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Biomedical subjects

Brigitte Rockstroh

Publications and source records attributed to Brigitte Rockstroh.

At least 19 recordsLinked to original sources
PubMed2006

[Ambivalences in the relationship of parents towards their schizophrenic or substance dependent adult child: a comparison to their relationships with healthy siblings and to ordinary parent-child-relationships].

OBJECTIVE: This study uses the concept of intergenerational ambivalence to compare the relationship of parents and their schizophrenic or substance dependent child to their relationship with the patient's siblings and to ordinary parent-child-relationships. METHOD: 24 parents of schizophrenic patients, 19 parents of substance dependent patients and 38 parents of healthy adults were interviewed about ambivalences, satisfaction and relatedness within their parent-child-relationships. RESULTS: Within both comparisons, parents experience in their relationship towards their mentally ill child stronger and more frequent ambivalences and less satisfaction, but feel equally strong related to him as to his sibling or as parents of healthy adults. This is especially true for parents of substance dependent adults. CONCLUSIONS: Therapeutic professionals should keep in mind such intergenerational ambivalences and address them in therapy and psychoeducation.

Adaptation, Psychological↗
PubMed2006

Brain regions essential for improved lexical access in an aged aphasic patient: a case report.

BACKGROUND: The relationship between functional recovery after brain injury and concomitant neuroplastic changes is emphasized in recent research. In the present study we aimed to delineate brain regions essential for language performance in aphasia using functional magnetic resonance imaging and acquisition in a temporal sparse sampling procedure, which allows monitoring of overt verbal responses during scanning. CASE PRESENTATION: An 80-year old patient with chronic aphasia (2 years post-onset) was investigated before and after intensive language training using an overt picture naming task. Differential brain activation in the right inferior frontal gyrus for correct word retrieval and errors was found. Improved language performance following therapy was mirrored by increased fronto-thalamic activation while stability in more general measures of attention/concentration and working memory was assured. Three healthy age-matched control subjects did not show behavioral changes or increased activation when tested repeatedly within the same 2-week time interval. CONCLUSION: The results bear significance in that the changes in brain activation reported can unequivocally be attributed to the short-term training program and a language domain-specific plasticity process. Moreover, it further challenges the claim of a limited recovery potential in chronic aphasia, even at very old age. Delineation of brain regions essential for performance on a single case basis might have major implications for treatment using transcranial magnetic stimulation.

Aged↗
PubMed2006

Disordered semantic representation in schizophrenic temporal cortex revealed by neuromagnetic response patterns.

BACKGROUND: Loosening of associations and thought disruption are key features of schizophrenic psychopathology. Alterations in neural networks underlying this basic abnormality have not yet been sufficiently identified. Previously, we demonstrated that spatio-temporal clustering of magnetic brain responses to pictorial stimuli map categorical representations in temporal cortex. This result has opened the possibility to quantify associative strength within and across semantic categories in schizophrenic patients. We hypothesized that in contrast to controls, schizophrenic patients exhibit disordered representations of semantic categories. METHODS: The spatio-temporal clusters of brain magnetic activities elicited by object pictures related to super-ordinate (flowers, animals, furniture, clothes) and base-level (e.g. tulip, rose, orchid, sunflower) categories were analysed in the source space for the time epochs 170-210 and 210-450 ms following stimulus onset and were compared between 10 schizophrenic patients and 10 control subjects. RESULTS: Spatio-temporal correlations of responses elicited by base-level concepts and the difference of within vs. across super-ordinate categories were distinctly lower in patients than in controls. Additionally, in contrast to the well-defined categorical representation in control subjects, unsupervised clustering indicated poorly defined representation of semantic categories in patients. Within the patient group, distinctiveness of categorical representation in the temporal cortex was positively related to negative symptoms and tended to be inversely related to positive symptoms. CONCLUSION: Schizophrenic patients show a less organized representation of semantic categories in clusters of magnetic brain responses than healthy adults. This atypical neural network architecture may be a correlate of loosening of associations, promoting positive symptoms.

