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[NEWS] Brain-controlled, non-invasive muscle stimulation allows chronic paraplegics to walk

Brain-controlled, non-invasive muscle stimulation allows chronic paraplegics to walk again and exhibit partial motor recovery

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IMAGE: THE NON-INVASIVE CLOSED-LOOP NEUROREHABILITATION PROTOCOL: I) EEG: ELECTROENCEPHALOGRAPHY, NON-INVASIVE BRAIN-RECORDING. II) BRAIN-MACHINE INTERFACE: REAL-TIME DECODING OF MOTOR INTENTIONS. III) THE LEFT OR RIGHT LEG MUSCLES ARE STIMULATED TO TRIGGER THE… view more 
CREDIT: WALK AGAIN PROJECT – ASSOCIAÇÃO ALBERTO SANTOS DUMONT PARA APOIO À PESQUISA

In another major clinical breakthrough of the Walk Again Project, a non-profit international consortium aimed at developing new neuro-rehabilitation protocols, technologies and therapies for spinal cord injury, two patients with paraplegia regained the ability to walk with minimal assistance, through the employment of a fully non-invasive brain-machine interface that does not require the use of any invasive spinal cord surgical procedure. The results of this study appeared on the May 1 issue of the journal Scientific Reports.

The two patients with paraplegia (AIS C) used their own brain activity to control the non-invasive delivery of electrical pulses to a total of 16 muscles (eight in each leg), allowing them to produce a more physiological walk than previously reported, requiring only a conventional walker and a body weight support system as assistive devices. Overall, the two patients were able to produce more than 4,500 steps using this new technology, which combines a non-invasive brain-machine interface, based on a 16-channel EEG, to control a multi-channel functional electrical stimulation system (FES), tailored to produce a much smoother gait pattern than the state of the art of this technique.

“What surprised us was that, in addition to allowing these patients to walk with little help, one of them displayed a clear motor improvement by practicing with this new approach. Patients required approximatively 25 sessions to master the training before they were able to walk using this apparatus,” said Solaiman Shokur one of the authors of the study.

The two patients that used this new rehabilitation approach had previously participated in the long-term neurorehabilitation study carried out using the Walk Again Project Neurorehabilitation (WANR) protocol. As reported in a recent publication from the same team (Shokur et al., PLoS One, Nov. 2018), all seven patients who participated in that protocol for a period of 28 months improved their clinical status, from complete paraplegia (AIS A or B, meaning no motor functions below the level of the injury, according to the ASIA classification) to partial paraplegia (AIS C, meaning partial recovery of sensory and motor function below the injury level). This significant neurological recovery included major clinical improvements in sensory discrimination (tactile, nociception, vibration, and pressure), voluntary motor control of abdomen and leg muscles, and important gains in autonomic control, such as bladder, bowel, and sexual functions.

“The last two studies published by the Walk Again Project clearly indicate that partial neurological and functional recovery can be induced in chronic spinal cord injury patients by combining multiple non-invasive technologies that are based around the concept of using a brain-machine interface to control different types of actuators, like virtual avatars, robotic walkers, or muscle stimulating devices, to allow the total involvement of patients in their own rehabilitation routine,” said Miguel Nicolelis, scientific director of the Walk Again Project and one of the authors of the study.

In a recent report by another group, one AIS C and two AIS D patients were able to walk thanks to the employment of an invasive method for spinal cord electrical stimulation, which required a spinal surgical procedure. In contrast, in the present study two AIS C patients – which originally were AIS A (see Supplemental Material below)- and a third AIS B subject, who recently achieved similar results, were able to regain a significant degree of autonomous walking without the need for such invasive treatments. Instead, these patients only received electrical stimulation patterns delivered to the skin surface of their legs, so that a total of eight muscles in each limb could be electrically stimulated in a physiologically accurate sequence. This was done in order to produce a smoother and more natural pattern of locomotion.

“Crucial for this implementation was the development of a closed-loop controller that allowed real-time correction of the patients’ walking pattern, taking into account muscle fatigue and external perturbations, in order to produce a predefined gait trajectory. Another major component of our approach was the use of a wearable haptic display to deliver tactile feedback to the patients´ forearms in order to provide them with a continuous source of proprioceptive feedback related to their walking,” said Solaiman Shokur.

To control the pattern of electrical muscle stimulation in each leg, these patients utilized an EEG-based brain-machine interface. In this setup, patients learned to alternate the generation of “stepping motor imagery” activity in their right and left motor cortices, in order to create alternated movements of their left and right legs.

