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Georg Juckel - One of the best experts on this subject based on the ideXlab platform.
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Loudness dependence of primary Auditory-Cortex-evoked activity as predictor of therapeutic outcome to prophylactic lithium treatment in affective disorders--a retrospective study.
Pharmacopsychiatry, 2004Co-Authors: Georg Juckel, Paraskevi Mavrogiorgou, Bredemeier S, Juergen Gallinat, Thomas Frodl, Christoph Schulz, H.-j. Möller, Ulrich HegerlAbstract:Introduction: Lithium has been found to be very effective in prophylactic treatment of affective disorders. However, approximately one-third of patients do not respond to this treatment, which does not become apparent until after a year or more of treatment. Therefore, predictors are needed to avoid a long and unsuccessful therapy with risk of severe side effects. Since lithium acts as a serotonin agonist in prophylactic treatment, a predictor of being able to identify patients with low serotonergic activity, who may be responders to lithium, is promising. To determine whether the loudness dependence (LDAEP) of primary, but not of Secondary, Auditory-Cortex-evoked activity, which is inversely related to central serotonergic neurotransmission, could be such a predictor, responders and non-responders to prophylactic lithium treatment were compared. Methods: Thirty patients with uni- and bipolar affective disorders, who have taken a prophylactic lithium medication continuously for at least 3 years, were included in the study. Patients were classified as responders if they had no hospitalization within the past 3 years. Dipole source analysis allowing us to separate evoked activity of the primary and Secondary Auditory Cortex was used. Results: The LDAEP of the primary, but not of the Secondary, Auditory Cortex was significantly stronger in the responders to the lithium treatment than in the non-responders, implicating low serotonergic function in these patients. Discussion: This finding, which is in line with previous studies, suggests that loudness dependence of primary Auditory-Cortex-evoked activity could be a clinically relevant predictor of prophylactic treatment with lithium in affective disorders.
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Serotonergic dysfunction in schizophrenia assessed by the loudness dependence measure of primary Auditory Cortex evoked activity.
Schizophrenia research, 2003Co-Authors: Georg Juckel, Jürgen Gallinat, Michael Riedel, Safet Sokullu, Carl Schulz, Hans-jürgen Möller, Norbert Müller, Ulrich HegerlAbstract:Increased serotonergic activity is discussed as an important pathogenetic factor in schizophrenia. Further support for this hypothesis is difficult to obtain due to the lack of valid indicators of the brain's serotonin system. A great deal of evidence discovered through human and animal studies suggests that a weak loudness dependence of Auditory evoked potentials (LDAEP) indicates high serotonergic activity and vice versa. The LDAEP is a measure of Auditory Cortex activity, reflecting increase or decrease of Auditory evoked potential amplitudes with increasing tone loudness, which is probably modulated by the serotonergic innervation there. This is true only for the LDAEP of the primary Auditory Cortex, since this region is more highly innervated by serotonergic fibers than the Secondary Auditory Cortex. The LDAEP (N1/P2 component) of 25 inpatients with schizophrenia free of medication and 25 healthy controls matched by age and gender, were recorded. Using dipole source analysis, the LDAEP of primary (tangential dipole) and this of Secondary Auditory Cortex (radial dipole) was separately analyzed. Following a 4-week treatment with the 5-HT(2) antagonists clozapine or olanzapine, patients were once again studied. The LDAEP of the primary, but not of the Secondary Auditory Cortex, was significantly weaker in the patients with schizophrenia than in healthy volunteers, indicating enhanced serotonergic neurotransmission. After treatment with the 5-HT(2) antagonists, the LDAEP (of the right hemisphere) tended to be increased, indicating normalization of serotonergic function in the patients with schizophrenia. These results suggest that the loudness dependence of primary Auditory Cortex evoked activity is well suitable to assess serotonergic dysfunction in schizophrenia.
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Comparison between the analysis of the loudness dependency of the Auditory N1/P2 component with LORETA and dipole source analysis in the prediction of treatment response to the selective serotonin reuptake inhibitor citalopram in major depression.
