Neuromuscular Disabilities Research Articles

Moving an object using EEG: an art of BCI

Brain-Computer Interface (BCI) provides a communication channel that allows individuals with neuromuscular disabilities to communicate with the environment. In this paper a simple model of an object movement is developed. The movement of the object is controlled by using the P300 signals generated in response to visual stimuli. The effectiveness of this model is examined online.

Sistema de Teleoperación Multi-Robot Basado en Interfaz Cerebro-Computador

This paper reports multi-robot teleoperation system based on a brain-computer interface, which allows the user to control simultaneously a non-predefined number of robots via internet, only by brain activity. These devices are oriented to people with severe neuromuscular disabilities, providing them telepresence with a interaction mode based on their thoughts. This work is an extension of a teleoperation system which has been improved to support the teleoperation of N robots, and that uses small and portable robots (of two orders of dimension below the original). The brain-computer interface is based on EEG with a P300-based protocol of control, and the robots are able to navigate, interact by sending alarms, and visually perceive the environments. The system has been validated with two healthy users and the main result is that all of them were able to successfully solve the proposed tasks with no failures, which demonstrates the validity and high robustness of the prototype.

Sistema de Teleoperación Multi-Robot basado en Interfaz Cerebro-Computador

This paper reports multi-robot teleoperation system based on a brain-computer interface, which allows the user to control simultaneously a non-predefined number of robots via internet, only by brain activity. These devices are oriented to people with severe neuromuscular disabilities, providing them telepresence with a interaction mode based on their thoughts. This work is an extension of a teleoperation system which has been improved to support the teleoperation of N robots, and that uses small and portable robots (of two orders of dimension below the original). The brain-computer interface is based on EEG with a P300-based protocol of control, and the robots are able to navigate, interact by sending alarms, and visually perceive the environments. The system has been validated with two healthy users and the main result is that all of them were able to successfully solve the proposed tasks with no failures, which demonstrates the validity and high robustness of the prototype.

Rapid Communication with a "P300" Matrix Speller Using Electrocorticographic Signals (ECoG).

A brain–computer interface (BCI) can provide a non-muscular communication channel to severely disabled people. One particular realization of a BCI is the P300 matrix speller that was originally described by Farwell and Donchin (1988). This speller uses event-related potentials (ERPs) that include the P300 ERP. All previous online studies of the P300 matrix speller used scalp-recorded electroencephalography (EEG) and were limited in their communication performance to only a few characters per minute. In our study, we investigated the feasibility of using electrocorticographic (ECoG) signals for online operation of the matrix speller, and determined associated spelling rates. We used the matrix speller that is implemented in the BCI2000 system. This speller used ECoG signals that were recorded from frontal, parietal, and occipital areas in one subject. This subject spelled a total of 444 characters in online experiments. The results showed that the subject sustained a rate of 17 characters/min (i.e., 69 bits/min), and achieved a peak rate of 22 characters/min (i.e., 113 bits/min). Detailed analysis of the results suggests that ERPs over visual areas (i.e., visual evoked potentials) contribute significantly to the performance of the matrix speller BCI system. Our results also point to potential reasons for the apparent advantages in spelling performance of ECoG compared to EEG. Thus, with additional verification in more subjects, these results may further extend the communication options for people with serious neuromuscular disabilities.

A P300-Based Brain–Computer Interface: Effects of Interface Type and Screen Size

As a nonmuscular communication and control system for people with severe motor disabilities, brain–computer interface (BCI) has found several applications. Although a few empirical studies of BCI user performance do exist, little to no research has specifically evaluated the impact of contributing factors on user performance in the BCI applications. To that end, our within-subjects design compared the impact of two different types of interface (ABC interface vs. frequency-based interface) and three levels of screen size (computer monitor, global positioning system, and cell phone screen) of a P300-based BCI application, P300 Speller, on user performance (accuracy, information transfer rate, amplitude, and latency) and usage preference. Ten participants with neuromuscular disabilities such as amyotrophic lateral sclerosis and cerebral palsy and 10 nondisabled participants were asked to type six, 10-character phrases in the P300 Speller. The overall accuracy was 79.7% for the nondisabled participants and 28.7% for participants with motor disabilities. The results showed that interface type and screen size have significant effects on user performance and usage preference, with varying degree of impact to participants with and without motor disabilities. Specifically, participants typed significantly more accurately in frequency-based interface and computer monitor screen. The results of this study should provide invaluable insights to the future research of P300-based BCI applications.

