Posts Tagged Electrodes

[Abstract] Digital mirror box: An interactive hand-motor BMI rehabilitation tool for stroke patients

Abstract:

We develop a brain-machine interface for the hand-motor rehabilitation of stroke patients. The interface provides both visual and proprioceptive feedback to the user based upon the successful generation of cortical motor commands. We discuss the details of the proposed system and provide a summary of the preliminary experiment. The experiment investigates the importance of simultaneous visual and proprioceptive feedback to the delivery of motor commands from the affected motor cortex of the patients. We also discuss a case study involving a chronic stroke patient who trained with the system for 14 days to recover functional movement in the hand. The results obtained by this study suggest that the developed system is effective at accelerating the recovery of motor function in stroke patients with hand paralysis.

Date of Conference: 13-16 Dec. 2016

Date Added to IEEE Xplore: 19 January 2017

ISBN Information:

Electronic ISBN: 978-9-8814-7682-1

Print on Demand(PoD) ISBN: 978-1-5090-2401-8

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Publisher: IEEE

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Source: Digital mirror box: An interactive hand-motor BMI rehabilitation tool for stroke patients – IEEE Xplore Document

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[Abstract] Design and Test of a Closed-Loop FES System for Supporting Function of the Hemiparetic Hand Based on Automatic Detection using the Microsoft Kinect sensor

Abstract:

This paper describes the design of a FES system automatically controlled in a closed loop using a Microsoft Kinect sensor, for assisting both cylindrical grasping and hand opening. The feasibility of the system was evaluated in real-time in stroke patients with hand function deficits. A hand function exercise was designed in which the subjects performed an arm and hand exercise in sitting position. The subject had to grasp one of two differently sized cylindrical objects and move it forward or backwards in the sagittal plane. This exercise was performed with each cylinder with and without FES support. Results showed that the stroke patients were able to perform up to 29% more successful grasps when they were assisted by FES. Moreover, the hand grasp-and-hold and hold-and-release durations were shorter for the smaller of the two cylinders. FES was appropriately timed in more than 95% of all trials indicating successful closed loop FES control. Future studies should incorporate options for assisting forward reaching in order to target a larger group of stroke patients.

Source: Design and Test of a Closed-Loop FES System for Supporting Function of the Hemiparetic Hand Based on Automatic Detection using the Microsoft Kinect sensor – IEEE Xplore Document

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[Abstract] Fatigue detection and estimation using auto-regression analysis in EEG

Abstract:

Estimation of fatigue is a required criteria in the field of physiology. The estimation of muscle fatigue and its development in the brain signals can provide a level of endurance among athletes and limits of a persons in doing physical tasks. In this paper a technique for detecting and estimating the fatigue development using regression parameters for EEG signals is discussed. The study of 14 subjects was undertaken and analysed for the fatigue development using Auto-Regression(AR) model. The behaviour of the error function obtained is analysed for the prediction of the stages and limits of muscle fatigue development.

I. Introduction

Muscle fatigue is a phenomenon associated with the muscle contraction. It is understood as the reduction in the ability of maximal force generation by the muscle with time, during its stressing, as the muscle contraction keeps on increasing. The nervous system’s limitation to generate sustainable signals and the reduction of ability of muscle fiber to contract are two major factors contributing to fatigue development [1]. Fatigue development limits the performance and capability of the individual in sports, long stretch driving conditions and in rigourous day to day activities. Hence a parameter that can estimate the fatigue levels and provide a break point for maximum fatigue can be useful for physiology and in other areas such as labour. People working under mines can be monitored for the fatigue break point and the overall productivity of such areas can be increased by proper analysis. The fatigue development in a person can be analysed via number of methods based on physiological changes. These include Electroencephalogram (EEG), Elec-tromyography(EMG), and Heart Rate Variability(HRV). Zadry et.al. [2] reported the increase in alpha band power level of EEG with time for fatigue development [3]. Ali et.al. also reported increase in RMS values of different bands in EEG [4]. Few studies measure brain activity in light repetitive task using EEG [5] to measure drowsiness or fatigue on drivers [6] [7] and night work [8] [9]. The EEG analysis for overall fatigue has been the focus of research, but research for specific muscle fatigue detection has been limited. The EEG based detection of fatigue has the advantage of quantitative based assessment. But, for real time application perspective faster computational power and signal processing methods are required. One of the challenges based on EEG based approach is the disturbances and contamination of the signal from eyes blinking action, muscle noise by movements and instrumental noises like line noise, electronic interferences [10]. Another problem is imposed by the inter-variability and intra-variability in EEG dynamics accompanying loss of alertness [11].

