Browsing by Author "Vanneste, Sven"
Now showing 1 - 20 of 26
- Results Per Page
- Sort Options
Item Auditory Cortex tACS and tRNS for Tinnitus: Single Versus Multiple SessionsClaes, Laura; Stamberger, Hannah; de Heyning, Paul Van; De Ridder, Dirk; Vanneste, Sven; 0000-0002-9906-1836 (Vanneste, S); Lab for Clinical & Integrative NeuroscienceTinnitus is the perception of a sound in the absence of an external acoustic source, which often exerts a significant impact on the quality of life. Currently there is evidence that neuroplastic changes in both neural pathways are involved in the generation and maintaining of tinnitus. Neuromodulation has been suggested to interfere with these neuroplastic alterations. In this study we aimed to compare the effect of two upcoming forms of transcranial electrical neuromodulation: alternating current stimulation (tACS) and random noise stimulation (tRNS), both applied on the auditory cortex. A database with 228 patients with chronic tinnitus who underwent noninvasive neuromodulation was retrospectively analyzed. The results of this study show that a single session of tRNS induces a significant suppressive effect on tinnitus loudness and distress, in contrast to tACS. Multiple sessions of tRNS augment the suppressive effect on tinnitus loudness but have no effect on tinnitus distress. In conclusion this preliminary study shows a possibly beneficial effect of tRNS on tinnitus and can be a motivation for future randomized placebo-controlled clinical studies with auditory tRNS for tinnitus. Auditory alpha-modulated tACS does not seem to be contributing to the treatment of tinnitus.Item Bi-Modal Stimulation in the Treatment of Tinnitus: A Study Protocol for an Exploratory Trial to Optimise Stimulation Parameters and Patient Subtyping(BMJ Publishing Group) D'Arcy, Shona; Hamilton, Caroline; Hughes, Stephen; Hall, Deborah A.; Vanneste, Sven; Langguth, Berthold; Conlon, Brendan; Vanneste, SvenINTRODUCTION: Tinnitus is the perception of sound in the absence of a corresponding external acoustic stimulus. Bimodal neuromodulation is emerging as a promising treatment for this condition. The main objectives of this study are to investigate the relevance of interstimulus timing and the choices of acoustic and tongue stimuli for a proprietary bimodal (auditory and somatosensory) neuromodulation device, as well as to explore whether specific subtypes of patients are differentially responsive to this novel intervention for reducing the symptoms of chronic tinnitus. METHODS AND ANALYSIS: This is a two-site, randomised, triple-blind, exploratory study of a proprietary neuromodulation device with a pre-post and 12-month follow-up design. Three different bimodal stimulation parameter sets will be examined. The study will enrol 342 patients, split 80: 20 between two sites (Dublin, Ireland and Regensburg, Germany), to complete 12 weeks of treatment with the device. Patients will be allocated to one of three arms using a stepwise stratification according to four binary categories: tinnitus tonality, sound level tolerance (using loudness discomfort level of <60 dB SL as an indicator for hyperacusis), hearing thresholds and presence of a noise-induced audiometric profile. The main indicators of relative clinical efficacy for the three different parameter sets are two patient-reported outcomes measures, the Tinnitus Handicap Inventory and the Tinnitus Functional Index, after 12 weeks of intervention. Clinical efficacy will be further explored in a series of patient subtypes, split by the stratification variables and by presence of a somatic tinnitus. Evidence for sustained effects on the psychological and functional impact of tinnitus will be followed up for 12 months. Safety data will be collected and reported. A number of feasibility measures to inform future trial design include: reasons for exclusion, completeness of data collection, attrition rates, patient's adherence to the device usage as per manufacturer's instructions and evaluation of alternative methods for estimating tinnitus impact and tinnitus loudness. ETHICS AND DISSEMINATION: This study protocol is approved by the Tallaght Hospital/St. James's Hospital Joint Research Ethics Committee in Dublin, Ireland, and by the Ethics Committee of the University Clinic Regensburg, Germany. Findings will be disseminated to relevant research, clinical, health service and patient communities through publications in peer-reviewed and popular science journals and presentations at scientific and clinical conferences.Item Changing Brain Networks Through