Does the ‘P300’ speller depend on eye gaze?

Many people affected by debilitating neuromuscular disorders such as amyotrophic lateral sclerosis, brainstem stroke or spinal cord injury are impaired in their ability to, or are even unable to, communicate. A brain–computer interface (BCI) uses brain signals, rather than muscles, to re-establish communication with the outside world. One particular BCI approach is the so-called ‘P300 matrix speller’ that was first described by Farwell and Donchin (1988 Electroencephalogr. Clin. Neurophysiol. 70 510–23). It has been widely assumed that this method does not depend on the ability to focus on the desired character, because it was thought that it relies primarily on the P300-evoked potential and minimally, if at all, on other EEG features such as the visual-evoked potential (VEP). This issue is highly relevant for the clinical application of this BCI method, because eye movements may be impaired or lost in the relevant user population. This study investigated the extent to which the performance in a ‘P300’ speller BCI depends on eye gaze. We evaluated the performance of 17 healthy subjects using a ‘P300’ matrix speller under two conditions. Under one condition (‘letter’), the subjects focused their eye gaze on the intended letter, while under the second condition (‘center’), the subjects focused their eye gaze on a fixation cross that was located in the center of the matrix. The results show that the performance of the ‘P300’ matrix speller in normal subjects depends in considerable measure on gaze direction. They thereby disprove a widespread assumption in BCI research, and suggest that this BCI might function more effectively for people who retain some eye-movement control. The applicability of these findings to people with severe neuromuscular disabilities (particularly in eye-movements) remains to be determined.

Evaluation of P300-Based Brain-Computer Interface in Real-World Contexts

Despite recent advances in brain-computer interface (BCI) development, system usability still remains a large oversight. The goal of this study was to investigate the usability of a P300-based BCI system, P300 Speller, by assessing how background noise and interface color contrast affect user performance and BCI usage preference. Fifteen able-bodied participants underwent a 2 (low and high interface color contrast) × 3 (low, medium, and high background noise level) within-subjects design experiment, in which participants were asked to type six 10-character phrases in the P300 Speller paradigm. The overall accuracy in the study was 80.2%. Participants showed higher accuracy, higher information transfer rate, bigger amplitude, and smaller latency in the high interface color contrast condition than in the low contrast condition. Participants had better performance in the noisy condition than in the quiet condition, but the background noise effects were not statistically significant in the present study. These results should give some insight to the real-world applicability of the current P300 Speller as a nonmuscular communication system, especially for individuals with severe neuromuscular disabilities.

Antioxidant dysfunction: potential risk for neurotoxicity in ethylmalonic aciduria

