Insight into the relationship between brain/behavioral speed and variability in patients with minimal hepatic encephalopathy

OBJECTIVE

Intra-individual variability (IIV) of response reaction times (RTs) and psychomotor slowing were proposed as markers of brain dysfunction in patients with minimal hepatic encephalopathy (MHE), a subclinical disorder of the central nervous system frequently detectable in patients with liver cirrhosis. However, behavioral measures alone do not enable investigations into the neural correlates of these phenomena. The aim of this study was to investigate the electrophysiological correlates of psychomotor slowing and increased IIV of RTs in patients with MHE.

METHODS

Event-related potentials (ERPs), evoked by a stimulus-response (S-R) conflict task, were recorded from a sample of patients with liver cirrhosis, with and without MHE, and a group of healthy controls. A recently presented Bayesian approach was used to estimate single-trial P300 parameters.

RESULTS

Patients with MHE, with both psychomotor slowing and higher IIV of RTs, showed higher P300 latency jittering and lower single-trial P300 amplitude compared to healthy controls. In healthy controls, distribution analysis revealed that single-trial P300 latency increased and amplitude decreased as RTs became longer; however, in patients with MHE the linkage between P300 and RTs was weaker or even absent.

CONCLUSIONS

These findings suggest that in patients with MHE, the loss of the relationship between P300 parameters and RTs is related to both higher IIV of RTs and psychomotor slowing.

SIGNIFICANCE

This study highlights the utility of investigating the relationship between single-trial ERPs parameters along with RT distributions to explore brain functioning in normal or pathological conditions.

Modulation of affective symptoms and resting state activity by brain stimulation in a treatment-resistant case of obsessive-compulsive disorder

The effect of transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) on psychopathological symptoms and resting state brain activity was assessed in a patient with obsessive-compulsive disorder (OCD). tDCS and rTMS had no effect on OC symptoms. tDCS, however, improved depression and anxiety. Functional magnetic resonance imaging at baseline showed an interhemispheric asymmetry with hyperactivation of the left and hypoactivation of the right anterior neural circuits. A reduction of interhemispheric imbalance was detected after tDCS but not after rTMS. tDCS seems to be more effective than rTMS in restoring interhemispheric imbalance and improving anxiety and depression in OCD.

Right hemisphere dysfunction and emotional processing in ALS: an fMRI study

Emotional processing may be abnormal in amyotrophic lateral sclerosis (ALS). Our aim was to explore functional anatomical correlates in the processing of aversive information in ALS patients. We examined the performance of nine non-demented ALS patients and 10 healthy controls on two functional MRI (fMRI) tasks, consisting of an emotional attribution task and a memory recognition task of unpleasant versus neutral stimuli. During the emotional decision task, subjects were asked to select one of three unpleasant or neutral words. During the memory task, subjects were asked to recognize words presented during the previous task. Controls showed, as expected, greater activation in the right middle frontal gyrus during selection of unpleasant than neutral words, and a greater activation mainly in right-sided cerebral areas during the emotional recognition task. Conversely, patients showed a general increase in activation of the left hemisphere, and reduced activation in right hemisphere in both emotional tasks. Such findings may suggest extra-motor neurodegeneration involving key circuits of emotions, mostly negative, commonly involved in FTD.

Categorical differentiation and intergroup relationships

In this study we attempted to replicate the well-known Doise & Sinclair (1973) procedure for manipulating category salience, in a different social context. We considered the relationship between two groups of professionals: doctors and nurses, as perceived by 40 members of the superior group. The results did not confirm those obtained by Doise & Sinclair since they showed reduced categorical differentiation when the out-group was evoked in advance of the intergroup evaluations. The implications of these findings for theories of social categorization and social identity are discussed.

[Management of disease carriers]

In the present communication there are exposed the treatment modalities of health carriers. The difficulties of action depends primarily on scarcity of health education and of adequate structures and manufacturing equipment in the places of work.

[Prevalence of tetanus immunity in metal mechanical workers]

The results of a seroepidemiological prevalence survey on the immune status against tetanus of steelmill workers (who, limited to the new work call ups, had to be vaccinated since 1968) are reported. We did not observe remarkable differences in protection against tetanus among those who had begun work before 1968 (46.4% protected) and after 1968 (53.5% protected). In both cases, the protective values were the result of immunization procedures that were performed exclusively in consequence of the military service and/or on the occasion of industrial accident and/or road accident or of accidents of other kinds. It appears, moreover, that the protection of workers against this disease is, nowadays, too often relying on serum prophylaxis, which was the only preventive measure adopted for over half of the workers. In the light of the reported data we need to enforce the existing legislative measures.