According to the authors, the patients exhibited not only “less dependency on walking assistance, but also partial neurological recovery, with substantial rates of motor improvement in one of them.” The improvement in motor control in this last AIS C patient was 9 points in the lower extremity motor score (LEMS), which was comparable with that observed using invasive spinal cord stimulation.

Based on the results obtained over the past 5 years, the WAP now intends to combine all its neurorehabilitation tools into a single integrated, non-invasive platform to treat spinal cord injury patients. This platform will allow patients to begin training soon after the injury occurs. It will also allow the employment of a multi-dimensional integrated brain-machine interface capable of simultaneously controlling virtual and robotic actuators (like a lowerlimb exoskeleton), a multi-channel non-invasive electrical muscle stimulation system (like the FES used in the present study), and a novel non-invasive spinal cord stimulation approach. In this final configuration, this WAP platform will incorporate all these technologies together in order to maximize neurological and functional recovery in the shortest possible time, without the need of any invasive procedure.

According to Dr. Nicolelis, “there is no silver bullet to treat spinal cord injuries. More and more, it looks like we need to implement multiple techniques simultaneously to achieve the best neurorehabilitation results. In this context, it is also imperative to consider the occurrence of cortical plasticity as a major component in the planning of our rehabilitation approach.”

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The other authors of this paper are Aurelie Selfslagh, Debora S.F. Campos, Ana R. C. Donati, Sabrina Almeida, Seidi Y. Yamauti, Daniel B. Coelho and Mohamed Bouri. This project was developed through a collaboration between the Neurorehabilitation Laboratory of the Associação Alberto Santos Dumont para Apoio à Pesquisa (AASDAP), the headquarters of the Walk Again Project, the Biomechanics and Motor Control Laboratory at the Federal University of ABC (UFABC), and the Laboratory of Robotic System at the Swiss Institute of Technology of Lausanne (EPFL). It was funded by a grant from the Brazilian Financing Agency for Studies and Projects (FINEP) 01.12.0514.00, Ministry of Science, Technology, Innovation and Communications (MCTIC), to AASDAP.

Supplemental Material:

https://www.youtube.com/watch?v=AZbQeuJiSOI

Supporting Research Studies:

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0206464

https://www.nature.com/articles/s41598-019-43041-9

 

via Brain-controlled, non-invasive muscle stimulation allows chronic paraplegics to walk | EurekAlert! Science News

 

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[Abstract] The Work Disability Functional Assessment Battery (WD-FAB) – Physical Medicine and Rehabilitation Clinics

Abstract

Accuracy in measuring function related to one’s ability to work is central to public confidence in a work disability benefits system. In the United States, national disability programs are challenged to adjudicate millions of work disability claims each year in a timely and accurate manner. The Work Disability Functional Assessment Battery (WD-FAB) was developed to provide work disability agencies and other interested parties a comprehensive and efficient approach to profiling a person’s function related to their ability to work. The WD-FAB is grounded by the International Classification of Functioning, Disability, and Health conceptual framework.

 

via The Work Disability Functional Assessment Battery (WD-FAB) – Physical Medicine and Rehabilitation Clinics

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[REVIEW] Strategies to implement and monitor in-home transcranial electrical stimulation in neurological and psychiatric patient populations: a systematic review – Full Text

Abstract

Background

Transcranial electrical stimulation is a promising technique to facilitate behavioural improvements in neurological and psychiatric populations. Recently there has been interest in remote delivery of stimulation within a participant’s home.

Objective

The purpose of this review is to identify strategies employed to implement and monitor in-home stimulation and identify whether these approaches are associated with protocol adherence, adverse events and patient perspectives.

Methods

MEDLINE, Embase Classic + Embase, Emcare and PsycINFO databases and clinical trial registries were searched to identify studies which reported primary data for any type of transcranial electrical stimulation applied as a home-based treatment.

Results

Nineteen published studies from unique trials and ten on-going trials were included. For published data, internal validity was assessed with the Cochrane risk of bias assessment tool with most studies exhibiting a high level of bias possibly reflecting the preliminary nature of current work. Several different strategies were employed to prepare the participant, deliver and monitor the in-home transcranial electrical stimulation. The use of real time videoconferencing to monitor in-home transcranial electrical stimulation appeared to be associated with higher levels of compliance with the stimulation protocol and greater participant satisfaction. There were no severe adverse events associated with in-home stimulation.

Conclusions

Delivery of transcranial electrical stimulation within a person’s home offers many potential benefits and appears acceptable and safe provided appropriate preparation and monitoring is provided. Future in-home transcranial electrical stimulation studies should use real-time videoconferencing as one of the approaches to facilitate delivery of this potentially beneficial treatment.

