Bradykinesia in minimal hepatic encephalopathy is due to disturbances in movement initiation

Hyperammonemia induces microglial NLRP3 inflammasome activation via mitochondrial oxidative stress in hepatic encephalopathy

BACKGROUND

The role of nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome in the pathogenesis of hepatic encephalopathy (HE) is unclear. Mitochondrial reactive oxygen species (mtROS) is a signal for NLRP3 inflammasome activation. Therefore, we aimed to determine whether mtROS-dependent NLRP3 inflammasome activation is involved in HE, using in vivo and in vitro models.

METHODS

Bile duct ligation (BDL) in C57/BL6 mice was used as an in vivo HE model. NLRP3 activation was assessed in the hippocampus. Immunofluorescence staining was performed to determine the cellular source of NLRP3 in the hippocampal tissue. For the in vitro experiment, BV-2 microglial cells were primed with lipopolysaccharide (LPS), followed by ammonia treatment. NLRP3 activation and mitochondrial dysfunction were measured. Mito-TEMPO was used to suppress mtROS production.

RESULTS

BDL mice showed cognitive impairment with hyperammonemia. Both the priming and activation steps of NLRP3 inflammasome activation were processed in the hippocampus of BDL mice. Moreover, intracellular ROS levels increased in the hippocampus, and NLRP3 was mainly expressed in the microglia of the hippocampus. In LPS-primed BV-2 cells, ammonia treatment induced NLRP3 inflammasome activation and pyroptosis, with elevation of mtROS and altered mitochondrial membrane potential. Pretreatment with Mito-TEMPO suppressed mtROS production and the subsequent NLRP3 inflammasome activation and pyroptosis under LPS and ammonia treatment in BV-2 cells.

CONCLUSIONS

Hyperammonemia in HE may be involved in mtROS overproduction and subsequent NLRP3 inflammasome activation. Further studies using NLRP3-specific inhibitor or NLRP3 knockout mice are needed to elucidate the important role of NLRP3 inflammasome in HE development.

Minimal Hepatic Encephalopathy Affects Daily Life of Cirrhotic Patients: A Viewpoint on Clinical Consequences and Therapeutic Opportunities

Minimal hepatic encephalopathy (MHE) is a frequent complication of hepatic encephalopathy (HE) and can affect up to 80% of patients with liver cirrhosis. It is characterized by the lack of obvious clinical signs and the presence of alterations detectable using psychometric or electrophysiological testing focused on attention, working memory, psychomotor speed and visuospatial ability. Ideally, each patient should be tested for this condition because, despite the absence of symptoms, it has severe repercussions on daily life activities. It may be responsible for an inability to drive, sleep disturbances, risk of falls and inability to work. Some studies have highlighted its prognostically unfavorable role on mortality and risk of "overt" HE (OHE). Finally, MHE severely affects the lives of patients and caregivers, altering their quality of life and their socioeconomic status. Several treatments have been proposed for MHE treatment, including non-absorbable disaccharides, poorly absorbable antibiotics, such as rifaximin, probiotics and branched-chain amino acids, with promising results. For this reason, early diagnosis and intervention with appropriate measures is essential, with the aim of improving both performance on psychometric tests, as well as clinical aspects related to this condition.

Time dependent alteration of locomotor behavior in rat with acute liver failure induced cerebellar neuroinflammation and neuro-astroglial damage

Hepatic encephalopathy (HE) is a neurophysiological syndrome secondary to acute or chronic liver failure. Studies showed that HE patients exhibit a deficit in motor coordination, which may result from cerebellar functional impairment. The aim of this study is to assess the time-dependent alteration of locomotor behavior and the glial and neuronal alteration in rat with acute HE induced chemically. The study was carried out in male Sprague-Dawley rats with thioacetamide (TAA) induced acute liver failure at different stages 12 h, 24 h and 36 h. Hepatic and renal functions were assessed via various biochemical and histopathological examinations, while the cerebellum and the midbrain were examined using histology and immunohistochemistry for tyrosine hydroxylase (TH), cyclooxygenase-2 (COX-2) and glial fibrillary acidic protein (GFAP). We used as well, the open field test and the Rotarod test for assessing the locomotor activity and coordination. Our data showed a progressive loss of liver function and a progressive alteration in locomotor behavior and motor coordination in acute HE rats. In the cerebellum, we noted an increase in the degeneration of cerebellar Purkinje neurons parallel to increased COX-2 immunoreactivity together with astrocytic morphology and density changes. Likewise, in substantia nigra pars compacta, TH levels were reduced. We showed through the current study, a progressive deterioration in locomotor behavior in acute HE rats, as a result of Purkinje neurons death and a deficient dopaminergic neurotransmission, together with the morpho-functional astroglial modifications involving the oxidative stress and neuroinflammation.

The role of astrocytes in generating circadian rhythmicity in health and disease

Evidence is accumulating that the mammalian circadian clock system is considerably more complex than previously believed, also in terms of the cell types that actually contribute to generating the oscillation within the master clock, in the suprachiasmatic nuclei of the hypothalamus. Here we review the evidence that has lead to the identification of a bona fide astrocytic circadian clock, and that of the potential contribution of such clock to the generation of circadian and seasonal rhythmicity in health and in neurodegenerative disorders. Finally, we speculate on the role of the astrocytic clock in determining some of the clinical features of hepatic encephalopathy, a reversible neuropsychiatric syndrome associated with advanced liver disease, which is characterized by transient, profound morphological and functional astrocytic abnormalities, in the absence of significant, structural neuronal changes.

Altered Intrinsic Brain Activity and Functional Connectivity Before and After Knee Arthroplasty in the Elderly: A Resting-State fMRI Study

Objective: This study aimed to investigate the brain functional alterations with resting-state functional magnetic resonance imaging (rs-fMRI) in older patients with knee osteoarthritis (KOA) before and after total knee arthroplasty (TKA) and to assess the causal relationship of the brain function and neuropsychological changes.

Methods: We performed rs-fMRI to investigate brain function of 23 patients aged ≥65 with KOA and 23 healthy matched controls. Of the KOA patients, 15 completed postoperative rs-fMRI examinations. Analyzes of the amplitude of low-frequency fluctuation (ALFF) and functional connectivity (FC) were used to estimate differences in brain functional parameters between KOA patients, postoperative patients, and the controls. The relationship between changes of pre- and post-surgical status in ALFF and neuropsychological test results was analyzed.

Results: Compared with the controls, all patients with KOA exhibited decreased ALFF in the default mode network (bilateral angular gyrus, precuneus gyrus, medial superior frontal gyrus) and increased ALFF in the bilateral amygdala and cerebellum posterior lobe before surgery (P < 0.001). Altered ALFF persisted in the same brain regions 1 week postoperatively. The decreased ALFF in the left precuneus gyrus and middle temporal gyrus was found after surgery when compared with preoperative data (P < 0.01). Preoperatively, the KOA patients exhibited increased FC between the left precuneus gyrus and the right supplementary motor area compared to the controls (P < 0.001), but this connectivity became no significant difference after TKA. The left Cerebelum_9 was found to have decreased FC with the right precuneus gyrus postoperatively (P < 0.001) although this was not significantly different before surgery. The significantly altered ALFF values were not correlated with changes in cognitive assessment scores.

