Neurophysiological assessment of early hepatic encephalopathy

Role of Brain Biomarkers S-100-Beta and Neuron-Specific Enolase for Detection and Follow-Up of Hepatic Encephalopathy in Cirrhosis before, during and after Treatment with L-Ornithine-L-Aspartate

INTRODUCTION

Hepatic encephalopathy (HE), in the context of liver cirrhosis, seems to result from low-grade cerebral edema of the astrocytes. Serum brain biomarkers S-100-beta und neuron-specific enolase (NSE) are often elevated in brain injury. We hypothesized that neuromarkers S-100-beta and NSE can be used in the diagnosis of HE, compared with standardized diagnostic tools.

MATERIAL AND METHODS

A prospective non-randomized intervention study was performed using L-ornithine-L-aspartate (LOLA) for HE treatment. Primary endpoint was the evaluation of neuromarkers S-100-beta and NSE for detection and diagnosis of follow-up of HE. As secondary endpoints, the efficacy of LOLA on the course of HE and the diagnostic role of Portosystemic-Encephalopathy-Syndrome score (PHES) and critical flicker frequency (CFF) were analyzed. For diagnosis of covert (CHE) and overt (OHE) HE, West-Haven criteria (WHC), PHES and CFF were assessed at study entry. LOLA was applied (20 g i.v.) for 6 days. At the end of the study, HE evaluation was repeated. S-100-beta, NSE and ammonia were assessed in each patient before, during and after therapy with LOLA.

RESULTS

30 patients were included. At study entry, CHE was diagnosed in 50% and OHE in 50% of all subjects. A total of 25 participants completed the study. After LOLA therapy, deterioration of HE occurred in <11%, while most patients showed improvement (e.g. improved CFF in 79%). No significant correlation with HE severity (as diagnosed by WHC, PHES and CFF) could be demonstrated for any biochemical parameter. In addition, there were no significant changes in brain biomarkers during the treatment period.

DISCUSSION

While CFF as well as PHES showed good correlation with treatment response, S-100-beta and NSE did not significantly correlate with HE severity compared to proven diagnostic methods, and do not seem reliable biochemical markers for the follow-up under therapy.

Laboratory Abnormalities of Hepatic Encephalopathy

Currently, there is no gold standard serologic or imaging modality to detect hepatic encephalopathy (HE). It is a clinical diagnosis gathered from the history and physical. Imaging is nonspecific; however, PET and MRI have shown areas of utility, but are not widely available, cost-efficient, or necessary for diagnosis. Electroencephalogram has shown promise as it can be used in conjunction with the Portal Systemic Hepatic Encephalopathy Score test to diagnose minimal HE. Further research on these techniques would need to be performed to identify strict criteria and cutoffs for diagnosing HE as well as associated sensitivities and specificities.

Muscle performance and fatigue in compensated chronic liver disease

Background: A common and debilitating symptom in patients with chronic liver disease is fatigue (CLD). Muscle dysfunction has been suggested to be a key mechanism of fatigue in CLD. Objective: We aimed to evaluate fatigue and the potential association with muscle performance and physical activity in outpatients with CLD. Methods: Two-hundred seventy outpatients with CLD were included, (52 ± 15 years, mean ± SD; 151 females) with autoimmune hepatitis (n = 49), primary biliary cholangitis (n = 45), primary sclerosing cholangitis (n = 46), chronic hepatitis B (n = 57) or C (n = 73). Patients with a Child-Pugh >6 were excluded. The questionnaire Fatigue Impact Scale (FIS) was used to evaluate fatigue, and physical activity was evaluated through a self-reported level of physical activity. Muscle function was assessed with four muscle tests, walking speed, handgrip strength, standing heel-rise test (SHT) and 'Timed Up and Go' test (TUG). Results: The median total FIS score was 30 (40% had FIS > 40, considered high-fatigue). Diminished muscle performance was observed in the SHT (% of predicted value: 53 ± 26%) and with maximum grip strength (85 ± 20%). The FIS score was significantly different between groups of CLDs (p = .004). In multivariate analysis the TUG (p = .001), SHT (p = .005), antidepressants (p < .001), and level of physical activity (p = .001) were associated with fatigue (R² = 29%). Subjects with higher levels of physical activity had lower FIS (p < .001). Conclusions: In patients with CLD, fatigue was associated with low muscle performance and reduced level of physical activity, which could be a potential therapeutic target.

The burden of minimal hepatic encephalopathy: from diagnosis to therapeutic strategies

Minimal hepatic encephalopathy (MHE) is the mildest form of hepatic encephalopathy (HE). It affects the performance of psychometric tests focused on attention, working memory, psychomotor speed, and visuospatial ability, as well as electrophysiological and other functional brain measures. MHE is a frequent complication of liver disease, affecting up to 80% of tested patients. By being related to falls, an impairment in fitness to drive and the development of overt HE, MHE severely affects the lives of patients and caregivers by altering their quality of life and their socioeconomic status. MHE is detected in clinically asymptomatic patients using appropriate psychometric tests and neurophysiological methods that highlight neuropsychological alterations, such as video-spatial orientation deficits, attention disorders, memory, reaction times, electroencephalogram slowing, prolongation of latency-evoked cognitive potentials, and reduction in the critical flicker frequency. Several treatments have been proposed for MHE treatment, including non-absorbable disaccharides, poorly absorbable antibiotics such as rifaximin, probiotics and branched-chain amino acids. However, because of the multiple diagnosis methods, the various endpoints of treatment trials and the variety of agents used in trials, the treatment of MHE is not currently recommended as routine, but only on a case-by-case basis.

Spectral electroencephalogram in liver cirrhosis with minimal hepatic encephalopathy before and after lactulose therapy

BACKGROUND AND AIM

Minimal hepatic encephalopathy (MHE) represents the mildest form of hepatic encephalopathy. Spectral electroencephalogram (sEEG) analysis improves the recognition of MHE by decreasing inter-operator variability and providing quantitative parameters of brain dysfunction. We compared sEEG in patients with cirrhosis with and without MHE and the effects of lactulose on sEEG in patients with MHE.

