Semantic context-processing deficit in thought-disordered schizophrenic patients: Evidence from new semantic priming paradigms

Introduction. Disorders in the processing of the semantic context are now a well-established phenomenon in thought-disordered (TD) schizophrenic patients, and have been revealed especially well by studies that have made use of the experimental paradigm of lexical decision tasks coupled with semantic priming. The main question addressed by this study was the evaluation of the experimental conditions under which TD schizophrenic patients are able to deploy cognitive strategies for semantic context processing. Methods. We studied semantic priming in two double lexical decision tasks (i.e., involving the explicit processing of the prime word) using a sequential presentation of words (stimulus onset asynchrony; SOA 500?ms) with a different proportion of related words (Experiment 1 with 25% vs. Experiment 2 with 15%) in 15 TD schizophrenic and 15 normal participants. Results. The results showed no significant differences between the semantic priming of TD schizophrenic and normal participants for Experiment 1, unlike Experiment 2 in which we observed a significant reduction of the amplitude of semantic priming in TD schizophrenic patients. The results of Experiment 1 contrast with those obtained previously (Besche et al., 1997) using a classical lexical decision task (implicit processing of the prime word) which also contained 25% related words. Conclusions. Experimental variables, such as the cognitive processing required by the prime word or the proportion of related words or the way they are manipulated, all seem to influence the emergence of semantic priming abnormalities in TD schizophrenic patients.     

Impaired Neuroendocrine and Immune Response to Acute Stress in Medication-Naive Patients With a First Episode of Psychosis

Little is known about how the biological stress response systems—the autonomic nervous system (ANS), the hypothalamic-pituitary-adrenal (HPA) axis, and the immune system—function during psychosis. Results of studies on the effect of stress on the immune and autonomic system in patients with schizophrenia are inconsistent. The present study investigates whether the stress response is impaired in medication-naive patients with a first episode of psychosis. Ten male patients with a first episode of psychosis and 15 controls were exposed to the stress of public speaking. Parameters of the ANS (heart rate and catecholamines), the HPA axis (plasma adrenocorticotropic hormone [ACTH] and cortisol), and the immune system (number and activity of natural killer [NK] cells) were measured. Peak responses were calculated to examine the relationship between stress-induced activation of the different systems. Subjective stress and anxiety before and during the task were assessed. Patients and controls displayed similar autonomic responses to acute stress. However, there was an impaired HPA axis response, slow onset and return of ACTH, and flattened cortisol response and a reduced increase in number NK cells and NK cell activity in patients with a first episode of psychosis. Furthermore, in patients, the relationship between the different stress response systems was weaker or absent compared with controls. These findings indicate that impairments in stress processing are associated with the endophenotype of psychosis and are not a result of illness progression or antipsychotic medication.     

18F]-Dopa positron emission tomography imaging in early-stage, non-parkin juvenile parkinsonism.

There are few reports of positron emission tomography (PET) in juvenile parkinsonism (JP). We report on the results of (18)F-6-fluoro-L-dopa (FD) PET in a 14-year-old patient with JP of 5 years duration associated with atypical features. This is the youngest subject to be investigated to date. There was a severe asymmetric reduction in striatal FD uptake, with a rostrocaudal gradient in the putamen similar to that seen in adult-onset idiopathic parkinsonism. Extensive DNA analysis in this patient did not show mutations in the parkin gene.     