Mitochondrial dysfunction and oxidative stress are central to the molecular basis of several human diseases associated with neuromuscular disabilities. We hypothesize that mitochondrial dysfunction also contributes to the neuromuscular symptoms observed in patients with ethylmalonic aciduria and homozygosity for ACADS c.625G>A-a common variant of the short-chain acyl-coenzyme A (CoA) dehydrogenase (SCAD) enzyme in the mitochondrial fatty acid oxidation pathway. This study sought to identify the specific factors that initiate cell dysfunction in these patients. We investigated fibroblast cultures from 10 patients with neuromuscular disabilities, elevated levels of ethylmalonic acid (EMA) (>50 mmol/mol creatinine), and ACADS c.625G>A homozygosity. Functional analyses, i.e., ACADS gene and protein expression as well as SCAD enzyme activity measurements, were performed together with a global nano liquid chromatography tandem mass spectroscopy (nano-LC-MS/MS)-based screening of the mitochondrial proteome in patient fibroblasts. Moreover, cell viability of patient fibroblasts exposed to menadione-induced oxidative stress was evaluated. Loss of SCAD function was detected in the patient group, most likely due to decreased ACADS gene expression and/or elimination of misfolded SCAD protein. Analysis of the mitochondrial proteome in patient fibroblasts identified a number of differentially expressed protein candidates, including reduced expression of the antioxidant superoxide dismutase 2 (SOD2). Additionally, patient fibroblasts demonstrated significantly higher sensitivity to oxidative stress than control fibroblasts. We propose that reduced mitochondrial antioxidant capacity is a potential risk factor for ACADS c.625G>A-associated ethylmalonic aciduria and that mitochondrial dysfunction contributes to the neurotoxicity observed in patients.

A novel P300-based brain–computer interface stimulus presentation paradigm: Moving beyond rows and columns

An electroencephalographic brain-computer interface (BCI) can provide a non-muscular means of communication for people with amyotrophic lateral sclerosis (ALS) or other neuromuscular disorders. We present a novel P300-based BCI stimulus presentation - the checkerboard paradigm (CBP). CBP performance is compared to that of the standard row/column paradigm (RCP) introduced by Farwell and Donchin (1988). Using an 8x9 matrix of alphanumeric characters and keyboard commands, 18 participants used the CBP and RCP in counter-balanced fashion. With approximately 9-12 min of calibration data, we used a stepwise linear discriminant analysis for online classification of subsequent data. Mean online accuracy was significantly higher for the CBP, 92%, than for the RCP, 77%. Correcting for extra selections due to errors, mean bit rate was also significantly higher for the CBP, 23 bits/min, than for the RCP, 17 bits/min. Moreover, the two paradigms produced significantly different waveforms. Initial tests with three advanced ALS participants produced similar results. Furthermore, these individuals preferred the CBP to the RCP. These results suggest that the CBP is markedly superior to the RCP in performance and user acceptability. The CBP has the potential to provide a substantially more effective BCI than the RCP. This is especially important for people with severe neuromuscular disabilities.

Medical equipment use in children with disabilities: A descriptive survey

To investigate the use of medical equipment by children with disabilities, the reasons for use, and prescribers of equipment. A convenience sample. Referral clinic for children with developmental conditions. Caregivers of children with motor disabilities completed an interview survey for children 0-21 years. 108 parents/caregivers reported 467 (mean=4.3 per patient) pieces of owned equipment. The mean age of children was 7.1 years (± 5.0), and 49% were female. The most common diagnoses were cerebral palsy (45%), 'Other' diagnoses including intellectual disability (19%), genetic abnormality (13%), spina bifida (13%), and neuromuscular diseases (7%). Survey participants described use of the following types of equipment: orthotics (82%), bath chair (37%), seating device (34%), stander (19%), augmentative communication devices (17%), walker (14%), and gait trainer (10%). Reasons for "non-use" of equipment included: outgrown (19%), not useful (14%), and child refusal (15%). Physicians were the sole prescriber for 15% of families, whereas physical or occupational therapists most commonly recommended new equipment (76%). Based on parental report, children with neuromuscular disabilities use most equipment that is medically recommended. The majority of equipment needs are identified by therapists. Pediatricians can benefit from additional expertise in the provision of medical equipment for children.

TWO CASES OF ACUTE ATRAUMATIC COMPARTMENT SYNDROME COMPLICATED WITH SEVERE HEAT STROKE

Acute compartment syndrome is a life-threatening complication in trauma patients. Not only regional neuromuscular disability, but also systemic organ disorders can result from prolonged tissue ischemia. In this report, we describe 2 cases of acute atraumatic compartment syndrome complicated with severe heat stroke. In both cases, emergency fasciotomy was rapidly performed after recognition of the syndrome, but serious regional neuromuscular disabilities remained. Microvascular endothelial injury is an important mechanism of acute atraumatic compartment syndrome. Thrombi diffusely formed in the compartmental space hinder establishment of reperfusion even after fasciotomy. Furthermore, disruption of fibrinolysis due to heat stroke could enhance this damage.