METHODS

One hundred patients with cirrhosis (50 with and 50 without MHE) were enrolled. Diagnosis of MHE was based on psychometric hepatic encephalopathy score (PHES) of ≤ -5. Critical flicker frequency, model of end-stage liver disease score, and sEEG were performed at baseline in all patients. The spectral variables considered were the mean dominant frequency (MDF) and relative power in beta, alpha, theta, and delta bands. Patients with MHE were given 3 months of lactulose, and all parameters were repeated.

RESULTS

Spectral electroencephalogram analysis showed lower MDF (7.8 ± 1.7 vs 8.7 ± 1.3 Hz, P < 0.05) and higher theta relative power (34.29 ± 4.8 vs 24 ± 6.7%, P = 001) while lower alpha relative power (28.6 ± 4.0 vs 33.5 ± 5.3%, P = .001) in patients with MHE than in patients without MHE. With theta relative power, sensitivity 96%, specificity 84%, and accuracy of 90% were obtained for diagnosis of MHE. After lactulose treatment, MHE improved in 21 patients, and significant changes were seen in MDF (7.8 ± 0.5 vs 8.5 ± 0.6), theta (34.2 ± 4.8 vs 23.3 ± 4.1%), alpha (28.6 ± 4.0 vs 35.5 ± 4.5%), and delta relative power (13.7 ± 3.5 vs 17.0 ± 3.3%) after treatment (P ≤ 0.05).

CONCLUSIONS

Spectral EEG is a useful objective and quantitative tool for diagnosis and to assess the response to treatment in patients with cirrhosis with MHE.

New spectral thresholds improve the utility of the electroencephalogram for the diagnosis of hepatic encephalopathy

OBJECTIVE

The utility of the electroencephalogram (EEG) for the diagnosis of hepatic encephalopathy, using conventional spectral thresholds, is open to question. The aim of this study was to optimise its diagnostic performance by defining new spectral thresholds.

METHODS

EEGs were recorded in 69 healthy controls and 113 patients with cirrhosis whose neuropsychiatric status was classified using clinical and psychometric criteria. New EEG spectral thresholds were calculated, on the parietal P3-P4 lead derivation, using an extended multivariable receiver operating characteristic curve analysis. Thresholds were validated in a separate cohort of 68 healthy controls and 113 patients with cirrhosis. The diagnostic performance of the newly derived spectral thresholds was further validated using a machine learning technique.

RESULTS

The diagnostic performance of the new thresholds (sensitivity 75.0%; specificity 77.4%) was better balanced than that of the conventional thresholds (58.3%; 93.2%) and comparable to the performance of a machine learning technique (72.9%; 76.8%). The diagnostic utility of the new thresholds was confirmed in the validation cohort.

CONCLUSIONS

Adoption of the new spectral thresholds would significantly improve the utility of the EEG for the diagnosis of hepatic encephalopathy.

SIGNIFICANCE

These new spectral EEG thresholds optimise the performance of the EEG for the diagnosis of hepatic encephalopathy and can be adopted without the need to alter data recording or the initial processing of traces.

Chronic Liver Disease Questionnaire would be a primary screening tool of neuropsychiatric test detecting minimal hepatic encephalopathy of cirrhotic patients

AIM

The neuropsychiatric test (NP test) is a clinically available modality to confirm minimal hepatic encephalopathy (MHE), but it takes at least 30 min for outpatients to complete. An easier primary screening tool of the NP test would be helpful to predict MHE in routine testing on the public.

METHODS

We performed a prospective cohort study on 59 cirrhotic outpatients at Kobe University Hospital. Laboratory measurements, the NP test and the Chronic Liver Disease Questionnaire (CLDQ) were performed. As an indicator of MHE, cases with and without two abnormal subsets or more in the NP test were compared, and the independent risk factors were statistically examined. Predictive scoring systems of the risk of MHE were established using multivariate logistic regression.

RESULTS

CLDQ worry (WO) was the best predictive factor of MHE diagnosed by the NP test (P = 0.006). The predictive model using CLDQ WO discriminated well between patients with and without MHE (area under the curve, 0.714; 95% confidence interval, 0.582-0.824). The predictive scores of MHE enable the patient-specific probability to be easily looked up.

CONCLUSION

CLDQ WO was shown to be an independent factor associated with the NP test to diagnose MHE in cirrhotic patients. The easy predictive scoring system of the risk of MHE using CLDQ WO could become a primary screening tool before performing the NP test in a social setting.

Clinical neurophysiology of hepatic encephalopathy

BACKGROUND/OBJECTIVES

Hepatic encephalopathy (HE) has relevant impact on the quality of life of patients and their caregivers and causes relevant costs because of hospitalizations and work days lost. Its quantification is important to perform adequate clinical trials on this relevant complication of cirrhosis and portal-systemic shunting. Clinical neurophysiology, which detects functional alterations of the nervous system, has been applied to the study of HE for over 60 years. This review aims at summarizing and clarifying the role of neurophysiologic techniques in the study of HE.

METHODS

A narrative review was performed aiming at interpreting the cited papers and the techniques on the basis of their physiological and pathophysiological meaning.

RESULTS

The potential role of EEG, quantified EEG, evoked potentials-both exogenous, endogenous and motor-have been clarified to the reader that may be unfamiliar with neurophysiology.

CONCLUSIONS

The EEG, reflecting the oscillatory changes of neural network is the preferable tool to detect and monitor HE, with the exception of its most severe stage, when EEG flattens. SSEP and MEP have indication to detect and monitor transmission alterations that are likely related to myelin changes and microedema.

Diagnosis of minimal hepatic encephalopathy

Minimal hepatic encephalopathy (mHE) has significant impact upon a liver patient's daily living and health related quality of life. Therefore a majority of clinicians agree that mHE should be diagnosed and treated. The optimal means for diagnosing mHE, however, is controversial. This paper describes the currently most frequently used methods-EEG, critical flicker frequency, Continuous Reaction time Test, Inhibitory Control Test, computerized test batteries such as the Cognitive Drug Research test battery, the psychometric hepatic encephalopathy score (PHES) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)-and their pros and cons.

