[Show abstract][Hide abstract] ABSTRACT: After rapid hypnotic induction, 12 healthy volunteers underwent hypnotic deepening with relaxation or with fractionation (without relaxation) in a random latin-square protocol. Electroencephalographic occipital alpha activity was measured, low-resolution brain electromagnetic tomography was performed, and hemodynamics (stroke volume, heart rate, cardiac output, mean arterial blood pressure, forearm arterial flow and resistance) were monitored in basal conditions and after deepening. After relaxation, both forearm flow (-18%) and blood pressure (-4%) decreased; forearm resistance remained unchanged. After fractionation, a forearm flow decrease comparable to that recorded after relaxation was observed, but blood pressure remained unchanged, leading to an increase of forearm resistance (+51%). Central hemodynamics did not change. Alpha activity increased in the precuneus after fractionation only. In conclusion, both relaxation and fractionation have vasoconstrictor effects, but fractionation is also associated with an increase in peripheral resistance.
International Journal of Clinical and Experimental Hypnosis 07/2012; 60(3):338-55.
[Show abstract][Hide abstract] ABSTRACT: Electroencephalography has not been completely quantified in patients with cirrhosis. We investigated the electroencephalogram (EEG) dynamics in patients with cirrhosis.
We performed closed-eye EEGs on 175 patients with cirrhosis (age, 55 ± 11 years; 24% Child-Pugh class A, 48% class B, and 285 class C), conducted clinical and psychometric assessments for hepatic encephalopathy (HE), and followed the patients for 1 year. EEG characteristics were assessed in the frequency domain, in the frontal (F3-F4) and parietal (P3-P4) derivations. Intrahemispheric (frontoparietal, right, and left) and interhemispheric (F3-F4 and P3-P4) coherence were computed. The EEGs of 50 healthy volunteers (age, 56 ± 17 years) served as controls.
Compared with controls, the EEGs of patients with cirrhosis had a reduced frequency in the posterior derivations (P3/P4 mean dominant frequency, 9.1 ± 1.8 and 8.9 ± 1.7 Hz vs 10.4 ± 1.3 and 10.2 ± 1.3 Hz, respectively; P < .01) and an increase in interhemispheric parietal relative coherence within the theta band (22.3% ± 5.5% vs 18.9% ± 3.5%; P < .01). These features were more prominent in patients with Child class C and in patients with a history of overt HE; they correlated with hyperammonemia and hyponatremia. The decrease in EEG frequency, along with the increase in interhemispheric theta coherence in the posterior derivations, was inversely associated with survival and the occurrence of overt HE during the follow-up period.
In patients with cirrhosis, alterations in the EEG were significantly associated with the severity of liver disease and HE; the EEG might be used in determining prognosis.
[Show abstract][Hide abstract] ABSTRACT: To compare electroencephalographic spectral analysis obtained by periodogram (calculated by means of Fast Fourier Transform) and autoregressive (AR) modelling for the assessment of hepatic encephalopathy.
The mean dominant frequency (MDF) and the relative power of delta, theta, alpha, and beta bands were computed by both techniques from the electroencephalograms (EEG) of 201 cirrhotics and were evaluated in the clinical and prognostic assessment of the patients.
The values of all the five indexes computed by periodogram and AR modelling matched each other, but the latter provided stable values after the analysis of fewer epochs. Independently of the technique, the relative power of theta and alpha bands fitted the clinical data and had prognostic value. The relative power of beta and delta bands computed by AR modelling fitted more closely with clinical data fitted the clinical data more closely.
The electroencephalographic spectral indexes obtained by periodogram and AR modelling were found to be, on average, undistinguishable, but the latter appeared less sensitive to noise and provided a more reliable assessment of low-power bands.