Adult↗
PubMed2006

Decoupling neural networks from reality: dissociative experiences in torture victims are reflected in abnormal brain waves in left frontal cortex.

From a neuroscience perspective, little is known about the long-term effect of torture. Dissociative experiences and posttraumatic stress disorder are often the results of this experience. We examined psychological dissociation within a group of 23 torture victims and report its manifestations within neural networks in the human brain. In particular, we observed that dissociative experiences are associated with slow abnormal brain waves generated in left ventrolateral frontal cortex. Given that focal slow waves often result from depriving neural networks of major input, the present results may indicate decoupling of frontal affective processors from left cortical language areas. This interpretation is consistent with the fact that disturbed access to structured verbal memory concerning traumatic events is a core feature of the dissociative experience.

Adult↗
PubMed2006

Processing of emotional adjectives: Evidence from startle EMG and ERPs.

Affective startle modulation in the electromyographic (EMG), auditory startle evoked potentials, and visually evoked potentials (VEPs) were assessed while subjects evaluated pleasant, unpleasant, and neutral adjectives. Acoustic startle probes were presented at random time points 2.5-4.0 s after word onset. The visual P2 and P3 potentials were generally larger during processing of emotional than of neutral adjectives. In contrast, the late positive component was enhanced and was correlated with larger EMG startle responses and auditory startle evoked potential P3 amplitudes for pleasant words only. During internal cognitive activity, the startle reflex represents a measure of "processing interrupt." Thus the startle tone interrupted processing of particularly pleasant adjectives and caused re-alerting to environmental stimuli. Specific effects for pleasant material may arise from a "positivity offset," favoring responses to pleasant material at lower arousal levels.

Acoustic Stimulation↗
PubMed2006

Electromagnetic brain activity evoked by affective stimuli in schizophrenia.

Schizophrenia is typically associated with cognitive deficits, but symptoms also point to alterations in the processing of affective material, with potential impact on behavioral performance. This impact may unfold on multiple time scales, but initial processing of rapidly unfolding social cues may be particularly important. MEG-assessed regional brain activity associated with the capacity to process the emotional content of rapid visual stimuli (3/s) was examined in 12 individuals with schizophrenia and 12 matched controls. Patients showed less differentiation of emotional versus neutral stimuli 90-300 ms following picture onset. Together with group differences in the lateral topography of valence effects, these results are discussed as evidence of deficient automatic processing of emotionally potent stimuli in schizophrenia.

Adult↗
PubMed2005

D3 dopamine receptor mRNA is elevated in T cells of schizophrenic patients whereas D4 dopamine receptor mRNA is reduced in CD4+ -T cells.

The expression of dopamine receptors was examined in purified human neutrophils, monocytes, B cells, natural killer cells and CD4+ - and CD8+ -T lymphocytes by RT-PCR. In healthy subjects, D1 and D2 receptors were not expressed in leukocytes. Real Time PCR for dopamine receptors D3 and D4 disclosed that D3 receptors are expressed in T cells and natural killer cells and D4 receptors in CD4+ -T cells. The comparison of schizophrenic patients with sex- and age-matched controls revealed a significantly higher expression of D3 receptor mRNA in T cells of schizophrenic patients, whereas D4 receptor mRNA in CD4+ -T cells was downregulated.

Adult↗
PubMed2005

Neuromagnetic brain responses to words from semantic sub- and supercategories.