Hepatic Encephalopathy: From the Pathogenesis to the New Treatments

Hepatic encephalopathy is a frequent and serious complication of liver cirrhosis; the pathophysiology of this complication is not fully understood although great efforts have been made during the last years. There are few prospective studies on the epidemiology of this complication; however, it is known that it confers with high short-term mortality. Hepatic encephalopathy has been classified into different groups depending on the degree of hepatic dysfunction, the presence of portal-systemic shunts, and the number of episodes. Due to the large clinical spectra of overt EH and the complexity of cirrhotic patients, it is very difficult to perform quality clinical trials for assessing the efficacy of the treatments proposed. The physiopathology, clinical manifestation, and the treatment of HE is a challenge because of the multiple factors that converge and coexist in an episode of overt HE.

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.

Minimal hepatic encephalopathy does not impair health-related quality of life in patients with cirrhosis: a prospective study

BACKGROUND

Minimal hepatic encephalopathy (HE) is a serious complication of cirrhosis; however, the impact of minimal HE on health-related quality of life (HRQoL) remains controversial. The Psychometric Hepatic Encephalopathy Score (PHES) remains a 'gold standard' for the assessment of minimal HE, but its results clearly differ between studied populations.

AIM

We studied the effect of minimal HE on patient HRQoL.

METHODS

Eighty-seven consecutive cirrhotic patients were included. All patients underwent clinical and psychometric evaluation at the same day. Ten subjects with overt HE confirmed with West Haven criteria were excluded from the study, thus 77 patients were finally analysed. Patients with minimal HE were identified on the grounds of altered PHES. HRQoL was assessed by the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) and the Chronic Liver Disease Questionnaire (CLDQ). Normative reference data for PHES were established from a cohort of 305 healthy Polish subjects.

RESULTS

Twenty-nine (37.7%) patients were diagnosed with minimal HE. When patients with and without minimal HE were compared, HRQoL was not significantly different in none of the SF-36 and CLDQ domains.

CONCLUSION

Minimal HE does not affect HRQoL.

New assessment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a common complication of cirrhosis that requires careful appraisal of the clinical manifestations, evaluation of the underlying neurological disorders, and assessment of liver function and the portal-systemic circulation. This article reviews recent developments in the assessment of HE and discusses the controversy regarding the use of a categorical or a continuous approach in measuring the severity of this condition. New scales facilitate effective monitoring and assessment of episodic HE. Neuropsychological test batteries and neurophysiological tests are of value for evaluating cognitive function in outpatients and can establish the diagnosis of minimal HE, and the severity of low-grade HE. These tools allow better evaluation of the origin of cognitive complaints and help in estimating the risk of accidents. It is now possible to complete the evaluation with measurement of the effects of cognitive impairment on daily living. In difficult cases, imaging of the brain and portal-systemic circulation with magnetic resonance imaging is especially helpful. Based on these studies, neurological signs and symptoms can be attributed to HE in patients with mild liver disease and in those with complex neurological manifestations. The new methods presented are also valuable for investigating the neurological manifestations occurring after liver transplantation.

Minimal hepatic encephalopathy: consensus statement of a working party of the Indian National Association for Study of the Liver

Hepatic encephalopathy (HE) is a major complication that develops in some form and at some stage in a majority of patients with liver cirrhosis. Overt HE occurs in approximately 30-45% of cirrhotic patients. Minimal HE (MHE), the mildest form of HE, is characterized by subtle motor and cognitive deficits and impairs health-related quality of life. The Indian National Association for Study of the Liver (INASL) set up a Working Party on MHE in 2008 with a mandate to develop consensus guidelines on various aspects of MHE relevant to clinical practice. Questions related to the definition of MHE, its prevalence, diagnosis, clinical characteristics, pathogenesis, natural history and treatment were addressed by the members of the Working Party.

Detecção de encefalopatia hepática mínima através de testes neuropsicológicos e neurofisiológicos e o papel da amônia no seu diagnóstico

CONTEXTO: A encefalopatia hepática mínima vem sendo sistematicamente investigada em pacientes com cirrose hepática. Entretanto, existem controvérsias quanto aos melhores métodos, bem como o papel da amônia para seu diagnóstico. OBJETIVO: Avaliar a frequência de encefalopatia hepática mínima diagnosticada através de testes neuropsicológicos e neurofisiológicos em cirróticos, bem como os possíveis fatores de risco para esta condição, incluindo o papel da concentração arterial de amônia em seu diagnóstico. MÉTODOS: Indivíduos com cirrose hepática foram avaliados através do teste de conexão numérica partes A e B (TCN-A e TCN-B) e potencial evocado relacionado a eventos (P300). O diagnóstico de encefalopatia hepática mínima foi feito quando da presença de anormalidade no P300 e em, pelo menos, um dos testes neuropsicológicos. As concentrações arteriais de amônia, a escolaridade e a gravidade da cirrose hepática também foram avaliadas em todos. RESULTADOS: Foram avaliados 48 pacientes cirróticos, com média de idade 50 ± 8 anos, sendo 79% do sexo masculino. As principais causas foram a alcoólica e a viral. O P300 foi anormal em 75% dos casos e o TCN-A e TCN-B anormais em 58% e 65% dos casos, respectivamente. Os resultados do TCN-B foram influenciados pela escolaridade. A frequência de encefalopatia hepática mínima foi de 50%. A concentração arterial de amônia não foi significantemente maior em pacientes com diagnóstico de encefalopatia hepática mínima (195 ± 152 mmol/L versus 148 ± 146 mmol/L; P>0,05). Não houve diferença significante entre os grupos com e sem encefalopatia hepática mínima quanto às demais variáveis estudadas. CONCLUSÃO:A encefalopatia hepática mínima é condição frequente em pacientes com cirrose hepática. A concentração arterial de amônia não parece ter papel importante no seu diagnóstico.

Development and evaluation of the quality of life instrument in chronic liver disease patients with minimal hepatic encephalopathy

OBJECTIVES

The objective was to develop a valid and reliable health-related quality of life (HRQOL) assessment tool to measure the functional and health status of patients with minimal hepatic encephalopathy (mHE).

