Left Temporoparietal Cortex Research Articles

Electric field and current density distribution in an anatomical head model during transcranial direct current stimulation for tinnitus treatment

Tinnitus is considered an auditory phantom percept. Recently, transcranial direct current stimulation (tDCS) has been proposed as a new approach for tinnitus treatment including, as potential targets of interest, either the temporal and temporoparietal cortex or prefrontal areas. This study investigates and compares the spatial distribution of the magnitude of the electric field and the current density in the brain tissues during tDCS of different brain targets. A numerical method was applied on a realistic human head model to calculate these field distributions in different brain structures, such as the cortex, white matter, cerebellum, hippocampus, medulla oblongata, pons, midbrain, thalamus, and hypothalamus. Moreover, the same distributions were evaluated along the auditory pathways. Results of this study show that tDCS of the left temporoparietal cortex resulted in a widespread diffuse distribution of the magnitude of the electric fields (and also of the current density) on an area of the cortex larger than the target brain region. On the contrary, tDCS of the dorsolateral prefrontal cortex resulted in a stimulation mainly concentrated on the target itself. Differences in the magnitude distribution were also found on the structures along the auditory pathways. A sensitivity analysis was also performed, varying the electrode position and the human head models. Accurate estimation of the field distribution during tDCS in different regions of the head could be valuable to better determine and predict efficacy of tDCS for tinnitus suppression.

The effect of rTMS on auditory hallucinations: Clues from an EEG-rTMS study

ObjectiveRepetitive transcranial magnetic stimulation (rTMS) to the temporoparietal region has been proposed as a therapeutic option for auditory verbal hallucinations (AVH). However, most large randomized controlled trials failed to demonstrate a superior effect of rTMS treatment as compared to sham. Previous studies applied daily rTMS sessions for one or more weeks to summate its effects. However, the effect of a single rTMS treatment on AVH-severity has never been studied, making it unclear if there is an initial effect that could be increased by repeated treatment. MethodsIn three separate sessions, twenty-four patients with a psychotic disorder received 1-Hz rTMS to the left temporoparietal cortex, its right-sided homologue or a centro-occipital control site. Severity of AVH was assessed before and after each rTMS session and resting-state EEGs were recorded to investigate the neuronal effects of rTMS. ResultsStimulation of the temporoparietal cortices was not more effective in reducing AVH-severity than control-site stimulation. In addition, EEG-related power and connectivity measures were not affected differently across stimulation sites and changes in neuronal activity did not correlate with changes in AVH-severity. ConclusionsThese results may suggest a placebo effect of a single session of 1-Hz rTMS treatment on AVH-severity.

Individual differences in skilled adult readers reveal dissociable patterns of neural activity associated with component processes of reading

We used fMRI to examine patterns of brain activity associated with component processes of visual word recognition and their relationships to individual differences in reading skill. We manipulated both the judgments adults made on written stimuli and the characteristics of the stimuli. Phonological processing led to activation in left inferior frontal and temporal regions whereas semantic processing was associated with bilateral middle frontal activation. Individual differences in reading subskills were reflected in differences in the degree to which cortical regions were engaged during reading. Variation in sight word reading efficiency was associated with degree of activation in visual cortex. Increased phonological decoding skill was associated with greater activation in left temporo-parietal cortex. Greater reading comprehension ability was associated with decreased activation in anterior cingulate and temporal regions. Notably, associations between reading ability and neural activation indicate that brain/behavior relationships among skilled readers differ from patterns associated with dyslexia and reading development.