Clinical Neurophysiology, 2002Co-Authors: Christoph Mulert, Georg Juckel, Holger Augustin, Ulrich HegerlAbstract:Abstract Objectives : The loudness dependency of the Auditory evoked potentials (LDAEP) is used as an indicator of the central serotonergic system and predicts clinical response to serotonin agonists. So far, LDAEP has been typically investigated with dipole source analysis, because with this method the primary and Secondary Auditory Cortex (with a high versus low serotonergic innervation) can be separated at least in parts. Methods : We have developed a new analysis procedure that uses an MRI probabilistic map of the primary Auditory Cortex in Talairach space and analyzed the current density in this region of interest with low resolution electromagnetic tomography (LORETA). LORETA is a tomographic localization method that calculates the current density distribution in Talairach space. Results : In a group of patients with major depression ( n =15), this new method can predict the response to an selective serotonin reuptake inhibitor (citalopram) at least to the same degree than the traditional dipole source analysis method ( P =0.019 vs. P =0.028). The correlation of the improvement in the Hamilton Scale is significant with the LORETA–LDAEP-values (0.56; P =0.031) but not with the dipole source analysis LDAEP-values (0.43; P =0.11). Conclusions : The new tomographic LDAEP analysis is a promising tool in the analysis of the central serotonergic system.
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Identifying psychiatric patients with serotonergic dysfunctions by event-related potentials
World Journal of Biological Psychiatry, 2000Co-Authors: Ulrich Hegerl, Georg JuckelAbstract:Summary: 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) is beginning to bridge the gap between ERP and neurochemkal aspects. Reliable indicators of the serotonin system are urgently needed because of its role in pathophysiology and as target of pharma-cotherapeutic interventions in psychiatric disorders. Converging arguments from preclinical and clinical studies support the hypothesis that the loudness dependence of the Auditory evoked Nl/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 Nl/P2-subcomponents, generated by the primary and Secondary Auditory Cortex known to be differentially innervated by serotonergic fibres, can be separated. A pronounced LDAEP of primary Auditory cortices is supposed to refl...
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Auditory Evoked Potentials Reflect Serotonergic Neuronal Activity—A Study in Behaving Cats Administered Drugs Acting on 5-HT_1A Autoreceptors in the Dorsal Raphe Nucleus
Neuropsychopharmacology, 1999Co-Authors: Georg Juckel, Ulrich Hegerl, Márk Molnár, Valéria Csépe, George KarmosAbstract:A valid indicator of central serotonergic neurotransmission would be useful for various diagnostic and psychopharmacological purposes in psychiatry. However, known peripheral serotonergic measures only partially reflect serotonergic function in the brain. Previous findings suggest that the intensity dependence of Auditory evoked potentials (AEPs) is closely related to central serotonergic activity. The present study examines the effects of microinjection of a 5-HT_1A agonist (8-OH-DPAT) and a 5-HT_1A antagonist (spiperone) into the dorsal raphe nucleus (DRN) on AEP recorded epidurally from the primary and Secondary Auditory Cortex in behaving cats. We found a stronger intensity dependence only of AEP from the primary Auditory Cortex after 8-OH-DPAT, which inhibits the firing rate of serotonergic DRN neurons, and a weaker intensity dependence after spiperone, which increases serotonergic cell firing, as compared to baseline measurements. These results demonstrate that the intensity dependence of AEP is inversely related to serotonergic neuronal activity and that it may be a promising tool for assessing central serotonergic function in humans (e.g., identifying patients with low serotonergic neurotransmission).
Ulrich Hegerl - One of the best experts on this subject based on the ideXlab platform.
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Loudness dependence of primary Auditory-Cortex-evoked activity as predictor of therapeutic outcome to prophylactic lithium treatment in affective disorders--a retrospective study.