Non-Invasive NeuromodulationTo, Wing Ting; De Ridder, Dirk; Hart, John, Jr.; Vanneste, Sven; Wang, Zijie; Perananthan, Sahila; Panangala, Samitha D.; Ferraris, John P.; Balkus, Kenneth J.; To, Wing Ting; Hart, John, Jr.; Vanneste, SvenBackground/Objective: Non-invasive neuromodulation techniques, such as repetitive Transcranial Magnetic Stimulation (rTMS) and transcranial Direct Current Stimulation (tDCS), have increasingly been investigated for their potential as treatments for neurological and psychiatric disorders. Despite widespread dissemination of these techniques, the underlying therapeutic mechanisms and the ideal stimulation site for a given disorder remain unknown. Increasing evidence support the possibility of non-invasive neuromodulation affecting a brain network rather than just the local stimulation target. In this article, we present evidence in a clinical setting to support the idea that non-invasive neuromodulation changes brain networks. Method: This article addresses the idea that non-invasive neuromodulation modulates brain networks, rather than just the local stimulation target, using neuromodulation studies in tinnitus and major depression as examples. We present studies that suppo rt this hypothesis from different perspectives. Main Results/Conclusion: Studies stimulating the same brain region, such as the dorsolateral prefrontal cortex (DLPFC), have shown to be effective for several disorders and studies using different stimulation sites for the same disorder have shown similar results. These findings, as well as results from studies investigating brain network connectivity on both macro and micro levels, suggest that non-invasive neuromodulation affects a brain network rather than just the local stimulation site targeted. We propose that non-invasive neuromodulation should be approached from a network perspective and emphasize the therapeutic potential of this approach through the modulation of targeted brain networks.Item Comparison of Neural Activity in Chronic Pain Patients during Tonic and Burst Spinal Cord Stimulation Using Fluorodeoxyglucose Positron Emission Tomography(Blackwell Publishing Inc., 2019-04-30) Yearwood, T.; De Ridder, D.; Yoo, Hye Bin; Falowski, S.; Venkatesan, L.; Ting To, W.; Vanneste, Sven; 0000-0002-9906-1836 (Vanneste, S); Yoo, Hye Bin; Vanneste, SvenObjective: Burst spinal cord stimulation (SCS) is a novel stimulation paradigm that seems to provide better pain relief compared to the classic tonic SCS with minimal paresthesia sensation. Based on source localized electroencephalography and clinical data, it has been proposed that burst stimulation as defined by Dirk De Ridder exerts this greater effect by not only modulating the lateral and the descending pain-inhibitory pathways (similar to tonic SCS) but also modulating the medial pain pathway, which encodes the affective, motivational aspects of pain. Material and Methods: The current study evaluates the supraspinal differences between burst and tonic stimulation with another functional imaging technique, namely fluorodeoxyglucose positron emission tomography (FGD-PET) scanning, in seven patients, who underwent both burst and tonic SCS, to confirm this notion of medial pain pathway modulation. Results: The results of the current FGD-PET study show that burst stimulation, in contrast to tonic stimulation, indeed modulates the dorsal anterior cingulate cortex (i.e., medial pain pathway) more than tonic stimulation. Discussion: Our data suggest an inherent difference in the central neural mechanisms during burst and tonic stimulation, which could potentially alter the patient's perception of pain. ©2019 International Neuromodulation SocietyItem Dysfunctional Noise Cancelling of the Rostral Anterior Cingulate Cortex in Tinnitus Patients(Public Library of Science) Song, Jae Jin; Vanneste, Sven; De Ridder, DirkBackground Peripheral auditory deafferentation and central compensation have been regarded as the main culprits of tinnitus generation. However, patient-to-patient discrepancy in the range of the percentage of daytime in which tinnitus is perceived (tinnitus awareness percentage, 0 - 100%), is not fully explicable only by peripheral deafferentation, considering that the deafferentation is a stable persisting phenomenon but tinnitus is intermittently perceived in most patients. Consequently, the involvement of a dysfunctional noise cancellation mechanism has recently been suggested with regard to the individual differences in reported tinnitus awareness. By correlating the tinnitus awareness percentage with