Deep transcranial magnetic stimulation add-on for the treatment of auditory hallucinations: a double-blind study

BackgroundAbout 25% of schizophrenia patients with auditory hallucinations are refractory to pharmacotherapy and electroconvulsive therapy. We conducted a deep transcranial magnetic stimulation (TMS) pilot study in order to evaluate the potential clinical benefit of repeated left temporoparietal cortex stimulation in these patients. The results were encouraging, but a sham-controlled study was needed to rule out a placebo effect.MethodsA total of 18 schizophrenic patients with refractory auditory hallucinations were recruited, from Beer Yaakov MHC and other hospitals outpatient populations. Patients received 10 daily treatment sessions with low-frequency (1 Hz for 10 min) deep TMS applied over the left temporoparietal cortex, using the H1 coil at the intensity of 110% of the motor threshold. Procedure was either real or sham according to patient randomization. Patients were evaluated via the Auditory Hallucinations Rating Scale, Scale for the Assessment of Positive Symptoms-Negative Symptoms, Clinical Global Impressions, and Quality of Life Questionnaire.ResultsIn all, 10 patients completed the treatment (10 TMS sessions). Auditory hallucination scores of both groups improved; however, there was no statistical difference in any of the scales between the active and the sham treated groups.ConclusionsLow-frequency deep TMS to the left temporoparietal cortex using the protocol mentioned above has no statistically significant effect on auditory hallucinations or the other clinical scales measured in schizophrenic patients.Trial RegistrationClinicaltrials.gov identifier: NCT00564096.

AS21-03 - Effect of low-frequency rtms on electromagnetic tomography (LORETA) and regional brain metabolism (PET) in schizophrenia patients with auditory hallucinations

It was repeatedly reported that low frequency (≤1 Hz) repetitive transcranial magnetic stimulation (rTMS) diminishes treatment-resistant auditory hallucinations. To evaluate the distribution of neuronal electrical activity and the brain metabolism changes after low-frequency rTMS in patients with auditory hallucinations. rTMS (0.9 Hz, 100% of MT, 20 min.) applied to the left temporo-parietal cortex was used for ten days in the treatment of medication-resistant auditory hallucinations in schizophrenia (N = 12). The effect of rTMS on the low resolution brain electromagnetic tomography (LORETA) and brain metabolism ( 18 FDG PET) was measured before and after two weeks of treatment. In a subsequent double blind sham controlled cross-over study (N = 15), the low frequency rTMS was applied using i) “neuronavigation” according to an individual metabolic local maxima of 18 FDG PET uptake; ii) “standard” positioning, and iii) inactive “sham”. The rTMS decreased the brain metabolism in the left superior temporal gyrus and in interconnected regions and effected increases in the contralateral cortex. We detected a decrease of current densities (LORETA) for the beta-1 and beta-3 bands in the left temporal lobe whereas an increase was found for beta-2 band contralaterally. The PET neuronavigated rTMS compared to both standard and inactive rTMS, revealed better outcome. The LORETA and PET indicate that the neuroplastic changes provide the substrate for a clinical effect. Congruently, 18 FDG PET navigated rTMS allows an individual approach to therapy of patient with treatment-resistant acoustic hallucinations.

Excitability changes induced in the human auditory cortex by transcranial direct current stimulation: direct electrophysiological evidence

Transcranial direct current stimulation (tDCS) can systematically modify behavior by inducing changes in the underlying brain function. Objective electrophysiological evidence for tDCS-induced excitability changes has been demonstrated for the visual and somatosensory cortex, while evidence for excitability changes in the auditory cortex is lacking. In the present study, we applied tDCS over the left temporal as well as the left temporo-parietal cortex and investigated tDCS-induced effects on auditory evoked potentials after anodal, cathodal, and sham stimulation. Results show that anodal and cathodal tDCS can modify auditory cortex reactivity. Moreover, auditory evoked potentials were differentially modulated as a function of site of stimulation. While anodal tDCS over the temporal cortex increased auditory P50 amplitudes, cathodal tDCS over the temporo-parietal cortex induced larger N1 amplitudes. The results directly demonstrate excitability changes in the auditory cortex induced by active tDCS over the temporal and temporo-parietal cortex and might contribute to the understanding of mechanisms involved in the successful treatment of auditory disorders like tinnitus via tDCS.