Pharmacopsychiatry, 2004Co-Authors: Georg Juckel, Paraskevi Mavrogiorgou, Bredemeier S, Juergen Gallinat, Thomas Frodl, Christoph Schulz, H.-j. Möller, Ulrich HegerlAbstract:Introduction: Lithium has been found to be very effective in prophylactic treatment of affective disorders. However, approximately one-third of patients do not respond to this treatment, which does not become apparent until after a year or more of treatment. Therefore, predictors are needed to avoid a long and unsuccessful therapy with risk of severe side effects. Since lithium acts as a serotonin agonist in prophylactic treatment, a predictor of being able to identify patients with low serotonergic activity, who may be responders to lithium, is promising. To determine whether the loudness dependence (LDAEP) of primary, but not of Secondary, Auditory-Cortex-evoked activity, which is inversely related to central serotonergic neurotransmission, could be such a predictor, responders and non-responders to prophylactic lithium treatment were compared. Methods: Thirty patients with uni- and bipolar affective disorders, who have taken a prophylactic lithium medication continuously for at least 3 years, were included in the study. Patients were classified as responders if they had no hospitalization within the past 3 years. Dipole source analysis allowing us to separate evoked activity of the primary and Secondary Auditory Cortex was used. Results: The LDAEP of the primary, but not of the Secondary, Auditory Cortex was significantly stronger in the responders to the lithium treatment than in the non-responders, implicating low serotonergic function in these patients. Discussion: This finding, which is in line with previous studies, suggests that loudness dependence of primary Auditory-Cortex-evoked activity could be a clinically relevant predictor of prophylactic treatment with lithium in affective disorders.
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Serotonergic dysfunction in schizophrenia assessed by the loudness dependence measure of primary Auditory Cortex evoked activity.
Schizophrenia research, 2003Co-Authors: Georg Juckel, Jürgen Gallinat, Michael Riedel, Safet Sokullu, Carl Schulz, Hans-jürgen Möller, Norbert Müller, Ulrich HegerlAbstract:Increased serotonergic activity is discussed as an important pathogenetic factor in schizophrenia. Further support for this hypothesis is difficult to obtain due to the lack of valid indicators of the brain's serotonin system. A great deal of evidence discovered through human and animal studies suggests that a weak loudness dependence of Auditory evoked potentials (LDAEP) indicates high serotonergic activity and vice versa. The LDAEP is a measure of Auditory Cortex activity, reflecting increase or decrease of Auditory evoked potential amplitudes with increasing tone loudness, which is probably modulated by the serotonergic innervation there. This is true only for the LDAEP of the primary Auditory Cortex, since this region is more highly innervated by serotonergic fibers than the Secondary Auditory Cortex. The LDAEP (N1/P2 component) of 25 inpatients with schizophrenia free of medication and 25 healthy controls matched by age and gender, were recorded. Using dipole source analysis, the LDAEP of primary (tangential dipole) and this of Secondary Auditory Cortex (radial dipole) was separately analyzed. Following a 4-week treatment with the 5-HT(2) antagonists clozapine or olanzapine, patients were once again studied. The LDAEP of the primary, but not of the Secondary Auditory Cortex, was significantly weaker in the patients with schizophrenia than in healthy volunteers, indicating enhanced serotonergic neurotransmission. After treatment with the 5-HT(2) antagonists, the LDAEP (of the right hemisphere) tended to be increased, indicating normalization of serotonergic function in the patients with schizophrenia. These results suggest that the loudness dependence of primary Auditory Cortex evoked activity is well suitable to assess serotonergic dysfunction in schizophrenia.
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Comparison between the analysis of the loudness dependency of the Auditory N1/P2 component with LORETA and dipole source analysis in the prediction of treatment response to the selective serotonin reuptake inhibitor citalopram in major depression.
Clinical Neurophysiology, 2002Co-Authors: Christoph Mulert, Georg Juckel, Holger Augustin, Ulrich HegerlAbstract:Abstract Objectives : The loudness dependency of the Auditory evoked potentials (LDAEP) is used as an indicator of the central serotonergic system and predicts clinical response to serotonin agonists. So far, LDAEP has been typically investigated with dipole source analysis, because with this method the primary and Secondary Auditory Cortex (with a high versus low serotonergic innervation) can be separated at least in parts. Methods : We have developed a new analysis procedure that uses an MRI probabilistic map of the primary Auditory Cortex in Talairach space and analyzed the current density in this region of interest with low resolution electromagnetic tomography (LORETA). LORETA is a tomographic localization method that calculates the current density distribution in Talairach space. Results : In a group of patients with major depression ( n =15), this new method can predict the response to an selective serotonin reuptake inhibitor (citalopram) at least to the same degree than the traditional dipole source analysis method ( P =0.019 vs. P =0.028). The correlation of the improvement in the Hamilton Scale is significant with the LORETA–LDAEP-values (0.56; P =0.031) but not with the dipole source analysis LDAEP-values (0.43; P =0.11). Conclusions : The new tomographic LDAEP analysis is a promising tool in the analysis of the central serotonergic system.
