Publications by authors named "Tomas Ros"

76 Publications

Real-time fMRI and EEG neurofeedback: A perspective on applications for the rehabilitation of spatial neglect.

Ann Phys Rehabil Med 2021 Aug 7;64(5):101561. Epub 2021 Aug 7.

Laboratory for Behavioral Neurology and Imaging of Cognition, Neuroscience Department, University of Geneva, Geneva, Switzerland.

Spatial neglect is a neuropsychological syndrome characterized by a failure to orient, perceive, and act toward the contralesional side of the space after brain injury. Neglect is one of the most frequent and disabling neuropsychological syndromes following right-hemisphere damage, often persisting in the chronic phase and responsible for a poor functional outcome at hospital discharge. Different rehabilitation approaches have been proposed over the past 60 years, with a variable degree of effectiveness. In this point-of-view article, we describe a new rehabilitation technique for spatial neglect that directly targets brain activity and pathological physiological processes: namely, neurofeedback (NFB) with real-time brain imaging methodologies. In recent proof-of-principle studies, we have demonstrated the potential of this rehabilitation technique. Using real-time functional MRI (rt-fMRI) NFB in chronic neglect, we demonstrated that patients are able to upregulate their right visual cortex activity, a response that is otherwise reduced due to losses in top-down attentional signals. Using real-time electroencephalography NFB in patients with acute or chronic condition, we showed successful regulation with partial restoration of brain rhythm dynamics over the damaged hemisphere. Both approaches were followed by mild, but encouraging, improvement in neglect symptoms. NFB techniques, by training endogenous top-down modulation of attentional control on sensory processing, might induce sustained changes at both the neural and behavioral levels, while being non-invasive and safe. However, more properly powered clinical studies with control groups and longer follow-up are needed to fully establish the effectiveness of the techniques, identify the most suitable candidates, and determine how the techniques can be optimized or combined in the context of rehabilitation.
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http://dx.doi.org/10.1016/j.rehab.2021.101561DOI Listing
August 2021

Personalized at-home neurofeedback compared to long-acting methylphenidate in children with ADHD: NEWROFEED, a European randomized noninferiority trial.

J Child Psychol Psychiatry 2021 Jun 24. Epub 2021 Jun 24.

Department of Child and Adolescent Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim/Heidelberg University, Mannheim, Germany.

Background: Neurofeedback is considered a promising intervention for the treatment of attention-deficit hyperactivity disorder (ADHD). NEWROFEED is a prospective, multicentre, randomized (3:2), reference drug-controlled trial in children with ADHD aged between 7 and 13 years. The main objective of NEWROFEED was to demonstrate the noninferiority of personalized at-home neurofeedback (NF) training versus methylphenidate in the treatment of children with ADHD.

Methods: The NF group (n = 111) underwent eight visits and two treatment phases of 16 to 20 at-home sessions with down-training of the theta/beta ratio (TBR) for children with high TBR and enhancing the sensorimotor rhythm (SMR) for the others. The control group (n = 67) received optimally titrated long-acting methylphenidate. The primary endpoint was the change between baseline and endpoint in the Clinician ADHD-RS-IV total score in the per-protocol population (90 NF/59 controls).

Trial Registration: US National Institute of Health, ClinicalTrials.gov #NCT02778360.

Results: Our study failed to demonstrate noninferiority of NF versus methylphenidate (mean between-group difference 8.09 90% CI [8.09; 10.56]). However, both treatment groups showed significant pre-post improvements in core ADHD symptoms and in a broader range of problems. Reduction in the Clinician ADHD-RS-IV total score between baseline and final visit (D90) was 26.7% (SMD = 0.89) in the NF and 46.9% (SMD = 2.03) in the control group. NF effects increased whereas those of methylphenidate were stable between intermediate and final visit.

Conclusions: Based on clinicians' reports, the effects of at-home NF were inferior to those of methylphenidate as a stand-alone treatment.
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http://dx.doi.org/10.1111/jcpp.13462DOI Listing
June 2021

Electrophysiological correlates of improved executive function following EEG neurofeedback in adult attention deficit hyperactivity disorder.

Clin Neurophysiol 2021 Aug 11;132(8):1937-1946. Epub 2021 Jun 11.

Department of Psychiatry, University of Geneva, Geneva, Switzerland; Centre for Biomedical Imaging (CIBM) Lausanne-Geneva, Geneva, Switzerland; Functional Brain Mapping Laboratory, Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland.

Objective: Event-related potentials (ERPs) are reported to be altered in relation to cognitive processing deficits in attention deficit hyperactivity disorder (ADHD). However, this evidence is mostly limited to cross-sectional data. The current study utilized neurofeedback (NFB) as a neuromodulatory tool to examine the ERP correlates of attentional and inhibitory processes in adult ADHD using a single-session, within-subject design.

Methods: We recorded high-density EEG in 25 adult ADHD patients and 22 neurotypical controls during a Go/NoGo task, before and after a 30-minute NFB session designed to down-regulate the alpha (8-12 Hz) rhythm.

Results: At baseline, ADHD patients demonstrated impaired Go/NoGo performance compared to controls, while Go-P3 amplitude inversely correlated with ADHD-associated symptomatology in childhood. Post NFB, task performance improved in both groups, significantly enhancing stimulus detectability (d-prime) and reducing reaction time variability, while increasing N1 and P3 ERP component amplitudes. Specifically for ADHD patients, the pre-to-post enhancement in Go-P3 amplitude correlated with measures of improved executive function, i.e., enhanced d-prime, reduced omission errors and reduced reaction time variability.