Adjunctive treatment of bimodal repetitive transcranial magnetic stimulation (rTMS) in pharmacologically non-responsive patients with schizophrenia: A preliminary study

We evaluated the efficacy of bimodal repetitive transcranial magnetic stimulation (rTMS) in treating pharmacologically non-responsive patients with schizophrenia. Ten patients with DSM-IV schizophrenia, unresponsive to pharmacological treatment, underwent treatment with 15 rTMS sessions, as an adjunctive therapy, for three weeks. Each session comprised 40 trains, beginning every 30s: 20 trains of 10 Hz rTMS to the left dorsolateral prefrontal cortex (DLPFC) with a 3-s duration and 20 trains of 1 Hz rTMS to the left temporoparietal cortex (TPC) with a 30-s duration. We assessed patients via the Positive and Negative Syndrome Scale (PANSS) and Korean Version of the Calgary Depression Scale for Schizophrenia (K-CDSS), at five time points: baseline, Days 8, 15, and 22, and 1 week after final treatment (Day 29). Patients who agreed to take neurocognitive tests underwent neurocognitive function evaluations at baseline and 1 week after final treatment. At Day 29, all PANSS subscale scores in had decreased significantly compared to baseline (Z=-2.214, p=0.027, positive; Z=-2.132, p=0.033, negative; Z=-2.023, p=0.043, general pathology; Z=-2.371, p=0.018, total). Effect over time was significant for the PANSS positive and negative subscale scores and total score (χ(2)=13.35, p=0.010; χ(2)=10.27, p=0.036; and χ(2)=16.50, p=0.002, respectively) but not for the general pathology subscale. Among the neurocognitive tests, the fourth and fifth trials and total K-AVLT scores showed significant increases (Z=-2.041, p=0.041; Z=-2.251, p=0.024; and Z=-2.201, p=0.028, respectively), suggesting improvement in short-term auditory verbal memory. Bimodal rTMS stimulation of left DLPFC and left TPC induced clinical improvement in pharmacologically non-responsive schizophrenia patients and may have improved their short-term verbal memories.

The Price of Your Soul: Neural Evidence for the Non-Utilitarian Representation of Sacred Values

Sacred values, such as those associated with religious or ethnic identity, underlie many important individual and group decisions in life, and individuals typically resist attempts to trade-off their sacred values in exchange for material benefits. Deontological theory suggests that sacred values are processed based on rights and wrongs irrespective of outcomes, while utilitarian theory suggests they are processed based on costs and benefits of potential outcomes, but which mode of processing an individual naturally uses is unknown. The study of decisions over sacred values is difficult because outcomes cannot typically be realized in a laboratory, and hence little is known about the neural representation and processing of sacred values. We utilized an experimental paradigm that used integrity as a proxy for sacredness and which paid real money to induce individuals to sell their personal values. Using functional magnetic resonance imaging (fMRI), we found that values that people refused to sell (sacred values) were associated with increased activity in the left temporoparietal junction and ventrolateral prefrontal cortex, regions previously associated with semantic rule retrieval. This suggests that sacred values affect behavior through the retrieval and processing of deontic rules and not through a utilitarian evaluation of costs and benefits.

Short duration repetitive transcranial magnetic stimulation for tinnitus treatment: A prospective Asian study

Background Tinnitus is a subjective auditory perception of sounds or noise not triggered by external auditory stimuli. To date, treatment in severe cases is generally unsatisfactory. Characteristic functional brain imaging changes associated with tinnitus include hyperactivity encompassing both the primary auditory cortex (AC) and the secondary or associative cortex. Brief repetitive transcranial magnetic stimulation (rTMS) trains applied to the scalp overlying the hyperactive left AC is known to produce moderate tinnitus attenuation. Objective Although Western studies have documented the value of rTMS in tinnitus treatment, we evaluate the efficacy of a short duration rTMS protocol for the first time in the Asian setting. Method Consecutive patients were recruited at our tinnitus clinic. Detailed history, examination, audiogram and baseline tinnitus scales were recorded. RTMS consisted of 1000 pulses/day at 1 Hz and 110% of the motor threshold, for five consecutive days over the left temporoparietal cortex. Tinnitus ratings were determined weekly for 4 weeks after rTMS. Result Fifteen patients completed the trial; none experienced significant side effects. Repeated measures ANOVA showed significant linear decrease in Tinnitus Handicap Inventory (THI) scores over the time period ( F (1,14) = 4.7, p = 0.04). However, none of the other parameters (severity, annoyance, effect on lifestyle and overall impression: visual analogue scale) showed beneficial outcomes. Conclusions Our findings point to a positive effect of short duration rTMS in tinnitus treatment using the THI. However, no significant benefits were demonstrated for other subjective patient ratings. Although well tolerated and convenient, short duration rTMS may prove inadequate for modulating maladaptive plastic changes at the cortical level, and our results suggest the need for delivery of more stimuli. Future studies will utilize at least 2000 pulses/day, in line with previous experience in Western settings.

