- Email: [email protected]
52 ERP as predictors of clinical response to serotonin agonists in psychiatric patients
Abstracts
/International
Journal
Department of Psychiatry, University of Naples SUN, Naples, Italy Investigations of the effects of psychotropic drugs on quantitative EEG (QEEG) have provided evidence that drugs influencing subject’s behavior also produce QEEG modifications, which are reproducible in different subject populations and thought to be specific for each class of drugs (e.g., antidepressants and anxiolytics). Studies investigating drug-induced QEEG changes in psychiatric populations will be reviewed, with particular reference to the use of QEEG indices in the prediction of clinical response to treatment with psychotropic drugs. It will be underscored that investigations in clinical populations have provided evidence that these indices, differently from other neurophysiological measures, might represent a useful tool in the early discrimination of responders (R) from nonresponders (NR) to treatment. Several studies have reported that after the administration of a neuroleptic drug, R show an increase of theta and or alpha activity, while NR exhibit either no change or a decrease of synchronized activity. Following the administration of anxiolytics or antidepressants an increased activity in the beta frequency range has been found, but only few data are available on relationships between these modifications and clinical response. We will argue that drug-induced QEEG changes in patients with a favourable response to treatment involve the transition from a random type of EEG activity to an oscillatory mode, which produces a change of state in neuronal networks. The frequency of EEG oscillatory rhythms is thought to influence functional connectivity in neuronal networks. Converging evidence from brain imaging studies support the hypothesis that changes in the connectivity within largely distributed networks might be involved in the mechanism of action of psychotropic drugs.
52 ERP AS PREDICTORS OF CLINICAL RESPONSE TO SEROTONIN AGONISTS IN PSYCHIATRIC PATIENTS J. Gallinat, P. Mavrogiorgou, G. Juckel, T. Frodl-Bauch, Munke, R. Bottlender, U. Hegerl Psychiatrische Klinik der Ludwig-Mazimilians-Universitlt Miinchen, Germany
A.
OBJECTIVE: Both preclinical and clinical studies indicate that the dependence of the auditory avoked potentials (AEP) on stimulus loudness is negatively related to central serotonergic neurotransmission and may be useful as predictor of clinical response to serotonin agonists. The hypothesis is tested that a strong loudness dependence of the AEP, which reflects 10~ serotonergic function, is related to a favorable clinical response to serotonin agonists in patients with affective disorders. METHOD: SSRI responders (50% decrease in Hamilton De-
of Psychophysiology
30 (1998)
7-94
23
pression Score after 4 weeks) and responders to preventive lithium treatment (no recurrence with hospitalisation during lithium medication in the last 4 years) were compared to the corresponding non-responders. AEP to stimuli with different intensities were recorded (32 channels). Using dipole source analysis, the loudness dependence of the tangential Nl/PZ-dipole activity was calculated. RESULTS: Responders to preventive lithium treatment as well as depressed patients responding to SSRI were characterised by a significantly stronger loudness dependence. CONCLUSION: The loudness dependence of the AEP can give clinically relevant information concerning the response probability to serotonin agonists in the individual patient. The underlying mechanisms will be discussed in detail.
53 EEG-REACTIVITY BEFORE AND DURING TREATMENT IN SCHIZOPHRENIC PATIENTS: DIFFERENCES BETWEEN RESPONDERS AND NON-RESPONDERS? M. Koukkou, M.C.G. Merlo, H. Kleinlogel Department of Psychiatry of University Bern, Brain Mapping Labor, Bolligenstrasse 111, CH-3000 Bern 60, Switzerland There is clear evidence that psychotropic drugs inlluence the brain’s way of functioning as measured in its electrical activity. Measures of EEG activity and EEG reactivity have been used to study the working brain as it is engaged in psychological meaningful activities in normals and in schizophrenics and the results have been discussed considering the functional significance of deviations in the characteristics of EEG reactivity for understanding the mode of action of neuroleptics in influencing productive schizophrenic symptoms. Multichannel EEG activity and EEG reactivity to verbal material and psychopathological ratings (the AMDP system) were assessed in first episode drug-naive psychotic patients before antipsychotic treatment (day 0) and after 28 days of treatment (day 28). The score of the AMDP-syndroms scales of each recording day were used to divide the patients in two groups: high and low psychopathology and the differences of the score between day 28 minus day 0 were used to estimate clinical changes. The results suggest that the best differentiation between high and low psychopathology patients and between patients who showed a significant reduction of the syndrom score (responders) and patients with less reduction (non-responders) is achieved with the measures of EEG reactivity as estimated mainly with the mean power and mean frequency of the theta and alpha frequency bands.