Conclusion: In older patients with end-stage KOA, functional alterations in important brain regions were detected with the persistence and further changes observed at an early stage after knee replacement. Our data further our understanding of brain functional abnormalities and cognitive impairment in older patients following knee replacement, which may provide therapeutic targets for preventive/treatment strategy to be developed.

Trial registration: Clinical Trial Registration: http://www.chictr.org.cn/index.aspx, ChiCTR1800016437; Registered June 1, 2018.

Motor and Cognitive Performance in Patients with Liver Cirrhosis with Minimal Hepatic Encephalopathy

Minimal hepatic encephalopathy (MHE) is associated with mild cognitive impairment and frailty. This study aims to identify cognitive and motor differences in cirrhotic patients with and without MHE, and the correlations between motor signs and cognitive performance. Gait, balance, hand strength and motor speed performance were evaluated in 66 cirrhotic patients (38 without and 28 with MHE, according to the Psychometric Hepatic Encephalopathy Score (PHES). Cognitive performance was measured with the Mini-Mental State Examination, Verbal Fluency Test, Aprendizaje Verbal España-Complutense Test (TAVEC), Wechsler Adult Intelligence Scale III, Hamilton Depression and Anxiety Rating Scale and Functioning Assessment Short Test (FAST). MHE patients performed worse than patients without MHE in cognitive and autonomous functioning, learning and long-term memory, and verbal fluency. The same pattern was found in gait, center of pressure movement, variability of hand strength performance and hand motor speed. In MHE patients, high correlations were found between balance and FAST test, gait velocity and verbal skills, hand strength variability and anxiety and depression, and motor speed and FAST and TAVEC. MHE patients showed worse motor and cognitive performance than patients without MHE. MHE patients could have impaired movement control expressed as bradykinesia, and this reduced motor performance could correlate with cognitive performance.

Important Unresolved Questions in the Management of Hepatic Encephalopathy: An ISHEN Consensus

Management of hepatic encephalopathy (HE) remains challenging from a medical and psychosocial perspective. Members of the International Society for Hepatic Encephalopathy and Nitrogen Metabolism recognized 5 key unresolved questions in HE management focused on (i) driving, (ii) ammonia levels in clinical practice, (iii) testing strategies for covert or minimal HE, (iv) therapeutic options, and (v) nutrition and patient-reported outcomes. The consensus document addresses these topical issues with a succinct review of the literature and statements that critically evaluate the current science and practice, laying the groundwork for future investigations.

Impact of previous episodes of hepatic encephalopathy on short-term brain function recovery after liver transplantation: a functional connectivity strength study

Neuropsychological studies have documented an incomplete reversal of pre-existing cognitive dysfunction in cirrhotic patients after liver transplantation (LT) and have found this is more severe in patients with hepatic encephalopathy (HE). In this study, we aimed to investigate the impact of prior HE episodes on post-transplantation brain function recovery. Resting-state functional magnetic resonance imaging data was collected from 30 healthy controls and 33 cirrhotic patients (HE, n = 15 and noHE, n = 18) before and one month after LT. Long- and short-range functional connectivity strength (FCS) analysis indicated that before transplantation both noHE and HE groups showed diffuse FCS abnormalities relative to healthy controls. For the noHE group, the abnormal FCS found before LT largely returned to normal levels after LT, except for in the cerebellum, precuneus, and orbital middle frontal gyrus. However, the abnormal FCS prior to LT was largely preserved in the HE group, including high-level cognition-related (frontal and parietal lobes) and vision-related areas (occipital lobe, cuneus, and precuneus). In addition, comparisons between HE and noHE groups revealed that weaker FCS in default mode network (DMN) in HE group persisted from pre- to post- LT. Correlation analysis showed that changes in FCS in the left postcentral and right middle frontal gyrus correlated with alterations in neuropsychological performance and ammonia levels. In conclusion, the findings in this study demonstrate potential adverse effects of pre-LT episode of HE on post-LT brain function recovery, and reveal that DMN may be the most affected brain region by HE episodes, which can't be reversed by LT.

Reduced resting state connectivity and gray matter volume correlate with cognitive impairment in minimal hepatic encephalopathy

BACKGROUND AND AIMS

Minimal hepatic encephalopathy (MHE) is associated with cognitive alterations and changes in connectivity. We assessed the relationship of the abnormalities of resting-state functional connectivity (rs-FC) and gray matter (GM) volume with different cognitive alterations and biochemical parameters associated to MHE.

METHODS

Thirty-nine cirrhotic patients (26 without and 13 with MHE) and 24 controls were widely cognitive assessed with a battery of psychometric tests. Atrophy was determined using Voxel-Based Morphometry and rs-FC was assessed by independent component analysis. Receiver operating characteristic (ROC) curves was performed to assess the diagnostic utility of rs-FC and GM reduction for the discrimination of patients with and without MHE. Blood ammonia, cGMP, and levels of pro-inflammatory interleukins were measured.

RESULTS

MHE patients showed significant decrease of GM volume and lesser degree of rs-FC in different networks related to attention and executive functions as compared to controls and patients without MHE. There is a progressive reduction in rs-FC in the default mode network with the progression of cognitive impairment. MHE patients showed GM reduction in the right frontal lobe, right insula and right cerebellum compared to patients without MHE. Alterations in GM volume and rs-FC correlated with the scores of different cognitive tests.

CONCLUSIONS

Decreased cognitive performance is associated by reduced rs-FC and GM atrophy in MHE patients. These changes could have predictive value for detecting MHE.

Predictive models of minimal hepatic encephalopathy for cirrhotic patients based on large-scale brain intrinsic connectivity networks

We aimed to find the most representative connectivity patterns for minimal hepatic encephalopathy (MHE) using large-scale intrinsic connectivity networks (ICNs) and machine learning methods. Resting-state fMRI was administered to 33 cirrhotic patients with MHE and 43 cirrhotic patients without MHE (NMHE). The connectivity maps of 20 ICNs for each participant were obtained by dual regression. A Bayesian machine learning technique, called Graphical Model-based Multivariate Analysis, was applied to determine ICN regions that characterized group differences. The most representative ICNs were evaluated by the performance of three machine learning methods (support vector machines (SVMs), multilayer perceptrons (MLP), and C4.5). The clinical significance of these potential biomarkers was further tested. The temporal lobe network (TLN), and subcortical network (SCN), and sensorimotor network (SMN) were selected as representative ICNs. The distinct functional integration patterns of the representative ICNs were significantly correlated with behavior criteria and Child-Pugh scores. Our findings suggest the representative ICNs based on GAMMA can distinguish MHE from NMHE and provide supplementary information to current MHE diagnostic criteria.

Altered postural control and stability in cirrhotic patients with minimal hepatic encephalopathy correlate with cognitive deficits

BACKGROUND & AIMS

Cognitive dysfunction in cirrhotic patients with minimal hepatic encephalopathy (MHE) is associated with falls. Alterations in postural control and stability could contribute to increase falls risk in these patients. We aimed to assess whether postural control and direction-specific limits of stability are altered in cirrhotic patients with MHE compared to patients without MHE and controls. We also assessed if alterations in postural control correlate with neurological impairment and/or blood biomarkers.

