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Biomedical subjects

U Hegerl

Publications and source records attributed to U Hegerl.

At least 55 records · Page 3Linked to original sources
PubMed2001

Event-related potentials. Do they reflect central serotonergic neurotransmission and do they predict clinical response to serotonin agonists?

The increasing knowledge concerning anatomical structures and cellular processes underlying event-related potentials (ERP) as well as methodological advances in ERP data analysis (e.g. dipole source analysis) begin to bridge the gap between ERP and neurochemical aspects. Reliable indicators of the serotonin system are urgently needed because of its role in pathophysiology and as target of pharmacotherapeutic interventions in psychiatric disorders. Converging arguments from preclinical and clinical studies support the hypothesis that the loudness dependence of the auditory evoked N1/P2-response (LDAEP) is regulated by the level of central serotonergic neurotransmission. Dipole source analysis represents an important methodological advance in this context, because the two N1/P2-subcomponents, generated by the primary and secondary auditory cortex known to be differentially innervated by serotonergic fibers, can be separated. A pronounced LDAEP of primary auditory cortices is supposed to reflect low central serotonergic neurotransmission, and vice versa. LDAEP is a parameter with potential clinical value since subgroups of patients with a serotonergic dysfunction can be identified and can be treated more specifically. In depressed patients, a significant relationship between strong LDAEP, indicating low serotonergic function, and a favorable response to SSRI has been found. Additionally, there is evidence from several studies with patients with affective disorders implicating a strong LDAEP as a predictor of favorable response to a preventive lithium treatment.

Arousal↗
PubMed2001

The effect of the skull on event-related P300.

OBJECTIVES: Event-related potentials (EP) indicate neuronal processes with a high temporal resolution, while functional magnetic resonance imaging (fMRI) has a high spatial distribution. Information from both techniques may complement each other. However, this combination is fraught with difficulty because of a possible interference of the skull or the scalp with scalp-recorded EP. The aim of the present study was to investigate this influence of skull and scalp thicknesses on event-related P300 potentials. METHODS: Thirty healthy controls were examined using an auditory evoked P300 elicited by a standard oddball paradigm. Skull and scalp thicknesses were determined using coronal T2-weighted magnetic resonance imaging (MRI). RESULTS: P3b-amplitudes were significantly correlated with temporo-parietal skull thickness (r=-0.42; P=0.021; regression slope of -1.14 microV/mm skull thickness), whereas scalp had no influence on P300. The amplitude of the more frontal subcomponent P3a was not related to frontal skull thickness. CONCLUSIONS: Therefore, the utility of P300 as a research tool can be enhanced when adjustment for skull thickness is made.

Adult↗
PubMed2001

Kinematic analysis of handwriting movements in patients with obsessive-compulsive disorder.

OBJECTIVES: Basal ganglia dysfunction is supposed to play a part in the pathophysiology of obsessive-compulsive disorder (OCD). A new computer aided technique for the analysis of hand movements, allowing the detection of subtle motor performance abnormalities, was applied in this study of patients with OCD and healthy controls. METHODS: Using a digitising graphic tablet, hand motor performance was studied in 22 unmedicated patients with OCD and compared with 22 healthy controls. All subjects drew superimposed concentric circles with both the right and the left hand, in addition to writing a given sentence, their personal signature, and letter sequences in four different sizes. Kinematic parameters were calculated to quantify hand motion. RESULTS: Patients with OCD had significant impairments of handwriting performance, reflected by lower peak velocity (sentence t=3.6; p=0.001; signature t=2.8; p=0.01) and micrographia (sentence t=3.4; p=0.002; signature t=2.5; p=0.02), compared with controls and shortened acceleration phases per stroke (sentence t=2.4; p=0.02; signature t=4.1; p=0.000). By contrast, in repetitive drawing, patients with OCD had higher peak velocity than healthy controls (group x task interaction p<0.01). There were no significant differences in left and right hand performance between groups. Patients with early versus late age of onset differed in handwriting parameters, such as handwriting consistency. Greater severity of obsessions and compulsions correlated with increasingly poor handwriting performance in patients with OCD. CONCLUSIONS: A subtle motor dysfunction in OCD can be detected with a digitising tablet. The findings show handwriting impairments in patients with OCD, in line with the assumption that basal ganglia dysfunction is part of OCD pathophysiology. Repetitive motor pattern performance was not impaired, but rather tended to be even better in patients with OCD than in controls. The findings also support the concept that patients with OCD with early versus late age of onset differ in pathophysiological mechanisms and basal ganglia dysfunction.

