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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

QEEG and MMPI-2 patterns of adults reporting childhood sexual abuse: Determining differences and predictor models.

Townsend, Alicia 12 1900 (has links)
Childhood sexual abuse (CSA) has been linked to a number of adult psychological maladies. The MMPI-2 has shown specific patterns such as an inverted V in the validity scales, a floating profile, and a 4-5-6 configuration to be present more often in adults who have experienced childhood trauma. Both children and adults who have experienced trauma have shown a number of neurophysiological differences when compared to non-traumatized individuals. However, little research has looked at differences in quantitative electroencephalography (QEEG) patterns in these individuals. The purpose of this study is to determine differences seen in the MMPI-2 and the QEEG when comparing adults who report CSA to adults who deny any history of childhood abuse. Differences between the two groups in MMPI-2 basic scales and supplementary scales PK and PS were determined. This study also examined the ability to correctly classify individuals into the two groups using three patterns seen in the MMPI-2 basic scale profiles (inverted V, floating profile, and 4-5-6 configuration). In addition, this research included exploratory analyses to develop predictor models for CSA group membership. Predictors in the models were derived from MMPI-2 scales, alpha relative power at each of the 19 sites in the International 10/20 electrode placement system, as well as alpha/delta, alpha/theta, and alpha/beta ratios at each of the 19 sites. A total of 46 participants were included in this study, 24 from archived files and 22 newly recruited individuals. Each participant received a MMPI-2 and a QEEG. Significant differences were found between the MMPI-2 scores of the two groups, but MMPI-2 patterns were unable to correctly classify individuals. Models were found which were clinically relevant and statistically significant. The models were based on depression and social maladjustment. The depression models included scales F and 2 of the MMPI-2 and alpha relative power at left frontal sites. The social maladjustment models included scales 4 and 8 of the MMPI-2 and alpha relative power at temporal sites. These findings support previous research showing higher levels of pathology in MMPI-2 profiles and evidence for temporal and left-frontal differences in adults who report CSA.
12

Perturbations des processus d’intégration sensori-motrice dans la crampe de l’écrivain : une étude physiopathologique combinant imagerie par résonance magnétique fonctionnelle et électroencéphalographie-haute résolution / Disruption of sensorimotor integration in writer's cramp : a pathophysiological study combining functional magnetic resonance imaging and high-resolution electroencephalography