[Show abstract][Hide abstract] ABSTRACT: The prevalence and the clinical implications of subclinical cognitive alterations in cirrhotic patients have not been well defined as yet. Therefore, we performed a study to assess the clinical features and the survival of cirrhotic patients with cognitive alterations detected by the number connection test (NCT) and a set of computerized psychometric tests (Scan, Choice1, and Choice2) measuring the reaction times and the percentage of errors in performing specific tasks. Ninety-four cirrhotic patients (aged 58 ± 9 years) without overt hepatic encephalopathy and 80 controls (aged 53 ± 15 years) were consecutively enrolled. The median follow-up in cirrhotic patients was 426 days (lower quartile = 213 days; upper quartile = 718 days). Results of the NCT, Scan test, and Choice2 test were significantly worse in cirrhotic patients, whereas Choice1 did not differ significantly from the controls. In cirrhotic patients, the prevalence of altered psychometric tests was 21% (CI95% = 14%-31%) by NCT, 23% (CI95% =15%-33%) by Scan test, and 20% (CI95% =16%-30%) by Choice2 test. The alterations of NCT, Scan, and Choice2 were found to be related to the severity of liver disease, independently of its etiology. Increased risk of death was found to be associated with altered Scan test (hazard ratio = 2.4; CI95% =1.1-5.3), or altered Choice2 test (hazard ratio = 2.8; CI95% = 1.2-6.3). Multivariate regression showed that Scan and Choice2 tests had prognostic value on survival, in addition to Child-Pugh classes in the first year of follow-up.
[Show abstract][Hide abstract] ABSTRACT: Spectral EEG analysis has been claimed to reduce subjective variability in EEG assessment of hepatic encephalopathy and to allow the detection of mild encephalopathy.
To test such assumptions, 43 digital EEG were recorded in 32 cirrhotics without overt encephalopathy or with grade 1 overt encephalopathy; 7 patients were re-tested (2-5 times) in their follow up. All patients underwent psychometric assessment. Nineteen controls were considered. EEG were blindly evaluated by two electroencephalographers and by spectral EEG analysis performed according to 3 different techniques.
The reliability of the classification based on spectral analysis (biparietal technique) was higher than that based on a three-degree qualitative visual reading (concordance/discordance = 58/4 versus 46/16 P < 0.01) and comparable with that of semiquantitative visual assessment based on posterior basic rhythm (concordance/discordance = 55/7 P = 0.5). The accuracy of spectral EEG analysis was higher than that of qualitative visual EEG readings alone (90 versus 75%) and comparable to semi-quantitative visual assessment (87%), however, statistical significance was not reached. In the follow-up, the variations of theta and delta relative power were found to be significantly correlated with psychometric variations.
In conclusion, spectral EEG analysis may improve the assessment of mild hepatic encephalopathy by decreasing inter-operator variability and providing reliable parameters correlated with mental status.
[Show abstract][Hide abstract] ABSTRACT: Attentional dysfunction, which influences overall cognitive productivity, is not well characterized in cirrhotic patients. The aim of this study was to clarify the features of covert visual attention orienting in cirrhotics without overt hepatic encephalopathy. One hundred consecutive cirrhotic patients and 40 controls were enrolled. Visual covert attention orienting was assessed by the Posner test, which evaluates the effect of a cue on visual reaction times. Patients were characterized by the number connection test (NCT) and electroencephalographic (EEG) spectral analysis. The severity of liver disease was graded using standard laboratory parameters and the Child-Pugh's classification. Fifty-five psychometric and EEG evaluations were performed in the follow-up of 17 patients to assess the relationship between the variations of psychometric and neurophysiological findings. NCT and quantified-EEG parameters (altered in 19% and 40% of cirrhotic patients, respectively) were linked to each other and to the severity of liver disease. The Posner test showed a delay of visual reaction times in class B-C cirrhotic patients. Reaction times were correlated with ammonia and EEG parameters. The effect of the cue was higher in cirrhotic patients than in controls, particularly in the invalid position. This study suggests that cirrhotic patients have a reduced activity rate and reduced capacity to disengage attention previously focused on a cue. Such alterations are linked to NCT and EEG findings.