Music and medicine

The co-existence of medicine and music is hardly new; the interplay between the two disciplines becomes ever closer as performing arts medicine is, increasingly, recognised as a medical specialty with...

Implementation of a brain computer interface to identify neurophysiologic activities

Event Abstract Back to Event Implementation of a brain computer interface to identify neurophysiologic activities Maruthamuthu Saravana1*, R. Srihari1 and V. Senthil1 1 Sri Krishna College of Engineering and Technology , India Brain computer interface (BCI) is a communication system that interprets and analyses electroencephalogram (EEG) to translate brain state into actions. It provides an alternate non-muscular communication and control channel for individuals with neuromuscular disabilities. The various EEG rhythms identify the neurophysiologic behavior of humans. In our project, we have designed two brain computer interfaces to identify neurophysiologic activities of healthy subjects. One BCI is sound card based system and other is a parallel port based system. The EEG signal acquisition hardware is designed using precision low power CMOS Instrumentation amplifier INA326 and zero drift operational amplifiers OPA335 of Texas Instruments. Amplitude modulation is used in sound card based EEG system to couple the acquired EEG signals to sound card of the computer to prevent rejection of low frequency EEG signals. Transformer coupling is used to isolate the acquired EEG signals from computer. In parallel port based BCI system the EEG signal from the acquisition hardware is fed to the ADC input of PIC16F72 microcontroller and is sampled at a rate of 256 Hz .The digitized EEG sequence is optically coupled to the parallel port of computer. The post processing system is developed using LabVIEW 8.0 software. We employ spatial filtering to remove artifacts and modulated carrier. The power spectral density and spectrograph is computed for the acquired EEG signal to analyze its characteristics. Conference: 10th International Conference on Cognitive Neuroscience, Bodrum, Türkiye, 1 Sep - 5 Sep, 2008. Presentation Type: Poster Presentation Topic: Abstracts Citation: Saravana M, Srihari R and Senthil V (2008). Implementation of a brain computer interface to identify neurophysiologic activities. Conference Abstract: 10th International Conference on Cognitive Neuroscience. doi: 10.3389/conf.neuro.09.2009.01.137 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Dec 2008; Published Online: 05 Dec 2008. * Correspondence: Maruthamuthu Saravana, Sri Krishna College of Engineering and Technology, Coimbatore, India, saravanaece@yahoo.co.in Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Maruthamuthu Saravana R. Srihari V. Senthil Google Maruthamuthu Saravana R. Srihari V. Senthil Google Scholar Maruthamuthu Saravana R. Srihari V. Senthil PubMed Maruthamuthu Saravana R. Srihari V. Senthil Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Sensory-motor enhancement in a virtual therapeutic environment

The sensory-motor skills of persons with neuromuscular disabilities have been shown to be enhanced by intensive and repetitive therapeutic interventions. This paper describes a form of low immersion virtual reality and a prototype, open source system that allow a user with significant physical disability to actively interact with computer-generated objects whose behaviors promote a game-like interaction. Unlike fully immersive and haptic virtual reality, this approach frees the user from head-mounted displays and gloves. It extracts the user’s real-time silhouette from the output of a remote video camera and uses that two-dimensional outline to interact with graphical objects on screen. In contrast to video games that have been modified with specialized interfaces, this virtual interaction system promotes the repetitive use of goal directed movements of the arms and body, which are essential to promote cortical reorganization, as well as discourage unwanted changes in muscle tissue that result in contracture. A prototype system demonstrates the potential of low immersion technology to motivate users and encourage participation in therapy. It also offers the potential of accommodating the sensory-motor skills of individuals with very significant impairment. The behaviors of the computer-generated graphics can be altered to allow use by those with very limited range of motion and/or motor control. These behaviors can be adjusted to provide a continuing challenge as the user’s skills improve. This prototype is described in terms of functional capabilities that include a silhouette extraction from a video image, and generation of graphical objects that interact with the silhouette. The work is extended with a discussion of a more sophisticated region of interest detection algorithm that can select specific parts of the body.