METHODS

Posturography analysis, attention Stroop test and bimanual and visuo-motor coordination tests were performed in 18 controls, 19 patients with cirrhosis without MHE and 17 with MHE, diagnosed by PHES. Posturography was assessed by NedSVE^® /IBV system under four sensory conditions. Limits of stability and rhythmic weight-shifting tests were also performed. Blood ammonia and serum interleukins were also measured. Falls were assessed after 12-24 months follow-up.

RESULTS

MHE patients show impaired balance, mainly on unstable surface with eyes open, with longer reaction and confinement times and lower success in Limits of Stability test compared to patients without MHE. Performance in attention and motor coordination tests correlated with most posturography parameters alterations. Logistic regression analysis shows that posturography parameters and bimanual coordination test are good predictors of falls.

CONCLUSION

Balance patterns and limits of stability in MHE patients are impaired compared to patients without MHE and controls. This seems to contribute to a higher falls risk. Attention and motor coordination deficits could contribute to balance impairment in patients with MHE.

Longitudinal Intrinsic Brain Activity Changes in Cirrhotic Patients before and One Month after Liver Transplantation

Objective

To evaluate the spontaneous brain activity alterations in liver transplantation (LT) recipients using resting-state functional MRI.

Materials and Methods

Twenty cirrhotic patients as transplant candidates and 25 healthy controls (HCs) were included in this study. All patients repeated the MRI study one month after LT. Amplitude of low-frequency fluctuation (ALFF) values were compared between cirrhotic patients (both pre- and post-LT) and HCs as well as between the pre- and post-LT groups. The relationship between ALFF changes and venous blood ammonia levels and neuropsychological tests were investigated using Pearson's correlation analysis.

Results

In the cirrhotic patients, decreased ALFF in the vision-related regions (left lingual gyrus and calcarine), sensorimotor-related regions (left postcentral gyrus and middle cingulate cortex), and the default-mode network (bilateral precuneus and left inferior parietal lobule) were restored, and the increased ALFF in the temporal and frontal lobe improved in the early period after LT. The ALFF decreases persisted in the right supplementary motor area, inferior parietal lobule, and calcarine. The ALFF changes in the right precuneus were negatively correlated with changes in number connection test-A scores (r = 0.507, p < 0.05).

Conclusion

LT improved spontaneous brain activity and the results for associated cognition tests. However, decreased ALFF in some areas persisted, and new-onset abnormal ALFF were possible, indicating that complete cognitive function recovery may need more time.

Identifying minimal hepatic encephalopathy in cirrhotic patients by measuring spontaneous brain activity

It has been demonstrated that minimal hepatic encephalopathy (MHE) is associated with aberrant regional intrinsic brain activity in cirrhotic patients. However, few studies have investigated whether altered intrinsic brain activity can be used as a biomarker of MHE among cirrhotic patients. In this study, 36 cirrhotic patients (with MHE, n = 16; without MHE [NHE], n = 20) underwent resting-state functional magnetic resonance imaging (fMRI). Spontaneous brain activity was measured by examining the amplitude of low-frequency fluctuations (ALFF) in the fMRI signal. MHE was diagnosed based on the Psychometric Hepatic Encephalopathy Score (PHES). A two-sample t-test was used to determine the regions of interest (ROIs) in which ALFF differed significantly between the two groups; then, ALFF values within ROIs were selected as classification features. A linear discriminative analysis was used to differentiate MHE patients from NHE patients. The leave-one-out cross-validation method was used to estimate the performance of the classifier. The classification analysis was 80.6 % accurate (81.3 % sensitivity and 80.0 % specificity) in terms of distinguishing between the two groups. Six ROIs were identified as the most discriminative features, including the bilateral medial frontal cortex/anterior cingulate cortex, posterior cingulate cortex/precuneus, left precentral and postcentral gyrus, right lingual gyrus, middle frontal gyrus, and inferior/superior parietal lobule. The ALFF values within ROIs were correlated with PHES in cirrhotic patients. Our findings suggest that altered regional brain spontaneous activity is a useful biomarker for MHE detection among cirrhotic patients.

Liver transplantation nearly normalizes brain spontaneous activity and cognitive function at 1 month: a resting-state functional MRI study

To investigate the short-term brain activity changes in cirrhotic patients with Liver transplantation (LT) using resting-state functional MRI (fMRI) with regional homogeneity (ReHo) method. Twenty-six cirrhotic patients as transplant candidates and 26 healthy controls were included in this study. The assessment was repeated for a sub-group of 12 patients 1 month after LT. ReHo values were calculated to evaluate spontaneous brain activity and whole brain voxel-wise analysis was carried to detect differences between groups. Correlation analyses were performed to explore the relationship between the change of ReHo with the change of clinical indexes pre- and post-LT. Compared to pre-LT, ReHo values increased in the bilateral inferior frontal gyrus (IFG), right inferior parietal lobule (IPL), right supplementary motor area (SMA), right STG and left middle frontal gyrus (MFG) in patients post-LT. Compared to controls, ReHo values of post-LT patients decreased in the right precuneus, right SMA and increased in bilateral temporal pole, left caudate, left MFG, and right STG. The changes of ReHo in the right SMA, STG and IFG were correlated with change of digit symbol test (DST) scores (P < 0.05 uncorrected). This study found that, at 1 month after LT, spontaneous brain activity of most brain regions with decreased ReHo in pre-LT was substantially improved and nearly normalized, while spontaneous brain activity of some brain regions with increased ReHo in pre-LT continuously increased. ReHo may provide information on the neural mechanisms of LT' effects on brain function.

Diagnosis and Treatment of Low-Grade Hepatic Encephalopathy

Minimal hepatic encephalopathy (mHE) is common among patients with cirrhotic liver disease and causes significant morbidity and mortality. It may present as cognitive impairment, behavioural changes and, less frequently, with neurological symptoms which make diagnosis of the disease challenging. A history of falls and accidents may also be suggestive of mHE. Diagnosis primarily relies on at least two positive psychometric tests of which the psychometric hepatic encephalopathy score (PHES) is essential. Alternatively, PHES and an electroencephalogram may be used to establish a diagnosis. Biochemical markers of encephalopathy currently have no role in the diagnosis of mHE. Treatment is not always advocated for a diagnosis of mHE but is dependent on the degree of impairment caused by the symptoms. After treatment of other metabolic abnormalities and co-morbidities associated with cirrhosis, more specific treatment for mHE largely relies on therapies used to lower ammonia levels. Laxatives and rifaximin are commonly used in treatment and work through decreasing ammonia absorption from the gut. Other therapies, such as BCAA, LOLA, L-carnitine and phenylbutyrate, modify responses to ammonia as well as enhancing metabolism and excretion. mHE resulting from spontaneous portosystemic shunts or transhepatic intraportal systemic shunts may require ablation or reduction of the shunt. Early detection and appropriate treatment of mHE is important to prevent significant cognitive impairments and progression to overt HE.

