Cortical Source Multivariate EEG Synchronization Analysis on Amnestic Mild Cognitive Impairment in Type 2 Diabetes

Is synchronization altered in amnestic mild cognitive impairment (aMCI) and normal cognitive functions subjects in type 2 diabetes mellitus (T2DM)? Resting eye-closed EEG data were recorded in 8 aMCI subjects and 11 age-matched controls in T2DM. Three multivariate synchronization algorithms (S-estimator (S), synchronization index (SI), and global synchronization index (GSI)) were used to measure the synchronization in five ROIs of sLORETA sources for seven bands. Results showed that aMCI group had lower synchronization values than control groups in parietal delta and beta2 bands, temporal delta and beta2 bands, and occipital theta and beta2 bands significantly. Temporal (r=0.629; P=0.004) and occipital (r=0.648; P=0.003) theta S values were significantly positive correlated with Boston Name Testing. In sum, each of methods reflected that the cortical source synchronization was significantly different between aMCI and control group, and these difference correlated with cognitive functions

L'effet de la psychoneurothérapie sur l'activité électrique du cerveau d'individus souffrant du trouble dépressif majeur unipolaire

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Psychophysiological Treatments and Neural Correlates of Chronic Tinnitus

Subjektiver chronischer Tinnitus ist eine dauerhaft oder mit Unterbrechungen auftretende auditorische Wahrnehmung, welche oft mit Schwerhörigkeit einhergeht. Sie ist charakterisiert durch die Abwesenheit einer Schallquelle (wird von niemandem sonst gehört) und kann zu vielfältigen psychologischen Problemen wie Schlafschwierigkeiten, Depressionen und Ängsten führen. Diese Dissertation hat das Ziel, Behandlungsmöglichkeiten darzulegen und die neuronalen Korrelate des chronischen Tinnitus und begleitender Affekt- und Angststörungen zu dokumentieren. Daher wird die Wirksamkeit verschiedener Behandlungsansätze einschließlich Psychotherapie, Soundtherapie, pharmakologischer Therapie sowie nicht-invasiver und invasiver Hirnstimulation bewertet. Obwohl es einige Behandlungen wie die kognitive Verhaltenstherapie oder Neuromodulationstechniken gibt, die Placebo-Effekte übertreffen, beeinflussen sie hauptsächlich sekundäre Beschwerden aber nicht den Tinnitus-Ton selbst. Des Weiteren halten die Effekte der Therapien oft nur eine begrenzte Zeit an. Um die unterschiedlichen neuronalen Muster von Patienten mit schwerem und weniger schwerem chronischem Tinnitus zu untersuchen, wurden 34 Tinnitus-Patienten einer dieser beiden Gruppen zugeordnet und die EEG-Ruhezustandsaktivität der beiden Gruppen verglichen. Unter Verwendung einer EEG-Source-Analyse wurde in der Gruppe mit schwerem Tinnitus ein signifikanter Anstieg der Theta-Aktivität in frontalen Hirnregionen festgestellt. Der Schweregrad von Depressionen und Ängsten hatte keinen Einfluss auf die elektrophysiologische Metrik. Diese Ergebnisse unterstützen die Annahme Tinnitus-bedingter Veränderungen im Gehirn, bei denen präfrontale Bereiche Teil eines Netzwerks sind, welches einen Top-down-Einfluss auf die auditorischen Kortizes ausübt. Die Größe dieses Einflusses hängt mit der subjektiven Stärke der Tinnitus-Belastung zusammen. In Bezug auf die Therapie von Tinnitus wird impliziert, dass sich Behandlungen sowohl auf die Verringerung der Überaktivität im auditorischen Kortex als auch auf die Verringerung des Top-down-Einflusses des Tinnitus-Netzwerks auf den temporalen Kortex fokussieren sollten.Subjective chronic tinnitus is a continuous or intermittent auditory percept without an external source, which is often accompanied by hearing deficits. As indicated, it is characterized by an absence of a corresponding acoustic source, not heard by anyone else, and may lead to various psychological problems including sleep disorder, depression, and anxiety. This dissertation aims to identify therapy and management options as well as to reveal some neural correlates of tinnitus severity and accompanying mood and anxiety disorders. Thus, the efficacy of various treatment approaches including psychotherapy, sound therapy, pharmacological therapy, and both non-invasive and invasive brain stimulation is evaluated. Albeit there are some therapies that surpass placebo effects, such as cognitive behavioral therapy (CBT) or neuromodulation techniques, they mainly influence secondary symptoms but not the tinnitus tone itself, and the effects usually last for a limited time only. To investigate the differential neuronal profile of patients with severe and less severe chronic tinnitus 34 tinnitus patients were assigned to two groups and their EEG resting state activity was compared. Using a source analysis approach a significant and substantial frontal increase in theta wave activity was found in the group with severe tinnitus. The correlated severity of depression and anxiety did not correlate with the electrophysiological metrics. These results support a tinnitus-related global network change in which prefrontal areas are part of a network which exerts a top-down influence on the auditory cortices. The magnitude of this influence may be linked to the subjective strength of the tinnitus distress. Therapies should focus on both reducing the hyperactivity in the auditory cortex and reducing the top-down influence of the tinnitus-related global network on the auditory cortical and subcortical systems