Conclusions: A single-session of alpha down-regulation NFB was able to reverse the abnormal neurocognitive signatures of adult ADHD during a Go/NoGo task.

Significance: The study demonstrates for the first time the beneficial neurobehavioral effect of a single NFB session in adult ADHD, and reinforces the notion that ERPs could serve as useful diagnostic/prognostic markers of executive dysfunction.
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http://dx.doi.org/10.1016/j.clinph.2021.05.017DOI Listing
August 2021

Elevated and Slowed EEG Oscillations in Patients with Post-Concussive Syndrome and Chronic Pain Following a Motor Vehicle Collision.

Brain Sci 2021 Apr 24;11(5). Epub 2021 Apr 24.

The Seekers Centre, Ottawa, ON K1Z 5Z9, Canada.

(1) Background: Mild traumatic brain injury produces significant changes in neurotransmission including brain oscillations. We investigated potential quantitative electroencephalography biomarkers in 57 patients with post-concussive syndrome and chronic pain following motor vehicle collision, and 54 healthy nearly age- and sex-matched controls. (2) Methods: Electroencephalography processing was completed in MATLAB, statistical modeling in SPSS, and machine learning modeling in Rapid Miner. Group differences were calculated using current-source density estimation, yielding whole-brain topographical distributions of absolute power, relative power and phase-locking functional connectivity. Groups were compared using independent sample Mann-Whitney U tests. Effect sizes and Pearson correlations were also computed. Machine learning analysis leveraged a post hoc supervised learning support vector non-probabilistic binary linear kernel classification to generate predictive models from the derived EEG signatures. (3) Results: Patients displayed significantly elevated and slowed power compared to controls: delta ( = 0.000000, = 0.6) and theta power ( < 0.0001, = 0.4), and relative delta power ( < 0.00001) and decreased relative alpha power ( < 0.001). Absolute delta and theta power together yielded the strongest machine learning classification accuracy (87.6%). Changes in absolute power were moderately correlated with duration and persistence of symptoms in the slow wave frequency spectrum (<15 Hz). (4) Conclusions: Distributed increases in slow wave oscillatory power are concurrent with post-concussive syndrome and chronic pain.
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http://dx.doi.org/10.3390/brainsci11050537DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8145977PMC
April 2021

PET Imaging of Dopamine Neurotransmission During EEG Neurofeedback.

Front Physiol 2020 11;11:590503. Epub 2021 Jan 11.

Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland.

Neurofeedback (NFB) is a brain-based training method that enables users to control their own cortical oscillations using real-time feedback from the electroencephalogram (EEG). Importantly, no investigations to date have directly explored the potential impact of NFB on the brain's key neuromodulatory systems. Our study's objective was to assess the capacity of NFB to induce dopamine release as revealed by positron emission tomography (PET). Thirty-two healthy volunteers were randomized to either EEG-neurofeedback (NFB) or EEG-electromyography (EMG), and scanned while performing self-regulation during a single session of dynamic PET brain imaging using the high affinity D receptor radiotracer, [F]Fallypride. NFB and EMG groups down-regulated cortical alpha power and facial muscle tone, respectively. Task-induced effects on endogenous dopamine release were estimated in the frontal cortex, anterior cingulate cortex, and thalamus, using the linearized simplified reference region model (LSRRM), which accounts for time-dependent changes in radiotracer binding following task initiation. Contrary to our hypothesis of a differential effect for NFB vs. EMG training, significant dopamine release was observed in both training groups in the frontal and anterior cingulate cortex, but not in thalamus. Interestingly, a significant negative correlation was observed between dopamine release in frontal cortex and NFB change in spontaneous alpha power, suggesting that intra-individual changes in brain state (i.e., alpha power) could partly result from changes in neuromodulatory tone. Overall, our findings constitute the first direct investigation of neurofeedback's effect on the endogenous release of a key neuromodulator, demonstrating its feasibility and paving the way for future studies using this methodology.
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http://dx.doi.org/10.3389/fphys.2020.590503DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7873858PMC
January 2021

[Psychiatry].

Rev Med Suisse 2021 Jan;17(720-1):85-89

Faculté de biologie et de médecine, Université de Lausanne, 1005 Lausanne.

The Covid-19 pandemic has a major impact on psychiatry by its social consequences and possible direct effect of certain forms of Covid-19 on mental health. During this crisis, the accessibility of technology meets a state of necessity, which has propelled telepsychiatry from the shadows into the light. The contribution of several technologies (i.e. virtual reality, actigraphy, computational psychiatry) combining clinical data and neuroscience underlines the great neurobehavioural variability even within the same diagnostic category, calling for greater precision in therapeutic offers as suggested e.g. by developments in neurofeedback. The place of intranasal esketamin in the panoply of antidepressent drug treatments for resistant depression has not yet been defined.
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January 2021

A randomized, controlled trial of alpha-rhythm EEG neurofeedback in posttraumatic stress disorder: A preliminary investigation showing evidence of decreased PTSD symptoms and restored default mode and salience network connectivity using fMRI.

Neuroimage Clin 2020 5;28:102490. Epub 2020 Nov 5.