Brain magnetic resonance in hepatic encephalopathy

The term hepatic encephalopathy (HE) covers a wide spectrum of neuropsychiatric abnormalities caused by portal-systemic shunting. The diagnosis requires demonstration of liver dysfunction or portal-systemic shunts and exclusion of other neurologic disorders. Most patients with this condition have liver dysfunction caused by cirrhosis, but it also occurs in patients with acute liver failure and less commonly, in patients with portal-systemic shunts that are not associated with hepatocellular disease. Various magnetic resonance (MR) techniques have improved our knowledge about the pathophysiology of HE. Proton MR spectroscopy and T1-weighted imaging can detect and quantify accumulations of brain products that are normally metabolized or eliminated such as glutamine and manganese. Other MR techniques such as T2-weighted and diffusion-weighted imaging can identify white matter abnormalities resulting from disturbances in cell volume homeostasis secondary to brain hyperammonemia. Partial or complete recovery of these abnormalities has been observed with normalization of liver function or after successful liver transplantation. MR studies have undoubtedly improved our understanding of the mechanisms involved in the pathogenesis of HE, and some findings can be considered biomarkers for monitoring the effects of therapeutic measures focused on correcting this condition.

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.

Covert hepatic encephalopathy: does the mini-mental state examination help?

BACKGROUND/OBJECTIVES

The Mini-Mental State Examination (MMSE) has been utilized for the diagnosis of hepatic encephalopathy (HE). However, its threshold of abnormality has not been formally tested in patients with cirrhosis and its diagnostic/prognostic validity remains unknown. The aim of this study was to assess it in a large group of well-characterized outpatients with cirrhosis and no overt HE.

METHODS

One-hundred-and-ninety-one patients underwent clinical assessment, MMSE, electroencephalography (EEG) and paper-and-pencil psychometry (PHES); 117 were followed up for 8 ± 5 months in relation to the occurrence of HE-related hospitalizations.

RESULTS

On the day of study, 81 patients (42%) had abnormal EEG and 67 (35%) abnormal PHES; 103 (60%) had a history of HE. Average MMSE was 26.6 ± 3.5; 22 (19%) patients had abnormal MMSE based on the standard threshold of 24. Patients with abnormal EEG/PHES/history of HE had worse MMSE performance than their counterparts with normal tests/negative history (25.7 ± 4.2 vs. 27.3 ± 2.7; P < 0.01; 25.5 ± 3.2 vs. 27.9 ± 1.8, P < 0.0001; 26.3 ± 3.7 vs. 27.4 ± 2.6, P < 0.05, respectively). Based on the above results, MMSE thresholds of 26 and 27 were tested against abnormalities in clinical/EEG/PHES indices and significant associations were observed. An MMSE threshold of 26 was also a predictor of HE-related hospitalization (Cox-Mantel: P = 0.001); patients with MMSE <26 were significantly older than those with MMSE ≥26 but comparable in terms of liver dysfunction and ammonia levels. When MMSE items were considered separately, those which correlated most significantly with standard HE indices where spatial orientation and writing.

CONCLUSION

In conclusion, an MMSE <26 identifies older patients with cirrhosis who are more prone to manifest HE signs.

The thalamus in cirrhotic patients with and without hepatic encephalopathy: a volumetric MRI study

BACKGROUND & AIMS

The thalamus is a major relay and filter station in the central neural system. Some previous studies have suggested that the thalamus maybe implicated in the pathogenesis of hepatic encephalopathy. The aim of our study was to investigate changing thalamic volumes in cirrhotic patients with and without hepatic encephalopathy.

METHODS

Neuropsychological tests and structural MR scanning were performed on 24 cirrhotic patients, 23 cirrhotic patients with minimal hepatic encephalopathy, 24 cirrhotic patients during their first episode of overt hepatic encephalopathy, and 33 healthy controls. Voxel-based morphometry analysis was performed to detect gray matter morphological changes. The thalamus and whole brain volume were extrapolated. A receiver operating characteristic curve analysis of thalamic volumes was used to discriminate patients with minimal hepatic encephalopathy from those with hepatic cirrhosis.

RESULTS

Thalamic volume increased in a stepwise manner in patients with progressively worse stages of hepatic encephalopathy compared to healthy subjects. Additionally, a comparison of gray matter morphometry between patients with Child-Pugh grades A, B, or C and controls revealed a progression in thalamic volumes in parallel with the degree of liver failure. Moreover, thalamic volume was significantly correlated with the number connection test A time and digit-symbol test score in cirrhotic patients with minimal hepatic encephalopathy (r=0.659, P=0.001; r=-0.577, P=0.004; respectively). The area under the receiver operating characteristic curve was 0.827 (P=0.001).

CONCLUSIONS

A significantly increased thalamic volume may be provide an objective imaging measure for predicting seizures due to minimal hepatic encephalopathy in cirrhotic patients.

Loss of tyrosine hydroxylase expression within the nigro-striato-cortical pathways in the cirrhotic rat: the possible restorative effect of the neurosteroid dehydroepiandrosterone sulfate

Hepatic encephalopathy (HE) is a neuropsychiatric disorder occurring as a consequence of both acute and chronic liver failure. Advanced HE is generally accompanied with extrapyramidal symptoms including rigidity and tremor, which may reflect alterations of the dopaminergic system. Recently we reported a beneficial effect of the neuroactive steroid dehydroepiandrosterone sulfate (DHEAS) in cirrhotic rats, however the mechanisms of such an effect by DHEAS were not addressed. In the present study, we describe the changes of the dopaminergic system occurring in the cirrhotic rats and concomitantly we investigated the effect of DHEAS on this system in Sprague-Dawley rats using the expression of tyrosine hydroxylase (TH) as a neuronal marker. Rats were submitted to bile duct ligation (BDL) surgery and TH immunohistochemistry was assessed in the Substantia nigra pars compacta (SNc), striatum, ventral tegmental area (VTA) and the cortex. TH immunoreactivity showed a significant diminution in both SNc and VTA concomitantly with the cortical and the striatal outputs in the BDL rats vs. controls. Three daily injections of 5mg/kg of DHEAS to BDL rats significantly normalized TH expression decrease in both SNc and VTA as well as dopaminergic projections to the striatum and the cortex of BDL rats. The present data support an involvement of the dopaminergic system in mild HE and a possible beneficial effect of the neurosteroid DHEAS as a potential pharmacological treatment of mild HE.

Altered regional homogeneity in the development of minimal hepatic encephalopathy: a resting-state functional MRI study

Background

Little is known about how spontaneous brain activity progresses from non-hepatic encephalopathy (non-HE) to minimal HE (MHE). The purpose of this study was to evaluate the evolution pattern of spontaneous brain activities in cirrhotic patients using resting-state fMRI with a regional homogeneity (ReHo) method.

Methodology/Principal Findings

Resting-state fMRI data were acquired in 47 cirrhotic patients (minimal HE [MHE], n = 20, and non-HE, n = 27) and 25 age-and sex-matched healthy controls. The Kendall’s coefficient of concordance (KCC) was used to measure the regional homogeneity. The regional homogeneity maps were compared with ANOVA tests among MHE, non-HE, and healthy control groups and t-tests between each pair in a voxel-wise way. Correlation analyses were performed to explore the relationships between regional ReHo values and Child-Pugh scores, number connection test type A (NCT-A), digit symbol test (DST) scores, venous blood ammonia levels. Compared with healthy controls, both MHE and non-HE patients showed decreased ReHo in the bilateral frontal, parietal and temporal lobes and increased ReHo in the bilateral caudate. Compared with the non-HE, MHE patients showed decreased ReHo in the bilateral precuneus, cuneus and supplementary motor area (SMA). The NCT-A of cirrhotic patients negatively correlated with ReHo values in the precuneus, cuneus and lingual gyrus. DST scores positively correlated with ReHo values in the cuneus, precuneus and lingual gyrus, and negatively correlated with ReHo values in the bilateral caudate (P<0.05, AlphaSim corrected).

