EEG windowed statistical wavelet scoring for evaluation and discrimination of muscular artifacts

EEG recordings are usually corrupted by spurious extra-cerebral artifacts, which should be rejected or cleaned up by the practitioner. Since manual screening of human EEGs is inherently error prone and might induce experimental bias, automatic artifact detection is an issue of importance. Automatic artifact detection is the best guarantee for objective and clean results. We present a new approach, based on the time–frequency shape of muscular artifacts, to achieve reliable and automatic scoring. The impact of muscular activity on the signal can be evaluated using this methodology by placing emphasis on the analysis of EEG activity. The method is used to discriminate evoked potentials from several types of recorded muscular artifacts—with a sensitivity of 98.8% and a specificity of 92.2%. Automatic cleaning ofEEGdata are then successfully realized using this method, combined with independent component analysis. The outcome of the automatic cleaning is then compared with the Slepian multitaper spectrum based technique introduced by Delorme et al (2007 Neuroimage 34 1443–9)

Computational Intelligence in Electromyography Analysis

Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG may be used clinically for the diagnosis of neuromuscular problems and for assessing biomechanical and motor control deficits and other functional disorders. Furthermore, it can be used as a control signal for interfacing with orthotic and/or prosthetic devices or other rehabilitation assists. This book presents an updated overview of signal processing applications and recent developments in EMG from a number of diverse aspects and various applications in clinical and experimental research. It will provide readers with a detailed introduction to EMG signal processing techniques and applications, while presenting several new results and explanation of existing algorithms. This book is organized into 18 chapters, covering the current theoretical and practical approaches of EMG research

Assessment of spasticity:from EMG to patients' perception

Spasticity is a common phenomenon which often develops after an upper motor neuro lesion, such as stroke, multiple sclerosis or spinal cord injury. The clinical picture after an UMN lesion depends primarily upon its location and extent, and the time since it occurred, rather than on the pathogenesis of the lesion. Spasticity is part of the positive phenomena, characterized by an exaggerated motor response, elicited for instance during physical examination. The interval between an acute lesion and the appearance of spasticity varies from days to months

Optimising the Application of Transcranial Direct Current Stimulation

The ability of transcranial direct current stimulation (tDCS) to modulate brain activity has vast scientific and therapeutic potential, however, its effects are often variable which limit its utility. Both current flow direction and variance in electric field intensities reaching a cortical target may be vital sources of the variable tDCS effects on neuroplastic change. Controlling for these and exploring the subsequent effects on corticospinal excitability is the aim of this thesis. I here attempted to optimise the delivery of tDCS application by investigating the controlled application of current flow direction and whether through the use of current flow models, we can deliver comparable electric fields with reduced variability across differential montages. To assess whether current flow models are useful, I further investigated if dose-control translates to more consistent physiological outcomes. I demonstrate, firstly, that different current flow directions did not differentially affect the two banks of the central sulcus. Secondly, with the use of dose-control, high-definition tDCS (HD-tDCS) remains focally more advantageous, even with the delivery of comparable electric field intensity and variability as posterior-anterior tDCS (PA-tDCS) to a cortical region. Thirdly, dose-controlled tDCS does not translate to reduced physiological variability. Together, the work presented here suggests that current flow models are useful for informing dose-controlled protocols and montage comparisons for improved tDCS delivery, however, controlling for anatomical differences in the delivery of electric fields to a target is not sufficient to reduce the variability of tDCS effects in physiology. Thus, the methodology for optimised tDCS delivery remains a subject for further improvement and investigation. Advancements in this field may lead to a trusted methodology assisting stroke survivors with a more effective and efficient motor recovery journey

EMG-to-Speech: Direct Generation of Speech from Facial Electromyographic Signals

The general objective of this work is the design, implementation, improvement and evaluation of a system that uses surface electromyographic (EMG) signals and directly synthesizes an audible speech output: EMG-to-speech

STUDY Of Electromyographic Patterns Of erector Spinae And Lower-limb Muscles during Different Modalities Of Gait In post-stroke Individuals

Stroke is one of the leading causes of motor disability in the world. New technologies have been developed to increase efficiency and reduce costs of rehabilitation of poststroke individuals. Objective: To compare electromyographic patterns related to muscle onset/offset, duration of activation and analysis of neuromuscular fatigue of erector spinae (ES) and lower-limb muscles during different modalities of gait in poststroke and healthy individuals. Methodology: The changes in the median frequency (MDF) was analyzed during isometric tasks and walking on a treadmill in healthy individuals (N = 10) to identify fatigue. Ten post-stroke and 30 healthy subjects participated of the second stage of the study, in which ES and three lower-limb muscles were analyzed during different gaits (walking on treadmill and ground, with and without arm swing, and using a walker), with the neuromuscular fatigue analyzed in stroke gait. Muscle analysis was also conducted with two post-stroke subjects while using the UFESs robotic walker. Results: For the healthy subjects, all the lower-limb muscles showed reduction in their MDF during walking on treadmill. Walking on treadmill had a stronger influence on the onset/offset muscles than the arm swing in the healthy individuals. For post-stroke subjects, their ES muscles presented a similar pattern to the healthy subjects, but the contralateral side had longer activation near the toe-off than the ipsilateral side in both gaits. All the observed changes in the activation for each phase indicated a longer duration of activation of the post-stroke subjects. Regarding neuromuscular fatigue, it was not possible to detect reduced MDF values for post-stroke individuals. The use of the UFESs robotic walker improved the symmetry of one post-stroke subject, and the symmetry of duration of activation in the swing phase for all muscles of the other subject. Conclusion: MDF changes were detected in non-strenuous exercises in healthy subjects. ES muscle activation is not influenced by arm swing in healthy individuals, with the same behavior in post-stroke individuals. As a finding of this research, we concluded that trunk muscles can be used in rehabilitation processes and also to control robotic devices for assistance or rehabilitation

Quantification of abnormal muscle tone following spinal cord injury: A clinical perspective

Abnormal muscle tone is a frequent complication following traumatic spinal cord injury with subsequent upper motor neurone paralysis. Treatment of this complex problem presents many difficulties for the clinician and appropriate assessment is a vital pre-requisite when devising a pertinent treatment regimen. The purpose of this study was to examine a variety of measures and to create a comprehensive assessment programme to quantify abnormal muscle tone in this patient group which was compatible with use in the clinical environment. The study examined the reliability of the five measurement techniques: therapist rating, patient rating, electrogoniometry and dynamometry augmented by polyelectromyography, prior to implementing the combined assessment programme in a group of spinal cord injured and neurologically intact subjects. The relationships between the findings of each assessment were examined and the suitability of the combined assessment programme was considered for routine use in the clinical environment. All the measures examined in the study proved to be reliable, able to differentiate between the spinal cord injured and neurologically intact subjects and practical for implementation within the clinical environment. The lack of correlation between the findings of the singular components of the assessment programme supports the hypothesis that it is necessary to include all the measures investigated if the clinician wishes to undertake a comprehensive evaluation of the individual person presenting with abnormal muscle tone following spinal cord injury