Departments of Neuroscience, Western University, London, ON, Canada; Departments of Psychiatry, Western University, London, ON, Canada; Imaging, Lawson Health Research Institute, London, ON, Canada. Electronic address:

Objective: The default-mode network (DMN) and salience network (SN) have been shown to display altered connectivity in posttraumatic stress disorder (PTSD). Restoring aberrant connectivity within these networks with electroencephalogram neurofeedback (EEG-NFB) has been shown previously to be associated with acute decreases in symptoms. Here, we conducted a double-blind, sham-controlled randomized trial of alpha-rhythm EEG-NFB in participants with PTSD (n = 36) over 20-weeks. Our aim was to provide mechanistic evidence underlying clinical improvements by examining changes in network connectivity via fMRI.

Methods: We randomly assigned participants with a primary diagnosis of PTSD to either the experimental group (n = 18) or sham-control group (n = 18). We collected resting-state fMRI scans pre- and post-NFB intervention, for both the experimental and sham-control PTSD groups. We further compared baseline brain connectivity measures pre-NFB to age-matched healthy controls (n = 36).

Results: With regard to the primary outcome measure of PTSD severity, we found a significant main effect of time in the absence of a group × time interaction. Nevertheless, we found significantly decreased PTSD severity scores in the experimental NFB group only, when comparing post-NFB (dz = 0.71) and 3-month follow-up scores (dz = 0.77) to baseline measures. Interestingly, we found evidence to suggest a shift towards normalization of DMN and SN connectivity post-NFB in the experimental group only. Both decreases in PTSD severity and NFB performance were correlated to DMN and SN connectivity post-NFB in the experimental group. Critically, remission rates of PTSD were significant higher in the experimental group (61.1%) as compared to the sham-control group (33.3%).

Conclusion: The current study shows mechanistic evidence for therapeutic changes in DMN and SN connectivity that are known to be associated with PTSD psychopathology with no patient dropouts. This preliminary investigation merits further research to demonstrate fully the clinical efficacy of EEG-NFB as an adjunctive therapy for PTSD.
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http://dx.doi.org/10.1016/j.nicl.2020.102490DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7708928PMC
June 2021

Classifying heterogeneous presentations of PTSD via the default mode, central executive, and salience networks with machine learning.

Neuroimage Clin 2020 22;27:102262. Epub 2020 Apr 22.

Department of Psychiatry, Western University, London, ON, Canada; Department of Neuroscience, Western University, London, ON, Canada; Imaging Division, Lawson Health Research Institute, London, ON, Canada.

Intrinsic connectivity networks (ICNs), including the default mode network (DMN), the central executive network (CEN), and the salience network (SN) have been shown to be aberrant in patients with posttraumatic stress disorder (PTSD). The purpose of the current study was to a) compare ICN functional connectivity between PTSD, dissociative subtype PTSD (PTSD+DS) and healthy individuals; and b) to examine the use of multivariate machine learning algorithms in classifying PTSD, PTSD+DS, and healthy individuals based on ICN functional activation. Our neuroimaging dataset consisted of resting-state fMRI scans from 186 participants [PTSD (n = 81); PTSD + DS (n = 49); and healthy controls (n = 56)]. We performed group-level independent component analyses to evaluate functional connectivity differences within each ICN. Multiclass Gaussian Process Classification algorithms within PRoNTo software were then used to predict the diagnosis of PTSD, PTSD+DS, and healthy individuals based on ICN functional activation. When comparing the functional connectivity of ICNs between PTSD, PTSD+DS and healthy controls, we found differential patterns of connectivity to brain regions involved in emotion regulation, in addition to limbic structures and areas involved in self-referential processing, interoception, bodily self-consciousness, and depersonalization/derealization. Machine learning algorithms were able to predict with high accuracy the classification of PTSD, PTSD+DS, and healthy individuals based on ICN functional activation. Our results suggest that alterations within intrinsic connectivity networks may underlie unique psychopathology and symptom presentation among PTSD subtypes. Furthermore, the current findings substantiate the use of machine learning algorithms for classifying subtypes of PTSD illness based on ICNs.
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http://dx.doi.org/10.1016/j.nicl.2020.102262DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7240193PMC
March 2021

Consensus on the reporting and experimental design of clinical and cognitive-behavioural neurofeedback studies (CRED-nf checklist).

Brain 2020 06;143(6):1674-1685

Department of Basic Psychological Research and Research Methods, Faculty of Psychology, University of Vienna, Vienna, Austria.

Neurofeedback has begun to attract the attention and scrutiny of the scientific and medical mainstream. Here, neurofeedback researchers present a consensus-derived checklist that aims to improve the reporting and experimental design standards in the field.
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http://dx.doi.org/10.1093/brain/awaa009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7296848PMC
June 2020

Linking alpha oscillations, attention and inhibitory control in adult ADHD with EEG neurofeedback.

Neuroimage Clin 2020 24;25:102145. Epub 2019 Dec 24.

Department of Psychiatry, University of Geneva, Geneva, Switzerland.