Conclusions/Significance

Diffused abnormal homogeneity of baseline brain activity was nonspecific for MHE, and only the progressively decreased ReHo in the SMA and the cuneus, especially for the latter, might be associated with the development of MHE. The ReHo analysis may be potentially valuable for detecting the development from non-HE to MHE.

Impairment of the organization of locomotor and exploratory behaviors in bile duct-ligated rats

Hepatic encephalopathy (HE) arises from acute or chronic liver diseases and leads to several problems, including motor impairment. Animal models of chronic liver disease have extensively investigated the mechanisms of this disease. Impairment of locomotor activity has been described in different rat models. However, these studies are controversial and the majority has primarily analyzed activity parameters. Therefore, the aim of the present study was to evaluate locomotor and exploratory behavior in bile duct-ligated (BDL) rats to explore the spatial and temporal structure of behavior. Adult female Wistar rats underwent common bile duct ligation (BDL rats) or the manipulation of common bile duct without ligation (control rats). Six weeks after surgery, control and BDL rats underwent open-field, plus-maze and foot-fault behavioral tasks. The BDL rats developed chronic liver failure and exhibited a decrease in total distance traveled, increased total immobility time, smaller number of rearings, longer periods in the home base area and decreased percentage of time in the center zone of the arena, when compared to the control rats. Moreover, the performance of the BDL rats was not different from the control rats for the elevated plus-maze and foot-fault tasks. Therefore, the BDL rats demonstrated disturbed spontaneous locomotor and exploratory activities as a consequence of altered spatio-temporal organization of behavior.

Significant volume reduction and shape abnormalities of the basal ganglia in cases of chronic liver cirrhosis

BACKGROUND AND PURPOSE

Chronic liver disease frequently includes cognitive and movement disorders, suggesting an alteration of the striatum. With the exception of hyperintensities evident on T1-weighted images indicative of Mn deposition, radiographic findings of the BG are nonspecific. Volumetric and morphometric analysis of DGM is limited. Whether DGM undergoes degeneration and whether this change is associated with pallidal hyperintensity and cognitive performance are currently unknown in patients with cirrhosis.

MATERIALS AND METHODS

The DGM volumes of 28 patients with chronic cirrhosis and 28 control patients were compared. Using 3D high-resolution MR images, the volume and shape of each structure were automatically analyzed by the FSL. Correlations between the DGM volume and other clinical variables, including the pallidal signal intensity, were assessed by multiple regression analysis.

RESULTS

Patients with Child B and Child C liver disease had significantly smaller bilateral putaminal volumes than control patients, and patients with Child C also demonstrated smaller left caudate nucleus and left amygdala volumes than control patients. Pallidal hyperintensity correlated with smaller striatum volume, which was linearly related to worse cognitive performance. The nonuniform distributed shape abnormalities in the striatum further support the ascending spiral interconnecting theory of the striatum.

CONCLUSIONS

These findings strongly suggest lower DGM volume develops according to the severity of the liver cirrhosis. The Mn deposition might contribute the striatum deficit. These findings support the value of additional psychomotor research associated with liver cirrhosis.

Manganese accumulation in the CNS and associated pathologies

Manganese (Mn) is an essential metal for life. It is a key constituent of clue enzymes in the central nervous system, contributing to antioxidant defenses, energetic metabolism, ammonia detoxification, among other important functions. Until now, Mn transport mechanisms are partially understood; however, it is known that it shares some mechanisms of transport with iron. CNS is susceptible to Mn toxicity because it possesses mechanisms that allow Mn entry and favor its accumulation. Cases of occupational Mn exposure have been extensively reported in the literature; however, there are other ways of exposure, such as long-term parental nutrition and liver failure. Manganism and hepatic encephalopathy are the most common pathologies associated with the effects of Mn exposure. Both pathologies are associated with motor and psychiatric disturbances, related in turn to mechanisms of damage such as oxidative stress and neurotransmitters alterations, the dopaminergic system being one of the most affected. Although manganism and Parkinson's disease share some characteristics, they differ in many aspects that are discussed here. The mechanisms for Mn transport and its participation in manganism and hepatic encephalopathy are also considered in this review. It is necessary to find an effective therapeutic strategy to decrease Mn levels in exposed individuals and to treat Mn long term effects. In the case of patients with chronic liver failure it would be worthwhile to test a low-Mn diet in order to ameliorate symptoms of hepatic encephalopathy possibly related to Mn accumulation.

Motor impairment in liver cirrhosis without and with minimal hepatic encephalopathy

AIM

Manifest hepatic encephalopathy (HE) goes along with motor symptoms such as ataxia, mini-asterixis, and asterixis. The relevance of motor impairments in cirrhotics without and with minimal HE (mHE) is still a matter of debate.

PATIENTS AND METHODS

We tested three different groups of patients with liver cirrhosis: no signs of HE (HE 0), mHE, and manifest HE grade 1 according to the West Haven criteria (HE 1). All patients (n = 24) and 11 healthy control subjects were neuropsychometrically tested including critical flicker frequency (CFF), a reliable measure for HE. Motor abilities were assessed using Fahn Tremor Scale and International Ataxia Rating Scale. Fastest alternating index finger movements were analyzed for frequency and amplitude.

RESULTS

Statistical analyses showed an effect of HE grade on tremor and ataxia (P < 0.01). Additionally, both ratings yielded strong negative correlation with CFF (P < 0.01, R = -0.5). Analysis of finger movements revealed an effect of HE grade on movement frequency (P < 0.03). Moreover, decreasing movement frequency and increasing movement amplitude parallel decreasing CFF (P < 0.01, R = 0.6).

CONCLUSION

Our results indicate that ataxia, tremor, and slowing of finger movements are early markers for cerebral dysfunction in HE patients even prior to neuropsychometric alterations becoming detectable.

Bifidobacterium combined with fructo-oligosaccharide versus lactulose in the treatment of patients with hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy (HE) is a reversible neuropsychiatric syndrome in patients with liver disease. It was suggested that Bifidobacterium+fructo-oligosaccharides (FOS) may decrease blood and brain ammonia levels.

AIM

The study was conducted to compare the efficacy of Bifidobacterium+FOS and lactulose in patients with HE.

METHODS

One hundred and twenty-five patients (35 hepatitis B virus infected, 70 hepatitis C virus infected and 20 cryptogenetic cirrhosis) were enrolled in the study. Patients were randomized either to a treatment for 60 days with Bifidobacterium and FOS (group A) or into-group receiving lactulose (group B) in double-blind.