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Identifying psychiatric patients with serotonergic dysfunctions by event-related potentials
World Journal of Biological Psychiatry, 2000Co-Authors: Ulrich Hegerl, Georg JuckelAbstract:Summary: 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) is beginning to bridge the gap between ERP and neurochemkal aspects. Reliable indicators of the serotonin system are urgently needed because of its role in pathophysiology and as target of pharma-cotherapeutic interventions in psychiatric disorders. Converging arguments from preclinical and clinical studies support the hypothesis that the loudness dependence of the Auditory evoked Nl/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 Nl/P2-subcomponents, generated by the primary and Secondary Auditory Cortex known to be differentially innervated by serotonergic fibres, can be separated. A pronounced LDAEP of primary Auditory cortices is supposed to refl...
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Auditory Evoked Potentials Reflect Serotonergic Neuronal Activity—A Study in Behaving Cats Administered Drugs Acting on 5-HT_1A Autoreceptors in the Dorsal Raphe Nucleus
Neuropsychopharmacology, 1999Co-Authors: Georg Juckel, Ulrich Hegerl, Márk Molnár, Valéria Csépe, George KarmosAbstract:A valid indicator of central serotonergic neurotransmission would be useful for various diagnostic and psychopharmacological purposes in psychiatry. However, known peripheral serotonergic measures only partially reflect serotonergic function in the brain. Previous findings suggest that the intensity dependence of Auditory evoked potentials (AEPs) is closely related to central serotonergic activity. The present study examines the effects of microinjection of a 5-HT_1A agonist (8-OH-DPAT) and a 5-HT_1A antagonist (spiperone) into the dorsal raphe nucleus (DRN) on AEP recorded epidurally from the primary and Secondary Auditory Cortex in behaving cats. We found a stronger intensity dependence only of AEP from the primary Auditory Cortex after 8-OH-DPAT, which inhibits the firing rate of serotonergic DRN neurons, and a weaker intensity dependence after spiperone, which increases serotonergic cell firing, as compared to baseline measurements. These results demonstrate that the intensity dependence of AEP is inversely related to serotonergic neuronal activity and that it may be a promising tool for assessing central serotonergic function in humans (e.g., identifying patients with low serotonergic neurotransmission).
George Karmos - One of the best experts on this subject based on the ideXlab platform.
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Auditory Evoked Potentials Reflect Serotonergic Neuronal Activity—A Study in Behaving Cats Administered Drugs Acting on 5-HT1A Autoreceptors in the Dorsal Raphe Nucleus
Neuropsychopharmacology, 1999Co-Authors: Georg Juckel, Ulrich Hegerl, Márk Molnár, Valéria Csépe, George KarmosAbstract:A valid indicator of central serotonergic neurotransmission would be useful for various diagnostic and psychopharmacological purposes in psychiatry. However, known peripheral serotonergic measures only partially reflect serotonergic function in the brain. Previous findings suggest that the intensity dependence of Auditory evoked potentials (AEPs) is closely related to central serotonergic activity. The present study examines the effects of microinjection of a 5-HT1A agonist (8-OH-DPAT) and a 5-HT1A antagonist (spiperone) into the dorsal raphe nucleus (DRN) on AEP recorded epidurally from the primary and Secondary Auditory Cortex in behaving cats. We found a stronger intensity dependence only of AEP from the primary Auditory Cortex after 8-OH-DPAT, which inhibits the firing rate of serotonergic DRN neurons, and a weaker intensity dependence after spiperone, which increases serotonergic cell firing, as compared to baseline measurements. These results demonstrate that the intensity dependence of AEP is inversely related to serotonergic neuronal activity and that it may be a promising tool for assessing central serotonergic function in humans (e.g., identifying patients with low serotonergic neurotransmission).