Adolescent↗
PubMed2001

Association of an interleukin-1beta genetic polymorphism with altered brain structure in patients with schizophrenia.

OBJECTIVE: This study investigated the effect on brain morphology of an interleukin-1beta genetic polymorphism (C-->T transition at position -511) in patients with schizophrenia. METHOD: In vivo magnetic resonance imaging and genotype analysis were used in the examination of 44 male schizophrenic patients and 48 healthy male comparison subjects. RESULTS: No association between the interleukin-1beta polymorphism and schizophrenia was detected. Within the patient group, bifrontal-temporal gray matter volume deficits and generalized white matter tissue deficits in allele 2 carriers (genotype T/T or C/T) were found. In contrast, the interleukin-1beta polymorphism had no influence on brain morphology within the healthy subjects. CONCLUSIONS: The data suggest that allele 2 within the promoter region of the interleukin-1beta gene at position -511 contributes to structural brain alterations in patients with schizophrenia.

Adolescent↗
PubMed2001

Prefrontal cortex modulation of mood and emotionally induced facial expressions: a transcranial magnetic stimulation study.

Repetitive transcranial magnetic stimulation (rTMS) can serve as a tool to experimentally test hypotheses of prefrontal cortex (PFC) modulation of emotions. The present study used rTMS to test whether self-rated mood and emotionally induced facial expressions are hemispherically lateralized depending on their valence, as indicated by previous studies. Healthy volunteers underwent mood self-rating and computerized analysis of emotionally induced facial expressions before and after rTMS of left or right PFC. Facial expression analysis revealed lateralized changes of facial expressions after rTMS, whereas changes of subjective mood ratings did not show a hemispheric lateralization. On the basis of this study, the authors propose to combine rTMS and facial expression analysis for further studies of the cortical modulation of emotions in humans.

Adult↗
PubMed2000

Digitized analysis of abnormal hand-motor performance in schizophrenic patients.

Many studies have shown a high prevalence of discrete neuromotor disturbances in schizophrenic patients. It was hypothesized that these disturbances are lateralized and reflect a neurodevelopmental disorder underlying schizophrenia. A new method for assessing subtle motor dysfunction and hemispheric asymmetries is the registration of hand movements with a digitizing tablet. Using this method, we studied hand-motor dysfunction and its lateralization in schizophrenics, as compared with healthy controls. All subjects (27 schizophrenic patients, 13 of them without neuroleptic medication, the others under neuroleptics; 31 healthy controls) drew super-imposed concentric circles. We computed kinematic parameters reflecting velocity and automatization to quantify neurological soft signs (NSS). The patients had significant impairments of regularity of repetitive hand movements, as compared with the healthy controls (F> or =5.35; p< or =0.024(*)). Comparing differences of left- and right-hand performance between patients and controls, we found longer stroke duration (F=(15,98); p=0.000***) and decreased automatization (F=18,14; p=0.000***), especially on the left side in schizophrenic patients. Measuring hand movements with a digitizing tablet is a sensitive method for assessing subtle motor dysfunction in schizophrenic patients, not reflected in the scores of clinical scales. Our findings show NSS in schizophrenic patients, independently of neuroleptics. Further, the hypothesis of lateralization of cerebral structures generating NSS towards the right hemisphere in schizophrenia is supported.

Adult↗
PubMed2000

Loudness dependence of auditory evoked potentials in obsessive-compulsive disorder: a pilot study.

In recent years it has been suggested that a serotonergic dysfunction is involved in the pathogenesis of obsessive-compulsive disorder (OCD). The loudness dependence of auditory evoked potentials (AEPs) is one of the best validated indicators of the activity of the serotonin system in humans. To explore the validity of the hypothesis of a serotonergic dysfunction in OCD, the loudness dependence of AEPs of 22 medication-free OCD patients were compared with those of 22 age- and gender-matched healthy subjects. Auditory evoked N1/P2 activity to tones of increasing intensity was studied using dipole source analysis. Contrary to the hypothesis, OCD patients and healthy controls did not differ in their LDAEPs of the tangential dipole in particular, located in the primary auditory cortex and closely related to central serotonergic activity. Furthermore, no significant correlation was found between the severity of obsessive-compulsive or depressive symptoms and the loudness dependence of AEPs. These findings do not support the hypothesis of a serotonergic dysfunction in OCD patients.

Adult↗
PubMed2000

[Pharmacotherapy of depression in the elderly].