Langbour, Nicolas 10 December 2012 (has links)
La crampe de l'écrivain est la forme la plus fréquente de dystonies de fonction. Elle se caractérise par l’apparition de contractions musculaires involontaires et soutenues aboutissant à une perturbation sévère de l’écriture. Cette dernière est une tâche motrice séquentielle complexe nécessitant un contrôle continu des informations proprioceptives afin d’adapter la position du membre supérieur et la pression des doigts sur le stylo au cours de l’activité motrice. Dans ce travail de thèse nous avons postulé que l’élément fondamental de la physiopathologie de la crampe de l’écrivain est un trouble de l’intégration sensori-motrice. Pour tester cette hypothèse, nous avons utilisé deux tâches comportementales n’induisant pas de symptôme dystonique. Le sujet devait exécuter une séquence motrice, soit de façon spontanée (tâche SGT), soit sur la base d’une séquence de stimulation tactile précédemment apprise (ST). Les modifications d’activité cérébrale au cours de ces deux tâches ont été étudiées par couplage des techniques d’imagerie par résonance magnétique fonctionnelle (IRMf) et d’électroencéphalographie quantitative (EEGq). Nos résultats suggèrent qu’en l’absence de symptôme dystonique, les patients atteints de crampe de l’écrivain présentent une altération de leur performance motrice dans les deux tâches. Durant l’analyse des informations proprioceptives, l’IRMf montre qu’il existe une diminution du signal Bold au niveau du cortex somesthésique primaire, de l’aire motrice supplémentaire (AMS) et du cortex pariétal. Les données d’EEGq révèlent une diminution de la désynchronisation β (DLEβ) au niveau de l’AMS et celles de la cohérence intra-corticale des perturbations du fonctionnement des réseaux pariéto-prémoteurs. Durant la phase motrice, l’IRMf ne révèle aucune différence inter-groupe, mais l’EEGq montre une augmentation de la DLEβ dans les régions pariétales postérieures pour la situation SGT, associée à une augmentation de cohérence intra-corticale. Après l’exécution du mouvement, des anomalies de synchronisation β (SLEβ) sont également retrouvées dans les deux tâches. Ces données montrent qu’il existe chez les patients présentant une crampe de l’écrivain, des perturbations de l’analyse séquentielle des informations proprioceptives, ainsi que des anomalies de l’intégration sensori-motrice. Elles sont en rapport avec une altération des relations fonctionnelles entre les cortex pariétaux et prémoteurs. Ces éléments expliquent pourquoi ces patients au cours de l’écriture ont des difficultés à élaborer une réponse motrice adaptée sur la base d’information proprioceptive séquentielle. / Writer's cramp is the most frequent form of task-specific dystonia. It is characterized by excessive and inappropriate muscle activation resulting in severe disturbance of writing. Writing is a complex sequential motor task requiring the on-line continuous monitoring of proprioceptive information to adjust the position of the upper limb and finger pressure on the pen. In this experimental work, we postulated that the main feature in the pathophysiology of writer's cramp is a sensorimotor integration disorder. To test this hypothesis, we used two behavioral tasks that does not induce dystonic symptoms. The subject performed a motor sequence, either spontaneously (SGT task), or on the basis of a sequence of proprioceptive stimuli previously presented (ST). Changes in brain activity during both tasks were studied by coupling functional magnetic resonance imaging (fMRI) with quantitative electroencephalography (qEEG). Our results show that writer's cramp patients had impaired motor performances in both tasks whereas they did not exhibit any dystonic symptoms. During the analysis of proprioceptive information, fMRI shows a Bold signal decrease in the primary somatosensory cortex, the supplementary motor area (SMA) and parietal cortex. EEGq data revealed a decrease of β desynchronization (βERD) in SMA and intra-cortical coherence a disruption of the functional connectivity of parieto-premotor networks. During the motor phase, fMRI reveals no between-group difference, but EEGq showed an increase of βERD in the posterior parietal regions for the SGT task associated with an increased intra-cortical coherence. During the post-movement period, abnormal β synchronization (βERS) is also found in both tasks. This data shows that writer's cramp patient exhibited a disruption in the sequential analysis of proprioceptive information, as well as abnormalities in sensorymotor integration during motor planning. These features are related to an alteration of the functional relationships between the parietal and premotor cortices. These phenomenons explain why writer's cramp patient fail to develop an appropriate motor response on the basis of sequential proprioceptive information, as in writing.
13

Efficacy of neurofeedback for children with histories of abuse and neglect: Pilot study and meta-analytic comparison to other treatments.

Huang-Storms, Lark 08 1900 (has links)
This two-part study investigates the effectiveness of neurofeedback training for reducing behavioral problems commonly observed in abused/neglected children, and compares its efficacy to other treatment interventions with this population. Neuro-developmental sequelae of early relationship trauma are explored as an etiological framework for understanding disturbed affect-regulation, which appears central to the behavioral and emotional difficulties commonly experienced by this pediatric population. It is suggested that neurofeedback teaches children to self-regulate brain rhythmicity mechanisms, which in turn affects global improvements in behavior and mood. The pilot study utilizes records of 20 children removed from their biological homes by Child Protective Services. Children were assessed prior to treatment using the Child Behavior Checklist (CBCL) and the Test of Variables of Attention (TOVA), and again after 30 sessions of individualized, qEEG-guided neurofeedback training. A t-test analysis of pre- and post-scores was computed, and indicated significant improvements following treatment. A meta-analysis of existing literature on treatment interventions with abused/neglected children provides individual and aggregate effect sizes for 33 outcome studies with this clinical population, and contextualizes the results of the present pilot study within other empirically validated treatment modalities. Establishment of an overall effect size for treatment for this pediatric population provides a needed method of comparing research results across studies when control groups may not be ethical or feasible.
14

QEEG and LORETA findings in children with histories of relational trauma.