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Auditory Evoked Potentials Reflect Serotonergic Neuronal Activity—A Study in Behaving Cats Administered Drugs Acting on 5-HT_1A Autoreceptors in the Dorsal Raphe Nucleus
Neuropsychopharmacology, 1999Co-Authors: Georg Juckel, Ulrich Hegerl, Márk Molnár, Valéria Csépe, George KarmosAbstract:A valid indicator of central serotonergic neurotransmission would be useful for various diagnostic and psychopharmacological purposes in psychiatry. However, known peripheral serotonergic measures only partially reflect serotonergic function in the brain. Previous findings suggest that the intensity dependence of Auditory evoked potentials (AEPs) is closely related to central serotonergic activity. The present study examines the effects of microinjection of a 5-HT_1A agonist (8-OH-DPAT) and a 5-HT_1A antagonist (spiperone) into the dorsal raphe nucleus (DRN) on AEP recorded epidurally from the primary and Secondary Auditory Cortex in behaving cats. We found a stronger intensity dependence only of AEP from the primary Auditory Cortex after 8-OH-DPAT, which inhibits the firing rate of serotonergic DRN neurons, and a weaker intensity dependence after spiperone, which increases serotonergic cell firing, as compared to baseline measurements. These results demonstrate that the intensity dependence of AEP is inversely related to serotonergic neuronal activity and that it may be a promising tool for assessing central serotonergic function in humans (e.g., identifying patients with low serotonergic neurotransmission).
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Auditory-evoked potentials as indicator of brain serotonergic activity first evidence in behaving cats
Biological Psychiatry, 1997Co-Authors: Georg Juckel, Ulrich Hegerl, Márk Molnár, Valéria Csépe, George KarmosAbstract:Due to the increasing importance of the central serotonergic neurotransmission for pathogenetic concepts and as a target of pharmacotherapeutic interventions in psychiatry, reliable indicators of this system are needed Several findings from basic and clinical research suggest that the stimulus intensity dependence of Auditory evoked potentials (AEP) may be such an indicator of behaviorally relevant aspects of serotonergic activity (Hegerl and Juckel 1993, Biol Psychiatry 33:173–187.). In order to study this relationship more directly, epidural recordings over the primary and Secondary Auditory Cortex were conducted in chronically implanted cats under intravenous (i.v.) administration of drugs influencing the serotonergic and other modulatory systems (8-OH-DPAT, m-CPP, ketanserin, DOI, apomorphine, atropine, clonidine). The intensity dependence of the cat AEP component with the highest functional similarity to this of the N1/P2-component in humans was significantly changed by influencing 5-HT 1a and 5-HT 2 receptors, but not 5-HT 1c receptors. This serotonergic modulation of the intensity dependence was only found for the primary Auditory Cortex which corresponds to the known different innervation of the primary and Secondary Auditory Cortex by serotonergic fibers. Our study supports the idea that the intensity dependence of AEP could be a valuable indicator of brain serotonergic activity; however, this indicator seems to be of relative specificity because at least cholinergic effects on the intensity dependence were also observed.
Aage R Moller - One of the best experts on this subject based on the ideXlab platform.
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transcranial magnetic stimulation and extradural electrodes implanted on Secondary Auditory Cortex for tinnitus suppression
Journal of Neurosurgery, 2011Co-Authors: D De Ridder, Stefan Sunaert, Silvia Kovacs, Paul Van De Heyning, Sven Vanneste, Tomas Menovsky, Aage R MollerAbstract:Object Tinnitus is a prevalent symptom, with clinical, pathophysiological, and treatment features analogous to pain. Noninvasive transcranial magnetic stimulation (TMS) and intracranial Auditory Cortex stimulation (ACS) via implanted electrodes into the primary or overlying the Secondary Auditory Cortex have been developed to treat severe cases of intractable tinnitus. Methods A series of 43 patients who benefited transiently from 2 separate placebo-controlled TMS sessions underwent implantation of Auditory Cortex electrodes. Targeting was based on blood oxygen level–dependent activation evoked by tinnitus-matched sound, using functional MR imaging–guided neuronavigation. Results Thirty-seven percent of the patients responded to ACS with tonic stimulation. Of the 63% who were nonresponders, half benefited from burst stimulation. In total, 33% remained unaffected by the ACS. The average tinnitus reduction was 53% for the entire group. Burst stimulation was capable of suppressing tinnitus in more patients a...