resting-state source-localized electroencephalography findings, we may be able to retrieve the cortical area that is negatively correlated with tinnitus awareness percentage, and then the area may be regarded as the core of the noise cancelling system that is defective in patients with tinnitus. Methods and Findings Using resting-state cortical oscillation, we investigated 80 tinnitus patients by correlating the tinnitus awareness percentage with their source-localized cortical oscillatory activity and functional connectivity. The activity of bilateral rostral anterior cingulate cortices (ACCs), left dorsal-and pregenual ACCs for the delta band, bilateral rostral/pregenual/subgenual ACCs for the theta band, and left rostral/pregenual ACC for the beta 1 band displayed significantly negative correlations with tinnitus awareness percentage. Also, the connectivity between the left primary auditory cortex (A1) and the rostral ACC, as well as between the left A1 and the subgenual ACC for the beta 1 band, were negatively correlated with tinnitus awareness percentage. Conclusions These results may designate the role of the rostral ACC as the core of the descending noise cancellation system, and thus dysfunction of the rostral ACC may result in perception of tinnitus. The present study also opens a possibility of tinnitus modulation by neuromodulatory approaches targeting the rostral ACC.Item Emerging Network Connectomics in Phantom Sound Perception(2018-05) Mohan, Anusha; 0000-0003-1904-0603 (Mohan, A); Vanneste, SvenThe brain is hypothesized to be a hierarchical prediction system. It constantly compares the incoming information from the sensory pathways with a pre-existing model of the environment. Damage at different locations in these pathways leads to the loss of sensory input, resulting in the brain receiving different input from what it would expect. This may lead to an uncertainty that may be minimized by the production of a phantom percept. A phantom percept is the perception of a sensation in the absence of an external source. In this dissertation, we specifically focus on the auditory phantom percept: Tinnitus. Tinnitus is accompanied by a “loudness” component and a variable emotional component or “distress.” The loudness is unique to the disorder (domain-specific) and distress is common to other pathologies as well (domain-general). A wealth of information is available about the relationship between these behavioral correlates and changes in static functional connectivity. However, their relationship with dynamic changes in network connectivity is yet to be explored. Thus, the aim of this study is to investigate changes in the flexibility and stability of time-varying functional connectivity (temporal variability) in tinnitus and its relation to loudness and distress. In the current study, we observed a spatio-temporal change of temporal variability in tinnitus. We also observed that the relationship between temporal variability and behavioral symptoms depended on the amount of distress experienced. In participants with low distress, there was no linear relationship between temporal variability and loudness or distress. However, in participants with high distress, we observed that as loudness increases, temporal variability increases; and as distress increases temporal variability decreases. This trend is observed in the parahippocampus in the alpha2 frequency band. The increasing temporal variability with increasing loudness may relate to a Bayesian search for updating deafferentation-based missing information. On the other hand, the decreasing temporal variability with increasing distress possibly reflects less adaptive, contextual processing. Therefore, the findings may reveal a way of understanding the changes in network dynamics not just in tinnitus, but in other brain disorders as well. This dissertation is divided into 5 Chapters. Chapter 1 systematically reviews the phantom percepts in various sensory domains and the different mechanisms of compensation to sensory uncertainty. Chapter 2 focuses specifically on tinnitus. It reviews the current literature on tinnitus, their drawbacks and outlines the purpose of the current study. It also serves as an introduction to temporal variability, the measure of dynamic functional connectivity used in this dissertation. Chapter 3 describes the tinnitus and control groups, materials, and experimental methods used in the current study. Chapter 4 details the results of the current study. Finally, Chapter 5 discusses these results, limitations and future applications