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ABSTRACT: Repetition blindness is the failure to report the detection of repeated items in rapid visually presented lists. It can be explained in terms of either a processing limitation or an active inhibitory process. In two studies conducted in either English or German language we set out to induce repetition blindness under various conditions in a total of 47 control subjects and 30 schizophrenic patients. The patients displayed the phenomenon to at least the same degree as normal control subjects. These results render unlikely accounts of repetition blindness which involve processes known to be dysfunctional in schizophrenic patients. Moreover, the study provides an example of how the performance of schizophrenic patients can constrain theories of normal cognition.
European Archives of Psychiatry and Clinical Neuroscience 02/1998; 248(3):136-40. · 3.49 Impact Factor
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ABSTRACT: Research in experimental psychosis has a long tradition extending through several stages. With the world wide abuse of psychoactive substances it came to an abrupt end. Systematic questions within this framework of research are still unresolved, and research on newly developed compounds is almost completely lacking. A review of the pharmacological and psychological effects of various psychoactive agents is provided, and results of recent experimental studies on arylalkylamines are discussed. It is argued that from a systematic as well as from a methodological viewpoint the traditional approach of experimental psychosis represents a valuable tool in psychiatric research.
Der Nervenarzt 10/1993; 64(9):562-71. · 0.68 Impact Factor
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ABSTRACT: The psychological, neuropsychological, and neurometabolic effects of the hallucinogenic agent mescaline were investigated in 12 normal men who were volunteers. Mescaline produced an acute psychotic state 3 1/2-4 hr after drug intake, as measured by the Brief Psychiatric Rating Scale (BPRS) and Paranoid Depression Scale (PDS). The Assessment of Altered States of Consciousness (APZ) questionnaire revealed specific effects of mescaline in the visual system. Neuropsychological effects were studied with a face/nonface decision task with known right-hemisphere advantage, in which mescaline induced a decrease of functioning of the right hemisphere. In functional brain imaging using single photon emission computed tomography (SPECT), mescaline produced a "hyperfrontal" pattern with an emphasis on the right hemisphere, which was correlated with mescaline-induced psychotic psychopathology. Our findings question the validity of the concept of hypofrontality as an explanation for schizophrenic symptomatology. The study of psychoactive substances under controlled laboratory conditions has the methodological advantage of intraindividual control, and hence, minimal variability of data.
Biological Psychiatry 01/1993; 32(11):976-91. · 8.28 Impact Factor
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ABSTRACT: In a retrospective study, data from 99 male and female inpatients with alcohol withdrawal syndrome or alcohol withdrawal delirium, treated between 1977 and 1987, were analyzed. DSM-III criteria were used to assign the diagnosis of either withdrawal delirium (with obligatory clouding of consciousness) or alcohol withdrawal syndrome (without disturbances of consciousness and/or perception). No statistically significant differences between the two groups were found with respect to the red and white blood count, liver enzymes, and electrolytes. Significant differences were found in calcium levels, lymphocyte counts, and in electrophoresis. However, these differences are of no use for diagnostic purpose. Moreover, they are unspecific with respect to etiology. Hence, the distinction between alcohol withdrawal syndrome and alcohol withdrawal delirium can only be made clinically, i.e., it is dependent on the presence or absence of a clouded consciousness. This is in line with the findings published by other investigators. In the light of our metabolic findings, alcohol withdrawal syndrome and alcohol withdrawal delirium represent the two extremes of a continuum rather than two separate nosological entities.
Psychiatrische Praxis 02/1992; 19(1):16-22. · 1.64 Impact Factor
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Journal of Clinical Psychopharmacology 03/1991; 11(1):76-7. · 4.10 Impact Factor
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ABSTRACT: The study of eye movement dysfunction in chronic schizophrenics by electronystagmography revealed a significant increase of saccadic dysmetria as well as saccadic intrusions in smooth pursuit in schizophrenic patients with tardive dyskinesia (TD) compared with those without TD and with healthy controls. The pattern of eye movement dysfunction in schizophrenia allows clear discrimination from patients with similar movement disorders due to Huntington's disease. Of several possible explanation's of the schizophrenic eye movement dysfunction the authors favour the hypothesis of a common pathogenetic link between TD and eye movement disorders in schizophrenia, consisting in an underlying dysfunction of regions involved in the regulation of involuntary attention such as the parietal cortex and striatolimbic structures of the right hemisphere. Recent literature supports the assumption of right hemispheric dysfunction in schizophrenia.