METHODS

Items potentially affecting the HRQOL of these patients were identified, based on the responses from 53 patients with minimal hepatic encephalopathy, from seven liver experts, four epidemiologists and from a PubMed search of the literature. Results were explored using factor analysis and redundant questions were eliminated. The final stated questionnaire was used in 178 patients with mHE to evaluate its reliability and validity.

RESULTS

Thirty-five items proved to be important for 32 respondents in the item reduction sample. The final instrument included five domains (30 items) which were shown as follows: physical functioning (8 items), psychological well-being (7 items), symptoms/side effects (7 items), social functioning (4 items) and general-health (4 items). An inter-item correlation for each of the five domains ranged from 0.220 to 0.776, with a mean of 0.280. Cronbach's alpha for above five domains was 0.8775, 0.8446, 0.8360, 0.7087 and 0.7016 respectively. The test-retest coefficients for the five domains were 0.94, 0.93, 0.96, 0.82 and 0.83 respectively. Factor analysis showed preservation of five components structure. Cumulative variance of principal components was 63.12%. Patients with more advanced disease seemed to have more impairment of their well-being, especially in the symptoms/side effects domain.

CONCLUSIONS

The instrument is short, easy to administer and is of good validity and reliability in patients with mHE.

Diagnosis of sub-clinical hepatic encephalopathy by Neuropsychological Tests (NP-tests)

AIM

At present, there are no generally accepted diagnostic criteria or methods for sub-clinical hepatic encephalopathy (SHE) associated with liver cirrhosis. We therefore developed an easily conducted computer-aided quantitative neuropsychological function test system for use in routine medical practice.

METHODS

The system was used prepare basic values according to age in 542 healthy subjects, and the results were compared with 292 liver cirrhosis patients. The software is composed of eight tests: NCT-A, NCT-B, Figure Design Test, Digit Symbol Test, Block Design Test, and the Reaction Time-A, Reaction Time-B, and Reaction Time-C.

RESULTS

Performance time is approximately 15 to 20 min. There is no need to select a specific test location and it is convenient to use even without a professional examiner. When the top and bottom 10%, which correspond to the outlier values statistically in the healthy subjects, were used as the cutoff values abnormal results were observed in approximately 25% of the liver cirrhosis patients. Moreover, 58% of the patients had abnormal values according to the results of at least one of the tests.

CONCLUSION

It is expected that this test will be used to further assess the diagnosis and pathology of SHE and that it will be utilized as a routine method of diagnosis.

M, Lucchesi L, Kondo M, Tufik S. Avaliação dos potenciais evocados relacionados a eventos (ERP-P300) em pacientes com cirrose hepática sem encefalopatia

RACIONAL: Na cirrose hepática ocorrem alterações na estrutura do fígado, levando à perda das funções do órgão, com conseqüências neuropsiquiátricas, como disfunções cognitivas. Um dos meios mais efetivos para avaliar objetivamente as funções cognitivas é medir a atividade eletrofisiológica do sistema nervoso central através do potencial evocado relacionado a eventos (ERP-P300). OBJETIVO: Estudar a utilidade do potencial evocado relacionado a eventos (ERP), para avaliar distúrbios cognitivos em pacientes com cirrose hepática e como auxiliar no diagnóstico da encefalopatia hepática mínima. MÉTODO: Foram selecionados 50 pacientes, diagnosticados com cirrose hepática sem sinais clínicos de encefalopatia hepática e 35 voluntários saudáveis de idades e sexo semelhantes. Em todos os pacientes foram realizados exames clínico-neurológico e laboratoriais. Para identificação do prejuízo cognitivo foi utilizado o ERP-P300 e obtida a média da latência da onda P300. RESULTADOS: Houve diferença significativa entre as médias da latência do ERP-P300 do grupo cirrótico e controle. CONCLUSÃO: A realização do ERP-P300 é simples, depende de fatores controláveis de variação e tem fácil reprodutibilidade, podendo ser útil para o rastreio de distúrbios cognitivos em pacientes com cirrose e auxiliar no diagnóstico de encefalopatia hepática mínima.

Minimal hepatic encephalopathy

Minimal hepatic encephalopathy (MHE), formerly known as subclinical hepatic encephalopathy, is the mild cognitive impairment commonly seen in patients who have cirrhosis. Current understanding suggests that MHE forms part of the spectrum of hepatic encephalopathy, although this remains to be proven. Although traditionally viewed as having negligible clinical significance, MHE has a significant impact on quality of life. MHE often goes undiagnosed because in many patients there is no evidence of clinically overt signs of impaired cognition. In addition, the diagnostic criteria for MHE have not been standardized, which means that the exact characteristics of MHE remain in question. This Review focuses on the pathogenesis and neuropsychological findings (incorporating neuroimaging) of MHE, as well as the effect of MHE on quality of life and survival, and developments in treatment.

Therapeutic studies in hepatic encephalopathy

This article has arisen from presentations made at the 4th International Hannover Conference on Hepatic Encephalopathy held in Dresden, 2006. Each author as listed describes their presentation given as part of a section entitled "Therapeutic Studies in Hepatic Encephalopathy." The first section deals with the justification for placebo-controlled trials in hepatic encephalopathy. The other two sections discuss, in detail, outcome parameters for therapeutic studies in the clinical and research setting, respectively.

Bifidobacterium longum with fructo-oligosaccharide (FOS) treatment in minimal hepatic encephalopathy: a randomized, double-blind, placebo-controlled study

Minimal hepatic encephalopathy (MHE) describes patients with chronic liver disease or cirrhosis who have no clinical symptoms of brain dysfunction but perform worse on psychometric tests compared with healthy subjects. The pathogenesis of hepatic encephalopathy is controversial although ammonia has been found to induce cerebral dysfunction. Increased intestinal ammonia production is due to bacterial urease activity and the production of other toxin methabolities, such as mercaptans, thioles. This study assesses the clinical efficacy of Bifidobacterium longum plus fructo-oligosaccharides (FOS) in the treatment of MHE. A total of 60 cirrhotic patients were randomly and equally divided into two groups receiving Bifidobacterium+FOS (17 males, 13 females; mean age, 46+/-11 years) or placebo (16 males, 14 females; mean age, 45+/-12 years), respectively. All patients underwent clinical and laboratory assessment psychometric tests and automated EEG analysis: neurophysiological assessment, liver function assessment, amd neuropsychological assessment. After 90 days of treatment, fasting NH(4) serum levels were significantly decreased (P=0.003), performance on Trail Making Test-A was significantly decreased (P=0.000), performance on Trail Making Test-B was significantly decreased (P=0.000), performance on the symbol digit modalities test was significantly improved (P<0.05), performance on block design was significantly improved (P=0.000), and performance on the MMSE test was significantly improved (P=0.000). We conclude that the improvement in biochemical and neuropsychological tests of the group treated with Bifidobacterium longum+FOS are interesting and merit further, close examination.