Bihemispheric Cerebral FDG PET Correlates of Cognitive Dysfunction as Assessed by the CERAD in Alzheimer's Disease

Alzheimer's disease (AD) is characterized by a variety of cognitive deficits which can be reliably assessed by the neuropsychological test battery of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), but the cerebral changes underlying the respective cognitive deficits are only partly understood. Measures of severity of dementia in AD as well as delayed episodic memory performance in mild cognitive impairment significantly correlated with bihemispheric cerebral glucose hypometabolism. We therefore hypothesized that the CERAD cognitive battery may represent cerebral dysfunction of both hemispheres in patients with AD. In 32 patients with AD, cerebral glucose metabolism was investigated using positron-emission-tomography with 18Fluorodeoxyglucose (FDG PET) and associated with the test scores of the CERAD cognitive battery by statistical parametric mapping. Episodic memory scores significantly correlated with temporopari etal glucose metabolism of both hemispheres while delayed episodic memory significantly was correlated with the right frontotemporal cortices. Verbal fluency and naming scores significantly correlated with glucose metabolism in left temporoparietal and right frontal cortices, whereas constructional praxis predominantly correlated significantly with the bilateral precuneus. In conclusion, the results of our study demonstrate that not only memory function but also functions of language and constructional praxis in AD are associated with glucose metabolism as revealed by FDG PET in subsets of uni- and bilateral brain areas. The findings of our study for the first time demonstrate that in AD neuropsychological deficits as assessed by the CERAD refer to different cerebral sites of both hemispheres.

Anatomical correlates for category-specific naming of living and non-living things

Introduction Selective naming categories impairments for living and non-living things are widely reported in brain damaged patients. Electrostimulation mapping was used to study the possible anatomical segregation of living/non-living categories in a prospective series of patients operated on for tumor removal. Materials and methods Fifty brain mappings (patients with no language impairment; range: 14–80 years; mean: 48 years; 26 males; 5 left handed) were performed in 46 left and 4 right hemispheres using two linguistically controlled tasks (naming for living and non-living things) during an awake surgery procedure. Fifteen regions and four macro cortical areas were designed to analyze the distribution of the interference sites. Results Over 761 sites stimulated in the lateral hemispheres, 130 naming interferences sites were detected in small cortical areas (< 1 cm 2). High individual variability was observed for living/non-living word retrieval localization and organization with a majority (62%) of shared living/non-living interferences. Specific living (12%) or non-living (26%) interferences were found too. In group analysis, no statistical significant anatomical localization was observed for living items in left lateral hemispheric cortex. A statistical significant representation of interference sites for non-living objects was found (Generalized Estimating Equation methodology, z-test = 2.28, p = 0.027) in the left posterolateral temporoparietal cortex. No influence of histopathology, gender and age on anatomical localization of naming categories was detected. Conclusion The existence of dedicated neural structures for naming non-living things in the left posterolateral temporoparietal cortex is supported by this study although high individual differences exist in the organization of word categories retrieval.

Functional disruption of the brain mechanism for reading: Effects of comorbidity and task difficulty among children with developmental learning problems.