BACKGROUND: We explored spatio-temporal patterns of cortical activity evoked by written words from super-ordinate and sub-ordinate semantic categories and hoped to find a differential cortical and/or temporal distribution of the brain response depending on the level of the categories. Twenty-three subjects saw 360 words belonging to six sub-ordinate categories (mammals, birds, fish, fruit, flowers, trees) within two super-ordinate categories (fauna, flora). Visually evoked magnetic fields were determined from whole-head (148-sensor) magnetoencephalography and analyzed in the source space (Minimum Norm Estimate). RESULTS: Activity (MNE amplitudes) 100-150 ms after stimulus onset in the left occipito-temporal area distinguished super-ordinate categories, while later activity (300-550 ms) in the left temporal area distinguished the six sub-ordinate categories. CONCLUSION: Our results document temporally and spatially distinct processing and representation of words according to their categorical information. If further studies can rule out possible confounds then our results may help constructing a theory about the internal structure of entries in the mental lexicon and its access.

Adult↗
PubMed2005

Long-term stability of improved language functions in chronic aphasia after constraint-induced aphasia therapy.

BACKGROUND AND PURPOSE: In response to the established notion that improvement of language functions in chronic aphasia only can be achieved through long-term treatment, we examined the efficacy of a short-term, intensive language training, constraint-induced aphasia therapy (CIAT). This program is founded on the learning principles of prevention of compensatory communication (constraint), massed practice, and shaping (induced). METHODS: Twenty-seven patients with chronic aphasia received 30 hours of training over 10 days. Twelve patients were trained with the CIAT program. For 15 patients the training included a module of written language and an additional training in everyday communication, which involved the assistance of family members (CIATplus). Outcome measures included standardized neurolinguistic testing and ratings of the quality and the amount of daily communication. RESULTS: Language functions improved significantly after training for both groups and remained stable over a 6-month follow-up period. Single case analyses revealed statistically significant improvements in 85% of the patients. Patients and relatives of both groups rated the quality and amount of communication as improved after therapy. This increase was more pronounced for patients of the group CIATplus in the follow-up. CONCLUSIONS: Results confirm that a short-term intense language training, based on learning principles, can lead to substantial and lasting improvements in language functions in chronic aphasia. The use of family and friends in the training provides an additional valuable element. This effective intervention can be successfully used in the rehabilitation of chronic aphasia patients. Additionally, its short-term design makes it economically attractive for service providers.

Adult↗
PubMed2005

Electroencephalography/magnetoencephalography study of cortical activities preceding prosaccades and antisaccades.

The temporal and spatial characteristics of brain activity preceding prosaccades and antisaccades were investigated using source reconstructions of 64-channel electroencephalography and 148-channel magnetoencephalography data. Stimulus-locked data showed early cuneus activity was stronger during antisaccades, and later occipital gyrus activity was stronger preceding prosaccades, which suggests a top-down influence on early visual processing. Response-locked data showed that supplementary eye field, prefrontal cortex, and medial frontal eye field activity was greater for antisaccades than for prosaccades prior to saccade generation. Lateral frontal eye field activity appeared to be inhibited prior to antisaccade response generation. The spatial and temporal resolution of combined electroencephalography/magnetoencephalography data allows the evaluation of specific cortical activities preceding saccades and for demonstration of how activities differ as a function of response contingencies.

Adult↗
PubMed2005

Khat use as risk factor for psychotic disorders: a cross-sectional and case-control study in Somalia.