[Show abstract][Hide abstract] ABSTRACT: Memory dysfunction is reported in cirrhotics. The aim of this paper was to increase insight into memory function of cirrhotic patients without overt hepatic encephalopathy. Eighty-six consecutive cirrhotics without overt hepatic encephalopathy (aged 54+/-10 yr., mean+/-s.d.) and 28 controls (52+/-10 yr.) with comparable education level were enrolled. Seventeen patients were class A, 55 class B, 14 class C according to Child-Pugh classification; 29 had alcoholic cirrhosis. The presence of subclinical signs of central nervous system dysfunction were assessed by Number Connection Test (NCT) and quantified EEG analysis. Memory scanning was evaluated by reaction times (RTs) in the Sternberg paradigm. MANOVA analysis showed that RTs were higher (F1,99=11, p<0.01) and time outs (TOs) more frequent (F1,110=10, p<0.01) in cirrhotics than in controls, whereas button press errors (BPEs) did not differ significantly (F1,110=2, p=n.s.). In cirrhotics, an interaction Child-Pugh class x memory set size was found (F2,146=4, p<0.05), showing exceedingly delayed RTs with greater memory set size in class C patients. Patients with altered NCT had significantly prolonged RTs (F1,71=4, p<0.05) and more TOs (F1,82=11, p<0.01) than patients with normal NCT. Cirrhotics with altered EEG had significantly prolonged RTs (F2,70=6, p<0.01). RTs were found to be correlated to alpha relative power (r=-0.4, p<0.01) and theta relative power (r=0.4, p<0.01). In conclusion, cirrhotics without over encephalopathy, but with NCT or EEG alterations, perform a computerized digit recognition task more slowly and with higher TOs than cirrhotic patients with normal NCT or EEG. In severe liver insufficiency (class C cirrhotics) also an impairment of memory scanning was detected. Sternberg test performance correlates with NCT and quantitative EEG parameters.
[Show abstract][Hide abstract] ABSTRACT: This article reviews the literature on the role of zinc in liver cirrhosis and dietary zinc supplementation for cirrhotic patients with hepatic encephalopathy. Zinc is a trace metal found in many proteins and enzymes having catalytical, cocatalytical and structural functions. Zinc deficiency has been demonstrated in cirrhotic patients, and dietary supplementation of this metal could benefit the urea cycle, glucose and protein metabolism, and central nervous system neurotransmission in these subjects. After some brief considerations on normal zinc metabolism, the role zinc plays in the central nervous system, and its conduct in patients with hepatic encephalopathy, possible links between zinc deficiency and the pathophysiology of central nervous system dysfunction in cirrhotic patients are discussed. The article concludes with a critical review of favorable and unfavorable evidence for zinc supplementation in patients with hepatic encephalopathy.
Annali italiani di medicina interna: organo ufficiale della Societa italiana di medicina interna 01/1998; 13(3):157-62.
[Show abstract][Hide abstract] ABSTRACT: It is not yet clear if benzodiazepine receptor ligands,implicated in the pathophysiology of hepatic coma, also have a role in subclinical cognitive orneurophysiological alterations in cirrhotic patients. Therefore, we carried out a double-blind,placebo-controlled study to evaluate the effectiveness of flumazenil, a benzodiazepine antagonist,on brainstem auditory evoked responses and on the number connection test in cirrhotic patientswith subclinical neurophysiological or cognitive alterations. Thirteen cirrhotic subjects withsubclinical neurophysiological or cognitive alterations were studied. A total of 3 mg of flumazenilor saline was infused intravenously. Before and after the infusion, the number connection test wasadministered and brainstem auditory evoked responses recorded. After 72 h, patients werecrossed over. Flumazenil did not influence brainstem auditory evoked responses or the numberconnection test. A screening test for benzodiazepines was negative in all subjects. We concludethat benzodiazepine receptor ligands have a negligible role, if any, in the pathophysiology of sub-clinical neurophysiological or cognitive alterations of cirrhotic patients.
[Show abstract][Hide abstract] ABSTRACT: The attention system in patients with liver cirrhosis has not yet been fully investigated. We therefore studied visual attention orienting in cirrhotic patients without overt hepatic encephalopathy. Seventy cirrhotic patients without overt hepatic encephalopathy (aged 5710 yr., means.d.) and 55 controls (aged 4912 yr.) were enrolled. Visual attention orienting was evaluated by a computerized neuropsychological test. The Reitan A test, commonly used to detect subclinical hepatic encephalopathy, was used to evaluate mental performance. Psychometric test scores were reduced in cirrhotics compared to controls (attention test: neutral condition =495149 vs. 40198 msec; valid condition =434110 vs. 39884 msec; invalid condition =485146 vs. 392110 msec; p