Introduction

Transcranial electrical stimulation (tES) is a technique used to modulate cortical function and human behaviour. It involves weak current passing through the scalp via surface electrodes to stimulate the underlying brain. A common type of tES is transcranial direct current stimulation (tDCS). Several studies have demonstrated tDCS is capable of modulating cortical function, depending on the direction of current flow [123]. When the anode is positioned over a cortical region, the current causes depolarisation of the neuronal cells, increasing spontaneous firing rates [4]. Conversely, positioning the cathode over the target cortical region causes hyperpolarisation and a decrease in spontaneous firing rates [4]. This modulation of cortical activity can be observed beyond the period of stimulation and is thought to be mediated by mechanisms which resemble long term potentiation and depression [5]. Along similar lines, transcranial alternating current stimulation (tACS) and transcranial random noise stimulation (tRNS) are also forms of tES. Both tACS and tRNS are thought to interact with ongoing oscillatory cortical rhythms in a frequency dependent manner to influence human behaviour [678].

The ability of tES to selectively modulate cortical activity offers a promising tool to induce behavioural change. Indeed, several studies have demonstrated that tES may be a favourable approach to reduce impairment following stroke [9], improve symptoms of neglect [10], or reduce symptoms of depression [11]. While these results appear promising, there remains debate around technical aspects of stimulation along with individual participant characteristics that may influence the reliability of a stimulation response [1213141516171819202122]. However, current evidence does suggest that effects of stimulation may be cumulative, with greater behavioural improvements observed following repeated stimulation sessions [20]. Furthermore, tES has shown potential as a tool for maintenance stimulation, with potential relapses of depression managed by stimulation which continued over several months [2324]. Therefore, it may be that repeated stimulation sessions will become a hallmark of future clinical and research trials aiming to improve behavioural outcomes. This would require participants to attend frequent treatment sessions applied over a number of days, months or years. Given that many participants who are likely to benefit from stimulation are those with higher levels of motor or cognitive impairment, the requirement to travel regularly for treatment may present a barrier, limiting potential clinical utility or ability to recruit suitable research participants [25]. In addition, regular daily treatments would also hinder those who travel from remote destinations to receive this potentially beneficial neuromodulation. Therefore, there is a requirement to consider approaches to safely and effectively deliver stimulation away from the traditional locations of research departments or clinical facilities.

One benefit of tES over other forms of non-invasive brain stimulation, such as repetitive transcranial magnetic stimulation, is the ability to easily transport the required equipment. This opportunity may allow for stimulation to be delivered in a participant’s home, which could represent the mode of delivery for future clinical applications. However, it may be unreasonable to expect that a participant would be capable of managing delivery of tES alone and would likely require some form of training and/or monitoring [25]. Although tES is considered relatively safe [26], stimulation should be delivered within established guidelines to avoid adverse events [27]. Inappropriate delivery of stimulation could result in neural damage, detrimental behavioural effects, irritation, burns or lesions of the skin [282930313233]. Therefore, in order to deliver stimulation safely to the appropriate cortical region, it is likely that in-home stimulation may require some form of monitoring [25].

It is currently unclear what the best approach is to implement and monitor in-home tES. An early paper proposed several guidelines to perform in home tES [34]. However, these guidelines were not based on evidence from published clinical trials as there were none available at the time of publication. One recent systematic review sought to discuss current work in this area and highlighted the need for further research to investigate safety, technical monitoring and assessment of efficacy [35]. Given the recent, and growing, interest in home-based brain stimulation, we felt it was now pertinent to conduct a review to specifically identify strategies employed to implement and monitor the use of in-home tES in neurological and psychiatric populations. The secondary questions were to report protocol adherence, adverse events and patient perspectives of in-home tES. Understanding optimal treatment fidelity for in-home brain stimulation will be instrumental to achieving higher levels of tES useability and acceptance within a participant’s home.[…]

 

via Strategies to implement and monitor in-home transcranial electrical stimulation in neurological and psychiatric patient populations: a systematic review | Journal of NeuroEngineering and Rehabilitation | Full Text

Fig. 2 Cochrane risk of bias tool was used to assess quality of included studies

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[Abstract] When does spasticity in the upper limb develop after a first stroke? A nationwide observational study on 861 stroke patients

Highlights

  • The post-stroke spasticity of upper limb can cause significant functional impairment.
  • This study for spasticity was a nationwide multicenter study in South Korea.
  • The median time to develop upper limb spasticity after stroke onset was 34 days.
  • The 13% of post-stroke spasticity cases developed after 90 days from onset.