of the study.Item Functional Connectivity Changes in Adults with Developmental Stuttering: A Preliminary Study using Quantitative Electro-Encephalography(Frontiers Research Foundation) Joos, Kathleen; De Ridder, Dirk; Boey, Ronny A.; Vanneste, Sven; 0000-0002-9906-1836 (Vanneste, S)Introduction: Stuttering is defined as speech characterized by verbal dysfluencies, but should not be seen as an isolated speech disorder, but as a generalized sensorimotor timing deficit due to impaired communication between speech related brain areas. Therefore we focused on resting state brain activity and functional connectivity.; Method: We included 11 patients with developmental stuttering and 11 age matched controls. To objectify stuttering severity and the impact on quality of life (QoL), we used the Dutch validated Test for Stuttering Severity-Readers (TSS-R) and the Overall Assessment of the Speaker's Experience of Stuttering (OASES), respectively. Furthermore, we used standardized low resolution brain electromagnetic tomography (sLORETA) analyses to look at resting state activity and functional connectivity differences and their correlations with the TSS-R and OASES.; Results: No significant results could be obtained when looking at neural activity, however significant alterations in resting state functional connectivity could be demonstrated between persons who stutter (PWS) and fluently speaking controls, predominantly interhemispheric, i.e., a decreased functional connectivity for high frequency oscillations (beta and gamma) between motor speech areas (BA44 and 45) and the contralateral premotor (BA6) and motor (BA4) areas. Moreover, a positive correlation was found between functional connectivity at low frequency oscillations (theta and alpha) and stuttering severity, while a mixed increased and decreased functional connectivity at low and high frequency oscillations correlated with QoL.; Discussion: PWS are characterized by decreased high frequency interhemispheric functional connectivity between motor speech, premotor and motor areas in the resting state, while higher functional connectivity in the low frequency bands indicates more severe speech disturbances, suggesting that increased interhemispheric and right sided functional connectivity is maladaptive.;Item Head-to-Head Comparison of Transcranial Random Noise Stimulation, Transcranial AC Stimulation, and Transcranial DC Stimulation for TinnitusVanneste, Sven; Fregni, F.; De Ridder, D.Tinnitus is the perception of a sound in the absence of an external sound stimulus. This phantom sound has been related to plastic changes and hyperactivity in the auditory cortex. Different neuromodulation techniques such as transcranial magnetic stimulation and transcranial direct current stimulation (tDCS) have been used in an attempt to modify local and distant neuroplasticity as to reduce tinnitus symptoms. Recently, two techniques of pulsed electrical stimulation using weak electrical currents - transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS) - have also shown significant neuromodulatory effects. In the present study we conducted the first head-to-head comparison of three different transcranial electrical stimulation (tES) techniques, namely tDCS, tACS, and tRNS in 111 tinnitus patients by placing the electrodes overlying the auditory cortex bilaterally. The results demonstrated that tRNS induced the larger transient suppressive effect on the tinnitus loudness and the tinnitus related distress as compared to tDCS and tACS. Both tDCS and tACS induced small and non-significant effects on tinnitus symptoms, supporting the superior effects of tRNS as a method for tinnitus suppression.Item Identifying Tinnitus-Related Genes based on a Side-Effect Network Analysis(Nature Publishing Group) Elgoyhen, A. B.; Langguth, B.; Nowak, W.; Schecklmann, M.; De Ridder, D.; Vanneste, SvenTinnitus, phantom sound perception, is a worldwide highly prevalent disorder for which no clear underlying pathology has been established and for which no approved drug is on the market. Thus, there is an urgent need for new approaches to understand this condition. We used a network pharmacology side-effect analysis to search for genes that are involved in tinnitus generation. We analyzed a network of 1,313 drug-target pairs, based on 275 compounds that elicit tinnitus as side effect and their targets reported in databases, and used a quantitative score to identify emergent significant targets that were more common than expected at random. Cyclooxigenase 1 and 2 were significant, which validates