Assessment of low-grade hepatic encephalopathy: a critical analysis

BACKGROUND/AIMS

The value of paper-pencil tests and West-Haven-criteria for assessment of low-grade hepatic encephalopathy under conditions of a randomized, double-blind, placebo-controlled, clinical trial was evaluated in a cohort of 217 cirrhotics.

METHODS

Patients were graded at least twice clinically for severity of hepatic encephalopathy and tested concomitantly with a recommended psychometric test battery.

RESULTS

Re-evaluation of the study documentation showed that at study entry 33% and during the study even 50% of the patients were wrongly allocated to minimal or overt hepatic encephalopathy. Despite the participating physicians' training, 31% of the number-connection-tests-A, 20% of the number-connection-tests-B and 28% of the line-tracing-test were in retrospect considered invalid by an independent psychologist. Neither the Portosystemic-Encephalopathy-Syndrome (PSE) test nor the Psychometric-Hepatic-Encephalopathy-Sum (PHES)-score reliably picked up clinical improvement in the individual patient. Although these test scores could statistically differentiate between patients with minimal and overt hepatic encephalopathy, the clinical classification of individual patients into one of the groups will have a high rate of error. The PHES-Score was less balanced than the score derived from the PSE-Syndrome-Test.

CONCLUSIONS

Inaccuracies in conducting paper-pencil tests together with the subjectivity and incorrectness of clinical HE-grading question the usefulness of West-Haven-criteria and paper-pencil tests including related scores for quantification of low-grade HE at least in multicenter approaches.

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.

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.

Electroencephalographic staging of hepatic encephalopathy by an artificial neural network and an expert system

AIM OF THE STUDY

To provide an objective EEG assessment of hepatic encephalopathy (HE), we set up and tested an entirely automatic procedure based on an artificial neural network-expert system software (ANNESS).

PATIENTS AND METHODS

A training set sample of 50 EEG (group A) and a test sample of 50 EEG (group B) of 100 cirrhotic patients were considered. The EEGs had been visually classified by an expert electroencephalographer, using a modified five-degree Parsons-Simith classification of HE. The efficiency of the ANNESS, trained in group A, was tested in group B.

RESULTS

Both the ANNESS and the visually-based classifications were found to be correlated to liver insufficiency, as assessed by the Child-Pugh score (Spearman's coefficient rho=0.485, P<0.0001; rho=0.489, P<0.0001, respectively) and by the biochemical indexes of hepatic function (bilirubin: rho=0.31 vs. 0.27; albumin: rho=-0.13 vs. -0.18; prothrombin time rho=-0.35 vs. -0.52). The classifications were found to be correlated to each other (rho=0.84 P<0.0001, Cohen's kappa=0.55). However, the ANNESS overestimated grade 2 EEG alterations.

CONCLUSION

An ANNESS-based classification of EEG in HE provided data comparable with a visually-based classification, except for mild alterations (class 2) that tended to be overestimated. Further optimization of automatic EEG staging of HE is desirable, as well as a prospective clinical evaluation.

Neuropsychological abnormalities in cirrhosis include learning impairment

BACKGROUND/AIMS

Minimal hepatic encephalopathy is a neurocognitive disorder secondary to liver failure that is characterized by a pattern of subcortical impairment. The most conspicuous neuropsychological abnormalities are on attention and psychomotor tests; memory has been inconsistently implicated. We designed a study to assess the presence of memory abnormalities in cirrhotic patients and the effects of liver transplantation.

METHODS

Ninety-seven cirrhotics without overt hepatic encephalopathy underwent neuropsychological assessment, including the Auditory Verbal Learning Memory Test. The results were compared to those of healthy controls (n=75) and the assessment was repeated at one year of follow-up (n=33) or after liver transplantation (n=23).

RESULTS

Cirrhotic patients exhibited multiple neuropsychological abnormalities, including several disturbances of the Auditory Verbal Learning memory test: learning, long-term memory and recognition. Abnormalities of long-term memory and recognition were corrected after adjusting for learning impairment. Memory abnormalities correlated to attention impairment and to parameters of liver function. Neuropsychological indexes following liver transplantation did not differ from controls. Repeated testing did not have a major effect on neuropsychological tests in healthy subjects and in non-transplanted cirrhotics.

CONCLUSIONS

Learning impairment is present in cirrhotic patients with neuropsychological abnormalities. This abnormality is consistent with attention deficit secondary to minimal hepatic encephalopathy.

Sleep apnoea syndrome and early stage cirrhosis: a pilot study

OBJECTIVES

Hepatic encephalopathy in patients with end-stage liver cirrhosis is associated with alterations in sleep patterns. Cirrhosis may also affect pulmonary function and it might be involved in the development of obstructive sleep apnoea syndrome (OSAS) in patients with ascites. We carried out a study to evaluate the presence of OSAS in cirrhotic patients without evidence of ascites (early stage cirrhosis).

METHODS

We investigated 20 patients with Child A or B cirrhosis (19 and one, respectively) and 10 non-cirrhotic patients with chronic viral hepatitis (disease control group). All subjects were interviewed and underwent a thorough physical examination, a full polysomnographic study and a pulmonary function testing by spirometry. Serum samples were also obtained in order to determine the liver function tests.

RESULTS

The presence of OSAS and inverted sleep patterns was similar in cirrhotic patients and disease controls. However, significant correlations were revealed between age and hypopnoeas per hour of sleep; age and the Apneas/Hypopneas Index (AHI); age and FEV1/FVC; gamma-glutamyl transpeptidase and FEV1/FVC; and total bilirubin and total sleep time.