Interactions between recording technique and AMPA receptor modulators

Whole cell recording (EPSCs) and extracellular recording (field EPSPs) were compared in hippocampal field CA1 with regard to the effects of experimental treatments that increase AMPA receptor gated currents. Cyclothiazide, which maintains AMPA receptors in the sensitized state, caused a rapid and pronounced increase in EPSCs but only minor changes in field EPSPs. This difference was evident in recordings carried out at 22 and 32 degrees C and with different solutions in the clamp pipette. The larger effect of cyclothiazide on EPSCs was unaffected by blockade of GABA and NMDA receptors. Two-dimensional current source density analyses derived from 64 recording sites were used to provide extracellular estimates of AMPA receptor mediated synaptic currents. With this method, cyclothiazide again had much smaller effects than were obtained with whole cell clamp. Differences between whole cell and extracellular recordings were present, although not as pronounced, for the ampakines, a class of drugs that slow both deactivation and desensitization of AMPA receptors. Additionally, increases in synaptic responses produced by frequency facilitation, a manipulation that enhances the number of bound receptors, were not qualitatively different between recording techniques. These results support the conclusion that the whole cell clamp technique may alter AMPA receptors in such a way as to increase the relative importance of desensitization.     

Primary dystonia: Is abnormal functional brain architecture linked to genotype?

The DYT1 dystonia mutation is associated with an abnormal metabolic brain network characterized by hypermetabolism of the basal ganglia, supplementary motor area, and the cerebellum. In this study, we quantified the activity of this network in carriers of other dystonia mutations to determine whether this functional abnormality is linked to genotype. The findings suggest that the DYT1 metabolic topography is not genotype specific and may be present in carriers of other dystonia mutations.     

An adolescent with significant emotional and medically unexplained complaints: case report and proposal of an intervention

Background

Ethiopia is a country in which child and adolescent mental health needs are often not met. In order to promote capacity building, a Collaborative International Exchange Programme has been established between Jimma University at Jimma, Ethiopia, and Ludwig-Maximilian University in Munich, Germany. The programme focuses on training non-physician health professionals in mental health speciality. One of the courses in the training programme, child psychiatry, involves a child psychiatrist and a children’s nurse supporting the management of a patient described in this case report. Its conceptual framework is based on the section “significant emotional and medically unexplained complaints” of the “WHO mental health GAP intervention guide for mental, neurological and substance use disorders in non-specialized health settings”.

Objective

The purpose of this case report is to promote confidence in mental health professionals when managing patients with similar conditions, and to stimulate further evaluation of the conceptual approach in developing countries.

Patient

The subject of this case report is a 14-year-old adolescent girl admitted to the psychiatric clinic at Jimma University Teaching Hospital. She was admitted for intractable retching, inability to eat, weight loss, and inability to walk. Challenges included the combination of medical and psychiatric symptoms, and the significant impairment of functioning in this adolescent. The first aim in the management of this patient was to guarantee vital functions. In a problem-oriented approach, different domains were addressed to restore nutritional, social, emotional, and motor functions. Treatment consisted of various elements of psychosocial interventions. The patient improved in 2 weeks and the final diagnosis was conversion disorder.

Conclusion

Psychosocial interventions can be developed in cooperation, and applied in a setting where little child mental health expertise is available. Case-based learning relying on local expertise is suitable in meeting local needs and in developing mental health services for children and adolescents.

     

Respiratory chain deficiency in a female with Aicardi-Goutières syndrome

Aicardi-Goutières syndrome (AGS) is an early-onset progressive encephalopathy characterized by calcifications of the basal ganglia, white matter abnormalities, chronic cerebrospinal fluid (CSF) lymphocytosis, and/or a raised level of CSF interferon (INF)-alpha. We report a female with mitochondrial respiratory chain deficiency fulfilling the criteria of AGS. Disease onset was in the first year of age with seizures and psychomotor regression. To date, at 4 years of age, she presents a severe encephalopathy, increased INF-alpha in the CSF, and calcifications of basal ganglia on computerized tomography. Cerebral magnetic resonance imaging showed bilateral and symmetric hypersignal of the posterior white matter. A complex I deficiency of the mitochondrial respiratory chain was found in skeletal muscle, which was associated with a complex IV deficiency in cultured skin fibroblasts. The question of whether this oxidative phosphorylation deficiency is primary or secondary in AGS is open to debate. We suggest giving consideration to systematic evaluation of the mitochondrial respiratory chain in skeletal muscle and skin fibroblasts of other AGS patients.