Abnormal patterns of electrical oscillatory activity have been repeatedly described in adult ADHD. In particular, the alpha rhythm (8-12 Hz), known to be modulated during attention, has previously been considered as candidate biomarker for ADHD. In the present study, we asked adult ADHD patients to self-regulate their own alpha rhythm using neurofeedback (NFB), in order to examine the modulation of alpha oscillations on attentional performance and brain plasticity. Twenty-five adult ADHD patients and 22 healthy controls underwent a 64-channel EEG-recording at resting-state and during a Go/NoGo task, before and after a 30 min-NFB session designed to reduce (desynchronize) the power of the alpha rhythm. Alpha power was compared across conditions and groups, and the effects of NFB were statistically assessed by comparing behavioral and EEG measures pre-to-post NFB. Firstly, we found that relative alpha power was attenuated in our ADHD cohort compared to control subjects at baseline and across experimental conditions, suggesting a signature of cortical hyper-activation. Both groups demonstrated a significant and targeted reduction of alpha power during NFB. Interestingly, we observed a post-NFB increase in resting-state alpha (i.e. rebound) in the ADHD group, which restored alpha power towards levels of the normal population. Importantly, the degree of post-NFB alpha normalization during the Go/NoGo task correlated with individual improvements in motor inhibition (i.e. reduced commission errors) only in the ADHD group. Overall, our findings offer novel supporting evidence implicating alpha oscillations in inhibitory control, as well as their potential role in the homeostatic regulation of cortical excitatory/inhibitory balance.
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http://dx.doi.org/10.1016/j.nicl.2019.102145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6948256PMC
December 2020

Personalized at-home neurofeedback compared with long-acting methylphenidate in an european non-inferiority randomized trial in children with ADHD.

BMC Psychiatry 2019 08 1;19(1):237. Epub 2019 Aug 1.

University of Zurich and ETH Zurich, Neuroscience Center Zurich, Zurich, Switzerland.

Background: Neurofeedback (NF) has gained increasing interest among non-pharmacological treatments for Attention Deficit Hyperactivity Disorder (ADHD). NF training aims to enhance self-regulation of brain activities. The goal of the NEWROFEED study is to assess the efficacy of a new personalized NF training device, using two different protocols according to each child's electroencephalographic pattern, and designed for use at home. This study is a non-inferiority trial comparing NF to methylphenidate.

Methods: The study is a prospective, multicentre, randomized, reference drug-controlled trial. One hundred seventy-nine children with ADHD, aged 7 to 13 years will be recruited in 13 clinical centres from 5 European countries. Subjects will be randomized to two groups: NF group (Neurofeedback Training Group) and MPH group (Methylphenidate group). Outcome measures include clinicians, parents and teachers' assessments, attention measures and quantitative EEG (qEEG). Patients undergo eight visits over a three-month period: pre-inclusion visit, inclusion visit, 4 "discovery" (NF group) or titration visits (MPH group), an intermediate and a final visit. Patients will be randomized to either the MPH or NF group. Children in the NF group will undergo either an SMR or a Theta/Beta training protocol according to their baselineTheta/Beta Ratio obtained from the qEEG.

Discussion: This is the first non-inferiority study between a personalized NF device and pharmacological treatment. Innovative aspects of Mensia Koala™ include the personalization of the training protocol according to initial qEEG characteristics (SMR or Theta/Beta training protocols) and an improved accessibility of NF due to the opportunity to train at home with monitoring by the clinician through a dedicated web portal.

Trial Registration: NCT02778360 . Date registration (retrospectively registered): 5-12-2016. Registered May 19, 2016.
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http://dx.doi.org/10.1186/s12888-019-2218-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6676623PMC
August 2019

Is there a cluster of high theta-beta ratio patients in attention deficit hyperactivity disorder?

Clin Neurophysiol 2019 08 9;130(8):1387-1396. Epub 2019 May 9.

Mensia Technologies SA, 130 rue de Lourmel, 75015 Paris, France.

Objective: It has been suggested that there exists a subgroup of ADHD patients that have a high theta-beta ratio (TBR). The aim of this study was to analyze the distribution of TBR values in ADHD patients and validate the presence of a high-TBR cluster using objective metrics.

Methods: The TBR was extracted from eyes-open resting state EEG recordings of 363 ADHD patients, aged 5-21 years. The TBR distribution was estimated with three Bayesian Gaussian Mixture Models (BGMMs) with one, two, and three components, respectively. The pairwise comparison of BGMMs was carried out with deviance tests to identify the number of components that best represented the data.

Results: The two-component BGMM modeled the TBR values significantly better than the one-component BGMM (p-value = 0.005). No significant difference was observed between the two-component and three-component BGMM (p-value = 0.850).

Conclusion: These results suggest that there exist indeed two TBR clusters within the ADHD population.

Significance: This work offers a global framework to understanding values found in the literature and suggest guidelines on how to compute theta-beta ratio values. Moreover, using objective data-driven method we confirm the existence of a high theta-beta ratio cluster.
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http://dx.doi.org/10.1016/j.clinph.2019.02.021DOI Listing
August 2019

Author Correction: Closed-loop brain training: the science of neurofeedback.

Nat Rev Neurosci 2019 May;20(5):314

Department of Mechanical Engineering, University of Texas at Austin, 204 E Dean Keeton Street, Austin, Texas, 78712, USA.

In this article, the affiliation for Mohit Rana was incorrectly listed as the Institute for Biological and Medical Engineering, Department of Psychiatry, and Section of Neuroscience, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860 Hernán Briones, piso 2, Macul 782-0436, Santiago, Chile. The listed affiliation should have been the following: Departamento de Psiquiatría, Escuela de Medicina, Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile; and the Laboratory for Brain-Machine Interfaces and Neuromodulation, Pontificia Universidad Católica de Chile, Santiago, Chile. An acknowledgement to Mohit Rana's funding source was also missing. The following sentence should have been included in the acknowledgments section: M.R. is supported by a Fondecyt postdoctoral fellowship (project no. 3100648).
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http://dx.doi.org/10.1038/s41583-019-0161-1DOI Listing
May 2019

Intrinsic connectivity network dynamics in PTSD during amygdala downregulation using real-time fMRI neurofeedback: A preliminary analysis.

Hum Brain Mapp 2018 11 13;39(11):4258-4275. Epub 2018 Jul 13.