BACKGROUND: Little is known about the prevalence of khat-induced psychotic disorders in East African countries, where the chewing of khat leaves is common. Its main psycho-active component cathinone produces effects similar to those of amphetamine. We aimed to explore the prevalence of psychotic disorders among the general population and the association between khat use and psychotic symptoms. METHODS: In an epidemiological household assessment in the city of Hargeisa, North-West Somalia, trained local interviewers screened 4,854 randomly selected persons from among the general population for disability due to severe mental problems. The identified cases were interviewed based on a structured interview and compared to healthy matched controls. Psychotic symptoms were assessed using the items of the WHO Composite International Diagnostic Interview and quantified with the Positive and Negative Symptoms Scale. Statistical testing included Student's t-test and ANOVA. RESULTS: Local interviewers found that rates of severe disability due to mental disorders were 8.4% among males (above the age of 12) and differed according to war experiences (no war experience: 3.2%; civilian war survivors: 8.0%; ex-combatants: 15.9%). The clinical interview verified that in 83% of positive screening cases psychotic symptoms were the most prominent manifestations of psychiatric illness. On average, cases with psychotic symptoms had started to use khat earlier in life than matched controls and had been using khat 8.6 years before positive symptoms emerged. In most cases with psychotic symptoms, a pattern of binge use (> two 'bundles' per day) preceded the onset of psychotic symptoms, in contrast to controls of the same age. We found significant correlations between variables of khat consumption and clinical scales (0.35 to 0.50; p < 0.05), and between the age of onset of khat chewing and symptom onset (0.70; p <0.001). CONCLUSION: Evidence indicates a relationship between the consumption of khat and the onset of psychotic symptoms among the male population, whereby not the khat intake per se but rather early onset and excessive khat chewing seemed to be related to psychotic symptoms. The khat problem must be addressed by means other than prohibition, given the widespread use and its role in Somali culture.

Adolescent↗
PubMed2004

Negative and positive childhood experiences across developmental periods in psychiatric patients with different diagnoses - an explorative study.

BACKGROUND: A high frequency of childhood abuse has often been reported in adult psychiatric patients. The present survey explores the relationship between psychiatric diagnoses and positive and negative life events during childhood and adulthood in psychiatric samples. METHODS: A total of 192 patients with diagnoses of alcohol-related disorders (n = 45), schizophrenic disorders (n = 52), affective disorders (n = 54), and personality disorders (n = 41) completed a 42-item self-rating scale (Traumatic Antecedents Questionnaire, TAQ). The TAQ assesses personal positive experiences (competence and safety) and negative experiences (neglect, separation, secrets, emotional, physical and sexual abuse, trauma witnessing, other traumas, and alcohol and drugs abuse) during four developmental periods, beginning from early childhood to adulthood. Patients were recruited from four Psychiatric hospitals in Germany, Switzerland, and Romania; 63 subjects without any history of mental illness served as controls. RESULTS: The amount of positive experiences did not differ significantly among groups, except for safety scores that were lower in patients with personality disorders as compared to the other groups. On the other side, negative experiences appeared more frequently in patients than in controls. Emotional neglect and abuse were reported in patients more frequently than physical and sexual abuse, with negative experiences encountered more often in late childhood and adolescence than in early childhood. The patients with alcohol-related and personality disorders reported more negative events than the ones with schizophrenic and affective disorders. CONCLUSIONS: The present findings add evidence to the relationship between retrospectively reported childhood experiences and psychiatric diagnoses, and emphasize the fact that a) emotional neglect and abuse are the most prominent negative experiences, b) adolescence is a more 'sensitive' period for negative experiences as compared to early childhood, and c) a high amount of reported emotional and physical abuse occurs in patients with alcohol-related and personality disorders respectively.

Adolescent↗
PubMed2004

Intensive language training enhances brain plasticity in chronic aphasia.

BACKGROUND: Focal clusters of slow wave activity in the delta frequency range (1-4 Hz), as measured by magnetencephalography (MEG), are usually located in the vicinity of structural damage in the brain. Such oscillations are usually considered pathological and indicative of areas incapable of normal functioning owing to deafferentation from relevant input sources. In the present study we investigated the change in Delta Dipole Density in 28 patients with chronic aphasia (>12 months post onset) following cerebrovascular stroke of the left hemisphere before and after intensive speech and language therapy (3 hours/day over 2 weeks). RESULTS: Neuropsychologically assessed language functions improved significantly after training. Perilesional delta activity decreased after therapy in 16 of the 28 patients, while an increase was evident in 12 patients. The magnitude of change of delta activity in these areas correlated with the amount of change in language functions as measured by standardized language tests. CONCLUSIONS: These results emphasize the significance of perilesional areas in the rehabilitation of aphasia even years after the stroke, and might reflect reorganisation of the language network that provides the basis for improved language functions after intensive training.

