathy.

P300 cognitive evoked potentials before and after liver transplantation

P300 cognitive evoked potentials have been shown to be effective for the assessment of mild hepatic encephalopathy but no investigations of their use with liver transplantation has been conducted. In this pilot study 12 subjects (7 male, 5 female, average age 43.9-years-old) underwent recording of auditory and visual P300 cognitive evoked potentials prior to liver transplantation and again 3-6 months subsequent to transplantation. Significant increases (p < 0.01) in P300 visual amplitude, as well as significant decreases in visual (p < 0.01) and auditory latencies (p < 0.01) were observed following transplantation. Auditory amplitudes increased but not to a statistically significant degree. P300 cognitive evoked potentials may provide a useful tool for monitoring the cerebral status of liver transplantation patients if combined with established methods such as cognitive testing and EEG. Further research of their usage with these patients is warranted.

Value of the critical flicker frequency in patients with minimal hepatic encephalopathy

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.

CONCLUSION

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.

Spatio-temporal decomposition of the electroencephalogram in patients with cirrhosis

BACKGROUND/AIMS

Slowing of the electroencephalogram (EEG) is a recognised feature of hepatic encephalopathy but its diagnostic sensitivity is indeterminate. Recent advances in EEG analysis should provide better quantifiable/more informative data. The aim of this study was to isolate and determine the scalp distribution of the posterior basic rhythm, in patients with cirrhosis, using a technique for spatio-temporal decomposition (SEDACA) of the EEG.

METHODS

One hundred and ten patients with cirrhosis, classified, using clinical and psychometric criteria, as neuropsychiatrically unimpaired or as having minimal/overt hepatic encephalopathy were studied. Eyes-closed, awake EEGs were obtained and subjected to standard spectral analysis and spatio-temporal decomposition. Control data were obtained from 26 reference EEGs.

RESULTS

The error in the estimate of the SEDACA-derived mean dominant frequency was lower than for the standard EEG derivation (P<0.00001). The SEDACA-derived spectral estimates correlated better with neuropsychiatric status and allowed differentiation of the patients with minimal hepatic encephalopathy from the reference population. The SEDACA-derived spatial information showed an anteriorization of the posterior basic rhythm, which became more prominent as the degree of neuropsychiatric impairment increased (P=0.00052).

CONCLUSIONS

Analysis of the EEG utilising SEDACA provides significantly more diagnostic information on the neuropsychiatric status of patients with cirrhosis than obtained conventionally.

Functional abnormalities of the motor tract in the rat after portocaval anastomosis and after carbon tetrachloride induction of cirrhosis

INTRODUCTION

Hepatic encephalopathy is a neurologic syndrome secondary to liver failure that causes cognitive and motor abnormalities. Impairment in the function of the first neuron of the motor tract (corticospinal tract) has been demonstrated in patients with cirrhosis and minimal hepatic encephalopathy.

AIM

Investigate the function of the first neuron of the motor tract in experimental models of minimal hepatic encephalopathy.

MATERIAL AND METHODS

Rats with portocaval anastomosis (n = 8) and rats with carbon tetrachloride induced cirrhosis (n = 11) underwent neurophysiological recording under light anesthesia with propofol. Motor evoked potentials were elicited applying a transcranial electric pulse and were recorded in the tibialis anterior muscle. The effect of the dose of anesthesia was assessed in a group of normal rats (n = 10).

RESULTS

Rats with portocaval anastomosis exhibited a decrease in motor evoked potentials amplitude following surgery (67 +/- 11 to 41 +/- 16%, P < 0.001). Cirrhotic rats exhibited an increase in motor evoked potentials latency after the appearance of ascites (4.65 +/- 0.43 to 5.15 +/- 0.67 ms., P = 0.04). Increasing doses of propofol produced a decrease in the amplitude and an increase in the latency of motor evoked potentials.

CONCLUSION

It is possible to reproduce functional abnormalities of the central motor tract in rats with portocaval anastomosis and carbon tetrachloride induced cirrhosis. The development of motor abnormalities in experimental models of minimal hepatic encephalopathy offers the possibility to investigate the mechanisms involved in the pathogenesis of hepatic encephalopathy and test therapeutic strategies.

[Normality tables in the Spanish population for psychometric tests used in the diagnosis of minimal hepatic encephalopathy]

BACKGROUND AND OBJECTIVE

Minimal hepatic encephalopathy (MHE) induces an impairment in the quality of life and has been found as the first stage in hepatic encephalopathy syndrome. Psychometric Hepatic Encephalopathy Score (PHES) is a psychometric test battery widely utilized in the diagnosis of MHE which requires correction by age and education.

POPULATION AND METHOD

Eight-hundred and eighty four healthy people were included. Trailmaking test-A (TMT-A), TMT-B, digit symbol test (DST), serial dotting (SDT) and line drawing test (LDT) were performed. Age, education, gender, alcohol consumption and hospitalization were recorded. T-student and Pearson correlation were utilized in univariate analyses. A multiple linear regression was performed to detect independent variables associated with psychometric test score. Using the equation from the multiple linear regression, normality tables were built.