Department of Neuroscience, Western University, London, Ontario, Canada.

Posttraumatic stress disorder (PTSD) has been associated with a disturbance in neural intrinsic connectivity networks (ICN), including the central executive network (CEN), default mode network (DMN), and salience network (SN). Here, we conducted a preliminary investigation examining potential changes in ICN recruitment as a function of real-time fMRI neurofeedback (rt-fMRI-NFB) during symptom provocation where we targeted the downregulation of neural response within the amygdala-a key region-of-interest in PTSD neuropathophysiology. Patients with PTSD (n = 14) completed three sessions of rt-fMRI-NFB with the following conditions: (a) regulate: decrease activation in the amygdala while processing personalized trauma words; (b) view: process trauma words while not attempting to regulate the amygdala; and (c) neutral: process neutral words. We found that recruitment of the left CEN increased over neurofeedback runs during the regulate condition, a finding supported by increased dlPFC activation during the regulate as compared to the view condition. In contrast, DMN task-negative recruitment was stable during neurofeedback runs, albeit was the highest during view conditions and increased (normalized) during rest periods. Critically, SN recruitment was high for both the regulate and the view conditions, a finding potentially indicative of CEN modality switching, adaptive learning, and increasing threat/defense processing in PTSD. In conclusion, this study provides provocative, preliminary evidence that downregulation of the amygdala using rt-fMRI-NFB in PTSD is associated with dynamic changes in ICN, an effect similar to those observed using EEG modalities of neurofeedback.
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http://dx.doi.org/10.1002/hbm.24244DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8022274PMC
November 2018

Effect of a single early EEG neurofeedback training on remediation of spatial neglect in the acute phase.

Ann Phys Rehabil Med 2018 Mar 1;61(2):111-112. Epub 2017 Dec 1.

Department of Neurology, Geneva University Hospital, Geneva, Switzerland; Department of Neurosciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland.

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http://dx.doi.org/10.1016/j.rehab.2017.11.001DOI Listing
March 2018

On assessing neurofeedback effects: should double-blind replace neurophysiological mechanisms?

Brain 2017 10;140(10):e63

Laboratory Behavioral Neurology and Imaging of Cognition, Department of Neuroscience, University Medical Center and Campus Biotech, Geneva, Switzerland.

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http://dx.doi.org/10.1093/brain/awx211DOI Listing
October 2017

Increased Alpha-Rhythm Dynamic Range Promotes Recovery from Visuospatial Neglect: A Neurofeedback Study.

Neural Plast 2017 25;2017:7407241. Epub 2017 Apr 25.

Laboratory Behavioral Neurology and Imaging of Cognition, Department of Neuroscience, University Medical Center and Campus Biotech, Geneva, Switzerland.

Despite recent attempts to use electroencephalogram (EEG) neurofeedback (NFB) as a tool for rehabilitation of motor stroke, its potential for improving neurological impairments of attention-such as visuospatial neglect-remains underexplored. It is also unclear to what extent changes in cortical oscillations contribute to the pathophysiology of neglect, or its recovery. Utilizing EEG-NFB, we sought to causally manipulate alpha oscillations in 5 right-hemisphere stroke patients in order to explore their role in visuospatial neglect. Patients trained to reduce alpha oscillations from their right posterior parietal cortex (rPPC) for 20 minutes daily, over 6 days. Patients demonstrated successful NFB learning between training sessions, denoted by improved regulation of alpha oscillations from rPPC. We observed a significant negative correlation between visuospatial search deficits (i.e., cancellation test) and reestablishment of spontaneous alpha-rhythm dynamic range (i.e., its amplitude variability). Our findings support the use of NFB as a tool for investigating neuroplastic recovery after stroke and suggest reinstatement of intact parietal alpha oscillations as a promising target for reversing attentional deficits. Specifically, we demonstrate for the first time the feasibility of EEG-NFB in neglect patients and provide evidence that targeting alpha amplitude variability might constitute a valuable marker for clinical symptoms and self-regulation.
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http://dx.doi.org/10.1155/2017/7407241DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5424484PMC
March 2018

Closed-loop brain training: the science of neurofeedback.

Nat Rev Neurosci 2017 02 22;18(2):86-100. Epub 2016 Dec 22.

Department of Mechanical Engineering, University of Texas at Austin, 204 E Dean Keeton Street, Austin, Texas 78712, USA.

Neurofeedback is a psychophysiological procedure in which online feedback of neural activation is provided to the participant for the purpose of self-regulation. Learning control over specific neural substrates has been shown to change specific behaviours. As a progenitor of brain-machine interfaces, neurofeedback has provided a novel way to investigate brain function and neuroplasticity. In this Review, we examine the mechanisms underlying neurofeedback, which have started to be uncovered. We also discuss how neurofeedback is being used in novel experimental and clinical paradigms from a multidisciplinary perspective, encompassing neuroscientific, neuroengineering and learning-science viewpoints.
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http://dx.doi.org/10.1038/nrn.2016.164DOI Listing
February 2017

Theta/beta neurofeedback in children with ADHD: Feasibility of a short-term setting and plasticity effects.

Int J Psychophysiol 2017 02 6;112:80-88. Epub 2016 Nov 6.

Department of Child and Adolescent Mental Health, University Hospital Erlangen, Schwabachanlage 6, 91054 Erlangen, Germany.

