1,044 research outputs found

    Human Activity Recognition and Fall Detection Using Unobtrusive Technologies

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    As the population ages, health issues like injurious falls demand more attention. Wearable devices can be used to detect falls. However, despite their commercial success, most wearable devices are obtrusive, and patients generally do not like or may forget to wear them. In this thesis, a monitoring system consisting of two 24×32 thermal array sensors and a millimetre-wave (mmWave) radar sensor was developed to unobtrusively detect locations and recognise human activities such as sitting, standing, walking, lying, and falling. Data were collected by observing healthy young volunteers simulate ten different scenarios. The optimal installation position of the sensors was initially unknown. Therefore, the sensors were mounted on a side wall, a corner, and on the ceiling of the experimental room to allow performance comparison between these sensor placements. Every thermal frame was converted into an image and a set of features was manually extracted or convolutional neural networks (CNNs) were used to automatically extract features. Applying a CNN model on the infrared stereo dataset to recognise five activities (falling plus lying on the floor, lying in bed, sitting on chair, sitting in bed, standing plus walking), overall average accuracy and F1-score were 97.6%, and 0.935, respectively. The scores for detecting falling plus lying on the floor from the remaining activities were 97.9%, and 0.945, respectively. When using radar technology, the generated point clouds were converted into an occupancy grid and a CNN model was used to automatically extract features, or a set of features was manually extracted. Applying several classifiers on the manually extracted features to detect falling plus lying on the floor from the remaining activities, Random Forest (RF) classifier achieved the best results in overhead position (an accuracy of 92.2%, a recall of 0.881, a precision of 0.805, and an F1-score of 0.841). Additionally, the CNN model achieved the best results (an accuracy of 92.3%, a recall of 0.891, a precision of 0.801, and an F1-score of 0.844), in overhead position and slightly outperformed the RF method. Data fusion was performed at a feature level, combining both infrared and radar technologies, however the benefit was not significant. The proposed system was cost, processing time, and space efficient. The system with further development can be utilised as a real-time fall detection system in aged care facilities or at homes of older people

    Affective, Interpersonal, and Subjective Aspects of Denial in Anosognosia for Hemiplegia: Neuroscientific and Psychoanalytic Perspectives

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    Some patients customarily deny left hand hemiplegia as a consequence of a right hemispheric stroke. Denial is a key aspect in Anosognosia for Hemiplegia, and is also an essential concept in the development and structure of psychoanalytic theory. In research on AHP, denial is approached from neuroscientific perspectives, which include empirical research on several aspects that are relevant in the presentation of the syndrome (e.g. senso-perception, cognition, neuroanatomy, etc.). Psychoanalysis has emphasised intrapsychic, developmental, and defensive aspects based upon clinical observation of mainly non-neurological patients. However, the Cognitive Arrest Hypothesis (a model stemming from psychoanalytic theory) has proposed a view of denial that is in accordance with, or does not contradict empirical evidence on AHP. Both fields have recognised the importance of affective, motivational, interpersonal, and subjective aspects in the presentation of denial. The Cognitive Arrest Hypothesis allows discussing evidences on denial in AHP research, and in psychoanalytic theory, under a common framework of reference. The present thesis aims at opening a debate between these two fields with the goal of demonstrating how can their arguments be of mutual assistance in further comprehending denial. Three research proposals are presented to illustrate practical ways to consider contributions from both fields in future research and clinical directions

    Water and Brain Function: Effects of Hydration Status on Neurostimulation and Neurorecording

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    Introduction: TMS and EEG are used to study normal neurophysiology, diagnose, and treat clinical neuropsychiatric conditions, but can produce variable results or fail. Both techniques depend on electrical volume conduction, and thus brain volumes. Hydration status can affect brain volumes and functions (including cognition), but effects on these techniques are unknown. We aimed to characterize the effects of hydration on TMS, EEG, and cognitive tasks. Methods: EEG and EMG were recorded during single-pulse TMS, paired-pulse TMS, and cognitive tasks from 32 human participants on dehydrated (12-hour fast/thirst) and rehydrated (1 Liter oral water ingestion in 1 hour) testing days. Hydration status was confirmed with urinalysis. MEP, ERP, and network analyses were performed to examine responses at the muscle, brain, and higher-order functioning. Results: Rehydration decreased motor threshold (increased excitability) and shifted the motor hotspot. Significant effects on TMS measures occurred despite being re-localized and re-dosed to these new parameters. Rehydration increased SICF of the MEP, magnitudes of specific TEP peaks in inhibitory protocols, specific ERP peak magnitudes and reaction time during the cognitive task. Rehydration amplified nodal inhibition around the stimulation site in inhibitory paired-pulse networks and strengthened nodes outside the stimulation site in excitatory and CSP networks. Cognitive performance was not improved by rehydration, although similar performance was achieved with generally weaker network activity. Discussion: Results highlight differences between mild dehydration and rehydration. The rehydrated brain was easier to stimulate with TMS and produced larger responses to external and internal stimuli. This is explainable by the known physiology of body water dynamics, which encompass macroscopic and microscopic volume changes. Rehydration can shift 3D cortical positioning, decrease scalp cortex distance (bringing cortex closer to stimulator/recording electrodes), and cause astrocyte swelling-induced glutamate release. Conclusions: Previously unaccounted variables like osmolarity, astrocyte and brain volumes likely affect neurostimulation/neurorecording. Controlling for and carefully manipulating hydration may reduce variability and improve therapeutic outcomes of neurostimulation. Dehydration is common and produces less excitable circuits. Rehydration should offer a mechanism to macroscopically bring target cortical areas closer to an externally applied neurostimulation device to recruit greater volumes of tissue and microscopically favor excitability in the stimulated circuits