The study investigated the relative degree and timing of cortical activation associated with phonological decoding in poor readers. Regional brain activity was assessed during performance of a pseudoword reading task and a less demanding, letter-sound naming task by three groups of students: children who experienced reading difficulties without attention problems (N = 50, RD) and nonreading impaired (NI) readers either with (N = 20) or without attention-deficit/hyperactivity disorder (ADHD; N = 50). Recordings were obtained with a whole-head neuromagnetometer, and activation profiles were computed through a minimum norm algorithm. Children with RD showed decreased amplitude of neurophysiological activity in the superior temporal gyrus, bilaterally, and in the left supramarginal and angular gyri during late stages of decoding, compared to typical readers. These effects were restricted to the more demanding pseudoword reading task. No differences were found in degree of activity between NI and ADHD students. Regression analyses provided further support for the crucial role of left hemisphere temporoparietal cortices and the fusiform gyrus for basic reading skills. Results were in agreement with fMRI findings and replicate previous MEG findings with a larger sample, a higher density neuromagnetometer, an overt pseudoword reading task, and a distributed current source-modeling method.

Deep transcranial magnetic stimulation for the treatment of auditory hallucinations: a preliminary open-label study

BackgroundSchizophrenia is a chronic and disabling disease that presents with delusions and hallucinations. Auditory hallucinations are usually expressed as voices speaking to or about the patient. Previous studies have examined the effect of repetitive transcranial magnetic stimulation (TMS) over the temporoparietal cortex on auditory hallucinations in schizophrenic patients. Our aim was to explore the potential effect of deep TMS, using the H coil over the same brain region on auditory hallucinations.Patients and methodsEight schizophrenic patients with refractory auditory hallucinations were recruited, mainly from Beer Ya'akov Mental Health Institution (Tel Aviv university, Israel) ambulatory clinics, as well as from other hospitals outpatient populations. Low-frequency deep TMS was applied for 10 min (600 pulses per session) to the left temporoparietal cortex for either 10 or 20 sessions. Deep TMS was applied using Brainsway's H1 coil apparatus. Patients were evaluated using the Auditory Hallucinations Rating Scale (AHRS) as well as the Scale for the Assessment of Positive Symptoms scores (SAPS), Clinical Global Impressions (CGI) scale, and the Scale for Assessment of Negative Symptoms (SANS).ResultsThis preliminary study demonstrated a significant improvement in AHRS score (an average reduction of 31.7% ± 32.2%) and to a lesser extent improvement in SAPS results (an average reduction of 16.5% ± 20.3%).ConclusionsIn this study, we have demonstrated the potential of deep TMS treatment over the temporoparietal cortex as an add-on treatment for chronic auditory hallucinations in schizophrenic patients. Larger samples in a double-blind sham-controlled design are now being preformed to evaluate the effectiveness of deep TMS treatment for auditory hallucinations.Trial registrationThis trial is registered with clinicaltrials.gov (identifier: NCT00564096).

A pilot double-blind sham-controlled trial of repetitive transcranial magnetic stimulation for patients with refractory schizophrenia treated with clozapine

Schizophrenia is a complex and heterogeneous psychiatric disorder. Auditory verbal hallucinations occur in 50–70% of patients with schizophrenia and are associated with significant distress, decreased quality of life and impaired social functioning. This study aimed to investigate the effects of active compared with sham 1-Hz repetitive transcranial magnetic stimulation (rTMS) applied to the left temporal-parietal cortex in patients with schizophrenia treated with clozapine. Symptom dimensions that were evaluated included general psychopathology, severity of auditory hallucinations, quality of life and functionality. Seventeen right-handed patients with refractory schizophrenia experiencing auditory verbal hallucinations and treated with clozapine were randomly allocated to receive either active rTMS or sham stimulation. A total of 384 min of rTMS was administered over 20 days using a double-masked, sham-controlled, parallel design. There was a significant reduction in Brief Psychiatric Rating Scale (BPRS) scores in the active group compared with the sham group. There was no significant difference between active and sham rTMS on Quality of Life Scale (QLS), Auditory Hallucinations Rating Scale (AHRS), Clinical Global Impressions (CGI) and functional assessment staging (FAST) scores. Compared with sham stimulation, active rTMS of the left temporoparietal cortex in clozapine-treated patients showed a positive effect on general psychopathology. However, there was no effect on refractory auditory hallucinations. Further studies with larger sample sizes are needed to confirm these findings.