CONCLUSIONS

Early stage cirrhosis is not associated with sleep disorders and OSAS. However, total bilirubin levels might be a useful laboratory marker for early assessment of disturbance in sleep patterns and therefore of subclinical hepatic encephalopathy in Child A cirrhosis.

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.

Attention dysfunction in cirrhotic patients: an inquiry on the role of executive control, attention orienting and focusing

Attention alterations are reported in cirrhotics. Aiming at clarifying attention functioning in cirrhotics, an inquiry on the functioning of the anterior (AAS) and the posterior (PAS) attention system was performed. Thirty-six cirrhotics without overt hepatic encephalopathy (24 with EEG or TMT-A alterations) and 16 matched control subjects were enrolled. The AAS was studied by the Stroop task measuring selective attention control, the PAS was studied by the Posner task and the Focus task measuring automatic covert orienting and visual focusing of attention respectively. Cirrhotics presented a task-dependent psychomotor slowing (Stroop > Posner > Focus) with an increased percentage of errors in the incongruent condition of the Stroop task [F(1, 57) = 4.9, p < 0.03]. Class C patients had both a selective slowing [F(1, 33) = 4.3, p < 0.05] and an increased percentage of errors in the incongruent condition [F(1, 34) = 5.1, p < 0.05] compared to Class A-B patients and controls. The patients with an altered EEG performed the Stroop test significantly slowly than those without EEG alterations [F(1, 41) = 8.9, p < 0.01] and with a clear trend for a higher number of errors in the incongruent condition [F(1, 39) = 3.8, p < 0.06]. In contrast, attention orienting and focusing were maintained. In conclusion, the AAS is more sensitive than the PAS to the early stages of hepatic encephalopathy.

Quantification of changes in electroencephalographic power spectra in a patient with Budd-Chiari-syndrome after implantation of a transjugular intrahepatic portosystemic stent shunt (TIPSS)

We examined a 41-year-old female with a subacute Budd-Chiari Syndrome (BCS) before and after implantation of a transjugular intrahepatic portosystemic stent shunt (TIPSS) by means of digital electroencephalography (EEG). After TIPSS implantation hepatic decompression had been achieved and the liver function as well as the clinical status improved daily. Simultaneously, the digital EEG showed a decrease in the power of the theta band and an increase in the physiological alpha frequency band. The theta/alpha ratio decreased after TIPSS, despite an elevated arterial ammonia level. The patient had a well-preserved liver parenchyma before the occurrence of the BCS. After portal decompression by TIPSS, the liver function normalized and the liver resumed efficient synthesis and parts of its detoxification task. This regeneration capacity was documented by a rise in cholinesterase after TIPSS. After temporary substitution of albumin the serum albumin concentration returned to normal. Thus, some neurotoxic substances with high albumin-binding capacity may not be absorbed by the central nervous system (CNS). Furthermore, it appears likely that the length of time the brain is exposed to neurotoxic substances plays a role in the clinical and electroencephalographic changes. Compared to the conventional EEG the theta/alpha ratio reflected better metabolically conditioned electroencephalographic changes after TIPSS.

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

There is no "gold standard" for diagnosing hepatic encephalopathy in patients with cirrhosis. In consequence, the presence of this condition, unless floridly overt, is often missed. As a result, the majority of patients are denied the benefits of treatment. There are a number of individual techniques, which access different aspects of cerebral function that can be used, singly or in combination, to provide diagnostic information in this condition, including mental state assessment, psychometric testing, electroencephalography, sensory and cognitive evoked potentials, and neuroimaging. These have been variously applied to the study of hepatic encephalopathy but fundamental differences in the essential aims of the studies, as well as differences in the patient populations and the acquisition and analysis of the data, have made comparisons difficult. Thus, there is no clear consensus as to the sensitivity, specificity, or validity of these tests when used alone or in combination. There are, however, a number of additional methods that could be used to analyze the electrophysiological data, and a number of alternative evoked potentials that could be measured to provide better diagnostic information. In addition, there are a number of techniques, such as critical flicker frequency and smooth pursuit eye movements, which have not yet been applied systematically in this condition and which may provide useful diagnostic information. Clearly the methods for assessing hepatic encephalopathy need to be reviewed, newer methods for analyzing the electrophysiological data and newer techniques for assessing alternative aspects of cerebral function need to be explored for their diagnostic utility. This process should aim at developing a multidimensional diagnostic tool.

Characteristics of minimal hepatic encephalopathy

The term minimal hepatic encephalopathy refers to the subtle changes in cognitive function, electrophysiological parameters, cerebral neurochemical/neurotransmitter homeostasis, cerebral blood flow, metabolism, and fluid homeostasis that can be observed in patients with cirrhosis who have no clinical evidence of hepatic encephalopathy. Use of this term emphasizes the fact that the entity of hepatic encephalopathy is a single syndrome with quantitatively distinct features relating to severity. The absence of clinical evidence of hepatic encephalopathy is key to the diagnosis and can only be determined by a detailed assessment of the patients' history and a comprehensive neurological assessment of consciousness, cognitive, and motor function. The neuropsychological features of minimal hepatic encephalopathy point to a disorder of executive functioning, particularly selective attention and psychomotor speed, but other abnormalities may be observed. Alterations in electrophysiological variables have been described; endogenous evoked potentials are, in principle, more likely to reflect the presence of minimal hepatic encephalopathy, since they reflect cognitive phenomena rather than mere stimulus conduction but the specificity of the changes observed is unclear at present. Changes have also been described in the execution of diadochokinetic movements and in the capacity to discriminate flickering light, both of which may have diagnostic potential. The changes observed in cerebral blood flow and metabolism in SPET, PET, and 1H and 31P MRS studies reflect the pathogenic process that underlies the condition rather than providing diagnostic information. Similarly, the morphological brain abnormalities identified in this population, including mild brain oedema, hyperintensity of the globus pallidus and other subcortical nuclei observed in cerebral MR studies, and the central and cortical atrophy observed in neural imaging studies, are unlikely to have diagnostic utility. The presence of minimal hepatic encephalopathy is not without clinical consequence; it has a detrimental effect on health-related quality of life, the ability to perform complex tasks such as driving, and on outcome.