Source: Fatigue detection and estimation using auto-regression analysis in EEG – IEEE Xplore Document

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[Abstract] Technical validation of an integrated robotic hand rehabilitation device: Finger independent movement, EMG control, and EEG-based biofeedback

Abstract:

The objective of this work was to design and experiment a robotic hand rehabilitation device integrated with a wireless EEG system, going towards patient active participation maximization during the exercise. This has been done through i) hand movement actively triggered by patients muscular activity as revealed by electromyographic signals (i.e., a target hand movement for the rehabilitation session is defined, the patient is required to start the movement and only when the muscular activity overcomes a predefined threshold, the patient-initiated movement is supported); ii) an EEG-based biofeedback implemented to make the user aware of his/her level of engagement (i.e., brain rhythms power ratio Beta/Alpha). The designed system is composed by the Gloreha hand rehabilitation glove, a device for electromyographic signals recording, and a wireless EEG headset. A strong multidisciplinary approach was the base to reach this goal, which is the fruitful background of the Think and Go project. Within this project, research institutes (Politecnico di Milano), clinical centers (INRCA-IRCCS), and companies (ab medica s.p.a., Idrogent, SXT) have worked together throughout the development of the integrated robotic hand rehabilitation device. The integrated device has been tested on a small pilot group of healthy volunteers. All the users were able to calibrate and correctly use the system, and they reported that the system was more challenging to be used with respect to the standard passive hand mobilization session, and required more attention and involvement. The results obtained during the preliminary tests are encouraging, and demonstrate the feasibility of the proposed approach.

Source: Technical validation of an integrated robotic hand rehabilitation device: Finger independent movement, EMG control, and EEG-based biofeedback – IEEE Xplore Document

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[VIDEO] Where to place electrodes – dorsiflexion with eversion – YouTube

Δημοσιεύτηκε στις 7 Νοε 2016

These following videos show electrode positions to produce:
1. Dorsiflexion with eversion
2. Dorsiflexion with less eversion
3. Balance of 1 and 2
4. Dorsiflexion with least eversion
For more information, see our website:
http://www.odstockmedical.com/knowled…

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[Abstract] Impairment of muscle force transmission in spastic-paretic muscles of stroke survivors

Abstract:

Hemispheric stroke survivors tend to have persistent motor impairments, with muscle weakness and muscle spasticity observed concurrently in the affected muscles.
The objective of this preliminary study was to identify whether impairment of muscle force transmission could contribute to weakness in spastic-paretic muscles of chronic stroke survivors. To characterize the efficiency of the transmission of muscle forces to the tendon, we activated biceps brachii muscle electrically by stimulating the musculocutaneous nerve with maximum current. The ratio between the elicited maximum twitch force amplitude and the maximum M-wave peak-peak amplitude was calculated as a measure of the efficiency of force transmission.
Based on the preliminary results of two stroke survivors, we show that the Force/M-wave ratio was reduced in the affected biceps brachii muscles in comparison with the contralateral muscles, indicating a potential impairment in the muscle force transmission in the affected muscles.
Our findings suggest that disrupted muscle force transmission to the tendon could contribute to weakness in spastic muscles of chronic stroke survivors.

