Clinical Neuroscience

[Investigation of the dopamine dysregulation hypothesis of schizophrenia with neuroimaging techniques]

SZEKERES György, PÁVICS László, JANKA Zoltán

AUGUST 20, 2002

Clinical Neuroscience - 2002;55(07-08)

[The most elaborated biochemical concept of schizophrenia is the dopamine hypothesis. However, this classical theory is based on indirect observations. It has recently become possible to study this theory directly by means of advanced functional neuroimaging techniques, the development of specific radioligands and study protocols that are eligible to monitor dynamic changes in the neurotransmitter systems. According to the early concept, the essence of schizophrenia is the hyperactivity of the dopamine system. Nevertheless, this idea has gone through many modifications. In accordance with the modified dopamine hypothesis, the cognitive deficit and negative symptoms are related to the hypoactivity of the dorsolateral prefrontal cortex while the acute phasis of the disease associates with hyperactivity of the ventral striatal elements of the dopaminergic system. Between these dysfunctions there is causality via their exuberant connections. Beyond that, the interactions between the prefrontal and striatal anomalies implicate the involvement of other neurotransmitters than dopamine. Observations from model psychosis induced by N-methyl-D-aspartate antagonists and in vivo neuroimaging investigations in humans support primarily the role of glutamatergic system. Our developing knowledge about the neurochemical mechanism of schizophrenia can significantly affect therapeutic strategies as well.]

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Clinical Neuroscience

[The molecular genetic control of bony developmental malformations affecting the craniocervical junction and the cervical spine]

DÁVID Károly, KASÓ Gábor, THOROGOOD Peter V, STEVENS John M, CROCKARD H Alan

[In this review a new interpretation of the origin of bony developmental malformations affecting the craniocervical junction and the cervical spine is presented based on recent advances in the understanding of embryonic development of the spine and its molecular genetic control. Radiographs, CT and MRI scans or CT myelograms of patients with Klippel-Feil syndrome were used for demonstration. Detailed clinical and radiologial analysis of these patients was published earlier [David KM, Stevens JM, Thorogood P, Crockard HA. The dysmorphic cervical spine in Klippel-Feil syndrome: interpretations from developmental biology. Neurosurg Focus 1999;6(6):1.]. Homeotic transformation due to mutations or disturbed expression of Hox genes is a possible mechanism responsible for C1 assimilation. Notochordal defects and/or signalling problems, that result in reduced or impaired Pax-1 gene expression, may underlie vertebral fusions. This, together with asymmetrical distribution of paraxial mesoderm cells and a possible lack of communication across the embryonic mid-line, could cause the asymmetrical fusion patterns. The wide and flattened shape of the fused vertebral bodies, their resemblance to the embryonic cartilaginous vertebrae and the process of progressive bony fusion with age suggest that the fusions occur before or, at the latest, during chondrification of vertebrae. The authors suggest that the aforementioned mechanisms are likely to be, at least in part, responsible for the origin of the bony developmental malformations affecting the craniocervical junction and the cervical spine.]

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FAZEKAS Gábor, FEHÉR Miklós, KOCSIS László, STEFANIK Györgyi, BOROS Zsuzsanna, JURÁK Mihály

[Evidence based medicine requires objective methods for the assessment of status of the patients. The method described by the authors makes it possible to assess motoric impairment of patients in an objective way. It is based on three-dimensional motion analysis. Authors present the case history of two patients with spastic hemiparesis due to central nervous system damage. Changes in motoric impairment were followed by three-dimensional motion analysis. This method can be adapted for the assessment of motor impairment arising from other reasons as well.]

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Clinical Neuroscience

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KASÓ Gábor, STEFANITS János, KÖVÉR Ferenc, HUDVÁGNER Sándor, DÓCZI Tamás

[Percutaneous vertebroplasty is a radiologically guided invasive technique consisting of the injection of surgical cement into the diseased vertebral body. The procedure results in immediate pain relief and strengthening of the bone due to the polymerization process of the filling material hardening the vertebral body and preventing further collapse. This method is suitable for the treatment of osteoporotic vertebral fractures and of osteolytic vertebral body metastases without neurological signs, in multiple appearance as well. Authors present technical details of the procedure performed by bi-directional fluoroscopy and combined CT-fluoroscopy control as well as short-term experience obtained by treatment of 17 patients.]

Clinical Neuroscience

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Clinical Neuroscience

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[Introduction - The purpose of our study was to find out whether the Hungarian adaptation of the RBANS (Repeatable Battery for the Assessment of Neuropsychological Status), a brief neurocognitive screening test, is appropriate for the differentation of healthy and non-healthy subject groups, or for the detection of differences between the cognitive performance of patient groups. Patients and method - The test battery was administrated to 38 healthy subjects, 69 schizophrenic patients, and 18 patients suffering from dementia (10 probable Alzheimer-type and eight vascular dementia). Results - There was a significant decrease of performance in all patient groups compared to the healthy group. In the schizophrenic group, the test indicated a deterioration of functioning in all cognitive areas. The patient group with Alzheimer-type dementia performed only slightly better than the schizophrenic group, because the fall of performance was not significant only one of the cognitive areas (in the visuo-spatial tasks) when compared to the healthy group. There was no difference between the performance of patients with vascular dementia and that of healthy subjects in direct memory, verbal and visuo-spatial tasks. The test results indicated an even deterioration of cognitive areas in patients with Alzheimer-type dementia. As for the vascular dementia group, the most vulnerable area proved to be that of attention, while their verbal functions were relatively spared. The deterioration in other cognitive functions shown by schizophrenic subjects was more moderate, but still significant. A comparison of the RBANS scores of the schizophrenic patients in our study and the result of an American study was also carried out. The global indeces showed no difference; only the pattern of the sub-scales was a little different. Conclusion - The Hungarian version of the RBANS seems appropriate for the differentiation of healthy and deteriorated cognitive performance in a Hungarian patient population.]

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Clinical Neuroscience

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