RESULTS

After 30 days of the study period, the Bifidobacterium+FOS-treated patients compared with lactulose-treated patients showed a significant decrease of Trail Making Test B (TMT B) (P<0.005), and a significant increase of Symbol Digit Modalities Test (P<0.001) and Block Design Test (P<0.001).After 60 days of the study period, the Bifidobacterium+FOS-treated patients compared with lactulose-treated patients showed a significant decrease of NH4 fasting HE1 (P<0.001), TMT A (P<0.05), TMT B (P<0.001), and a significant increase of Symbol Digit Modalities Test (P<0.001) and Block Design Test (P<0.001).

CONCLUSION

The treatment with Bifidobacterium+FOS is an alternative to the use of lactulose in patients with cirrhosis, for its usefulness in reducing blood ammonia levels and improvement of psychometric tests.

Hepatic encephalopathy: pathophysiology and emerging therapies

Hepatic encephalopathy is characterized by neuropsychiatric abnormalities in patients with liver failure. Severe hepatic encephalopathy is an indication for liver transplantation as it portends poor outcome. Treatment of hepatic encephalopathy involves correction of precipitating factors such as sepsis, gastrointestinal bleeding, medications, and electrolyte imbalance. Effective therapies include lactulose and antibiotics such as neomycin, metronidazole, and rifaximin.

MR imaging findings in hepatic encephalopathy

The term hepatic encephalopathy (HE) includes a spectrum of neuropsychiatric abnormalities occurring in patients with liver dysfunction. Most cases are associated with cirrhosis and portal hypertension or portal-systemic shunts, but the condition can also be seen in patients with acute liver failure and, rarely, with portal-systemic bypass and no associated intrinsic hepatocellular disease. Although HE is a clinical condition, several neuroimaging techniques, particularly MR imaging, may eventually be useful for the diagnosis because they can identify and measure the consequences of central nervous system (CNS) increase in substances that under normal circumstances, are efficiently metabolized by the liver. Classic MR imaging abnormalities include high signal intensity in the globus pallidum on T1-weighted images, likely a reflection of increased tissue concentrations of manganese, and an elevated glutamine/glutamate peak coupled with decreased myo-inositol and choline signals on proton MR spectroscopy, representing disturbances in cell-volume homeostasis secondary to brain hyperammonemia. Recent data have shown that white matter abnormalities, also related to increased CNS ammonia concentration, can also be detected with several MR imaging techniques such as magnetization transfer ratio measurements, fast fluid-attenuated inversion recovery sequences, and diffusion-weighted images. All these MR imaging abnormalities, which return to normal with restoration of liver function, probably reflect the presence of mild diffuse brain edema, which seems to play an essential role in the pathogenesis of HE. It is likely that MR imaging will be increasingly used to evaluate the mechanisms involved in the pathogenesis of HE and to assess the effects of therapeutic measures focused on correcting brain edema in these patients.

Minimal hepatic encephalopathy matters in daily life

Minimal hepatic encephalopathy is a neuro-cognitive dysfunction which occurs in an epidemic proportion of cirrhotic patients, estimated as high as 80% of the population tested. It is characterized by a specific, complex cognitive dysfunction which is independent of sleep dysfunction or problems with overall intelligence. Although named “minimal”, minimal hepatic encephalopathy (MHE) can have a far-reaching impact on quality of life, ability to function in daily life and progression to overt hepatic encephalopathy. Importantly, MHE has a profound negative impact on the ability to drive a car and may be a significant factor behind motor vehicle accidents. A crucial aspect of the clinical care of MHE patients is their driving history, which is often ignored in routine care and can add a vital dimension to the overall disease assessment. Driving history should be an integral part of care in patients with MHE. The lack of specific signs and symptoms, the preserved communication skills and lack of insight make MHE a difficult condition to diagnose. Diagnostic strategies for MHE abound, but are usually limited by financial, normative or time constraints. Recent studies into the inhibitory control and critical flicker frequency tests are encouraging since these tests can increase the rates of MHE diagnosis without requiring a psychologist. Although testing for MHE and subsequent therapy is not standard of care at this time, it is important to consider this in cirrhotics in order to improve their ability to live their life to the fullest.

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.

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.

Hyperammonaemia alters the mechanisms by which metabotropic glutamate receptors in nucleus accumbens modulate motor function

Activation of metabotropic glutamate receptors by injecting (S)3,5-dihydroxyphenylglycine (DHPG) in nucleus accumbens (NAcc) increases motor activity by different mechanisms in control rats and in rats with chronic liver failure due to portacaval shunt. In control rats DHPG increases extracellular dopamine in NAcc and induces locomotion by activating the 'normal' circuit: NAcc-->ventral pallidum-->medial-dorsal thalamus-->prefrontal cortex, which is not activated in portacaval shunt rats. In these rats, DHPG activates an 'alternative' circuit: NAcc-->substantia nigra pars reticulata-->ventro-medial thalamus-->prefrontal cortex, which is not activated in control rats. The reasons by which liver failure leads to activation of this 'alternative' circuit remain unclear. The aim of this work was to assess whether hyperammonaemia could be responsible for the alterations found in chronic liver failure. We injected DHPG in NAcc of control or hyperammonaemic rats and analysed, by in vivo brain microdialysis, the neurochemical responses of the 'normal' and 'alternative' circuits. In hyperammonaemic rats DHPG injection in NAcc activates both the 'normal' and 'alternative' circuits. In hyperammonaemia, activation of the 'alternative' circuit and increased motor response following metabotropic glutamate receptors activation in NAcc seem due to an increase in extracellular glutamate which activates AMPA receptors.

Motor activity is modulated via different neuronal circuits in rats with chronic liver failure than in normal rats

The mechanisms by which liver failure alters motor function remain unclear. It has been suggested that liver disease alters the neuronal circuit between basal ganglia and cortex that modulates motor function. Activation of group I metabotropic glutamate receptors in the nucleus accumbens (NAcc) by injecting (S)-3,5-dihydroxyphenylglycine (DHPG) activates this circuit and induces locomotion We analysed by in vivo brain microdialysis the function of the circuits that modulate motor function in rats with liver failure due to portacaval shunt (PCS). We inserted cannulae in the NAcc and microdialysis probes in the NAcc, ventral pallidum (VP), substantia nigra pars reticulata (SNr), medio-dorsal thalamus (MDT), ventro-medial thalamus (VMT) or prefrontal cortex (PFCx). We injected DHPG in the NAcc and analysed extracellular neurotransmitters concentration in these areas. The results indicate that in control rats DHPG induces locomotion by activating the 'normal' neuronal circuit: NAcc --> VP --> MDT --> PFCx. In PCS rats this circuit is not activated. In PCS rats, DHPG injection activates an 'alternative' circuit: NAcc --> SNr --> VMT --> PFCx. This circuit is not activated in control rats. DHPG injection increases dopamine in the NAcc of control but not of PCS rats, and glutamate in PCS but not in control rats. DHPG-induced increase in dopamine would activate the 'normal' neuronal circuit, while an increase in glutamate would activate the 'alternative' circuit. The identification of the mechanisms responsible for altered motor function and coordination in liver disease would allow designing treatments to improve motor function in patients with hepatic encephalopathy.