Adult↗
PubMed2004

Cerebral lateralization in schizophrenia and dyslexia: neuromagnetic responses to auditory stimuli.

Many studies have shown altered hemispheric asymmetry-particularly in perisylvian regions-in schizophrenia patients as well as in individuals with dyslexia. Here we explore the similarity of these findings comparing the localization of the magnetic auditory N100m to the German syllable [ba:] in schizophrenia patients, dyslexic adults, and healthy control subjects. Control subjects showed the typical finding of more anterior sources in the right than in the left perisylvian region. In contrast, both schizophrenia patients and dyslexic subjects displayed a symmetrical N100m source configuration. While in people with dyslexia the alteration appears to originate in the right hemisphere, left-hemispheric deviations might contribute to reduced asymmetry in schizophrenia patients. Our results indicate that an absence of lateralized auditory responses in the temporal lobes may reflect a common deviance present in dyslexia and schizophrenia. The nonspecific finding of reduced cerebral laterality may be accounted for by population-specific differences in the functional organization of perisylvian sites.

Acoustic Stimulation↗
PubMed2004

Left-hemispheric abnormal EEG activity in relation to impairment and recovery in aphasic patients.

Focal electromagnetic slow-wave activity is generated in the vicinity of brain lesions. The present study confirmed this for the EEG delta band (1-4 Hz): Activity in the waking state was pronounced over the hemisphere of the lesion in 11 stroke patients suffering from aphasia, but not in 10 healthy controls. Changes of abnormal slow waves patterns were tracked from 1-3 months to 2 years poststroke by recording the EEG five times at 4-month intervals. Across the first year poststroke, mean left-hemispheric delta amplitude and equivalent current dipole strength decreased in parallel with the spontaneous recovery of language function, whereas the regional distribution of delta activity sources was stabile across time. No changes were observed during the second year poststroke. Results suggest that abnormal slow waves in the vicinity of brain lesions may be related to impairment in brain function, and that their measurement may assist in depicting the course of functional recovery.

Adult↗
PubMed2004

Gender differences in hemispheric asymmetry of syllable processing: left-lateralized magnetic N100 varies with syllable categorization in females.

The present study used magnetic source imaging to examine gender differences in the functional hemispheric asymmetry of auditory processing. The auditory evoked N100m was examined in male and female subjects in response to natural syllables with varying consonant and vowel as well as nonspeech noise. In an additional task subjects had to categorize different syllables from the first 35 ms of syllables, that is, the plosive and the formant transition. Syllable-evoked N100m activity was larger in the left than in the right hemisphere in female but not in male subjects. This gender-specific hemispheric asymmetry was speech specific, that is, absent when processing meaningless noise. Only in females did the degree of left-lateralization predict successful syllable categorization from short syllable bursts: Results suggest gender-specific differences in spectro-temporal analysis of speech.

Adult↗
PubMed2004

Reorganization of human cerebral cortex: the range of changes following use and injury.

Animal and human research over the past decades have increasingly detailed the brain's capacity for reorganization of neural network architecture to adapt to environmental needs. In this article, the authors outline the range of reorganization of human representational cortex, encompassing 1) reconstruction in concurrence with enhanced behaviorally relevant afferent activity (examples include skilled musicians and blind Braille readers); 2) injury-related response dynamics as, for instance, driven by loss of input (examples include stroke, amputation, or in blind individuals); and 3) maladaptive reorganization pushed by the interaction between neuroplastic processes and aberrant environmental requirements (examples include synchronicity of input nurturing focal hand dystonia). These types of neuroplasticity have consequences for both understanding pathological dynamics and therapeutic options. This will be illustrated in examples of motor and language rehabilitation after stroke, the treatment of focal hand dystonia, and concomitants of injury-related reorganization such as phantom limb pain.

Brain Injuries↗