RESULTS

Age and education were associated with all 5 tests. An alcohol consumption higher than 10 g per day was associated with a lower score in DST and SDT. A gender influence was seen in TMT-A and TMT-B. Moreover, some differences were found in SDT, TMT-B and LDT according to hospital procedence. In multivariate analyses using multiple linear regression, age and education were independently associated with all five tests.

CONCLUSIONS

Normality tables of the PHES allow investigating MHE in cirrhotics avoiding local control groups. Taking in mind normality tables, PHES could become a gold standard test to analyze further diagnostic methods and to evaluate drugs efficacy in MHE. Normality tables are freely available at http://www.redEH.org.

The EEG assessment of low-grade hepatic encephalopathy: Comparison of an artificial neural network-expert system (ANNES) based evaluation with visual EEG readings and EEG spectral analysis

OBJECTIVE

The EEG provides an objective staging of hepatic encephalopathy (HE), but its interpretation may be biased by inter-observer variability. This study aims at comparing an entirely automatic EEG classification of HE based on an artificial neural network-expert system procedure (ANNES) with visual and spectral analysis based EEG classifications.

METHODS

Two hundred and thirty-eight consecutive cirrhotic patients underwent closed-eye EEG. They were followed up for up to one-year to detect bouts of overt HE and death. The EEG was classified by ANNES, qualitative visual reading, main basic rhythm frequency and spectral analysis. The classifications were assessed on the basis of: (i) match with liver function, (ii) prognostic value and (iii) repeatability.

RESULTS

All classifications were found to be related to the severity of liver failure, with cognitive findings and a history of previous bouts of HE. All of them had prognostic value on the occurrence of overt HE and on survival. The ANNES based classification was more repeatable than the qualitative visual one, and had the advantage of detecting low power EEG, but its efficiency in analyzing low-grade alterations was questionable.

CONCLUSIONS

An entirely automatic - ANNES based - EEG classification of HE can improve the repeatability of EEG assessment, but further improvement of the device is required to classify mild alterations.

SIGNIFICANCE

The ANNES based EEG grading of HE needs further improvements to be recommended in clinical practice, but it is already sufficient for detecting normal and clearly altered EEG tracings.

Analysis of EEG tracings in frequency and time domain in hepatic encephalopathy

Spectral EEG analysis in hepatic encephalopathy (HE) is usually performed disregarding the effect of epoch length, statistical errors and equipment noise. A study on these items was carried out. In addition, spectral analysis and a new analysis, performed in time domain, were compared in the assessment of HE. The EEG tracings of 73 cirrhotic patients with HE were analyzed. Artifact-free periods of about 1 min were selected. Equipment noise was measured by short-circuiting all the electrodes. The equipment noise was notable below 1.5 Hz; the best epoch length was 4s and the statistical errors were minimal for the band with the highest relative power. Nineteen per cent of the tracings were unstable. The spectral values were found to be related to liver function and to the degree of HE, whereas the relationship with psychometric variables was poor. The indexes computed by time-domain analysis were found to be better related to psychometric findings. We have provided information on the optimisation of spectral EEG analysis and presented a time-domain analysis giving results related to psychometric tests and liver function.

Olfactory deficits in patients affected by minimal hepatic encephalopathy: a pilot study

Minimal hepatic encephalopathy (MHE) is the earliest stage of hepatic encephalopathy and is associated with changes in cognitive functions, in electrophysiological parameters, and in cerebral neurochemical/neurotransmitter homeostasis. MHE can be observed in patients with cirrhosis who have no clinical evidence of hepatic encephalopathy (HE). At present, no data are available on a possible olfactory dysfunction in such a syndrome, although the pathophysiology of HE may alter olfactory functions since some of the neurotransmitters impaired in the syndrome are involved in the transmission of olfactory information. In the present paper, we performed a preliminary study aimed at detecting whether identification and recognition odor memory is altered in patients with MHE. Twelve patients diagnosed as MHE on the basis of their scores at the portosystemic encephalopathy (PSE)-syndrome test battery, and 12 age-matched controls were studied. Consistent with the hypothesis, patients performed significantly worse than controls for both odor identification and recognition tasks. In addition, a significant correlation between the two olfactory tests and the PSE-syndrome test score was found. This pattern supports the notion that olfactory alterations related to cognitive dysfunction in patients with MHE may be linked to the pathophysiology of HE.

Neurophysiological investigation of hepatic encephalopathy

The neurophysiological tools used to study hepatic encephalopathy (HE) are the electroencephalogram (EEG) and the evoked potentials (EPs), both exogenous and endogenous. These tools are used (1) to diagnose HE in patients with severe liver disease and mental alteration, (2) to grade overt HE and monitor the effect of treatment for HE, (3) to diagnose minimal HE (4) to predict the occurrence of episodes of overt HE or liver-related death. The rationale for the use of each of these tools together with their theoretical and practical role is reviewed.