our approach, since salicylate is a known tinnitus generator. More importantly, we predict previously unknown tinnitus-related targets. The present results have important implications toward understanding tinnitus pathophysiology and might pave the way toward the design of novel pharmacotherapies.Item Increased Parietal Circuit-Breaker Activity in Delta Frequency Band and Abnormal Delta/Theta Band Connectivity in Salience Network in Hyperacusis Subjects(Public Library of Science) Han, Jae Joon; Jang, Ji Hye; De Ridder, Dirk; Vanneste, Sven; Koo, Ja-Won; Song, Jae-Jin; 0000-0002-9906-1836 (Vanneste, S); Vanneste, SvenRecent studies have suggested that hyperacusis, an abnormal hypersensitivity to ordinary environmental sounds, may be characterized by certain resting-state cortical oscillatory patterns, even with no sound stimulus. However, previous studies are limited in that most studied subjects with other comorbidities that may have affected cortical activity. In this regard, to assess ongoing cortical oscillatory activity in idiopathic hyperacusis patients with no comorbidities, we compared differences in resting-state cortical oscillatory patterns between five idiopathic hyperacusis subjects and five normal controls. The hyperacusis group demonstrated significantly higher electrical activity in the right auditory-related cortex for the gamma frequency band and left superior parietal lobule (SPL) for the delta frequency band versus the control group. The hyperacusis group also showed significantly decreased functional connectivity between the left auditory cortex (AC) and left orbitofrontal cortex (OFC), between the left AC and left subgenual anterior cingulate cortex (sgACC) for the gamma band, and between the right insula and bilateral dorsal anterior cingulate cortex (dACC) and between the left AC and left sgACC for the theta band versus the control group. The higher electrical activity in the SPL may indicate a readiness of circuit-breaker activity to shift attention to forthcoming sound stimuli. Also, because of the disrupted salience network, consisting of the dACC and insula, abnormally increased salience to all sound stimuli may emerge, as a consequence of decreased top-down control of the AC by the dACC and dysfunctional emotional weight attached to auditory stimuli by the OFC. Taken together, abnormally enhanced attention and salience to forthcoming sound stimuli may render hyperacusis subjects hyperresponsive to non-noxious auditory stimuli.Item Influencing Connectivity and Cross-Frequency Coupling by Real-Time Source Localized Neurofeedback of the Posterior Cingulate Cortex Reduces Tinnitus Related Distress(Elsevier Science Inc) Vanneste, Sven; Joos, Kathleen; Ost, Jan; De Ridder, Dirk; 0000-0002-9906-1836 (Vanneste, S); Vanneste, SvenBackground: In this study we are using source localized neurofeedback to moderate tinnitus related distress by influencing neural activity of the target region as well as the connectivity within the default network. Hypothesis: We hypothesize that up-training alpha and down-training beta and gamma activity in the posterior cingulate cortex has a moderating effect on tinnitus related distress by influencing neural activity of the target region as well as the connectivity within the default network and other functionally connected brain areas. Methods: Fifty-eight patients with chronic tinnitus were included in the study. Twenty-three tinnitus patients received neurofeedback training of the posterior cingulate cortex with the aim of up-training alpha and down-training beta and gamma activity, while 17 patients underwent training of the lingual gyrus as a control situation. A second control group consisted of 18 tinnitus patients on a waiting list for future tinnitus treatment. Results: This study revealed that neurofeedback training of the posterior cingulate cortex results in a significant decrease of tinnitus related distress. No significant effect on neural activity of the target region could be obtained. However, functional and effectivity connectivity changes were demonstrated between remote brain regions or functional networks as well as by altering cross frequency coupling of the posterior cingulate cortex. Conclusion: This suggests that neurofeedback could remove the information, processed in beta and gamma, from the carrier wave, alpha, which transports the high frequency information and influences the salience attributed to the tinnitus sound. Based on the observation that much pathology is the result of an abnormal functional connectivity within and