Guidelines for the recording and evaluation of pharmaco-EEG data in man: the International Pharmaco-EEG Society (IPEG)

The International Pharmaco-EEG Society (IPEG) presents updated guidelines summarising the requirements for the recording and computerised evaluation of pharmaco-EEG data in man. Since the publication of the first pharmaco-EEG guidelines in 1982, technical and data processing methods have advanced steadily, thus enhancing data quality and expanding the palette of tools available to investigate the action of drugs on the central nervous system (CNS), determine the pharmacokinetic and pharmacodynamic properties of novel therapeutics and evaluate the CNS penetration or toxicity of compounds. However, a review of the literature reveals inconsistent operating procedures from one study to another. While this fact does not invalidate results per se, the lack of standardisation constitutes a regrettable shortcoming, especially in the context of drug development programmes. Moreover, this shortcoming hampers reliable comparisons between outcomes of studies from different laboratories and hence also prevents pooling of data which is a requirement for sufficiently powering the validation of novel analytical algorithms and EEG-based biomarkers. The present updated guidelines reflect the consensus of a global panel of EEG experts and are intended to assist investigators using pharmaco-EEG in clinical research, by providing clear and concise recommendations and thereby enabling standardisation of methodology and facilitating comparability of data across laboratories

Étude des rythmes cérébraux dans la régulation émotionnelle à l’aide d’un électroencéphalogramme quantitatif

Contexte : La régulation émotionnelle est un ensemble de processus responsables du contrôle, de l’évaluation et de l’ajustement des émotions dans un objectif. Les résultats d’imagerie fonctionnelle s’accordent sur l’implication des structures frontales et limbiques tandis que les résultats en neurophysiologie, encore rares, suggèrent un rôle du rythme alpha dans l’induction émotionnelle et du rythme thêta dans la régulation. Objectifs et hypothèses : Notre objectif était d’étudier le rythme thêta et alpha pendant la réévaluation de stimuli déplaisants. Nous avons émis l’hypothèse que l’activité alpha serait modulée lors de l’induction émotionnelle seulement tandis que l’activité thêta préfrontale serait positivement corrélée à une régulation réussie. Méthode : Vingt-quatre participants sains ont été enregistrés avec 64 électrodes EEG alors qu’ils regardaient passivement ou réévaluaient des images négatives et neutres. Les rythmes thêta et alpha ont été comparés lors de l’induction émotionnelle puis dans les conditions de maintien, de diminution et d’augmentation de l’émotion, et une localisation de la source a estimé les générateurs. Résultats : Le rythme alpha était non sensible à l’induction et à la régulation. L’activité thêta était systématiquement plus élevée dans la condition de régulation à la hausse que dans la condition de maintien (p=.04) principalement au début de la régulation (1-3 sec) pour thêta bas et plus tard (5-7 sec) pour le thêta haut avec comme générateur du thêta bas le gyrus frontal moyen et le cortex cingulaire antérieur dorsal. Conclusion : Le rythme thêta était impliqué dans les processus de réévaluation à la hausse de l’émotion.Context: Emotion regulation is a set of processes responsible for controlling, evaluating and adjusting reactions to achieve a goal. Results derived from magnetic resonance imaging agreed on the involvement of frontal and limbic structures in this process. Findings using cognition and physiology interactions are still scarce but suggest a role for alpha rhythm in emotional induction and theta in regulation. Objectives and hypotheses: Our goal was to investigate theta and alpha rhythm during the reappraisal of aversive stimuli. We hypothesized that an implication of alpha rhythm in emotional induction only and an increase in prefrontal theta rhythm positively correlated with successful regulation. Method: Twenty-four healthy participants were recorded with 64 EEG electrodes while asked to passively watch or reappraise negative pictures. Theta and alpha rhythms were compared across maintain, decrease and increase regulation conditions, and a source localization estimated the generators. Results: Theta activity was consistently higher in the upregulation than in the maintenance condition (p=.04) for the entire control period, but mainly at the beginning of regulation (1-3 sec) for low-theta and later (5-7 sec) for high-theta. Moreover, our results confirm that a low-theta generator correlated with mainly the middle frontal gyrus and the dorsal anterior cingulate cortex during upregulation. Theta was sensitive to emotion upregulation, whereas the alpha oscillation was non-sensitive to emotion induction and regulation. Conclusion: The low-theta rhythm was involved explicitly in emotion upregulation processes that occur at a definite time during reappraisal, whereas the alpha rhythm was not altered by emotion induction and regulation