Neurofeedback (NF) is increasingly used as a therapy for attention-deficit/hyperactivity disorder (ADHD), however behavioral improvements require 20 plus training sessions. More economic evaluation strategies are needed to test methodological optimizations and mechanisms of action. In healthy adults, neuroplastic effects have been demonstrated directly after a single session of NF training. The aim of our study was to test the feasibility of short-term theta/beta NF in children with ADHD and to learn more about the mechanisms underlying this protocol. Children with ADHD conducted two theta/beta NF sessions. In the first half of the sessions, three NF trials (puzzles as feedback animations) were run with pre- and post-reading and picture search tasks. A significant decrease of the theta/beta ratio (TBR), driven by a decrease of theta activity, was found in the NF trials of the second session demonstrating rapid and successful neuroregulation by children with ADHD. For pre-post comparisons, children were split into good vs. poor regulator groups based on the slope of their TBR over the NF trials. For the reading task, significant EEG changes were seen for the theta band from pre- to post-NF depending on individual neuroregulation ability. This neuroplastic effect was not restricted to the feedback electrode Cz, but appeared as a generalized pattern, maximal over midline and right-hemisphere electrodes. Our findings indicate that short-term NF may be a valuable and economical tool to study the neuroplastic mechanisms of targeted NF protocols in clinical disorders, such as theta/beta training in children with ADHD.
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http://dx.doi.org/10.1016/j.ijpsycho.2016.11.004DOI Listing
February 2017

Alpha oscillation neurofeedback modulates amygdala complex connectivity and arousal in posttraumatic stress disorder.

Neuroimage Clin 2016;12:506-516. Epub 2016 Jul 14.

Department of Neuroscience, Western University, London, ON, Canada; Department of Psychiatry, Western University, London, ON, Canada; Imaging, Lawson Health Research Institute, London, ON, Canada.

Objective: Electroencephalogram (EEG) neurofeedback aimed at reducing the amplitude of the alpha-rhythm has been shown to alter neural networks associated with posttraumatic stress disorder (PTSD), leading to symptom alleviation. Critically, the amygdala is thought to be one of the central brain regions mediating PTSD symptoms. In the current study, we compare directly patterns of amygdala complex connectivity using fMRI, before and after EEG neurofeedback, in order to observe subcortical mechanisms associated with behavioural and alpha oscillatory changes among patients.

Method: We examined basolateral (BLA), centromedial (CMA), and superficial (SFA) amygdala complex resting-state functional connectivity using a seed-based approach via SPM Anatomy Toolbox. Amygdala complex connectivity was measured in twenty-one individuals with PTSD, before and after a 30-minute session of EEG neurofeedback targeting alpha desynchronization.

Results: EEG neurofeedback was associated with a shift in amygdala complex connectivity from areas implicated in defensive, emotional, and fear processing/memory retrieval (left BLA and left SFA to the periaqueductal gray, and left SFA to the left hippocampus) to prefrontal areas implicated in emotion regulation/modulation (right CMA to the medial prefrontal cortex). This shift in amygdala complex connectivity was associated with reduced arousal, greater resting alpha synchronization, and was negatively correlated to PTSD symptom severity.

Conclusion: These findings have significant implications for developing targeted non-invasive treatment interventions for PTSD patients that utilize alpha oscillatory neurofeedback, showing evidence of neuronal reconfiguration between areas highly implicated in the disorder, in addition to acute symptom alleviation.
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http://dx.doi.org/10.1016/j.nicl.2016.07.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5030332PMC
July 2016

Editorial: Neurofeedback in ADHD.

Front Hum Neurosci 2015 30;9:602. Epub 2015 Oct 30.

Institute of Medical Psychology and Behavioral Neurobiology, University of Tuebingen Tuebingen, Germany.

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http://dx.doi.org/10.3389/fnhum.2015.00602DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4626559PMC
November 2015

Tuning pathological brain oscillations with neurofeedback: a systems neuroscience framework.

Front Hum Neurosci 2014 18;8:1008. Epub 2014 Dec 18.

Laboratory for Neurology and Imaging of Cognition, Department of Neurosciences, University of Geneva Geneva, Switzerland.

Neurofeedback (NFB) is emerging as a promising technique that enables self-regulation of ongoing brain oscillations. However, despite a rise in empirical evidence attesting to its clinical benefits, a solid theoretical basis is still lacking on the manner in which NFB is able to achieve these outcomes. The present work attempts to bring together various concepts from neurobiology, engineering, and dynamical systems so as to propose a contemporary theoretical framework for the mechanistic effects of NFB. The objective is to provide a firmly neurophysiological account of NFB, which goes beyond traditional behaviorist interpretations that attempt to explain psychological processes solely from a descriptive standpoint whilst treating the brain as a "black box". To this end, we interlink evidence from experimental findings that encompass a broad range of intrinsic brain phenomena: starting from "bottom-up" mechanisms of neural synchronization, followed by "top-down" regulation of internal brain states, moving to dynamical systems plus control-theoretic principles, and concluding with activity-dependent as well as homeostatic forms of brain plasticity. In support of our framework, we examine the effects of NFB in several brain disorders, including attention-deficit hyperactivity (ADHD) and post-traumatic stress disorder (PTSD). In sum, it is argued that pathological oscillations emerge from an abnormal formation of brain-state attractor landscape(s). The central thesis put forward is that NFB tunes brain oscillations toward a homeostatic set-point which affords an optimal balance between network flexibility and stability (i.e., self-organised criticality (SOC)).
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http://dx.doi.org/10.3389/fnhum.2014.01008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270171PMC
January 2015

Mind over chatter: plastic up-regulation of the fMRI salience network directly after EEG neurofeedback.