A $\mu $-Rhythm Matched Filter for Continuous Control of a Brain-Computer Interface

A brain-computer interface (BCI) is a system that provides an alternate nonmuscular communication/control channel for individuals with severe neuromuscular disabilities. With proper training, individuals can learn to modulate the amplitude of specific electroencephalographic (EEG) components (e.g., the 8-12 Hz mu rhythm and 18-26 Hz beta rhythm) over the sensorimotor cortex and use them to control a cursor on a computer screen. Conventional spectral techniques for monitoring the continuous amplitude fluctuations fail to capture essential amplitude/phase relationships of the mu and beta rhythms in a compact fashion and, therefore, are suboptimal. By extracting the characteristic mu rhythm for a user, the exact morphology can be characterized and exploited as a matched filter. A simple, parameterized model for the characteristic mu rhythm is proposed and its effectiveness as a matched filter is examined online for a one-dimensional cursor control task. The results suggest that amplitude/phase coupling exists between the mu and beta bands during event-related desynchronization, and that an appropriate matched filter can provide improved performance.

Family Caregivers of Women with Physical Disabilities.

Cross-sectional, correlational analyses of data from two separate studies were conducted to examine the correlates of adjustment among family caregivers of women with disabilities. Participants included 40 caregivers of women with spinal cord injuries in the first study and 53 caregivers of women with cerebral palsy, traumatic brain injury, and other neuromuscular disabilities in the second study. It was hypothesized that a negative problem-solving style would be associated with greater caregiver distress in both studies, and that caregiver adjustment would be associated with care recipient depression in the second study. As expected, results indicated that a higher negative orientation toward solving problems was associated with caregiver depression and lower well-being. However, in the second study, caregiver characteristics were not associated with care recipient depression. These data indicate that considerable variability exists in caregiver adjustment. Methodological limitations and the implications for research, service, and policy formation are! discussed.

Passive exoskeletons for assisting limb movement

This article presents the state of the art in passive devices for enhancing limb movement in people with neuromuscular disabilities. Both upper- and lower-limb projects and devices are described. Special emphasis is placed on a passive functional upper-limb orthosis called the Wilmington Robotic Exoskeleton (WREX). The development and testing of the WREX with children with limited arm strength are described. The exoskeleton has two links and 4 degrees of freedom. It uses linear elastic elements that balance the effects of gravity in three dimensions. The experiences of five children with arthrogryposis who used the WREX are described.

Relevance of the Pediatric Powered Wheelchair Screening Test for children with cerebral palsy

In a previous study we developed a cognitive assessment battery called the Pediatric Powered Wheelchair Screening Test (PPWST) to help clinicians determine a young child's readiness to drive a powered wheelchair. The current multicenter study sought to determine: (1) whether the PPWST is appropriate for use in a population of children with cerebral palsy (CP) who use joysticks to drive their wheelchair; (2) whether two additional factors (symbolic representation and coping) would increase the predictive power of the PPWST for this group and for children with orthopedic or neuromuscular disabilities only; and (3) whether the test was appropriate for children with severe motor impairments who use switches to control their wheelchair. Fifty children (27 males, 23 females) between the ages of 21 months and 6 years 11 months participated. Twenty‐six children (mean age 4 years 4 months, SD 15 months) had triplegic or tetraplegic CP and 24 children (mean age 27 months, SD 5 months) had orthopedic or neuromuscular disabilities. Sixty‐nine per cent of children had some limited form of mobility (such as rolling or scooting) but none was a functional ambulator. Each child was assessed with the PPWST and with measures of symbolic representation and coping. After six wheelchair training sessions, driving ability was scored. The PPWST was found to be predictive of functional driving ability for children with CP who used a joystick to control their wheelchair. Assessment of symbolic representation skills increased the predictive power for this group but not for children with orthopedic or neuromuscular disabilities; coping scores did not increase the predictive power for either group. The PPWST accounted for only 20% of the variance in overall driving skills for switch users, and thus is not yet considered an adequate screening device for this group. The PPWST is designed to help clinicians determine whether a child currently has the specific cognitive skills found to be related to powered wheelchair driving but is not intended to be used exclusively to determine whether or not a child is ultimately a candidate for powered mobility.