Abnormalities of the corpus callosum in non-psychotic high-risk offspring of schizophrenia patients

Alterations in the structure of the corpus callosum (CC) have been observed in schizophrenia. Offspring of schizophrenia parents have 10–15 times higher risk for developing schizophrenia. We examined CC volume in offspring at genetic high-risk (HR) subjects. Since the sub-regions of the CC are topographically mapped to cortical brain regions, we hypothesized that HR subjects may show a decrement in total volume and differential volume decreases in sub-regions of the CC. The offspring of schizophrenia parents (HR; n = 70; 36 males) and healthy volunteers with no family or personal history of psychotic disorders (healthy controls (HC); n = 73; 37 males) matched for age, gender and education were selected for the study. Magnetic resonance images were collected using a GE 1.5 T scanner and processed using FreeSurfer image analysis software. The CC was divided into five neuroanatomically based partitions. The volume of total CC and the five sub-regions were measured blind to clinical information. With covariation for intracranial volume, HR subjects had significantly reduced total CC, more prominently observed in the anterior splenium. An age-related increase in CC volume was found in the anterior and posterior splenium of healthy controls but not in HR subjects. The volume reduction was greater in male than female HR subjects. The volume reduction in the CC may reflect a reduction in axonal fibers crossing the hemispheres and/or myelination between the left and right temporo-parietal cortices. The absence of an age-related volume increase suggests an abnormal developmental trajectory that may underlie susceptibility to schizophrenia.

Relief From Chronic Intractable Auditory Hallucinations After Long-Term Bilateral Theta Burst Stimulation