Neuroimage 2013 Jan 26;65:324-35. Epub 2012 Sep 26.

Department of Psychiatry, University of Western Ontario, London, Ontario, Canada.

Neurofeedback (NFB) involves a brain-computer interface that allows users to learn to voluntarily control their cortical oscillations, reflected in the electroencephalogram (EEG). Although NFB is being pioneered as a noninvasive tool for treating brain disorders, there is insufficient evidence on the mechanism of its impact on brain function. Furthermore, the dominant rhythm of the human brain is the alpha oscillation (8-12 Hz), yet its behavioral significance remains multifaceted and largely correlative. In this study with 34 healthy participants, we examined whether during the performance of an attentional task, the functional connectivity of distinct fMRI networks would be plastically altered after a 30-min session of voluntary reduction of alpha rhythm (n=17) versus a sham-feedback condition (n=17). We reveal that compared to sham-feedback, NFB induced an increase of connectivity within regions of the salience network involved in intrinsic alertness (dorsal anterior cingulate), which was detectable 30 min after termination of training. The increase in salience network (default-mode network) connectivity was negatively (positively) correlated with changes in 'on task' mind-wandering as well as resting state alpha rhythm. Crucially, we observed a causal dependence between alpha rhythm synchronization during NFB and its subsequent change at resting state, not exhibited by the SHAM group. Our findings provide neurobehavioral evidence for the brain's exquisite functional plasticity, and for a temporally direct impact of NFB on a key cognitive control network, suggesting a promising basis for its use to treat cognitive disorders under physiological conditions.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5051955PMC
http://dx.doi.org/10.1016/j.neuroimage.2012.09.046DOI Listing
January 2013

Penile paraffinoma after subcutaneous injection of paraffin. Treatment with a two step cutaneous plasty of the penile shaft with scrotal skin.

Arch Esp Urol 2012 Jun;65(5):575-8

Urology Department, Reina Sofia University Hospital, Murcia, Spain.

Objective: To report a rare case of penile paraffinoma caused by the subcutaneous or intra-urethral injection of foreign substances containing long-chain saturated hydrocarbons. These were injected in order to increase the penis size which generated a chronic granulomatous inflammatory reaction. This is a rare practice in the western world.

Methods: We present the case of a 32-year-old Bulgarian male who presented with a two-year history of elastic, slightly painful penis swelling after subcutaneous liquid paraffin injection. The proposed treatment was excision of the affected tissue and penile reconstruction in a two-stage procedure.

Results: The operative procedure was successful and the patient had good aesthetic and functional results. Paraffin and other materials injected into the penis can produce many complications. Foreign body granuloma, skin necrosis, penile deformity, chronic and unhealed ulcer, painful erection, and the inability to achieve a satisfactory sexual relationship are some of the resulting complications. Intralesional or systemic steroids have been used in primary sclerosing lipogranuloma resulting in the disappearance of the granuloma, but in our opinion the treatment of choice should be radical excision, and, if necessary, secondary reconstruction of the penis.

Conclusion: The injection of foreign substances to enhance penis size is currently an unjustifiable practice. However, it is still carried out, especially in Eastern Europe and Asia. In most cases surgical treatment is needed to treat the complications and the best modality seems to be radical excision together with follow-up.
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June 2012

Dynamic changes of ICA-derived EEG functional connectivity in the resting state.

Hum Brain Mapp 2013 Apr 17;34(4):852-68. Epub 2012 Feb 17.

Department of Psychology, Goldsmiths, University of London, London, United Kingdom.

An emerging issue in neuroscience is how to identify baseline state(s) and accompanying networks termed "resting state networks" (RSNs). Although independent component analysis (ICA) in fMRI studies has elucidated synchronous spatiotemporal patterns during cognitive tasks, less is known about the changes in EEG functional connectivity between eyes closed (EC) and eyes open (EO) states, two traditionally used baseline indices. Here we investigated healthy subjects (n = 27) in EC and EO employing a four-step analytic approach to the EEG: (1) group ICA to extract independent components (ICs), (2) standardized low-resolution tomography analysis (sLORETA) for cortical source localization of IC network nodes, followed by (3) graph theory for functional connectivity estimation of epochwise IC band-power, and (4) circumscribing IC similarity measures via hierarchical cluster analysis and multidimensional scaling (MDS). Our proof-of-concept results on alpha-band power demonstrate five statistically clustered groups with frontal, central, parietal, occipitotemporal, and occipital sources. Importantly, during EO compared with EC, graph analyses revealed two salient functional networks with frontoparietal connectivity: a more medial network with nodes in the mPFC/precuneus which overlaps with the "default-mode network" (DMN), and a more lateralized network comprising the middle frontal gyrus and inferior parietal lobule, coinciding with the "dorsal attention network" (DAN). Furthermore, a separate MDS analysis of ICs supported the emergence of a pattern of increased proximity (shared information) between frontal and parietal clusters specifically for the EO state. We propose that the disclosed component groups and their source-derived EEG functional connectivity maps may be a valuable method for elucidating direct neuronal (electrophysiological) RSNs in healthy people and those suffering from brain disorders.
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http://dx.doi.org/10.1002/hbm.21475DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6870341PMC
April 2013

Endogenous control of waking brain rhythms induces neuroplasticity in humans.

Eur J Neurosci 2010 Feb;31(4):770-8

Department of Psychology, Goldsmiths, University of London, Lewisham Way, New Cross, London SE146NW, UK.