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primary and Secondary Auditory Cortex stimulation for intractable tinnitus
Operations Research Letters, 2006Co-Authors: D De Ridder, Gert De Mulder, Edwin Verstraeten, Karolien Van Der Kelen, Stefan Sunaert, Marion Smits, Silvia Kovacs, J Verlooy, Paul Van De Heyning, Aage R MollerAbstract:Introduction: Recent research suggests tinnitus is a phantom phenomenon based on hyperactivity of the Auditory system, which can be visualized by functional neuroimaging, and transi
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primary and Secondary Auditory Cortex stimulation for intractable tinnitus commentary
ORL, 2006Co-Authors: D De Ridder, Gert De Mulder, Edwin Verstraeten, Karolien Van Der Kelen, Stefan Sunaert, Marion Smits, Silvia Kovacs, J Verlooy, Paul Van De Heyning, Aage R MollerAbstract:Introduction: Recent research suggests tinnitus is a phantom phenomenon based on hyperactivity of the Auditory system, which can be visualized by functional neuroimaging, and transiently modulated by transcranial magnetic stimulation (TMS). We present the results of the first implanted electrodes on the primary and Secondary Auditory Cortex after a successful TMS suppression. Methods and Materials: Twelve patients underwent an Auditory Cortex implantation, 10 for unilateral and 2 for bilateral tinnitus, based on >50% suppression applying TMS. Results were analyzed for pure tone tinnitus and white noise tinnitus. Results: TMS results in 77% pure tone tinnitus and 67% white noise reduction. Electrical stimulation via an implanted electrode results in a mean of 97% pure tone tinnitus and 24% white noise suppression. Mean Visual Analogue Scale score decreases from 9.5 to 1.5 for pure tone and from 8.8 to 6.8 for white noise postoperatively. Discussion: Pure tone tinnitus might be the conscious percept of focal neuronal hyperactivity of the Auditory Cortex. Once visualized, this hyperactivity can be modulated by neurostimulation. Conclusion: The preliminary results of the first implantations suggest that patients with unilateral pure tone tinnitus are good surgical candidates for electrode implantation and permanent electrical stimulation of the Auditory Cortex, provided that the tinnitus is of recent origin and can be suppressed by TMS.
D De Ridder - One of the best experts on this subject based on the ideXlab platform.
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Contralateral parahippocampal gamma-band activity determines noise-like tinnitus laterality: a region of interest analysis.
Neuroscience, 2011Co-Authors: Sven Vanneste, P. Van De Heyning, D De RidderAbstract:Abstract Tinnitus is described as an Auditory perception in the absence of any external sound source. Tinnitus loudness has been correlated to sustained high frequency gamma-band activity in Auditory Cortex. It remains unknown whether unilateral tinnitus is always generated in the left Auditory Cortex, irrespective of the side on which the tinnitus is perceived, or in the contralateral Auditory Cortex. In order to solve this enigma source localized electroencephalographic (EEG) recordings of a homogenous group of unilateral left and right-sided tinnitus patients presenting with noise-like tinnitus was analyzed. Based on a region of interest analysis, the most important result of this study is that tinnitus lateralization depended on the gamma-band activity of the contralateral parahippocampal area. As for the Auditory Cortex no differences were found between left-sided and right-sided tinnitus patients. However, in comparison to a control group both left and right-sided tinnitus patients had an increased gamma-band activity in both the left and right primary and Secondary Auditory Cortex. Thus whereas in tinnitus the primary and Secondary Auditory cortices of both sides are characterized by increased gamma-band activity, the side on which the tinnitus is perceived relates to gamma-band activity in the contralateral parahippocampal area.