Bigby, Janice A. 05 1900 (has links)
Abuse and neglect occurring in childhood have been associated with a number of functional and physiological effects on the brain. This study extends previous research that investigated the quantitative electroencephalogram (qEEG) patterns in children with histories of relational trauma through the inclusion of additional participants and measures. As in previous studies, the relative power, absolute power, and coherence values in children with histories of abuse were compared to the Neuroguide database. Results did not show any significant differences in relative or absolute power in the theta range. Similarly, there were no significant coherence differences. Database comparisons were also made using low resolution electromagnetic tomography (LORETA) in order to determine which sub-cortical brain structures may be affected by abuse or trauma, though there were no significant differences in any frequency (0-30Hz). A review of the literature suggests that the prevalence of mu in normal adults and children ranges from 0 to 19%. The present study found a mu prevalence rate of 60.6% in the children who experienced abuse or neglect. Finally, comparisons were made between participants who demonstrate a mu pattern and those who do not to determine if this pattern is associated with certain behavioral and/or attention problems as assessed by the Child Behavior Checklist (CBCL) and the Tests of Variables of Attention (TOVA), respectively. There were no significant differences between children with a mu pattern versus children who did not exhibit a mu pattern on the Social Problems, Thought Problems, or Attention subscale scores on the CBCL or on the Commission subscale score on the TOVA.
15

Screening and monitoring of stress using biofeedback equipment

Mare, Irma Adele 13 July 2012 (has links)
Biofeedback equipment is intended to train conscious regulation of normally sub-conscious processes like autonomic nervous system activities. The manufacturers claim that measurements made with the equipment are accurate enough for research purposes, but these claims have not been vigorously tested. The subconscious processes recorded with biofeedback equipment are often disturbed by stress, and the aim of this study was to determine if the markers of stress could be accurately determined with biofeedback equipment. The physiological processes that were screened were:<ul><li> Time and frequency domain heart rate variability (HRV) determined from blood-volume-pulse (BVP) </li><li> Time and frequency domain HRV determined from electrocardiogram (ECG) </li><li> The amplitude of the BVP</li><li> Electromyographic (EMG) activity</li><li> The pulse transit time</li><li> Respiration rate and depth</li><li> Skin conductivity</li><li> Fingertip temperature</li><li> Quantitative electroencephalographic (QEEG) activity</li></ul> The accuracy of the HRV measurements were tested by comparing them to readings made simultaneously with a gold-standard device (Actiheart), and the main findings were:<ul><li> The hardware capabilities of the two systems are comparable when it comes to registering heartbeats and calculating heart rate</li><li> The frequency domain biofeedback HRV variables had relatively good correlations to the Actiheart results, but improvements are necessary</li><li> Frequency domain HRV variables differ when calculated with fast Fourier transform or with autoregression</li><li> The BVP signal is prone to movement artifact and other forms of interference</li></ul> The HRV measurements of both the biofeedback and Actiheart device were correlated to psychometric evaluations of anxiety and burnout, two conditions closely related to the concept of stress. The main findings were:<ul><li> Worry and anxiety can have a cardiac accelerating effect, largely mediated by vagal withdrawal </li><li> A decrease in resting autonomic variability associated with anxiety</li><li> Significant autonomic nervous system inflexibility occurs in the face of a cognitive stressor with increased anxiety</li><li> An increase in vagal and a decrease in sympathetic cardiac control correlated with increased levels of vital exhaustion</li><li> HRV assessment with specialized software such as Polar Precision Performance Software and the advanced HRV Analysis 1.1 software for windows (Biomedical Signal Analysis Group) were superior to assessments by means of the Biograph Infinity program</li></ul> Next it was investigated whether any association existed between levels of anxiety, burnout and that of Biograph-derived physiological indicators such as BVP amplitude, BVP HRV, ECG HRV, pulse transit time, EMG, fingertip temperature, respiration rate and amplitude, skin conductivity and QEEG levels. The overriding observations with increases in the levels of stress-related emotional conditions such as anxiety were that of a decrease in variability in almost all physiological functions assessed by Biograph. In conclusion, relatively good associations were found between certain, but not all, Biofeedback monitor results and that of other assessments of stress. The potential exists to develop a program which would accurately reflect stress levels. / Dissertation (MSc)--University of Pretoria, 2012. / School of Health Systems and Public Health (SHSPH) / Unrestricted
16