between neural networks various pathologies should be considered eligible candidates for the application of source localized EEG based neurofeedback training.Item Investigating the Functional Role of Medial Prefrontal Cortex During Memory Retrieval Using High-definition Transcranial Direct Current Stimulation(2020-04-15) Huang, Yuefeng; Vanneste, Sven; Hart Jr., JohnEmerging studies have started to focus on the medial prefrontal cortex’s (mPFC) role in memory function. Previous research revealed increased activity in mPFC, particularly during remote memory retrieval in humans. However, this link between mPFC and remote memory retrieval in human subjects is still a correlational-based relationship. In the current study, our goal is to determine a causal relationship between the mPFC and remote memory retrieval in humans using a non-invasive neuromodulation technique known as high-definition transcranial direct current stimulation (HD-tDCS). We applied HD-tDCS to participants during a remote memory retrieval task, which tested them on Swahili word pairs learned one week prior to the retrieval task. Our results demonstrated participants in the cathodal stimulation group performed significantly better than anodal and sham stimulation groups on the remote-memory retrieval task. Additionally, two sessions of resting-state electroencephalography (rs-EEG) were acquired before and after the HDtDCS paired remote-memory retrieval task. A positive correlation through a whole-brain correlation analysis was obtained between performance in the remote memory task and gamma frequency band activity in the posterior cingulate cortex (PCC), retrosplenial cortex (RSC), and hippocampus (HPC) after stimulation (post-rs-EEG – pre-rs-EEG). Our results provide, for the first time, evidence to support the existence of a causal relation between mPFC and remote memory retrieval in humans. Our data also suggests that cathodal stimulation in mPFC could potentially improve memory retrieval, presumably through an optimal range of excitation/inhibition (E/I) balance in mPFC, which benefits the process of remote memory retrieval.Item Meta-Analysis of Functional Subdivisions within Human Posteromedial Cortex(Springer Heidelberg, 2018-10-26) Huang, Yuefeng; Hullfish, Jeffrey; De Ridder, Dirk; Vanneste, Sven; Huang, Yuefeng; Hullfish, Jeffrey; Vanneste, SvenThe posteromedial cortex (PMC) comprising posterior cingulate cortex (PCC), retrosplenial cortex (RSC), and the precuneus (PrC) is perhaps best known for its involvement in the default mode network. There is no consensus regarding the specific functions of PMC, however, and its component regions each exhibit distinct, but partially overlapping functional profiles. To date, there has been minimal effort to disentangle the functions of these regions. In the present study, we use Neurosynth (http://neurosynth.org) to conduct an unbiased meta-analysis of the PMC based on fMRI coactivation and semantic information extracted from 11,406 studies. Our analyses revealed six PMC clusters with distinct functional profiles: superior and inferior dorsal PCC, anterior and posterior PrC, ventral PCC, and RSC. We discuss these findings in the context of the existing literature and suggest several fruitful avenues for continued research.Item The Neural Correlates of the Unified Percept of Alcohol-Related Craving: A fMRI and EEG StudyHuang, Yuefeng; Mohan, Anusha; De Ridder, Dirk; Sunaert, Stefan; Vanneste, Sven; Huang, Yuefeng; Mohan, Anusha; Vanneste, SvenAlcohol addiction is accompanied by aberrant neural activity. Previously, task-based fMRI and resting-state EEG studies have revealed that craving, a critical component of addiction, is linked to abnormal activity in cortical regions including the dorsal anterior cingulate cortex (dACC), nucleus accumbens (NAcc), posterior cingulate cortex (PCC) and pregenual anterior cingulate cortex (pgACC), etc. In this study, we combine these two imaging techniques to investigate a group of alcohol-addicted patients and provide convergent evidence for the neural correlates of craving not only in alcohol but substance abuse in general. We observe abnormal BOLD signal levels in the dACC, NAcc, pgACC, PCC, amygdala, and parahippocampus (PHC) in a cue-reactivity fMRI experiment. These findings are consistent with increased beta-band activity in the dACC and pgACC in resting-state EEG. We further observe desynchronization characterized by decreased functional connectivity in cue-based fMRI and hypersynchronization characterized by increased functional connectivity between these