Bradykinesia in cirrhotic patients with early hepatic encephalopathy is related to a decreased glucose uptake of frontomesial cortical areas relevant for movement initiation

BACKGROUND/AIMS

Bradykinesia is one of the first symptoms of hepatic encephalopathy (HE). Recently it has been suggested that bradykinesia in HE is due to disturbances in movement initiation. Areas involved in self-initiated movement are the motor- and premotor cortex, the supplementary motor cortex, the motor areas of the cingulate gyrus, and part of the frontomesial- and parietal cortex. The present study aimed to test the hypothesis that bradykinesia in HE is due to a functional disturbance of these areas.

METHODS

Fourteen cirrhotics with grade 0-I HE were examined. Patients with alcoholic cirrhosis or concomitant cerebral disorder were excluded. Patients underwent a 3-dimensional computer-assisted movement analysis for forearm pronation and supination, hand tapping and finger tapping and a (18)F-fluorodesoxy-glucose-PET-examination during rest, analysed with statistical parametric mapping (SPM99).

RESULTS

The frequency of finger- and hand tapping was significantly correlated to the glucose metabolism of the motor area of the cingulate gyrus and frontomedial, frontodorsal and parietal cortical areas known to be activated with self-initiated movements. A decrease of movement frequency was associated with a reduction of glucose metabolism within these areas.

CONCLUSIONS

These data support the hypothesis that bradykinesia in cirrhotics with HE is caused by an alteration of movement initiation.

Top-down and bottom-up processes in the extrastriate cortex of cirrhotic patients: An ERP study

OBJECTIVE

This study aims to evaluate the efficiency of top-down and bottom-up processes in the extrastriate cortex of cirrhotic patients without overt hepatic encephalopathy (HE).

METHODS

Reaction times (RTs), accuracy and event-related potentials (ERPs) were recorded during the execution of a visual Simon task in 17 cirrhotic patients and 10 healthy controls. Amplitude and latency of the P1 and N1 (indexes of bottom-up processes) and of the N2pc (index of top-down processes) were measured.

RESULTS

Patients were slower than controls, and patients with minimal HE (MHE) were slower than patients without MHE. The distribution analysis of RTs showed that the Simon effect decays with slower RTs in all the groups and that the shape of the distribution was different in MHE patients. No differences were found between cirrhotic patients and controls for P1 and N1 amplitude and latency. In contrast, N2pc latency was delayed in cirrhotic patients compared to controls independently of MHE.

CONCLUSIONS

In the extrastriate cortex of cirrhotic patients without HE, top-down processes are altered whereas bottom-up processes are preserved.

SIGNIFICANCE

The analysis of exogenous and endogenous visual components of ERPs provides a model to study the functional dissociation between top-down and bottom-up processes inside the extrastriate cortex.

Noncirrhotic portal vein thrombosis exhibits neuropsychological and MR changes consistent with minimal hepatic encephalopathy

Hepatic encephalopathy can arise from portal-systemic shunting in the absence of intrinsic liver disease. However, there are few descriptions of this form of encephalopathy. Portal vein thrombosis is an infrequent disease that causes portal-systemic shunting. Episodic hepatic encephalopathy has been described in patients with portal vein thrombosis, but it is not known if these patients develop minimal hepatic encephalopathy. We designed a study to investigate the neurological consequences of portal vein thrombosis in patients without cirrhosis and no clinical signs of encephalopathy. For this purpose, 10 patients underwent neuropsychological tests, an oral glutamine challenge test, and brain magnetic resonance (MR) imaging. The results were compared with those obtained in 10 healthy controls. Patients with portal vein thrombosis exhibited abnormalities in the results of neuropsychological tests, oral glutamine challenge test, and MR similar to those described in hepatic encephalopathy associated with cirrhosis. MR spectroscopy revealed a decrease in myo-inositol and an increase in glutamine. The increase in glutamine correlated with an increase in ammonia following the oral glutamine challenge test, signs of increased brain water (decrease in magnetization transfer ratio), and impairment of attention tests. In conclusion, patients with noncirrhotic portal vein thrombosis develop subclinical neurological abnormalities compatible with minimal hepatic encephalopathy. These disturbances, which include signs of increase in brain water and a compensatory osmotic response (decrease in brain myo-inositol), appear to be secondary to brain exposure to ammonia induced by portal-systemic shunting.

Impairment of response inhibition precedes motor alteration in the early stage of liver cirrhosis: a behavioral and electrophysiological study

Abnormality in movement initiation may partially explain psychomotor delay of cirrhotic patients, even in the absence of overt hepatic encephalopathy (HE). Therefore, the aim of this study was to determine the mechanisms of psychomotor delay observed in patients with cirrhosis in the absence of overt HE. Fourteen patients with nonalcoholic cirrhosis and 12 healthy matched control subjects underwent the lateralized readiness potential (LRP) measurement elicited by a visuospatial compatibility task (Simon task). Stimulus-triggered LRPonset reflects the time in which response is selected, while response-triggered LRP onset reflects motor execution. Cirrhotic patients showed delayed reaction times (RTs) compared to controls, particularly those with trial-making test A (TMT-A) or electroencephalogram (EEG) alterations. Stimulus-triggered LRP onset was found to be delayed in cirrhotic patients compared to controls, with a significant Group-versus-Condition interaction, showing a reduced cognitive ability to cope with interfering codes, even in patients without minimal HE (MHE). Response-triggered LRP was found to be delayed only in the patients with TMT-A or EEG alterations. In conclusion, cirrhotic patients without overt HE display a psychomotor slowing, depending first lyon response inhibition and only later accompanied by impaired motor execution.

Altered modulation of motor activity by group I metabotropic glutamate receptors in the nucleus accumbens in hyperammonemic rats

One of the neurological complications in hepatic encephalopathy is the impairment of motor coordination and function. Clinical signs of basal ganglia, cortico-spinal and cerebellar dysfunction have been commonly detected in these patients. We are studying the molecular bases of the alterations in motor coordination and function in hepatic encephalopathy. Hyperammonemia is considered the main factor responsible for the neurological alterations in patients with hepatic encephalopathy. Activation of metabotropic glutamate receptors (mGluRs) in the nucleus accumbens (NAcc) induces locomotion in rats. Asa first step in our studies on the alterations in motor co-ordination and function in hyperammonemia and hepatic encephalopathy we studied whether the control of motor function by mGluRs in the NAcc is altered in hyperammonemic rats. The locomotor activity induced by injection into the nucleus accumbens (NAcc) of DHPG, an agonist of group I mGluRs was significantly increased in hyperammonemic rats. Injection of DHPG increased extracellular dopamine but not glutamate in the NAcc of control rats. In hyperammonemic rats DHPG-induced increase in dopamine was significantly reduced, and extracellular glutamate increased 6-fold. The content of mGluR 1 but not mGluR 5, is increased in the NAcc of hyperammonemic rats. Blockade of mGluR 1 completely prevented motor and neurochemical effects induced by DHPG. These results show that modulation of both motor function and extracellular concentration of neurotransmitters by mGluRs in the NAcc is altered in hyperammonemia. This may contribute to the alterations in motor function in hepatic encephalopathy.