    The Neural Correlates of Bodily Self-Consciousness in Virtual Worlds

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    Bodily Self-Consciousness (BSC) is the cumulative integration of multiple sensory modalities that contribute to our sense of self. Sensory modalities, which include proprioception, vestibulation, vision, and touch are updated dynamically to map the specific, local representation of ourselves in space. BSC is closely associated with bottom-up and top-down aspects of consciousness. Recently, virtual- and augmented-reality technology have been used to explore perceptions of BSC. These recent achievements are partly attributed to advances in modern technology, and partly due to the rise of virtual and augmented reality markets. Virtual reality head-mounted displays can alter aspects of perception and consciousness unlike ever before. Consequently, many strides have been made regarding BSC research. Previous research suggests that BSC results from the perceptions of embodiment (i.e., the feeling of ownership towards a real or virtual extremity) and presence (i.e., feeling physically located in a real or virtual space). Though physiological mechanisms serving embodiment and presence in the real world have been proposed by others, how these perceptual experiences interact and whether they can be dissociated is still poorly understood. Additionally, less is known about the physiological mechanisms underlying the perception of presence and embodiment in virtual environments. Therefore, five experiments were conducted to examine the perceptions of embodiment and presence in virtual environments to determine which physiological mechanisms support these perceptions. These studies compared performance between normal or altered embodiment/presence conditions. Results from a novel experimental paradigm using virtual reality (Experiment 4) are consistent with studies in the literature that reported synchronous sensorimotor feedback corresponded with greater strength of the embodiment illusion. In Experiment 4, participants recorded significantly faster reaction times and better accuracy in correlated feedback conditions compared to asynchronous feedback conditions. Reaction times were also significantly faster, and accuracy was higher for conditions where participants experienced the game from a first- versus third-person perspective. Functional magnetic resonance imaging (fMRI) data from Experiment 5 revealed that many frontoparietal networks contribute to the perception of embodiment, which include premotor cortex (PMC) and intraparietal sulcus (IPS). fMRI data revealed that activity in temporoparietal networks, including the temporoparietal junction and right precuneus, corresponded with manipulations thought to affect the perception of presence. Furthermore, data suggest that networks associated with embodiment and presence overlap, and brain areas that support perception may be predicated upon those that support embodiment. The results of these experiments offer further clues into the psychophysiological mechanisms underlying BSC

    Application of Advanced MRI to Fetal Medicine and Surgery

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    Robust imaging is essential for comprehensive preoperative evaluation, prognostication, and surgical planning in the field of fetal medicine and surgery. This is a challenging task given the small fetal size and increased fetal and maternal motion which affect MRI spatial resolution. This thesis explores the clinical applicability of post-acquisition processing using MRI advances such as super-resolution reconstruction (SRR) to generate optimal 3D isotropic volumes of anatomical structures by mitigating unpredictable fetal and maternal motion artefact. It paves the way for automated robust and accurate rapid segmentation of the fetal brain. This enables a hierarchical analysis of volume, followed by a local surface-based shape analysis (joint spectral matching) using mathematical markers (curvedness, shape index) that infer gyrification. This allows for more precise, quantitative measurements, and calculation of longitudinal correspondences of cortical brain development. I explore the potential of these MRI advances in three clinical settings: fetal brain development in the context of fetal surgery for spina bifida, airway assessment in fetal tracheolaryngeal obstruction, and the placental-myometrial-bladder interface in placenta accreta spectrum (PAS). For the fetal brain, MRI advances demonstrated an understanding of the impact of intervention on cortical development which may improve fetal candidate selection, neurocognitive prognostication, and parental counselling. This is of critical importance given that spina bifida fetal surgery is now a clinical reality and is routinely being performed globally. For the fetal trachea, SRR can provide improved anatomical information to better select those pregnancies where an EXIT procedure is required to enable the fetal airway to be secured in a timely manner. This would improve maternal and fetal morbidity outcomes associated with haemorrhage and hypoxic brain injury. Similarly, in PAS, SRR may assist surgical planning by providing enhanced anatomical assessment and prediction for adverse peri-operative maternal outcome such as bladder injury, catastrophic obstetric haemorrhage and maternal death