Human testing of pesticides: ethical and scientific considerations

I reviewed ethical and scientific aspects of 6 human pesticide-dosing studies submitted to the Environmental Protection Agency (EPA) for consideration during the pesticide reregistration process. All had serious ethical or scientific deficiencies-or both-including unacceptable informed consent procedures, unmanaged financial conflicts of interest, inadequate statistical power, inappropriate test methods and endpoints, and distorted results. Given today's knowledge of the effects of pesticides, there is no assurance that any such study can be completely free of short-term risks, long-term risks, or both. Therefore, there is no basis for allowing pesticide studies to continue or for using them during the pesticide reregistration process. An EPA committee that is free from political and financial conflicts of interest should review this practice.

Synbiotic modulation of gut flora: effect on minimal hepatic encephalopathy in patients with cirrhosis

Minimal hepatic encephalopathy (MHE) is an important disorder that may seriously impair daily functioning and quality of life in patients with cirrhosis. Treatment with lactulose is of benefit. The possible role of synbiotics (probiotics and fermentable fiber) has not been assessed. We screened 97 consecutive cirrhotic patients without overt hepatic encephalopathy for MHE using the number connection test and measurement of brainstem auditory evoked potentials. MHE, defined by abnormality on at least one test modality, was present in 58 (60%) patients. Fifty-five of these patients with MHE were randomized to receive a synbiotic preparation (n = 20), fermentable fiber alone (n = 20), or placebo (n = 15) for 30 days. Cirrhotic patients with MHE were found to have substantial derangements in the gut microecology, with significant fecal overgrowth of potentially pathogenic Escherichia coli and Staphylococcal species. Synbiotic treatment significantly increased the fecal content of non-urease-producing Lactobacillus species at the expense of these other bacterial species. Such modulation of the gut flora was associated with a significant reduction in blood ammonia levels and reversal of MHE in 50% of patients. Synbiotic treatment was also associated with a significant reduction in endotoxemia. The Child-Turcotte-Pugh functional class improved in nearly 50% of cases. Treatment with fermentable fiber alone was also of benefit in a substantial proportion of patients. In conclusion, treatment with synbiotics or fermentable fiber is an alternative to lactulose for the management of MHE in patients with cirrhosis.

Minimal hepatic encephalopathy impairs fitness to drive

It has been suggested that the ability to drive a car is impaired in patients with cirrhosis of the liver and minimal hepatic encephalopathy (MHE). However, the only study using an on-road driving test did not reveal such an impairment. In a prospective controlled study, we evaluated patients with cirrhosis of the liver for MHE and the ability to drive a car. MHE was diagnosed using three psychometric tests: Number Connection Test Part A, Digit Symbol Test, and a Complex Choice Reaction Test. In a standardized on-road driving test (22 miles, 90 minutes), designed for patients with brain impairment, a professional driving instructor blind to the subjects' diagnosis and test results assessed the driving performance. Four global driving categories (car handling, adaptation to traffic situation, cautiousness, maneuvering), 17 specific driving actions (e.g., changing lanes, overtaking, etc.), and a total score of driving performance were rated using a 6-point scale. Of 274 consecutive patients with liver cirrhosis, 48 fulfilled the medical and driving inclusion criteria, 14 of them with and 34 without MHE. Forty-nine subjects in a stable phase of chronic gastroenterological diseases and with normal liver findings served as controls. The total driving score of patients with MHE was significantly reduced in comparison to either cirrhotic patients without MHE or to controls (P <.05). Significant differences in ratings were found in the following driving categories: car handling, adaptation, and cautiousness. Significant differences were also found in specific driving actions. The instructor had to intervene in the driving of 5 of the 14 MHE patients to avoid an accident, significantly more than in cirrhotic patients without MHE and in controls. There was no significant difference in any driving category or specific driving action in cirrhotic patients without MHE compared to controls. In conclusion, fitness to drive a car can be impaired in patients with MHE. Therefore, patients with liver cirrhosis should be tested for MHE and informed in the case of abnormal test results. Therapy known to improve psychometric test results should be initiated.

Effects of haemodialysis and continuous ambulatory peritoneal dialysis on P300 cognitive potentials in uraemic patients

The aim of this study was to determine the effects of haemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) on P300 cognitive potentials in patients with chronic renal failure (CRF) and to find out if P300 potential is a valuable marker for following subclinical cognitive disorder. This study was performed in 42 patients with chronic uraemia, of whom 25 were on HD and 17 on CAPD, and in 25 healthy subjects. All the subjects were investigated in terms of P300 cognitive potential obtained from auditory stimuli with the oddball paradigm and the Mini-Mental State (MMS) examination. Patients undergoing HD were evaluated before (pre-dialysis) and after (post-dialysis) standard HD treatment. P300 latency was longer in HD patients than in the control group and CAPD patients. The MMS score was greater and P300 latency was shorter after a standard HD session when compared to pre-dialysis values in HD patients (p < 0.001 for both values). There was a negative correlation between P300 latency and MMS scores, and a positive correlation between P300 amplitude and MMS scores. In conclusion, P300 is useful for evaluating cognitive function in uraemia, even in asymptomatic patients, and CAPD is superior to HD in the management of cognitive impairment.

Value of regional cerebral blood flow in the evaluation of chronic liver disease and subclinical hepatic encephalopathy

AIMS

Regional changes in cerebral blood flow in patients with chronic hepatitis, cirrhosis and subclinical hepatic encephalopathy were investigated in the present study using single photon emission computed tomography (SPECT).

METHODS

Twenty patients with cirrhosis, 11 patients with chronic hepatitis, and nine healthy controls were included in the study. Cerebral SPECT were obtained for all patients. The percentages of cerebral blood flow of 14 regions to the cerebellar blood flow were determined. Only the patients with cirrhosis underwent psychometric evaluation: visual evoked potentials (VEP) measurements and electroencephalogram (EEG) recordings along with blood levels of albumin, bilirubin, and ammonia were measured and prothrombin time was determined in cirrhotic patients. These patients were classified according to the Child-Pugh classification.

