Cortical activations underlying human bipedal balance control

Human bipedal balance is a complex sensorimotor task controlled by the central nervous system. Balance impairments, caused by aging or neuromuscular diseases, often lead to falls which are one of the leading causes of injury and subsequent increases in health care costs. Hence, understanding the mechanisms underlying human bipedal balance control has many functional and clinical implications. Traditionally, it was believed that balance control is mediated by subcortical structures. However, evidence from research in the past few decades has shown that the cerebral cortex plays a major role in bipedal balance control. Nevertheless, the cortical contributions in balance control are still unclear. Hence, the purpose of this thesis was to extend the understanding of cortical involvement in human bipedal balance control. Specifically, the two overarching goals of this thesis were to examine evidence of a cortical network involvement and its generalizability across reactive and predictive balance control. These two overarching goals were addressed through four different studies. Study 1 explored the frequency characteristics and mechanisms underlying the generation of perturbation-evoked potentials. Study 2 investigated cortical activity linked to ‘automatic’ balance reactions that occur continuously while standing still and its dependence on the amplitude of these balance reactions. Study 3 examined the cortical activations related to the preparation and execution of anticipatory postural adjustments that precede a step and whether the activations are dependent on the context of control. Study 4 was designed to examine the functional connectivity in balance control and whether similar networks underlie reactive and predictive balance control. Studies were conducted on young healthy adults and cortical activations were acquired using electroencephalography during feet-in-place balance reactions, standing still, and voluntary stepping. Overall, the findings of these studies provided direct and indirect evidence for the involvement of a cortical network in balance control and its generalizability across different classes of balance control. This work reinforces the view that cortical networks likely play an important role in the control of stability. It is proposed that the synchronized activation of neural assemblies distributed across the cortex might have contributed to the balance-related cortical activations. The findings of this thesis extend the understanding of cortical control of human bipedal balance that may help to inform future, more precise models of the cortical contributions to balance control. This, in turn, can inform future diagnostic and therapeutic approaches to improve mobility among those with balance impairments

Early Detection of Neurodegenerative Diseases from Bio-Signals: A Machine Learning Approach

Given the fact that people, especially in advanced countries, are living longer due to the advancements in medical sciences which resulted in the prevalence of age-related diseases like Alzheimer’s and dementia. The occurrence of such diseases continues to increase and ultimately the cost of caring for these groups will become unsustainable. Addressing this issue has reached a critical point and failing to provide a strategic way forward will negatively affect patients, national health services and society as a whole.Three distinctive development stages of neurodegenerative diseases (Retrogenesis, Cognitive Impairment and Gait Impairment) motivated me to divide this research work into two main parts. To fully achieve the purpose of early detection/diagnosis, I aimed at analysing the gait signals as well as EEG signals, separately, as both of these signals severely get affected by any neurological disease.The first part of this research work focuses on the discrimination analysis of gait signals of different neurodegenerative diseases (Parkinson’s, Huntington, and Amyotrophic Lateral Sclerosis) and also of control subjects. This involves relevant feature extraction, solving the issues of imbalanced datasets and missing entries and lastly classification of multiclass datasets. For the classification and discrimination of gait signals, eleven (11) classifiers are selected representing linear, non-linear and Bayes normal classification techniques. Results revealed that three classifiers have provided us with higher accuracy rate which are UDC, LDC and PARZEN with 65%, 62.5% and 60% accuracy, respectively. Further, I proposed and developed a new classifier fusion strategy that combined classification algorithms with combining rules (voting, product, mean, median, maximum and minimum). It generates better results and classifies subjects more accurately than base-level classifiers.The last part of this research work is based on the rectification and computation of EEG signals of mild Alzheimer’s disease patients and control subjects. To detect the perturbation in EEG signals of Alzheimer’s patients, three neural synchrony measurement techniques; phase synchrony, magnitude squared coherence and cross correlation are applied on three different databases of mild Alzheimer’s disease (MiAD) patients and healthy subjects. I have compared right and left temporal parts of brain with rest of the brain area (frontal, central and occipital), as temporal regions are relatively the first ones to be affected by Alzheimer’s. Two novel methods are proposed to compute the neural synchronization of the brain; Average synchrony measure and PCA based synchrony measure. These techniques are evaluated for three different datasets of MiAD patients and control subjects using the Wilcoxon ranksum test (Mann-Whitney U test). Results demonstrated that PCA based method helped us to find more significant features that can be used as biomarkers for the early diagnosis of Alzheimer’s