Back to table of contents Previous article Next article Communications and UpdatesFull AccessRelief From Chronic Intractable Auditory Hallucinations After Long-Term Bilateral Theta Burst StimulationMark-Christian Eberle, M.D., Dirk Wildgruber, M.D., Barbara Wasserka, Andreas J. Fallgatter, M.D., and Christian Plewnia, M.D.Mark-Christian EberleTübingen, GermanySearch for more papers by this author, M.D., Dirk WildgruberTübingen, GermanySearch for more papers by this author, M.D., Barbara WasserkaTübingen, GermanySearch for more papers by this author, Andreas J. FallgatterTübingen, GermanySearch for more papers by this author, M.D., and Christian PlewniaTübingen, GermanySearch for more papers by this author, M.D.Published Online:1 Nov 2010https://doi.org/10.1176/appi.ajp.2010.10070988AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail To the Editor: Auditory hallucinations in patients with schizophrenia are severely distressing and increase the risk for violence and suicide. In up to 25% of patients, such hallucinations resist therapeutic efforts. Repetitive transcranial magnetic stimulation (rTMS) to the left temporoparietal cortex has been established as an effective new treatment option (1, 2). However, the effectiveness and sustainability of this treatment are still under debate. Bilateral stimulation and prolongation of the treatment course might enhance the size and maintenance of the effect. The use of continuous theta burst stimulation, a patterned form of rTMS with brief stimulation sessions, could improve clinical practicability (3). We report on the case of a patient who received continuous theta burst stimulation applied to the left and right temporoparietal cortex.“Mr. C” was a 52-year-old right-handed man with a 22-year history of paranoid schizophrenia (consistent with DSM-IV criteria). The patient suffered from chronic, continuous, distressing voices that were resistant to different antipsychotics in correct doses for correct treatment periods as well as to cognitive behavioral therapy. Continuous theta burst stimulation was applied to the left and right temporoparietal cortex once per working day in the morning for 9 weeks (International 10-20 system for EEG electrode placement: between positions T3/P3 and T4/P4; 40 sec; three stimuli at 50 Hz every 200 msec; 80% active motor threshold). Treatment with clozapine (200 mg/ day) and amisulpride (600 mg/day) was continued. An EEG obtained before treatment showed clozapine-induced changes but no epilepsy typical signs. No side effects were noted. Auditory hallucinations were evaluated using the subjective Hallucination Chan ge Scale, quantifying the change of hallucinations around the baseline score of 10 from 0 to 20 (1). In the first week of treatment, the patient reported a suppression of auditory hallucinations for several minutes immediately after each stimulation (Hallucination Change Scale score: 9). Subsequently, he described a reduction of loudness in the second week (Hallucination Change Scale score: 7); longer periods without auditory hallucinations in the fourth week (Hallucination Change Scale score: 5); rare hallucinations in the fifth week (Hallucination Change Scale score: 3); and lasting, complete suppression from the sixth week onward (Hallucination Change Scale score: 0). His score on the Positive and Negative Syndrome Scale decreased from 93 to 61 (positive subscale score: 27→11, negative subscale score: 25→22, general psychopathology subscale score: 41→28). His score on the Global Assessment of Functioning increased from 42 to 55. Weekly evaluation of hallucinations confirmed their continuous absence for 3 months.The observation in the present case provides the first evidence, to our knowledge, that a long-term bilateral application of continuous theta burst stimulation can achieve a complete and long-lasting elimination of auditory hallucinations and an improvement in global function. Of note, an amelioration of delusions, anxiety, tension, and unusual thought content was also accomplished. Since auditory hallucination-associated cortical activities are not limited to the left hemisphere, we opted for bilateral stimulation to optimize efficacy. Notably, improvement was achieved gradually, with complete remission, pointing toward a benefit of prolonged treatment, not occurring until 6 weeks. As intended, continuous theta burst stimulation beyond remission was followed by maintenance of the effect. However, in addition to briefer treatment sessions, an advantage of continuous theta burst stimulation relative to rTMS cannot be derived from this report. Further trials are needed to disentangle the influence of treatment duration, laterality, and stimulation paradigm in order to determine treatment efficacy, clinical practicability, and sustainability.Tübingen, GermanyDr. Wildgruber has received grant support from the Academy of Science, Heidelberg (WIN-Kolleg); the German Research Foundation (DFG WI2101/1-1, SFB 550 B10, WI2101/2-1); and the Center for Integrative Neuroscience, Tübingen (CIN 2008-001, CIN 2009-002, CIN 2009-017). Dr. Fallgatter has received grant support from the German Research Council (DFG; TRR 58, subproject C4); the University of Wuerzburg (IZKF; N-146, F-138); and the Federal Ministry of Education and Research (BMBF). Dr. Plewnia has received grant support from the German Research Foundation (DFG; 253 PL1-1); and the University of Tübingen (AKF; 238-0-0).Dr. Eberle and Ms. Wasserka report no financial relationships with commercial interests.accepted for publication in September 2010.

P.3.a.035 Cognitive responce as a predictor of repetitive transcranial magnetic stimulation (rTMS) efficacy in schizophrenia

Schizophrenia is a disabling disease with a significant proportion of patients experiencing persistent symptoms. Repetitive transcranial magnetic stimulation (rTMS) is a promising new therapeutic tool that could benefit to schizophrenic patients. In this study we sought to assess the efficacy of active rTMS compared to sham stimulation in the treatment of patients with schizophrenia.Eighteen schizophrenic patients according to DSM-IV criteria were randomly allocated to receive active or sham rTMS for 10 days over the left temporoparietal cortex (80% of the motor threshold, 1 Hz, five trains of 1 min). Psychopathological dimensions were measured with the positive and negative syndrome scale and clinical global impression at baseline and after 10 session of rTMS.All patients were improved at the end of the trial but no significant group differences were found. Patients receiving sham stimulation showed the same pattern of improvement compared to active condition on all the subscales of the positive and negative syndrome scale and clinical global impression scores (p > 0.05).In our study, active rTMS failed to show superiority over sham stimulation in the treatment of schizophrenic symptoms. Although previous results have shown that rTMS reduces auditory hallucination, its efficacy on other positive schizophrenic symptoms is not yet established. Nevertheless, the results of our study, even though negative, provide further insights in the pathophysiology of schizophrenia.