Abstract

This study investigated the time taken for upper extremity spasticity to develop and its regional difference after first-ever stroke onset in a nationwide multicenter study in South Korea. The retrospective observational study included 861 individuals with post-stroke spasticity in the upper limbs. Spasticity in the upper extremity joints was defined as a modified Ashworth Scale score ≥1. The median time to develop upper limb spasticity after stroke onset was 34 days. 12% of post-stroke spasticity cases developed between 2 months and 3 months and 13% developed after 3 months from onset. At the time of diagnosis of spasticity, most patients showed only a slight increase in muscle tone, which was observed most frequently in the elbow, followed by the wrist, and fingers. Younger stroke survivors were more spastic, and the severity of spasticity increased with time. Approximately half of the patients with post-stroke spasticity developed spasticity during the first month. However, post-stroke spasticity can develop more than 3 months after stroke onset. Therefore, it is important to assess spasticity, even in the chronic state.

via When does spasticity in the upper limb develop after a first stroke? A nationwide observational study on 861 stroke patients – Journal of Clinical Neuroscience

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[ARTICLE] Benefits and challenges with gamified multi-media physiotherapy case studies: a mixed method study – Full Text

Abstract

Background

The use of gamification in higher education context has become popular in recent years with one aim of enhancing learning motivation, yet, it is unknown how physiotherapy students perceive gamified education experience. Using gamification together with multi-media patient case studies, this study explored whether and how gamified education motivated physiotherapy students’ learning. It also investigated how other factors such as class design and mechanics affected gamified experience.

Method

Six case studies in the subject Neurological Physiotherapy were transformed from paper-based cases to multi-media cases built by iSpring suite 8.1. Simulated, real or animated clients were used. Gamification mechanics such as leaderboards, scoring and prioritisation were embedded in the case studies. These gamified case studies were used in classes with Year-3 students enrolled in this subject. After taking these classes, 10 students participated in two focus groups and 32 students responded to a survey to share their experiences and perceptions on this pedagogy.

Results

Results showed that students perceived gamified education as motivating since this satisfied their competence and social needs and enhanced their self-efficacy. In addition, authentic patient videos, class activities that allowed conflict resolution and reflection, and the use of leaderboards were enablers in this gamified experience.

Conclusion

Future gamified education in physiotherapy can provide authentic experience through class designs and gamification mechanics to foster learning motivation. A suggested mapping of gamified lessons for physiotherapy education is provided based on the results of this study.

Background

Learning is an inherently human activity that involves many complex active and interactive processes. Motivation appears to be a key driver to both initial and ongoing learning, as well as improved learning outcomes [1234]. Gamification, or the use of game elements in non-game contexts [5], promotes achievement, challenge, goal, competition and collaboration to learning [6], which in turn motivates learners [7]. Gamification is thought to enhance motivation and engagement through three levels of processes: cognitive, psychological/emotional and social [89]. At the cognitive level, learners experience processes such as problem-solving and decision-making [10]. At the psychological/emotional level, learners’ positive emotions (e.g. feeling competent) with certain experiences would wire into their memories to enhance further learning of similar experiences [1112]. At the social level, interactions with other learners facilitate knowledge constructions [13]. Gamified education should be structured to promote these processes.

To promote the aforementioned processes, better conceptualisations of gamification are needed. Gamification mechanics are often classified by reward or process-tracking types; namely leaderboards, badges, points (or scores), feedback and prizes [79]. Some educational gamification systems use one type of mechanics while others use a mix-and-match approach. Pedersen and Poulsen [9] found that feedback and points showed an increase in positive outcomes in terms of learning motivations, while other mechanics warrant further investigations. In addition, it is important to differentiate between game-based learning, gamification and serious game. Game-based learning is the use of games (digital or non-digital) as learning tools [14], while gamification does not necessarily include a game but embed game elements (such as competitions) in learning tasks [5]. The term serious game is sometimes used interchangeably with game-based learning as it applies to any game with a purpose other than pleasure; here learning fits into this rationale [81516]. The focus of this study is on gamification rather than game-based learning and serious game.