Hemispheric asymmetry and information processing in post-traumatic stress disorder.

Mayo, Therese January 2008 (has links)
Previous studies have suggested that mechanisms for neural compensation involve a reorganisation to right hemisphere processing in people with post-traumatic stress disorder (PTSD), and are associated with functional alterations in the capacity for behavioural flexibility. However, research has not established a direct relationship between the complex physiological and psychological processes of the heterogeneous disorder and right hemisphere cortical activity. The present study examined cognitive information processing in people with PTSD, reaction patterns associated with perceived traumatic stressors, and quantitative electroencephalographic (qEEG) indices of hemispheric asymmetry. Individuals with PTSD (N=34) and age and sex-matched normal controls (N=136) completed standardised web-based self-report questionnaires assessing traumatic stressor events and reaction patterns to those events. Neuropsychological indices of verbal, visuospatial, sensori-motor performance, and electrophysiological recordings, were examined for right hemisphere coding. The relationships among traumatic characteristic reaction patterns of numbing and avoidance, cognitive performance, and frontal and posterior EEG alpha asymmetry were also investigated. Structural and functional alterations were shown in those with PTSD, using indices of working memory for the retrieval of verbal and psychomotor information, indicating a reduced speed of processing and alterations to background cortical arousal in left hemisphere frontal regions. The study supported and extended previous findings of verbal working memory abnormality, alterations to left frontal cortical rhythmic oscillations, and low EEG alpha amplitudes in those diagnosed with PTSD. Results indicated a pattern of compensatory mechanisms associated with reduced speed of information processing and right-sided activation patterns in PTSD participants and control participants who experienced strong reactions to perceived traumatic events. Findings support the impact of traumatic events on psychobiological health in high-risk populations, implicating an association with specific patterns of neural and cognitive functioning in characteristic numbing and avoidance behaviours. / Thesis (Ph.D.) -- University of Adelaide, School of Population Health and Clinical Practice, 2008
17

Assessing the transfer of video game play versus attention training using 3D-Multiple Object Tracking