Source: IEEE Xplore Document – Impairment of muscle force transmission in spastic-paretic muscles of stroke survivors

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[WEB PAGE] Axelgaard Education Chapter 1: Electrode Placement and Functional Movement

We are pleased to sponsor the Electrode Placement and Functional Movement™ series presented by Dr. Lucinda Baker, Associate Professor at USC Division of Biokinesiology and Physical Therapy.

These videos provide comprehensive information on the preparation and use of electrodes for effective neurostimulation treatment. All electrodes used in the video presentation are PALS® neurostimulation electrodes.

We trust these videos will assist your efforts in providing the most effective treatment to your patients.

Chapters

DVD copies available for purchase.

Source: Axelgaard Education Chapter 1: Electrode Placement and Functional Movement

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[ARTICLE] Electrical Stimulation of the Brain and the development of Cortical Visual Prostheses: An Historical Perspective – Full Text HTML/PDF

Highlights

  • We revisit the discovery of visual cortex and of the brain’s electrical excitability.
  • We detail early experiences with electrical stimulation of visual cortex.
  • Subsequent attempts to develop a cortical visual prosthesis are explored.
  • We detail the development of technologies critical to current prosthesis designs.

Abstract

Rapid advances are occurring in neural engineering, bionics and the brain-computer interface. These milestones have been underpinned by staggering advances in micro-electronics, computing, and wireless technology in the last three decades. Several cortically-based visual prosthetic devices are currently being developed, but pioneering advances with early implants were achieved by Brindley followed by Dobelle in the 1960s and 1970s. We have reviewed these discoveries within the historical context of the medical uses of electricity including attempts to cure blindness, the discovery of the visual cortex, and opportunities for cortex stimulation experiments during neurosurgery. Further advances were made possible with improvements in electrode design, greater understanding of cortical electrophysiology and miniaturization of electronic components. Human trials of a new generation of prototype cortical visual prostheses for the blind are imminent.

Introduction

Advances in medicine, surgery and electronics have set the stage for a fusion of the physical and biological sciences; one in which prosthetic devices may restore lost functional capacity to the disabled. The emerging field of neuro-prosthetics embodies the totality of this integration, whereby sensory (Carlson et al., 2012, Guenther et al., 2012 and Weiland and Humayun, 2014), motor (Hochberg et al., 2012) and even cognitive (Hampson et al., 2012 and Hampson et al., 2013) deficits may be addressed. A significant share of the worldwide research effort in this regard is directed towards the development of visual prosthetics for the blind. Potential stimulation targets currently being investigated for visual prostheses include the retina (Chow et al., 2004, Dorn et al., 2013, Gerding et al., 2007 and Stingl et al., 2013), optic nerve (Brelen et al., 2010, Sakaguchi et al., 2009 and Wu et al., 2010), lateral geniculate body (Panetsos et al., 2011 and Pezaris and Eskandar, 2009) and the cerebral cortex (Brindley and Lewin, 1968b, Dobelle, 2000 and Schmidt et al., 1996). Human testing of implanted cortical electrode arrays for the evocation of visual percepts predates similar attempts at the retinal level by almost 30 years (Brindley and Lewin, 1968b, Humayun et al., 1996 and Humayun et al., 1999). Moreover, visual cortical prostheses offering limited functionality were chronically implanted in a number of patients throughout the 1970’s (Brindley, 1982, Dobelle et al., 1976 and Dobelle et al., 1979). Two retinal devices recently obtained regulatory approval in Europe (Argus II and Alpha IMS), with the Argus II also having obtained regulatory approval in the US (Weiland and Humayun, 2014). Cortical devices remain experimental only. Imminent human trials of a new generation of improved cortical devices render it timely to review the history of their development, including early electrical stimulation of human cerebral cortex and the first pioneering attempts to restore visual sensation to a profoundly blind person over 50 years ago.

Full Text HTML —> Electrical Stimulation of the Brain and the development of Cortical Visual Prostheses: An Historical Perspective

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