EEG Power Spectral Measurements Comparing Normal and “Thatcherized” Faces

ABSTRACTIn this paper we have made a broadband analysis to detect the electroencephalogram (EEG) frequencies that change selectively during the presentation of normal and “thatcherized” faces. Referential recordings to linked ears were obtained in 21 leads in 48 right-handed healthy male volunteers. Increase of delta power (1.75–3.91 Hz) was observed, related to the detection of distortion in faces at bifrontal and left temporoparietal cortex. The other bands had no contribution, when normal and modified faces were compared. These results support our hypothesis that a change in EEG power spectral may be related to discrimination between normal and thatcherized faces.

Elucidating the Nature of Deregulated Semantic Cognition in Semantic Aphasia: Evidence for the Roles of Prefrontal and Temporo-parietal Cortices

Semantic cognition--semantically driven verbal and nonverbal behavior--is composed of at least two interactive principal components: conceptual representations and executive control processes that regulate and shape activation within the semantic system. Previous studies indicate that semantic dementia follows from a progressive yet specific degradation of conceptual knowledge. In contrast, multimodal semantic impairment in aphasic patients (semantic aphasia [SA]) reflects damage to the control component of semantic cognition [Jefferies, E., & Lambon Ralph, M. A. Semantic impairment in stroke aphasia versus semantic dementia: A case-series comparison. Brain, 129, 2132-2147, 2006]. The purpose of the present study was to examine the nature of the semantic control deficits in SA in detail for the first time. Seven patients with SA were tested on four comprehension and naming tasks that directly manipulated the requirement for executive control in different ways. In line with many theories of cognitive control, the SA patients demonstrated three core features of impaired control: (i) they exhibited poor on-line manipulation and exploration of semantic knowledge; (ii) they exhibited poor inhibition of strongly associated distractors; and (iii) they exhibited reduced ability to focus on or augment less dominant aspects of semantic information, although the knowledge itself remained and could be successfully cued by external constraints provided by the examiner. Our findings are consistent with the notion that the anterior temporal lobes are crucial for conceptual knowledge whereas the left prefrontal and temporo-parietal cortices, damaged in patients with SA, play a critical role in regulating semantic activation in a task-appropriate fashion.

Contralateral versus ipsilateral rTMS of temporoparietal cortex for the treatment of chronic unilateral tinnitus: comparative study

Repetitive transcranial magnetic stimulation (rTMS) applied over left temporoparietal cortex has been reported to have a long-term therapeutic effect on tinnitus. We compare the impact of 1 and 25 Hz rTMS delivered either contralateral or ipsilateral to symptoms in 62 patients with unilateral chronic tinnitus. Patients were randomly assigned to one of four treatment groups: with stimulation at 1 or 25 Hz applied either ipsilateral or contralateral to symptoms. Two thousand pulses per session were given daily for 2 weeks. Changes in tinnitus handicap inventory (THI), self-rating scores of loudness, awareness, and annoyance were measured monthly for 10 months. Duration of residual inhibition (RI) and psychiatric morbidity were evaluated monthly for 3 months. There was a significant main effect of time (P < 0.0001) and a significant time x side interaction (P = 0.032) between groups. This was because of the fact that contralateral stimulation had a greater effect on THI than ipsilateral stimulation; it was also superior to left side stimulation (P = 0.027). Ratings of loudness improved more after contralateral rTMS (P = 0.037). Twenty patients had no remaining tinnitus after 3 months; the remainder had a significant increase in RI. Patients with the shortest history of tinnitus tended to respond better to rTMS. There was a significant correlation between changes in THI score and changes in Hamilton anxiety and depression scores. Ten daily treatments of 1 and 25 Hz rTMS contralateral to the side of tinnitus have a greater beneficial effect on symptoms than either ipsilateral or left side stimulation.