Antidepressants are not only effective in younger adults but also in older persons with depression. However there are peculiarities, which have to be taken into account when treating older patients. The enhanced risk of side effects has to be balanced with the more serious consequences of an untreated depression in old age. The efficacy in older patients has been proven not only for tricyclic antidepressants but also for SSRI and other newer antidepressants. The easy handling, the side effect profile and the safety in overdose are advantages of SSRI and newer antidepressants, which become particularly important in old age. The advantages and disadvantages of different classes of antidepressants with regard to comorbidity and comedication are discussed. In older subjects, changes of dosage should be slower and for some, but not for all antidepressants, dosage should be lower.

Adult↗
PubMed2000

[The state of psychiatry in Ukraine. Psychiatric hospitals in Kiev and Shitomir].

The situation of psychiatric patients in the Ukraine is determined by the financial and economic difficulties of this country. In the larger cities, so-called polyclinics take care of ambulant psychiatric patients. However, no other social psychiatric institutions exist. Here, the modalities of hospital psychiatric treatment are discussed using the psychiatric hospitals in Kiev and Shitomir as examples. Undertreatment is also a problem, because only a few psychopharmacological drugs are produced in the Ukraine. Import of new psychopharmacological agents is hampered by economical problems. Improving the availability of psychopharmacological drugs and the establishment of a social psychiatric network are major aims for psychiatrists working in Ukraine.

Commitment of Persons with Psychiatric Disorders↗
PubMed2000

The loudness dependency of the auditory evoked N1/P2-component as a predictor of the acute SSRI response in depression.

RATIONALE: A serotonergic dysfunction is supposed to play a pathogenetic role in depression, but there is a considerable number of non-responders in the acute treatment of depression with serotonergic agents like SSRI. Thus, an indicator of central serotonergic activity could lead to a more specific pharmacological treatment of depression. In animal and human data there is a growing amount of evidence that a strong loudness dependency of late auditory evoked potentials (LDAEP) is an indicator of low serotonergic activity and vice versa. OBJECTIVE: In 29 depressive inpatients (DSM-III-R diagnosis 296.x in 28 patients, 300.4 in one patient), the hypothesis was tested that a strong LDAEP prior to treatment can predict a better clinical outcome under SSRI treatment over 4 weeks. RESULTS: Patients with a strong pre-treatment LDAEP had a significantly greater decrease of depressive symptoms (Hamilton Scale for Depression) after 4 weeks than patients with a flat LDAEP. Significantly more responders fell into the group with a high LDAEP. Contrary to what might be expected, a second recording in a subsample of 19 patients after 4 weeks of treatment failed to show changes in the LDAEP. CONCLUSION: Our finding confirms the hypothesis that a strong LDAEP, indicating a low serotonergic activity, is related to a favorable response to acute SSRI treatment in depression. The LDAEP is a promising tool for the prediction of response to serotonin agonists in depression and it seems to be of clinical importance.

Acoustic Stimulation↗
PubMed2000

Dipole localization of P300 and normal aging.

At present, our understanding of how normal aging affects in vivo brain function is rudimentary. Therefore, the aim of the present study was to investigate age effects on auditory P300 topography. A recently developed dipole source model for P300 distinguishes overlapping P300 subcomponents and enhances reliability as well as validity of the measurement. 67 healthy subjects were examined using the P300 dipole model in addition to the scalp data measurement. The results show that P300 subcomponents reflect functionally different processes concerning age changes of P300 activities. Temporo-parietal P300 is smaller in older subjects, whereas frontal P300 is not attenuated. Age affected both P300 subcomponents' latencies. Therefore, the functionally different alteration of P300 subcomponents might be the reason for P300 topography changes with the P300 maximum more frontally in older age.

Acoustic Stimulation↗
PubMed2000

[Digitized analysis of hand movements in psychiatry. Methods, clinical findings and perspectives].