Motor dysfunction in patients with liver cirrhosis: impairment of handwriting

Motor dysfunction is an important clinical finding in patients with liver cirrhosis and mild forms of hepatic encephalopathy. The mechanisms and clinical appearance of motor impairment in patients with liver cirrhosis are not completely understood. We studied fine motor control in forty four patients with advanced liver cirrhosis (excluding those with hepatic encephalopathy grade II) and 48 healthy controls using a kinematic analysis of standardized handwriting tests. We analysed parameters of velocity, the ability to coordinate and the level of automatisation of handwriting movements. Furthermore, we studied the association between impairment of handwriting and clinical neuro-psychiatric symptoms. As compared with control subjects, patients showed a statistically significant reduction of movement peak velocity in all handwriting tasks as well as a substantial increase of number of velocity inversions per stroke. Using a z-score based assessment we found impairment of handwriting in fourteen out of forty four patients (31.8 %). The deterioration of handwriting was associated with clinical symptoms of motor dysfunction, such as bradykinesia, adiadochokinesia, dysmetria of upper extremities and gait ataxia. This is the first study that quantitatively investigates impairment of handwriting in patients with liver cirrhosis. Our findings suggest the application of kinematic analysis of handwriting for diagnostics of motor dysfunction in patients with mild forms of hepatic encephalopathy.

Multidimensional assessment of neuro-psychiatric symptoms in patients with low-grade hepatic encephalopathy: A clinical rating scale

AIM: To evaluate the feasibility of a new clinical rating scale for a standardized assessment of cirrhosis-associated neuro-psychiatric symptoms.

METHODS: Forty patients with liver cirrhosis (LC, with or without low-grade hepatic encephalopathy) were invest-igated using a clinical neuro-psychiatric rating scale based on a comprehensive list of neurological, psychomotor, cognitive, affective, behavioral symptoms, and symptoms of disturbed bioregulation.

RESULTS: The analysis revealed that the majority of cirrhotic patients showed, besides characteristic neurological symptoms of hepatic encephalopathy, various psychomotor, affective and bioregulatory symptoms (disturbed sleep and sexual dysfunction). Patients were impaired in the following subscales: sleep and biorhythm disorder (75.0% of patients), Parkinsonoid symptoms (25.0%), affective symptoms (17.5%), and psychomotor retardation (12.5%). The increase of total neuro-psychiatric clinical score was significantly associated with the degree of hepatic enceph-alopathy.

CONCLUSION: This study suggests that a substantial number of patients with LC and low-grade hepatic encephalopathy manifest various clinical neuro-psychiatric symptoms. The use of a rating scale, which explores clinical dimensions of hepatic encephalopathy, would improve the management of patients with LC.

Neurological and neuropsychiatric syndromes associated with liver disease

The clinical presentation of acute liver failure and hepatic encephalopathy (HE) in patients with cirrhosis differs significantly. The most serious neurological complication of acute liver failure is the development of devastating brain oedema. Therefore, intracranial pressure monitoring is urgently needed in these patients. Brain oedema is amplified by hypoglycemia, hypoxia and seizures, which are also frequent complications of acute liver failure. Therefore, these parameters must also be monitored. In contrast to acute liver failure in which cerebral dysfunction progresses rapidly, cognitive decline may be clinically undetectable for a long time in cirrhotic patients, until clinically overt symptoms such as psychomotor slowing, disorientation, confusion, extrapyramidal and cerebellar symptoms or a decrease in consciousness occur. Clinically, overt HE is preceded by minimal alterations of cerebral function that can only be detected by neuropsychological or neurophysiological measures, but which nevertheless interfere with the patient's daily living. Rapidly progressing spastic paraparesis (hepatic myelopathy) is a rare complication of cirrhosis. In contrast to HE, it does not respond to blood ammonia lowering therapies but must be considered as an indication for urgent liver transplantation. Cognitive dysfunction has recently been detected in hepatitis C virus (HCV)-infected patients with normal liver function. The patients presented with severe fatigue, cognitive dysfunction and mood disorders. Alterations in brain metabolites, as detected by magnetic resonance spectroscopy, indicated central nervous system alteration in these patients. In contrast to patients with HE, HCV-infected patients did not show motor symptoms or deficits in visual perception, but considerable deficits in attention and concentration ability.

Disruption of smooth pursuit eye movements in cirrhosis: relationship to hepatic encephalopathy and its treatment

Smooth pursuit eye movements (SPEM) are the conjugate movements used to track the smooth trajectory of small dots. Jerky or 'saccadic' ocular pursuit has been reported in patients with cirrhosis, but no formal assessment of SPEM has ever been undertaken. The aim of this study was to evaluate SPEM in patients with cirrhosis and varying degrees of hepatic encephalopathy. The patient population comprised 56 individuals (31 men, 25 women) of mean age 51.1 (range, 25-70) years, with biopsy-proven cirrhosis, classified, using clinical, electroencephalographic, and psychometric variables, as either neuropsychiatrically unimpaired or as having minimal or overt hepatic encephalopathy; patients were further categorized in relation to their treatment status. The reference population comprised 28 healthy volunteers (12 men, 16 women) of mean age 47.3 (range, 26-65) years. SPEM was assessed using an electro-oculographic technique. Visual inspection of the SPEM recordings showed clear disruption of smooth pursuit in the patients with minimal hepatic encephalopathy, and more pronounced disruption, if not complete loss, of smooth pursuit in patients with overt hepatic encephalopathy. The differences observed in quantifiable SPEM indices between the healthy volunteers/unimpaired patients and those with overt hepatic encephalopathy were significant (P < .05). In conclusion, SPEM performance is impaired in patients with hepatic encephalopathy in parallel with the degree of neuropsychiatric disturbance: the pathophysiology of these changes is unknown, but retinal, extrapyramidal, and attentional abnormalities are likely to play a role. Treatment status confounds the classification of neuropsychiatric status and should be taken into account when categorizing these patients.

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.

Diagnostic value of fine motor deficits in patients with low-grade hepatic encephalopathy

AIM: The role of motor dysfunction in early diagnosis of low-grade hepatic encephalopathy remains uncertain. We performed a pilot study to comparatively investigate the kinematic characteristics of small and large rapid alternating movements in patients with liver cirrhosis and low-grade hepatic encephalopathy.

METHODS: A kinematic analysis of alternating handwriting (7.5 mm) and large drawing movements (DM, 175 mm) was performed in 30 patients with liver cirrhosis (no hepatic encephalopathy: n = 10; minimal hepatic encephalopathy: n = 9; grade I hepatic encephalopathy: n = 11; healthy controls: n = 12). The correlation between kinematic parameters, clinical neuro-psychiatric symptoms of cerebral dysfunction and the grade of encephalopathy was investigated.

RESULTS: Both movement types, handwriting and drawing, were significantly slower in cirrhotic patients. In contrast to large DM, the deterioration of handwriting movements significantly correlated with the increase of symptoms of motor dysfunction and differentiated significantly within the group of cirrhosis patients corresponding to the degree of hepatic encephalopathy.

CONCLUSION: The deterioration of fine motor control is an important symptom of low-grade hepatic encephalopathy. The kinematic analysis of handwriting allows the quantitative analysis of alterations of motor function and is a possible tool for diagnostics and monitoring of motor dysfunction in patients with low-grade hepatic encephalopathy.