European Archives of Psychiatry and Neurological Sciences 02/1990; 239(4):241-5.
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Der Nervenarzt 02/1990; 61(1):66. · 0.68 Impact Factor
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Psychiatry Research 10/1989; 29(3):335-6. · 2.52 Impact Factor
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ABSTRACT: The paper discusses a recent international conference in Munich (FRG) on brain-laterality research. An open letter on the goals of the conference is considered. In this letter, the "automatic" moral and intellectual decay of "left brain" modern society was predicted, and a clarion call for the reinsertion of "whole brain" values into our over-mechanized culture was sounded. Discussion of the conference itself focuses on the political and social risks involved in selling irrationalist ideologies - even well-meaning ones - in the name of science. The paper calls for a more responsible attitude among modern brain-laterality researchers who would participate in scientific conferences that blur the distinction between description and social prescription.
European Archives of Psychiatry and Neurological Sciences 02/1989; 239(3):141-3.
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ABSTRACT: We report a large family with an isolated case of Huntington's disease (HD), which is probably the result of a new mutation. The patient developed clinical signs typical of HD at the age of 36. The clinical course of the patient's disease is documented by several clinical admissions over a period of 14 years at present. The family history is strikingly negative with the parents having been clearly unaffected into their 80s and with 13 older and two younger, living, healthy sibs. Extensive testing of polymorphic markers (blood groups, red cell and serum proteins, HLA antigens) showed no indication of non-paternity, but rather gave strong support to the hypothesis that the proband is a full sib. In addition, DNA typing for several RFLPs known to be closely linked to the HD gene locus indicated that several clearly unaffected sibs share one or the other or both of the patient's haplotypes. This is further evidence in favour of the hypothesis of a new mutation at the HD locus. The posterior probability of a new mutation to HD in the patient exceeds 99%, even if an a priori probability of non-paternity of 10% and a mutation rate of HD of 10(-7) is assumed.
Journal of Medical Genetics 02/1989; 26(1):18-27. · 6.36 Impact Factor
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Der Nervenarzt 01/1989; 59(12):731-3. · 0.68 Impact Factor
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ABSTRACT: The long-term consequences of partial callosal lesions were examined in 7 neurosurgically treated patients. Detailed clinical and neuropsychological assessment of the interhemispheric transfer (multimodal sensory and motor tasks) as well as memory and attention tests were used. The results revealed some disconnection symptoms with minor clinical significance, which could not be attributed to particular sites of the corpus callosum, except the splenium. It is questionable whether the reported memory and attention impairments are caused by the callosal lesion or by extracallosal pathology. The results indicate that the transcallosal approach is a safe and feasible alternative in the management of pathological midline processes in the brain.
European Archives of Psychiatry and Neurological Sciences 10/1988; 237(6):365-75.
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ABSTRACT: Empirical findings and arguments in the hitherto controversial field of experimental psychosis are reviewed historically and systematically. Similarities and differences of experimental psychosis and schizophrenia are discussed on the background of disturbances of perception, consciousness and ego experience ("reflektierender Ich-Rest"). Better psychopathological, biochemical and neuropsychological assessment strategies could lead to a revival of experimental psychosis which some brief suggestions are made for.
Fortschritte der Neurologie · Psychiatrie 03/1988; 56(2):48-58. · 0.74 Impact Factor
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ABSTRACT: While modern neuropsychological and electrophysiological studies claim a functional disturbance of the left hemisphere (LH) in schizophrenia, historical clinical and anatomical work rather points to the right hemisphere (RH) as the main site of psychosis. In the light of an interhemispheric functional balance of inhibition and release, LH-dysfunction in schizophrenia could be interpreted as a consequence of an overactive and inhibiting RH. Since the RH is especially activated by emotional stimuli, and exaggerated distractability and sensitivity to emotional stimuli are hallmarks of schizophrenia, we compared the emotional irritability of the RH and LH in 35 acute schizophrenics and 22 matched controls. Using tachistoscopic half-field presentation we found in acute schizophrenics a selective impairment of RH-function with simultaneous improvement of LH-performance induced by emotional distractors. We therefore suggest that a right hemispheric dysfunction and hypersensitivity to emotional material plays an essential catalytic role in acute schizophrenia.