Numerous morbo- and pharmacogenic motor disorders are signs of psychiatric disease. In past, their exact and quantitative registration has not been possible or only possible using quite extensive procedures. Now we can use newer methods like the computer-aided analysis of hand movements, an elegant procedure allowing the detailed representation of discrete motor dysfunction. While these procedures are used with increasing tendency in neurology, their use aiming the investigation of psychiatric hypotheses is still at the beginning. Relevant application fields of the computer-aided analysis of hand movement are the differentiated and quantitative registration of movement disorders that could only be detected by use of rating scales so far; the registration of subclinical motor abnormalities leading to the detection of the participation of the motor system in certain subgroups of psychiatric patients; the differentiation of morbo- and pharmacogenic motor disorders (e.g. hypokinesia induced by neuroleptics versus schizophrenic negative symptomatology); the registration of neurological soft signs (e.g. in schizophrenic patients); the individual dose adjustment accounting for the threshold of extrapyramidal motor side effects (EPMS) under neuroleptic treatment and the detection and documentation of clinical and subclinical tremor. For some of these application fields there already exist promising findings. Some newer results will be presented. Schizophrenic patients were found to manifest impairments of velocity and degree of automatization and a reduced regularity of repetitive hand movements (fine motor dysdiadochokinesia)--a possible indicator for a disturbance of cerebral development. Patients with Alzheimer's disease showed loss of automatization and well preserved peak velocity. This finding could be relevant for the early detection of Alzheimer's dementia. Distal EPMS induced by neuroleptics can be exactly documented and their course can be represented using this method. The quick and economical utilization of digitized analysis of hand movements makes this procedure suitable for a broader application in the ambulatory setting.

Hand↗
PubMed2000

Platelet monoamine oxidase activity in alcoholics with and without a family history of alcoholism.

A number of studies point at platelet monoamine oxidase (MAO) activity being reduced in alcoholics with a family history of drinking, this being a possible vulnerability marker for alcoholism. To test this hypothesis, we examined a group of recently detoxified alcoholics with high (n = 25) and low genetic loading for alcoholism (n = 28) and a group of healthy controls (n = 21). Clinical assessments were made using the SCID II interview for psychiatric disorders, the Family History Assessment Module and the Semi-Structural Assessment of Genetics in Alcoholism, a questionnaire especially designed for genetic studies. Platelet MAO activity with and without ethanol stimulation and the percentage of MAO activity with ethanol did not differ between groups. The only significant difference was a lower inhibition of MAO activity with ethanol in alcoholics both with and without a family history compared to controls. In patients with antisocial personality traits, platelet MAO activity was also not found to be different from other alcoholics. Our findings question the hypothesis of reduced platelet MAO activity to be a possible vulnerability marker for alcoholism.

Adult↗
PubMed2000

Lithium-induced EEG changes in patients with affective disorders.

In 12 patients with affective disorders (ICD-10: F31, F32, F33), EEGs were recorded before and after 4.4 months of lithium treatment. Effects of lithium on the EEG were analyzed by power spectral analysis controlled for vigilance. We found (1) an increase in relative power in both delta and theta band which was related to the lithium plasma level, (2) a decrease in relative alpha power especially at occipital leads and (3) a reduction of the dominant alpha frequency. The changes in relative power were more pronounced in the right hemisphere, which is in contrast to the hypothesis of a site-specific localization of lithium effects only in left anterior regions.

Aged↗
PubMed2000

Periodic motor impairments in a case of 48-hour bipolar ultrarapid cycling before and under treatment with valproate.

Motor impairments of psychiatric patients can be assessed with digital recordings of handwriting tasks. The investigation of patients with bipolar affective disorders differentiates intraindividual changes related to the patient's fluctuating affective states. An unmedicated 67-year-old male with 48-hour bipolar ultrarapid cycling was investigated during 8 consecutive days of ultrarapid cycling and 4 weeks later, after remission under treatment with valproate. The handwriting skills of the patient followed the same rhythmic changes of the psychopathology in the first part of the study and a steady pattern in the second phase, after remission. Therefore, it can be assumed that the handwriting skills reflect a state marker of the disease. Poorer handwriting skills on the manic days, as compared to the depressive ones, support the hypothesis of a low arousal in manic patients.

Aged↗
PubMed2000

Adhesio interthalamica in male patients with schizophrenia.

OBJECTIVE: The authors investigated whether absence of the adhesio interthalamica in patients with schizophrenia constitutes a marker of early developmental neuropathological changes. METHOD: Thirty male patients with schizophrenia and 30 healthy male subjects were recruited for study. Magnetic resonance imaging was performed, and the presence or absence of the adhesio interthalamica was determined for each subject. The length and volume of the third ventricle were also measured. RESULTS: No differences in the presence or absence of the adhesio interthalamica were found between patients with schizophrenia and normal comparison subjects. Patients without the adhesio interthalamica had significantly higher scores for negative symptoms than patients with the adhesio interthalamica. There was no correlation between absence of the adhesio interthalamica and length and volume of the third ventricle in either patients or comparison subjects. CONCLUSIONS: The findings suggest that patients with schizophrenia who do not have the adhesio interthalamica are characterized by more severe negative symptoms.

Adolescent↗