regions in the theta frequency band. The results of our study show a consistent pattern of alcohol craving elicited by external cues and internal desires. Given the advantage of superior spatial and temporal resolution, we hypothesize a "central craving network" that integrates the different aspects of alcohol addiction into a unified percept.Item Neuronal Correlates of Maladaptive Coping: An EEG-Study in Tinnitus Patients(Public Library of Science) Vanneste, Sven; Joos, Kathleen; Langguth, Berthold; To, Wing Ting; De Ridder, DirkHere we aimed to investigate the neuronal correlates of different coping styles in patients suffering from chronic tinnitus. Adaptive and maladaptive coping styles were determined in 85 tinnitus patients. Based on resting state EEG recordings, coping related differences in brain activity and connectivity were found. Maladaptive coping behavior was related to increases in subjective tinnitus loudness and distress, higher tinnitus severity and higher depression scores. EEG recordings demonstrated increased alpha activity over the left dorsolateral prefrontal cortex (DLPFC) and subgenual anterior cingulate cortex (sgACC) as well as increased connectivity in the default (i.e. resting state) network in tinnitus patients with a maladaptive coping style. Correlation analysis revealed that the changes in the DLPFC correlate primarily with maladaptive coping behavior, whereas the changes in the sgACC correlate with tinnitus severity and depression. Our findings are in line with previous research in the field of depression that during resting state a alpha band hyperconnectivity exists within the default network for patients who use a maladaptive coping style, with the sgACC as the dysfunctional node and that the strength of the connectivity is related to focusing on negative mood and catastrophizing about the consequences of tinnitus.;Item Optimization of Transcranial Direct Current Stimulation of Dorsolateral Prefrontal Cortex for Tinnitus: A Non-Linear Dose-Response Effect(Nature Publishing Group) Shekhawat, Giriraj Singh; Vanneste, Sven; Shekhawat, Giriraj Singh; 0000-0002-9906-1836 (Vanneste, S); Vanneste, SvenNeuromodulation is defined as the process of augmenting neuroplasticity via invasive or non-invasive methods. Tinnitus is the perception of sound in the absence of its external source. The objective of this study was to optimize the parameters of transcranial direct current stimulation (tDCS) of dorsolateral prefrontal cortex (DLPFC) for tinnitus suppression. The following factors were optimized in the dose-response design (n = 111): current intensity (1.5 mA or 2 mA), stimulation duration (20 min or 30 min), and number of stimulation sessions (2, 4, 6, 8, or 10), with a 3-4 day washout period between each session. Participants underwent a minimum of 2 sessions in 1 week or maximum of 10 sessions in 5 weeks' time. Tinnitus loudness was measured in pre-post design using a 10-point numeric rating scale. There was a significant reduction in tinnitus loudness after tDCS of DLPFC. There was no significant difference between the intensity and duration of stimulation. As the number of sessions increased, there was a higher reduction in the tinnitus loudness; however, this effect plateaued after 6 sessions.Item Pairing Sound with Vagus Nerve Stimulation Modulates Cortical Synchrony and Phase Coherence in Tinnitus: An Exploratory Retrospective Study(Nature Publishing Group) Vanneste, Sven; Martin, Jeffrey S.; Rennaker, Robert L.; Kilgard, Michael P.; 0000 0001 2879 2132 (Rennaker, RL); 0000 0001 3852 473X (Kilgard, MP); 0000-0002-9906-1836 (Vanneste, S); Vanneste, Sven; Martin, Jeffrey S.; Rennaker, Robert L.; Kilgard, Michael P.Recent research has shown that vagus nerve stimulation (VNS) paired with tones or with rehabilitative training can help patients to achieve reductions in tinnitus perception or to expedite motor rehabilitation after suffering an ischemic stroke. The rationale behind this treatment is that VNS paired with experience can drive neural plasticity in a controlled and therapeutic direction. Since previous studies observed that gamma activity in the auditory cortex is correlated with tinnitus loudness, we assessed resting-state source-localized EEG before and after one to three months of VNS-tone pairing in chronic tinnitus patients. VNS-tone pairing reduced gamma band activity in left auditory cortex. VNStone pairing also reduced the phase coherence between the auditory cortex and areas associated with tinnitus distress, including the cingulate cortex. These results