Pakdaman Lahiji, Robyn 12 1900 (has links)
Durant la dernière décennie, la recherche sur les jeux vidéo et leur implication sur les habiletés perceptivo-cognitives a gagné en intérêt. Plusieurs études ont démontré que les jeux vidéo (particulièrement les jeux d’action) possèdent la capacité d’influencer et d’améliorer différentes aptitudes perceptives et cognitives telles que l’attention visuo-spatiale, la vitesse de traitement de l’information, la mémoire visuelle à court terme ainsi que la poursuite d’objets en mouvement. Cependant, plusieurs autres études n’ont pas réussi à reproduire les mêmes résultats. D’un autre côté, un nouveau type d’entraînement perceptivo-cognitif, nommé 3-Dimensional Multiple-Object Tracking (3D-MOT), et qui consiste à traiter des scènes visuelles dynamiques dénuées de contexte, a démontré son implication sur différents types d’attention, la mémoire de travail ainsi que la vitesse de traitement de l’information. L’étude actuelle a examiné quatre groupes de joueurs inexpérimentés qui s’entrainaient durant 10 séances à l’aide d’un exercice perceptivo-cognitif (3D-MOT), ou d’un jeu de haut niveau visuel (jeu vidéo d’action : Call of Duty), de bas niveau visuel (Tetris) ou d’un jeu non-visuel (Sudoku). Des mesures d’électroencéphalographie quantitative et des tests neuropsychologiques effectués avant et après l’entraînement ont démontré que le 3D-MOT, par comparaison aux autres jeux testés, améliorait de façon plus efficace les fonctions reliées à l’attention, la mémoire de travail ainsi que la vitesse de traitement de l’information. Pour la première fois, cette étude démontre que l’entraînement non-contextuel de 3D-MOT améliore les habiletés perceptivo-cognitives plus efficacement que l’entraînement à des jeux de divertissement tels que les jeux vidéo. / In the past decade, research on video games and their implications on cognitive abilities have gained significant interest. Various studies suggest that video games (in particular action video games) have the inherent ability to influence and improve attentional abilities such as visual spatial attention, processing speed, visual short-term memory and multiple-object tracking. However, many other studies have been unable to replicate similar results. On the other hand, a recent cognitive enhancement tool that is visually dynamic and void of context called 3-Dimensional Multiple-Object tracking (3D-MOT), has demonstrated robust effects on cognitive-perceptual abilities such as divided, selective, and sustained attention as well as working memory and information processing speed. The current study examines four groups of non-video game players that train for 10 sessions on the cognitive enhancing technique (3D-MOT) or on one of three different visually stimulating games: highly visually stimulating game (Call of Duty), lowly visually stimulating game (Tetris), or non-visually stimulating puzzle (Sudoku). A battery of cognitive tests and quantitative electroencephalography preformed before and after training, demonstrated that training on 3D-MOT improved cognitive functions related to attention, working memory, and visual information processing compared to video games. For the first time, this study demonstrated that non-contextual training with 3D-MOT improves perceptual-cognitive abilities more efficiently than video game playing.
18

Effects of Childhood Sexual Abuse on Brain Function as Measured by Quantitative EEG, Neuropsychological, and Psychological Tests

Black, Lisa Myers 08 1900 (has links)
Childhood sexual abuse (CSA) has been the subject of much recent controversy as a result of Rind, Tromovitch and Bauserman's (1998) meta-analytic examination of CSA, which found a weak relationship between CSA and self-reported psychopathology in college samples. There have been few studies of CSA which look beyond self-report. The present study is an exploration of the relationships between CSA, quantitative electroencephalographic (QEEG), neuropsychological, and psychological measurements in 24 high-functioning, unmedicated CSA adults who were matched for age, gender, and handedness with a group of adults without CSA (NCSA). The objectives of this study were to: 1) examine EEG abnormalities associated with CSA, 2) investigate QEEG cortical coherence in the groups using neuroelectric Eigen image (NEI) connectivity indices (Hudspeth, 1999), 3) integrate personality differences associated with CSA with EEG differences, and 4) better understand left versus right hemisphere functioning in CSA using intelligence testing. An examination of QEEG cortical coherence revealed moderate to large effect sizes indicating patterns of decreased connectivity between brain regions on the right frontally in the delta band, and frontally and centro-temporally on the right in the alpha band, and posteriorly in the alpha and beta bands, as well as in the cross-correlation; increased connectivity between brain regions was evidenced centrally across the motor strip and on the left temporally in the delta band, which differentiated the groups. Large effect sizes obtained on measures of personality were related to poorer adjustment for CSA adults in comparison to NCSA adults. In contrast to prior findings with clinical groups (Black, Hudspeth, Townsend, & Bodenhamer-Davis, 2002; Ito et al., 1993), hypotheses related to QEEG cortical coherence (left hemisphere alpha hypercoherence and right hemisphere theta hypocoherence), EEG abnormalities, and IQ (Verbal less than Performance) were not supported. Walker's (2003) theoretical modular coherence model was utilized to integrate coherence and personality variables and provide treatment options.
19

Changes in Quantitative EEG and Low Resolution Tomography Following Cranial Electrotherapy Stimulation.