International Journal of Psychophysiology 01/1988; 5(4):261-4. · 2.14 Impact Factor
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ABSTRACT: Huntington's chorea is an autosomal dominant inherited disease with a chronic course and atrophy of the corpus striatum. PET examination shows reduced glucose metabolism in the caudate nucleus. We examined seven patients with Huntington's chorea by SPECT, using 99mTc-HMPAO. All patients had cortical defects of varying severity. In addition, five patients showed increased uptake in the region of the caudate nucleus. The specific tracer uptake due to the metabolic processes in the region of the caudate nucleus in Huntington's chorea is discussed.
RöFo - Fortschritte auf dem Gebiet der R 01/1988; 147(6):666-8. · 2.76 Impact Factor
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ABSTRACT: Most studies on childhood autism emphasize a left hemispheric disturbance. In the presented case a primary right (and only secondary left) hemispheric dysfunction seems to be obvious. This seems to be true also for other reports in the literature. Supported by the hypermasculine aspect of our patient a pathological intrauterine testosterone level is suggested to be responsible for the observed altered cerebral asymmetry and consecutive hemispheric dysfunction. The advantage of such neuropsychologic findings and hypothesis should stimulate further studies on autism and other psychiatric disturbances.
Der Nervenarzt 11/1987; 58(10):644-7. · 0.68 Impact Factor
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ABSTRACT: A young man with a previously untreated schizophrenia developed a neuroleptic malignant syndrome (NMS) on the second day of neuroleptic treatment. The dominant symptom was deep coma. The NMS occurred on the second day of neuroleptic therapy with rapidly progressing mental deterioration, temperature elevation, and extrapyramidal signs. After anticholinergics were injected the patient regained consciousness. This suggests that a cholinergic hyperactivity in the central nervous system (rather than hyperthermia) is responsible for the disturbance of consciousness in NMS. The experimental evidence that central cholinergic systems are stimulated by neuroleptics is discussed. It is concluded that anticholinergics might be helpful in treating coma during NMS.
Pharmacopsychiatry 08/1987; 20(4):168-70. · 2.07 Impact Factor
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ABSTRACT: This study reports the development of a severe life threatening catatonia in a 19 years old woman. Initially she displayed paranoia and hallucinations, which were complicated under neuroleptic treatment by extended rigor, temperature and autism. ECT led to a certain improvement of all symptoms, but complete recovery was only reached after neuroleptic drug withdrawal. The course of this case shows that the differential-diagnosis between genuine "pernicious" catatonia and the neuroleptica malignant syndrome is very difficult clinically. Therefore, before the application of ECT, an observation period without any neuroleptic drugs is recommended in similar cases with rigor, stupor and raised temperature, to avoid additional risks by narcosis and ECT itself. Diagnostic and therapeutic outlines are given.
Fortschritte der Neurologie · Psychiatrie 07/1986; 54(6):189-95. · 0.74 Impact Factor
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ABSTRACT: The influence of Piracetam on Parkinsonism was studied in 18 patients and 18 matched controls. Clinical, visuomotor and psychometric variables were measured. Piracetam improved visuomotor reaction time (RT) and accuracy in 6 mildly affected and tracing time in 6 moderately affected patients, the clinical condition and the organic brain syndrome in all patients investigated. The improvement of the prolonged RT seems to be correlated with bradyphrenia. No drug influence could be observed in the prolonged interhemispheric transfer time. As the mildly affected patients displayed the clearest effect of Piracetam, its administration in early and mild stage of parkinsonism is recommended.
Pharmacopsychiatry 12/1985; 18(6):343-6. · 2.07 Impact Factor
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ABSTRACT: In 15 patients with Huntington's disease, 17 offspring at risk and 63 healthy controls, visuomotor performances were assessed by quantitative (statistical) and qualitative analysis. The much enlarged error score of the nondominant left hand in patients with Huntington's disease was explained as callosal dyspraxia. Five of the 17 offspring revealed results similar to that of the patients.
Journal of Neurology Neurosurgery & Psychiatry 06/1985; 48(5):426-33. · 4.76 Impact Factor