This study explores the possibility of noninvasively inducing long-term changes in human corticomotor excitability by means of a brain-computer interface, which enables users to exert internal control over the cortical rhythms recorded from the scalp. We demonstrate that self-regulation of electroencephalogram rhythms in quietly sitting, naive humans significantly affects the subsequent corticomotor response to transcranial magnetic stimulation, producing durable and correlated changes in neurotransmission. Specifically, we show that the intrinsic suppression of alpha cortical rhythms can in itself produce robust increases in corticospinal excitability and decreases in intracortical inhibition of up to 150%, which last for at least 20 min. Our observations may have important implications for therapies of brain disorders associated with abnormal cortical rhythms, and support the use of electroencephalogram-based neurofeedback as a noninvasive tool for establishing a causal link between rhythmic cortical activities and their functions.
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http://dx.doi.org/10.1111/j.1460-9568.2010.07100.xDOI Listing
February 2010

Optimizing microsurgical skills with EEG neurofeedback.

BMC Neurosci 2009 Jul 24;10:87. Epub 2009 Jul 24.

Department of Psychology, Goldsmiths, University of London, London, UK.

Background: By enabling individuals to self-regulate their brainwave activity in the field of optimal performance in healthy individuals, neurofeedback has been found to improve cognitive and artistic performance. Here we assessed whether two distinct EEG neurofeedback protocols could develop surgical skill, given the important role this skill plays in medicine.

Results: National Health Service trainee ophthalmic microsurgeons (N = 20) were randomly assigned to either Sensory Motor Rhythm-Theta (SMR) or Alpha-Theta (AT) groups, a randomized subset of which were also part of a wait-list 'no-treatment' control group (N = 8). Neurofeedback groups received eight 30-minute sessions of EEG training. Pre-post assessment included a skills lab surgical procedure with timed measures and expert ratings from video-recordings by consultant surgeons, together with state/trait anxiety self-reports. SMR training demonstrated advantages absent in the control group, with improvements in surgical skill according to 1) the expert ratings: overall technique (d = 0.6, p < 0.03) and suture task (d = 0.9, p < 0.02) (judges' intraclass correlation coefficient = 0.85); and 2) with overall time on task (d = 0.5, p = 0.02), while everyday anxiety (trait) decreased (d = 0.5, p < 0.02). Importantly the decrease in surgical task time was strongly associated with SMR EEG training changes (p < 0.01), especially with continued reduction of theta (4-7 Hz) power. AT training produced marginal improvements in technique and overall performance time, which were accompanied by a standard error indicative of large individual differences. Notwithstanding, successful within session elevation of the theta-alpha ratio correlated positively with improvements in overall technique (r = 0.64, p = 0.047).

Conclusion: SMR-Theta neurofeedback training provided significant improvement in surgical technique whilst considerably reducing time on task by 26%. There was also evidence that AT training marginally reduced total surgery time, despite suboptimal training efficacies. Overall, the data set provides encouraging evidence of optimised learning of a complex medical specialty via neurofeedback training.
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http://dx.doi.org/10.1186/1471-2202-10-87DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2723116PMC
July 2009

EEG applications for sport and performance.

Methods 2008 Aug 3;45(4):279-88. Epub 2008 Aug 3.

Department of Psychology, Goldsmiths College, University of London, New Cross, London SE14 6NW, UK.

One approach to understanding processes that underlie skilled performing has been to study electrical brain activity using electroencephalography (EEG). A notorious problem with EEG is that genuine cerebral data is often contaminated by artifacts of non-cerebral origin. Unfortunately, such artifacts tend to be exacerbated when the subject is in motion, meaning that obtaining reliable data during exercise is inherently problematic. These problems may explain the limited number of studies using EEG as a methodological tool in the sports sciences. This paper discusses how empirical studies have generally tackled the problem of movement artifact by adopting alternative paradigms which avoid recording during actual physical exertion. Moreover, the specific challenges that motion presents to obtaining reliable EEG data are discussed along with practical and computational techniques to confront these challenges. Finally, as EEG recording in sports is often underpinned by a desire to optimise performance, a brief review of EEG-biofeedback and peak performance studies is also presented. A knowledge of practical aspects of EEG recording along with the advent of new technology and increasingly sophisticated processing models offer a promising approach to minimising, if perhaps not entirely circumventing, the problem of obtaining reliable EEG data during motion.
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http://dx.doi.org/10.1016/j.ymeth.2008.07.006DOI Listing
August 2008

[Multilocular cystic nephroma. A diagnostic and therapeutic challenge. Report of two cases].

Arch Esp Urol 2004 May;57(4):431-4

Servicio de Urología, Hospital General Universitario, Murcia, España.

Objectives: Multilocular cystic nephroma is a rare benign entity grouped among the cystic non genetic diseases, which usually presents with a clinical picture and radiological features indistinguishable from malignant neoplasias, making impossible to rule out malignancy preoperatively.

Methods: We report two cases of multilocular cystic nephroma which were treated with different surgical attitudes despite their clinical and radiological similarities, because on the second case intraoperative pathologic study of the specimen was performed.

Results: The diagnosis of multilocular cystic nephroma was confirmed in both cases, with the difference that radical nephrectomy was performed in the first case whereas the intraoperative study of the tumor in the second allowed to perform tumorectomy with renal parenchyma preservation.

Conclusions: We consider that in the presence of a multiloculated renal mass of complex appearance and benign clinical behavior, the intraoperative study of the tumor will avoid performance of radical surgery.
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May 2004
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