Sleep homeostasis in the European jackdaw (<i>Coloeus monedula</i>):Sleep deprivation increases NREM sleep time and EEG power while reducing hemispheric asymmetry

Introduction: Sleep is a wide-spread phenomenon that is thought to occur in all animals. Yet, the function of it remains an enigma. Conducting sleep experiments in different species may shed light on the evolution and functions of sleep. Therefore, we studied sleep architecture and sleep homeostatic responses to sleep deprivation in the European jackdaw (Coloeus monedula).Methods: A total of nine young adult birds were implanted with epidural electrodes and equipped with miniature data loggers for recording movement activity (accelerometery) and electroencephalogram (EEG). Individually-housed jackdaws were recorded under controlled conditions with a 12:12-h light-dark cycle.Results: During baseline, the birds spent on average 48.5% of the time asleep (39.8% non-rapid eye movement (NREM) sleep and 8.7% rapid eye movement (REM) sleep). Most of the sleep occurred during the dark phase (dark phase: 75.3% NREM sleep and 17.2% REM sleep; light phase 4.3% NREM sleep and 0.1% REM sleep). After sleep deprivation of 4 and 8 h starting at lights off, the birds showed a dose-dependent increase in NREM sleep time. Also, NREM sleep EEG power in the 1.5–3 Hz frequency range, which is considered to be a marker of sleep homeostasis in mammals, was significantly increased for 1-2 h after both 4SD and 8SD. While there was little true unihemispheric sleep in the Jackdaws, there was a certain degree of hemispheric asymmetry in NREM sleep EEG power during baseline, which reduced after sleep deprivation in a dose-dependent manner.Conclusion: In conclusion, jackdaws display homeostatic regulation of NREM sleep and sleep pressure promotes coherence in EEG power

Dementia in Parkinson’s Disease

An estimated 50% to 80% of individuals with Parkinson’s disease experience Parkinson’s disease dementia (PDD). Based on the prevalence and clinical complexity of PDD, this book provides an in-depth update on topics including epidemiology, diagnosis, and treatment. Chapters discuss non-medical therapies and examine views on end-of-life issues as well. This book is a must-read for anyone interested in PDD whether they are a patient, caregiver, or doctor

Detection of Eye Movements

Import 05/08/2014Předmětem této bakalářské práce je detekce pohybů očí. Po provedení teoretického rozboru problematiky byla vybrána metoda elektrookulografie, která v dnešní době představuje možný kompromis mezi cenou a přesností zařízení. Rozvoji této metody bezpochyby prospívá i současný trend miniaturizace, kdy je možné elektrody upevnit např. do obrub brýlí. Elektrody tak není nutné mít přilepeny na obličeji, čímž se zvyšuje ochota lidí tuto metodu využívat. Cílem této práce je dostat elektrookulografii do podvědomí studentů. První část práce je věnována teoretickému rozboru elektrookulografie, nejnovějším poznatkům v této oblasti a jejímu srovnání s dalšími metodami. V praktické části je představeno vlastní hardwarové řešení elektrookulografu a vizualizační software, který pomůže studentům názorně předvést princip měření elektrookulografie a mohou si vyzkoušet přesnost elektrookulografu a ovládání jednoduché aplikace pohyby oka.The subject of this thesis is detection of eye movement. After the theoretical analysis, the method of electrooculography (EOG) was chosen. Nowadays, this method represents a possible compromise between the price and accuracy of equipment. Development of this method also benefits from the contemporary trend of miniaturization, when an electrode can be attached e.g. to the goggles so it is not necessary to have the electrodes attached on your face. This thesis aims at bringing the electrooculography to the awareness of students. In the first part I devote to the theoretical analysis electrooculography, the newest findings in this field and its comparison with other methods. In the practical part I present the hardware solution of electro-oculography and visualization software. This software helps students understand this method, enabling them to test the accuracy of electrooculograph and control of simple application with eye movement.450 - Katedra kybernetiky a biomedicínského inženýrstvívýborn