54 MULTICHANNE L EEG COMPLEXITY AND OTHER GLOBAL MEASURES IN STUDIES OF DRUG INDUCED CHANGES OF BRAIN FUNCTIONS Jiri Wackermann Neuroscience Technology Research s.r.0. 26, Zitna Street, CZ-12000 Praha 2 (Czech Republic)
/International
Journal
Department of Psychiatry, University of Naples SUN, Naples, Italy Investigations of the effects of psychotropic drugs on quantitative EEG (QEEG) have provided evidence that drugs influencing subject’s behavior also produce QEEG modifications, which are reproducible in different subject populations and thought to be specific for each class of drugs (e.g., antidepressants and anxiolytics). Studies investigating drug-induced QEEG changes in psychiatric populations will be reviewed, with particular reference to the use of QEEG indices in the prediction of clinical response to treatment with psychotropic drugs. It will be underscored that investigations in clinical populations have provided evidence that these indices, differently from other neurophysiological measures, might represent a useful tool in the early discrimination of responders (R) from nonresponders (NR) to treatment. Several studies have reported that after the administration of a neuroleptic drug, R show an increase of theta and or alpha activity, while NR exhibit either no change or a decrease of synchronized activity. Following the administration of anxiolytics or antidepressants an increased activity in the beta frequency range has been found, but only few data are available on relationships between these modifications and clinical response. We will argue that drug-induced QEEG changes in patients with a favourable response to treatment involve the transition from a random type of EEG activity to an oscillatory mode, which produces a change of state in neuronal networks. The frequency of EEG oscillatory rhythms is thought to influence functional connectivity in neuronal networks. Converging evidence from brain imaging studies support the hypothesis that changes in the connectivity within largely distributed networks might be involved in the mechanism of action of psychotropic drugs.
52 ERP AS PREDICTORS OF CLINICAL RESPONSE TO SEROTONIN AGONISTS IN PSYCHIATRIC PATIENTS J. Gallinat, P. Mavrogiorgou, G. Juckel, T. Frodl-Bauch, Munke, R. Bottlender, U. Hegerl Psychiatrische Klinik der Ludwig-Mazimilians-Universitlt Miinchen, Germany
A.
OBJECTIVE: Both preclinical and clinical studies indicate that the dependence of the auditory avoked potentials (AEP) on stimulus loudness is negatively related to central serotonergic neurotransmission and may be useful as predictor of clinical response to serotonin agonists. The hypothesis is tested that a strong loudness dependence of the AEP, which reflects 10~ serotonergic function, is related to a favorable clinical response to serotonin agonists in patients with affective disorders. METHOD: SSRI responders (50% decrease in Hamilton De-
of Psychophysiology
30 (1998)
7-94
23
pression Score after 4 weeks) and responders to preventive lithium treatment (no recurrence with hospitalisation during lithium medication in the last 4 years) were compared to the corresponding non-responders. AEP to stimuli with different intensities were recorded (32 channels). Using dipole source analysis, the loudness dependence of the tangential Nl/PZ-dipole activity was calculated. RESULTS: Responders to preventive lithium treatment as well as depressed patients responding to SSRI were characterised by a significantly stronger loudness dependence. CONCLUSION: The loudness dependence of the AEP can give clinically relevant information concerning the response probability to serotonin agonists in the individual patient. The underlying mechanisms will be discussed in detail.
53 EEG-REACTIVITY BEFORE AND DURING TREATMENT IN SCHIZOPHRENIC PATIENTS: DIFFERENCES BETWEEN RESPONDERS AND NON-RESPONDERS? M. Koukkou, M.C.G. Merlo, H. Kleinlogel Department of Psychiatry of University Bern, Brain Mapping Labor, Bolligenstrasse 111, CH-3000 Bern 60, Switzerland There is clear evidence that psychotropic drugs inlluence the brain’s way of functioning as measured in its electrical activity. Measures of EEG activity and EEG reactivity have been used to study the working brain as it is engaged in psychological meaningful activities in normals and in schizophrenics and the results have been discussed considering the functional significance of deviations in the characteristics of EEG reactivity for understanding the mode of action of neuroleptics in influencing productive schizophrenic symptoms. Multichannel EEG activity and EEG reactivity to verbal material and psychopathological ratings (the AMDP system) were assessed in first episode drug-naive psychotic patients before antipsychotic treatment (day 0) and after 28 days of treatment (day 28). The score of the AMDP-syndroms scales of each recording day were used to divide the patients in two groups: high and low psychopathology and the differences of the score between day 28 minus day 0 were used to estimate clinical changes. The results suggest that the best differentiation between high and low psychopathology patients and between patients who showed a significant reduction of the syndrom score (responders) and patients with less reduction (non-responders) is achieved with the measures of EEG reactivity as estimated mainly with the mean power and mean frequency of the theta and alpha frequency bands.
54 MULTICHANNE L EEG COMPLEXITY AND OTHER GLOBAL MEASURES IN STUDIES OF DRUG INDUCED CHANGES OF BRAIN FUNCTIONS Jiri Wackermann Neuroscience Technology Research s.r.0. 26, Zitna Street, CZ-12000 Praha 2 (Czech Republic)