RESULTS

Among cirrhotic patients, six had abnormal results in VEP studies, 11 in psychometric tests and with six in EEG evaluation. Any abnormality in psychometric tests and/or VEP studies is taken as the main criterion; subclinical hepatic encephalopathy was detected in 12 of 20 patients. According to SPECT results in patients with subclinical encephalopathy, a statistically significant decrease in cerebral blood flow in right thalamus and nearly significant decrease in left thalamus were observed. Regional blood flow was significantly higher in the frontal lobes of patients with cirrhosis when compared with healthy controls. Similarly, cerebral blood flow in frontal and cingulate regions was significantly higher in patients with chronic hepatitis than in healthy controls. There was no relationship between cerebral blood flow and blood levels of ammonia or Child-Pugh score, in cirrhotic patients.

CONCLUSION

Significant changes in cerebral blood flow may be present in chronic liver diseases and the authors suggest that the measurement of changes in cerebral blood flow might be useful in detecting subclinical hepatic encephalopathy.

Auditory P300 event related potentials and serotonin reuptake inhibitor treatment in patients with fibromyalgia

BACKGROUND

The P300 components of auditory event related potentials (ERPs) are objective measures related to information and cognitive processing.

OBJECTIVES

To assess P300 ERPs in female patients with fibromyalgia (FM) in comparison with healthy age matched controls. To investigate the relationship between P300 potentials and pain threshold levels of patients, and subsequent effect of sertraline treatment on P300 potentials.

METHODS

P300 auditory ERPs were studied in 13 untreated female patients with FM and 10 healthy controls matched for age, sex, and education. Pain pressure thresholds and total myalgic scores (TMS) were assessed with an algometer. Patients were evaluated for clinical measures and P300 potentials (recorded from the vertex) at the first visit, and then in the fourth and eighth weeks of sertraline treatment.

RESULTS

Patients with FM had significantly lower P300 amplitudes, but not significantly different P300 latencies, than controls at entry. P300 latencies in patients correlated negatively with TMS (r(s)=-0.79, p<0.01) and P300 amplitudes correlated significantly with TMS (r(s)=0.53, p<0.05). Anxiety and depression scores did not correlate significantly with P300 latencies or amplitudes at the study entry. P300 auditory ERPs had increased amplitudes that had reached nearly the same levels as those of the controls at the eighth week without any significant change in their latencies.

CONCLUSION

The results show reduced P300 amplitudes in patients with FM. Further studies assessing the relationship between P300 ERPs and neuropsychiatric tests are required for better clarification of the clinical relevance of P300 potentials in FM.

Electrophysiological and neuropsychological tests for the diagnosis of subclinical hepatic encephalopathy and prediction of overt encephalopathy

BACKGROUND

Subclinical hepatic encephalopathy (SHE) features in 30-84% of patients with cirrhosis of the liver. Its clinical significance with regards to progression to overt encephalopathy has however, not been established.

AIMS

The present study was conducted (i) to compare the diagnostic usefulness of neuropsychological tests with that of electrophysiological (EP) tests in detection of SHE, and (ii) to examine the natural course of SHE.

METHODS

Seventy-five-nonencephalopathic cirrhotics (11 females, 64 males; mean (+/- SD) age 43.6 (+/- 11.7) years; mean (+/- SD) education 11(+/- 3) years) were studied using a battery of tests for intelligence and memory, the number connection test (NCT), and EP tests viz. electroencephalogram (EEG) and auditory P300 event related potentials (P3ERP). All the patients were followed up for a period of 6 months to 2 years for development of overt encephalopathy.

RESULTS

Thirty-five out of 75(47%) patients were diagnosed to have SHE based on at least one abnormal test result. The P3ERP latencies detected SHE in maximum number of patients (23%) followed by EEG (21%). Nearly 59% of patients with SHE progressed to overt encephalopathy within a mean duration of 4 months. Multivariate analysis showed that prior episode of encephalopathy (RR = 6.3; 95% CI = 2.0-19.7), abnormality on EEG (RR = 7.5; 95% CI = 2.2-25.3), abnormal performance on psychometric battery of tests (RR = 35.2; 95% CI = 4.3-287.3), occurrence of gastrointestinal bleed (RR = 19.3; 95% CI = 4.1-88.9), occurrence of dehydration (RR = 10.7; 95% CI = 2.5-45.4) and infection (RR = 11.4; 95% CI = 2.0-64.4) had significantly higher risk for development of overt encephalopathy.

CONCLUSIONS

EP methods were more sensitive in detection of SHE. Amongst all the tests used, presence of only an abnormal EEG was significantly associated with development of overt encephalopathy along with the precipitating factors.

Quantification of the electroencephalographic theta/alpha ratio for the assessment of portal-systemic encephalopathy following implantation of transjugular intrahepatic portosystemic stent shunt (TIPSS)

The aim of the study was the quantification of metabolically caused electroencephalographic changes of portal-systemic encephalopathy, a prototype of hepatic encephalopathy. We examined 12 patients with liver cirrhosis before and after implantation of a transjugular intrahepatic portosystemic stent shunt (TIPSS) by means of quantitative digital electroencephalography (EEG). One month after TIPSS implantation, all patients showed an increase in the power of the theta frequency band as well as a decrease in the power of the alpha frequency band. To reduce the error variance, we formed the quotient of the relative power of the theta and alpha frequency band. Theta/alpha quotient values over 0.7 indicate a general change of the EEG with a sensitivity of 93% and a specificity of 87%. The results we have to hand indicate a correlation between the albumin concentration and the theta/alpha quotient 1 and 3 months after TIPSS. No significant correlation was revealed with regard to the Child-Pugh score or the liver function parameters cholinesterase, bilirubin, and prothrombin time. Neither the arterial ammonia concentration nor the performance in the psychometric test showed significance in relation to the theta/alpha quotient. Substances with a high albumin bond and potential neurotoxicity may--in the case of lower albumin levels--be absorbed with increased frequency in the CNS and may be responsible for the observed EEG change.