Smart Biofeedback

Smart biofeedback is receiving attention because of the widespread availability of advanced technologies and smart devices that are used in effective collection, analysis, and feedback of physiologic data. Researchers and practitioners have been working on various aspects of smart biofeedback methodologies and applications by using wireless communications, the Internet of Things (IoT), wearables, biomedical sensors, artificial intelligence, big data analytics, clinical virtual reality, smartphones, and apps, among others. The current paradigm shift in information and communication technologies (ICT) has been propelling the rapid pace of innovation in smart biofeedback. This book addresses five important topics of the perspectives and applications in smart biofeedback: brain networks, neuromeditation, psychophysiological psychotherapy, physiotherapy, and privacy, security, and integrity of data

QEEG profile changes following three total body modification (TBM) treatments

The main research question of this study was to determine if the application of TBM would affect baseline states of QEEG activity. It was hypothesized that after completing three treatments of TBM there would be an increase of left hemispheric activity as well as an increase in mood states. This is hypothesized because depression has been shown to cause a decrease of frontal activity, specifically left hemispheric. Therefore, an increase of mood should lead to an increase of left hemispheric activityHonours Essa

Brain Dynamics as Confirmatory Biomarker of Dementia with Lewy Bodies Versus Alzheimer’s Disease - an Electrophysiological Study

PhD ThesisIntroduction Dementia with Lewy bodies (DLB), Parkinson’s disease dementia (PDD) and Alzheimer’s disease dementia (AD) are associated with different pathologies. Nevertheless, symptomatic overlap between these conditions may lead to misdiagnosis. Resting-state functional connectivity features in DLB as assessed with electroencephalography (EEG) are emerging as diagnostic biomarkers. However, their pathological significance is still questioned. This study aims to further investigate this aspect and to infer functional and structural sources of EEG abnormalities in DLB. Methods Graph theory analysis was first performed to assess EEG network differences between healthy controls (HC) and dementia groups. Source localisation and Network Based Statistics (NBS) were used to infer EEG cortical network and dominant frequency (DF) alterations in DLB compared with AD. Further analysis aimed to assess the subnetwork associated with visual hallucination (VH) symptom in DLB and PDD, i.e. LBD, compared with not-hallucinating (NVH) patients. Finally, probabilistic tractography was performed on diffusion tensor imaging (DTI) data between cortical regions, thalamus, and basal forebrain (NBM). Correlation between structural and functional connectivity was tested. Results EEG α-band (7-13.5 Hz) network features were affected in LBD compared with HC, whilst DLB β-band network (14-20.5 Hz) was weaker and more segregated when compared with AD. This scenario replicated in the source domain. DF was significantly lower in DLB compared with AD, and positively correlated with structural connectivity strength between NBM and the cortex. Functional visual ventral network connectivity and cholinergic projections towards the cortex were affected in VH compared with NVH, and significantly correlated in NVH. Conclusions Functional connectivity as assessed with EEG is more affected in DLB compared with AD. Moreover, the visual ventral network is functionally altered in VH compared with NVH. Results from structural analysis provide empirical evidence on the role of cholinergic dysfunctions in DLB and PDD pathology and corresponding functional correlates

Math anxiety:brain cortical network changes in anticipation of doing mathematics

Following our previous work regarding the involvement of math anxiety (MA) in math-oriented tasks, this study tries to explore the differences in the cerebral networks' topology between self-reported low math-anxious (LMA) and high math-anxious (HMA) individuals, during the anticipation phase prior to a mathematical related experiment. For this reason, multichannel EEG recordings were adopted, while the solution of the inverse problem was applied in a generic head model, in order to obtain the cortical signals. The cortical networks have been computed for each band separately, using the magnitude square coherence metric. The main graph theoretical parameters, showed differences in segregation and integration in almost all EEG bands of the HMAs in comparison to LMAs, indicative of a great influence of the anticipatory anxiety prior to mathematical performance