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The neural network of phantom sound changes over time: a comparison between recent‐onset and chronic tinnitus patients
European Journal of Neuroscience, 2011Co-Authors: Sven Vanneste, Paul Van De Heyning, D De RidderAbstract:Tinnitus is characterized by an ongoing conscious perception of a sound in the absence of any external sound source. Chronic tinnitus is notoriously characterized by its resistance to treatment. In the present study the objective was to verify whether the neural generators and ⁄or the neural tinnitus network, evaluated through EEG recordings, change over time as previously suggested by MEG. We therefore analyzed the source-localized EEG recordings of a very homogenous group of left-sided narrow-band noise tinnitus patients. Results indicate that the generators involved in tinnitus of recent onset seem to change over time with increased activity in several brain areas [Auditory Cortex, supplementary motor area and dorsal anterior cingulate Cortex (dACC) plus insula], associated with a decrease in connectivity between the different Auditory and nonAuditory brain structures. An exception to this general connectivity decrease is an increase in gamma-band connectivity between the left primary and Secondary Auditory Cortex and the left insula, and also between the Auditory cortices and the right dorsal lateral prefrontal Cortex. These networks are both connected to the left parahippocampal area. Thus acute and chronic tinnitus are related to differential activity and connectivity in a network comprising the Auditory cortices, insula, dACC and premotor Cortex.
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transcranial magnetic stimulation and extradural electrodes implanted on Secondary Auditory Cortex for tinnitus suppression
Journal of Neurosurgery, 2011Co-Authors: D De Ridder, Stefan Sunaert, Silvia Kovacs, Paul Van De Heyning, Sven Vanneste, Tomas Menovsky, Aage R MollerAbstract:Object Tinnitus is a prevalent symptom, with clinical, pathophysiological, and treatment features analogous to pain. Noninvasive transcranial magnetic stimulation (TMS) and intracranial Auditory Cortex stimulation (ACS) via implanted electrodes into the primary or overlying the Secondary Auditory Cortex have been developed to treat severe cases of intractable tinnitus. Methods A series of 43 patients who benefited transiently from 2 separate placebo-controlled TMS sessions underwent implantation of Auditory Cortex electrodes. Targeting was based on blood oxygen level–dependent activation evoked by tinnitus-matched sound, using functional MR imaging–guided neuronavigation. Results Thirty-seven percent of the patients responded to ACS with tonic stimulation. Of the 63% who were nonresponders, half benefited from burst stimulation. In total, 33% remained unaffected by the ACS. The average tinnitus reduction was 53% for the entire group. Burst stimulation was capable of suppressing tinnitus in more patients a...
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primary and Secondary Auditory Cortex stimulation for intractable tinnitus
Operations Research Letters, 2006Co-Authors: D De Ridder, Gert De Mulder, Edwin Verstraeten, Karolien Van Der Kelen, Stefan Sunaert, Marion Smits, Silvia Kovacs, J Verlooy, Paul Van De Heyning, Aage R MollerAbstract:Introduction: Recent research suggests tinnitus is a phantom phenomenon based on hyperactivity of the Auditory system, which can be visualized by functional neuroimaging, and transi
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primary and Secondary Auditory Cortex stimulation for intractable tinnitus commentary
ORL, 2006Co-Authors: D De Ridder, Gert De Mulder, Edwin Verstraeten, Karolien Van Der Kelen, Stefan Sunaert, Marion Smits, Silvia Kovacs, J Verlooy, Paul Van De Heyning, Aage R MollerAbstract:Introduction: Recent research suggests tinnitus is a phantom phenomenon based on hyperactivity of the Auditory system, which can be visualized by functional neuroimaging, and transiently modulated by transcranial magnetic stimulation (TMS). We present the results of the first implanted electrodes on the primary and Secondary Auditory Cortex after a successful TMS suppression. Methods and Materials: Twelve patients underwent an Auditory Cortex implantation, 10 for unilateral and 2 for bilateral tinnitus, based on >50% suppression applying TMS. Results were analyzed for pure tone tinnitus and white noise tinnitus. Results: TMS results in 77% pure tone tinnitus and 67% white noise reduction. Electrical stimulation via an implanted electrode results in a mean of 97% pure tone tinnitus and 24% white noise suppression. Mean Visual Analogue Scale score decreases from 9.5 to 1.5 for pure tone and from 8.8 to 6.8 for white noise postoperatively. Discussion: Pure tone tinnitus might be the conscious percept of focal neuronal hyperactivity of the Auditory Cortex. Once visualized, this hyperactivity can be modulated by neurostimulation. Conclusion: The preliminary results of the first implantations suggest that patients with unilateral pure tone tinnitus are good surgical candidates for electrode implantation and permanent electrical stimulation of the Auditory Cortex, provided that the tinnitus is of recent origin and can be suppressed by TMS.