    Contributions of Human Prefrontal Cortex to the Recogitation of Thought

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    Human beings have a unique ability to not only verbally articulate past and present experiences, as well as potential future ones, but also evaluate the mental representations of such things. Some evaluations do little good, in that they poorly reflect facts, create needless emotional distress, and contribute to the obstruction of personal goals, whereas some evaluations are the converse: They are grounded in logic, empiricism, and pragmatism and, therefore, are functional rather than dysfunctional. The aim of non-pharmacological mental health interventions is to revise dysfunctional thoughts into more adaptive, healthier ones; however, the neurocognitive mechanisms driving cognitive change have hitherto remained unclear. Therefore, this thesis examines the role of the prefrontal cortex (PFC) in this aspect of human higher cognition using the relatively new method of functional near-infrared spectroscopy (fNIRS). Chapter 1 advances recogitation as the mental ability on which cognitive restructuring largely depends, concluding that, as a cognitive task, it is a form of open-ended human problem-solving that uses metacognitive and reasoning faculties. Because these faculties share similar executive resources, Chapter 2 discusses the systems in the brain involved in controlled information processing, specifically the nature of executive functions and their neural bases. Chapter 3 builds on these ideas to propose an information-processing model of recogitation, which predicts the roles of different subsystems localized within the PFC and elsewhere in the context of emotion regulation. This chapter also highlights several theoretical and empirical challenges to investigating this neurocognitive theory and proposes some solutions, such as to use experimental designs that are more ecologically valid. Chapter 4 focuses on a neuroimaging method that is best suited to investigating questions of spatial localization in ecological experiments, namely functional near-infrared spectroscopy (fNIRS). Chapter 5 then demonstrates a novel approach to investigating the neural bases of interpersonal interactions in clinical settings using fNIRS. Chapter 6 explores physical activity as a ‘bottom-up’ approach to upregulating the PFC, in that it might help clinical populations with executive deficits to regulate their mental health from the ‘top-down’. Chapter 7 addresses some of the methodological issues of investigating clinical interactions and physical activity in more naturalistic settings by assessing an approach to recovering functional events from observed brain data. Chapter 8 draws several conclusions about the role of the PFC in improving psychological as well as physiological well-being, particularly that rostral PFC is inextricably involved in the cognitive effort to modulate dysfunctional thoughts, and proposes some important future directions for ecological research in cognitive neuroscience; for example, psychotherapy is perhaps too physically stagnant, so integrating exercise into treatment environments might boost the effectiveness of intervention strategies

    Effectivity of Combined Rhythmic Auditory Stimulation Rehabilitation Approach on Gait post Stroke

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    Effectivity of Combined Rhythmic Auditory Stimulation Rehabilitation Approach on Gait post Stroke Abstract Background: this review is assessing the effectiveness of combing forms of rhythmic auditory stimulation (a form of neurologic music therapy) to commonly used physiotherapeutic methods in the treatment of gait for hemiplegic/paresis stroke patients. Aim: to evaluate the extent in which Rhythmic Auditory Stimulation (RAS) combined therapy has a positive effect on gait for stroke patients, and whether RAS combined therapy is a more effective approach than conventional physiotherapeutic approaches. Methods: Databases Cochrane Central Register of Controlled Trials, Pubmed and Science Direct were searched. All databases were searched using a publication year range from 2009- 2022. Studies accepted were either Randomized Control Trials, Clinical Control Trails or Case Control Studies, evaluating RAS combined therapy versus conventional physiotherapeutic methods for Hemiplegic/paresis stroke patients. The outcome measures evaluated were gait and balance ability, according to spatiotemporal gait parameters and balance or lower extremity function assessments. Data was extracted according to PRISMA guidelines as well as with the help of a reference manager. The studies were analysed for risk of bias according to...Účinnost kombinovaného přístupu rytmické sluchové stimulace v rehabilitaci chůze u pacientů po cévní mozkové příhodě Abstrakt Východiska: práce je věnována posouzení účinnosti forem rytmické sluchové stimulace (forma neurologické muzikoterapie) k běžně používaným fyzioterapeutickým metodám v léčbě chůze u pacientů po cévní mozkové příhodě s hemiplegií. Cíl: zhodnotit, do jaké míry má kombinovaná terapie rytmické sluchové stimulace pozitivní vliv na chůzi u pacientů po cévní mozkové příhodě a zda je tato kombinovaná terapie účinnějším přístupem než běžné, konvenční fyzioterapeutické přístupy. Metody: Studie pro rešerši byly vyhledávány v databázích Cochrane Central Register of Controlled Trials, Pubmed a Science Direct. Pro zařazení studií bylo stanoveno období publikování v letech 2009-2022. Přijaté studie byly randomizované kontrolované studie, klinické kontrolované studie nebo případové kontrolované studie, hodnotící kombinovanou terapii rytmické sluchové stimulace oproti konvenčním fyzioterapeutickým metodám u pacientů s hemiplegií po cévní mozkové příhodě. Pro hodnocení efektu terapie byla použita chůze a schopnost rovnováhy dle časoprostorových parametrů chůze, hodnocení rovnováhy nebo funkce dolních končetin. Data byla extrahována dle PRISMA doporučených postupů a studie byly analyzovány vzhledem...Katedra fyzioterapieDepartment of PhysiotherapyFaculty of Physical Education and SportFakulta tělesné výchovy a sport
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