support the hypothesis that VNS-tone pairing can direct therapeutic neural plasticity. Targeted plasticity therapy might also be adapted to treat other conditions characterized by hypersynchronous neural activity.Item Polarity Specific Suppression Effects of Transcranial Direct Current Stimulation for Tinnitus(Hindawi Pub. Corp) Joos, Kathleen; De Ridder, Dirk; Van, de Heyning; Vanneste, SvenTinnitus is the perception of a sound in the absence of an external auditory stimulus and affects 10-15% of the Western population. Previous studies have demonstrated the therapeutic effect of anodal transcranial direct current stimulation (tDCS) over the left auditory cortex on tinnitus loudness, but the effect of this presumed excitatory stimulation contradicts with the underlying pathophysiological model of tinnitus. Therefore, we included 175 patients with chronic tinnitus to study polarity specific effects of a single tDCS session over the auditory cortex (39 anodal, 136 cathodal). To assess the effect of treatment, we used the numeric rating scale for tinnitus loudness and annoyance. Statistical analysis demonstrated a significant main effect for tinnitus loudness and annoyance, but for tinnitus annoyance anodal stimulation has a significantly more pronounced effect than cathodal stimulation. We hypothesize that the suppressive effect of tDCS on tinnitus loudness may be attributed to a disrupting effect of ongoing neural hyperactivity, independent of the inhibitory or excitatory effects and that the reduction of annoyance may be induced by influencing adjacent or functionally connected brain areas involved in the tinnitus related distress network. Further research is required to explain why only anodal stimulation has a suppressive effect on tinnitus annoyance. ;Item A Quantitative Electroencephalography Study on Cochlear Implant-Induced Cortical Changes in Single-Sided Deafness with Tinnitus(Frontiers Media SA) Song, Jae-Jin; Kim, Kyungsoo; Sunwoo, Woongsang; Mertens, Griet; Van de Heyning, Paul; De Ridder, Dirk; Vanneste, Sven; Lee, Sang-Youp; Park, Kyung-Joon; Choi, Hongsoo; Choi, Ji-Woong; Vanneste, SvenThe mechanism of tinnitus suppression after cochlear implantation (CI) in single-sided deafness (SSD) is not fully understood. In this regard, by comparing pre-and post-CI quantitative electroencephalography (qEEG), we explored cortical changes relevant to tinnitus improvement. In SSD patients who underwent CI, qEEG data were collected: (1) before CI, (2) 6 months post-operatively with CI-on, and (3) 30 min after CI-off and source-localized cortical activity/functional connectivity analyses were performed. Compared to the pre-operative baseline, the CI-on condition demonstrated significantly decreased activity in the right auditory-and orbitofrontal cortices (OFC) for the delta frequency band as well as decreased connectivity between the auditory cortex/posterior cingulate cortex for the delta/beta2 bands. Meanwhile, compared to the CI-off condition, the CI-on condition displayed decreased activity in the right auditory cortices/OFC for the delta band, and in bilateral auditory cortices, left inferior frontal cortex/OFC for the gamma band. However, qEEG analyses showed no significant differences between the CI-off and baseline conditions. CI induced overall decreased cortical activity and functional connectivity. However, judging from no differences between the CI-off and baseline conditions, CI-induced cortical activity and functional connectivity changes are not by cortical plastic changes, but by dynamic peripheral reafferentation.Item Thalamocortical Dysrhythmia Detected by Machine Learning(Nature Publishing Group) Vanneste, Sven; Song, Jae-Jin; De Ridder, Dirk; Vanneste, SvenThalamocortical dysrhythmia (TCD) is a model proposed to explain divergent neurological disorders. It is characterized by a common oscillatory pattern in which resting-state alpha activity is replaced by cross-frequency coupling of low- and high-frequency oscillations. We undertook a data-driven approach using support vector machine learning for analyzing resting-state electroencephalography oscillatory patterns in patients with Parkinson's disease, neuropathic pain, tinnitus, and depression. We show a spectrally equivalent but spatially distinct form of TCD that depends on the specific disorder. However, we also identify brain areas that are common to the pathology of Parkinson's disease, pain, tinnitus, and depression. This study therefore supports the validity of TCD as an oscillatory mechanism underlying diverse neurological disorders.