Relevance of the Pediatric Powered Wheelchair Screening Test for children with cerebral palsy.

In a previous study we developed a cognitive assessment battery called the Pediatric Powered Wheelchair Screening Test (PPWST) to help clinicians determine a young child's readiness to drive a powered wheelchair. The current multicenter study sought to determine: (1) whether the PPWST is appropriate for use in a population of children with cerebral palsy (CP) who use joysticks to drive their wheelchair; (2) whether two additional factors (symbolic representation and coping) would increase the predictive power of the PPWST for this group and for children with orthopedic or neuromuscular disabilities only; and (3) whether the test was appropriate for children with severe motor impairments who use switches to control their wheelchair. Fifty children (27 males, 23 females) between the ages of 21 months and 6 years 11 months participated. Twenty-six children (mean age 4 years 4 months, SD 15 months) had triplegic or tetraplegic CP and 24 children (mean age 27 months, SD 5 months) had orthopedic or neuromuscular disabilities. Sixty-nine per cent of children had some limited form of mobility (such as rolling or scooting) but none was a functional ambulator. Each child was assessed with the PPWST and with measures of symbolic representation and coping. After six wheelchair training sessions, driving ability was scored. The PPWST was found to be predictive of functional driving ability for children with CP who used a joystick to control their wheelchair. Assessment of symbolic representation skills increased the predictive power for this group but not for children with orthopedic or neuromuscular disabilities; coping scores did not increase the predictive power for either group. The PPWST accounted for only 20% of the variance in overall driving skills for switch users, and thus is not yet considered an adequate screening device for this group. The PPWST is designed to help clinicians determine whether a child currently has the specific cognitive skills found to be related to powered wheelchair driving but is not intended to be used exclusively to determine whether or not a child is ultimately a candidate for powered mobility.

Further insights into post-exercise effects on H-reflexes and motor evoked potentials of the flexor carpi radialis muscles.

The present study investigated the relative contribution of the cortical and spinal mechanisms for post-exercise excitability changes in human motoneurons. Seven healthy right-handed adults with no known neuromuscular disabilities performed an isometric voluntary wrist flexion at submaximum continuous exertion. After the subjects continued muscle contraction until volitional fatigue, the H-reflexes induced by an electric stimulation and motor evoked potentials (MEPs) induced by a transcranial magnetic stimulation (TMS) from a flexor carpi radialis (FCR) muscle were recorded 7 times every 20 s. The H-reflex was used to assess excitability changes at the spinal level, and the MEP was used to study excitability changes at the cortical level. Hreflexes showed a depression (30% of control value) soon after the cessation of wrist flexion and recovered with time thereafter. On the other hand, an early (short latency) MEP showed facilitation immediately after the cessation of wrist flexion (50% of control value) and thereafter decreased. A possible mechanism for the contradictory results of the 2 tests, in spite of focusing on the same motoneuron pool, might be the different test potential sizes between them. In addition, a late (long latency) MEP response appeared with increasing exercise. With regard to the occurrence of late MEP response, a central mechanism may be proposed to explain the origin-that is, neural pathways with a high threshold that do not participate under normal circumstances might respond to an emergency level of muscle exercise, probably reflecting central effects of fatigue.