Kennerly, Richard C. 08 1900 (has links)
The effects of cranial electrotherapy stimulation (CES) on human EEG and brain current density were evaluated by quantitative electroencephalography (qEEG) and low resolution brain electromagnetic tomography (LORETA). A total of 72 research subjects were provided with a single session of CES, 38 were provided with 0.5 Hz CES while 34 were provided with 100 Hz CES. The qEEG paired t-tests revealed that in both frequencies of CES there was a significant (.05) increase in alpha relative power with concomitant decreases in delta and beta relative power. The 0.5 Hz CES decreased a wider frequency range of delta activity, while the 100 Hz CES decreased a wider frequency range of beta activity; suggesting some difference may exist in the EEG response to different frequencies of CES. The changes found in qEEG relative power were consistent with the affective and cognitive effects of CES reported in the literature, such as increased relaxation and decreased anxiety. Statistically significant changes for qEEG values other than relative power, such as coherence, amplitude asymmetry, phase lag and power ratios were also found. The LORETA paired t-tests found statistically significant (.05) increases in cortical and subcortical theta and alpha frequency current density with concomitant decreases in delta and beta current density. The effects of CES on current density varied by frequency, but did not show a differential in response based on proximity to the contacts, or structures within the brain. Statistically significant changes in current density were found in all 2394 gray matter voxels represented by LORETA, indicating a whole brain response to the CES stimulus. The qEEG and LORETA findings revealed that a single 20-minute session of CES does have a significant effect on the cortical and subcortical activity of the human brain resulting in activity consistent with decreased anxiety and increased relaxation.
20

Language Pathways Defined in a Patient with Left Temporal Lobe DamageSecondary to Traumatic Brain Injury: A QEEG & MRI Study

Bailey, Janelle Lee 01 December 2014 (has links) (PDF)
Though the current understanding of language processing is incomplete, it has been established that the left hemisphere is dominant for language in the majority of the population. Damage to language centers of the brain and to white matter tracts connecting these language centers results in a language deficit known as aphasia. Neuroplasticity in the brain can often compensate for these language deficits by strengthening neuronal connections between the right and left hemisphere, or by enhancing the neuronal connectivity of undamaged areas in the left hemisphere. Thus the brain can compensate for damaged language centers by using alternative cortical areas. These compensatory language areas may be homologous areas of the right hemisphere, or other undamaged portions of the left hemisphere. Various imaging techniques have been used to demonstrate this phenomenon. The current neuroimaging technique known as quantitative electroencephalographic brain imaging allows investigators to evaluate the functional anatomical location of language processing. When this mapping is overlaid on a magnetic resonance image, investigators are able to locate areas in the brain of the participant that are electrically activated during elicited speech tasks. This method was used in a single case study to examine the brain of an individual with a unique traumatic brain injury in which the anterior portion of the individual's left temporal lobe was surgically removed and considerable recovery of language subsequently occurred. The stimulus for the quantitative electroencephalography included identifying syntactically incorrect sentences. Imaging results from the participant with traumatic brain injury were compared to imaging results obtained from an age-matched control. Differences in quantitative electroencephalography between the two participants included a delayed P1-N1-P2 response and an absent P600 in the participant with traumatic brain injury. Behavioral results include an increased number of incorrect responses from the participant with traumatic brain injury as compared to the control participant. These results imply an interesting cortical distribution of language processing that could be further assessed by functional magnetic resonance imaging.

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