The utility of the auditory brainstem response in children with atypical saccadic eye movements

Full version unavailable due to 3rd party copyright restrictionsLesions in the brainstem result in widespread damage to a number of sensorimotor systems including oculomotor and auditory neural circuits. Although these systems are spatially separate and highly specialised, they are also co-located. This thesis, investigates whether lesions in the oculomotor system will also cause co-morbid dysfunction in the auditory pathways. Specifically, we investigated the usefulness of the Auditory Brainstem Response (ABR) in two oculomotor conditions: slow saccades in Gaucher disease (GD) and opsoclonus in Dancing Eye Syndrome (DES). We present four empirical studies. In our first study we systematically investigated the ABR in GD. We found that multimodal testing can better delineate underlying neurological deficits in neuronopathic GD (nGD) and distinguish between phenotypes. In the second study we examined the ABR's utility as a longitudinal, objective marker of disease burden and in a randomised clinical control trial. ABRs continued to deteriorate regardless of treatment. In our third study we assessed audiological function in DES. We found that at least 43% of DES patients have hyperacusis. We also found subtle abnormalities in the auditory brainstem, as shown by the ABR. Our final study explored the onset-offset response in the ABR and assessed its utility as a clinical marker. Overall, this thesis provides new evidence that auditory pathways are also affected in diseases which are traditionally assumed to be ‘oculomotor’ in nature. We believe that there is sufficient evidence to warrant the inclusion of audiological testing, such as the ABR, as part of the standard assessment of newly diagnosed GD patients and that they undergo these tests prior to commencing treatment. These tests may also have a wider application as longitudinal outcome measures for use in clinical trials or as markers of neurological burden in GD and we believe may be useful in other metabolic diseases; we found that current therapies for GD have low efficacy. Understanding the underlying neurological deficits in these debilitating illnesses can only help to improve treatments and the long-term outlook for these patients

Aerospace medicine and biology: A continuing bibliography with indexes (supplement 389)

This bibliography lists 234 reports, articles, and other documents recently introduced into the NASA Scientific and Technical Information System. Subject coverage includes: aerospace medicine and physiology, life support systems and man/system technology, protective clothing, exobiology and extraterrestrial life, planetary biology, and flight crew behavior and performance

Proceedings of the 3rd International Mobile Brain/Body Imaging Conference : Berlin, July 12th to July 14th 2018

The 3rd International Mobile Brain/Body Imaging (MoBI) conference in Berlin 2018 brought together researchers from various disciplines interested in understanding the human brain in its natural environment and during active behavior. MoBI is a new imaging modality, employing mobile brain imaging methods like the electroencephalogram (EEG) or near infrared spectroscopy (NIRS) synchronized to motion capture and other data streams to investigate brain activity while participants actively move in and interact with their environment. Mobile Brain / Body Imaging allows to investigate brain dynamics accompanying more natural cognitive and affective processes as it allows the human to interact with the environment without restriction regarding physical movement. Overcoming the movement restrictions of established imaging modalities like functional magnetic resonance tomography (MRI), MoBI can provide new insights into the human brain function in mobile participants. This imaging approach will lead to new insights into the brain functions underlying active behavior and the impact of behavior on brain dynamics and vice versa, it can be used for the development of more robust human-machine interfaces as well as state assessment in mobile humans.DFG, GR2627/10-1, 3rd International MoBI Conference 201

Mental-State Estimation, 1987

Reports on the measurement and evaluation of the physiological and mental state of operators are presented