Gamification has been applied across different disciplines in higher education, such as computer science, mathematics, language and health education [171819]. Currently, there is a lack of literature describing or studying gamification in physiotherapy education. In a recent systematic review on gamification in health care education by Wang, DeMaria [20], only two out of 48 reviewed studies included physiotherapy students as participants. This paucity warrants investigation in the use of gamification in physiotherapy education given its reported benefits on learning.[…]

 

Continue —>  Benefits and challenges with gamified multi-media physiotherapy case studies: a mixed method study | Archives of Physiotherapy | Full Text

Fig. 1 Title pages of the three gamified virtual patient cases

 

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[Abstract] Cognitive rehabilitation post traumatic brain injury: A systematic review for emerging use of virtual reality technology

Highlights

  • Virtual reality technology improves cognitive function post-traumatic brain injury.
  • Optimal treatment protocol is; 10–12 sessions, 20–40 min in duration with 2–4 sessions per week.
  • There was weak evidence for positive effect of virtual reality on attention.

Abstract

Background

Traumatic brain injury (TBI) can causes numerous cognitive impairments usually in the aspects of problem-solving, executive function, memory, and attention. Several studies has suggested that rehabilitation treatment interventions can be effective in treating cognitive symptoms of brain injury. Virtual reality (VR) technology potential as a useful tool for the assessment and rehabilitation of cognitive processes.

Objectives

The aims of present systematic review are to examine effects of VR training intervention on cognitive function, and to identify effective VR treatment protocol in patients with TBI.

Methods

PubMed, Scopus, PEDro, REHABDATA, EMBASE, web of science, and MEDLINE were searched for studies investigated effect of VR on cognitive functions post TBI. The methodological quality were evaluated using PEDro scale. The results of selected studies were summarized.

Results

Nine studies were included in present study. Four were randomized clinical trials, case studies (n = 3), prospective study (n = 1), and pilot study (n = 1). The scores on the PEDro ranged from 0 to 7 with a mean score of 3. The results showed improvement in various cognitive function aspects such as; memory, executive function, and attention in patients with TBI after VR training.

Conclusion

Using different VR tools with following treatment protocol; 10–12 sessions, 20–40 min in duration with 2–4 sessions per week may improves cognitive function in patients with TBI. There was weak evidence for effects of VR training on attention post TBI.

via Cognitive rehabilitation post traumatic brain injury: A systematic review for emerging use of virtual reality technology – Journal of Clinical Neuroscience

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[ARTICLE] Mechanics and energetics of post-stroke walking aided by a powered ankle exoskeleton with speed-adaptive myoelectric control – Full Text

Abstract

Background

Ankle exoskeletons offer a promising opportunity to offset mechanical deficits after stroke by applying the needed torque at the paretic ankle. Because joint torque is related to gait speed, it is important to consider the user’s gait speed when determining the magnitude of assistive joint torque. We developed and tested a novel exoskeleton controller for delivering propulsive assistance which modulates exoskeleton torque magnitude based on both soleus muscle activity and walking speed. The purpose of this research is to assess the impact of the resulting exoskeleton assistance on post-stroke walking performance across a range of walking speeds.

Methods

Six participants with stroke walked with and without assistance applied to a powered ankle exoskeleton on the paretic limb. Walking speed started at 60% of their comfortable overground speed and was increased each minute (n00, n01, n02, etc.). We measured lower limb joint and limb powers, metabolic cost of transport, paretic and non-paretic limb propulsion, and trailing limb angle.

Results

Exoskeleton assistance increased with walking speed, verifying the speed-adaptive nature of the controller. Both paretic ankle joint power and total limb power increased significantly with exoskeleton assistance at six walking speeds (n00, n01, n02, n03, n04, n05). Despite these joint- and limb-level benefits associated with exoskeleton assistance, no subject averaged metabolic benefits were evident when compared to the unassisted condition. Both paretic trailing limb angle and integrated anterior paretic ground reaction forces were reduced with assistance applied as compared to no assistance at four speeds (n00, n01, n02, n03).

Conclusions

Our results suggest that despite appropriate scaling of ankle assistance by the exoskeleton controller, suboptimal limb posture limited the conversion of exoskeleton assistance into forward propulsion. Future studies could include biofeedback or verbal cues to guide users into limb configurations that encourage the conversion of mechanical power at the ankle to forward propulsion.

Trial registration

N/A.

Background

Walking after a stroke is more metabolically expensive, leading to rapid exhaustion, limited mobility, and reduced physical activity [1]. Hemiparetic walking is slow and asymmetric compared to unimpaired gait. Preferred walking speeds following stroke range between < 0.2 m s− 1 and ~ 0.8 m s− 1 [2] compared to ~ 1.4 m s− 1 in unimpaired adults, and large interlimb asymmetry has been documented in ankle joint power output [34]. The ankle plantarflexors are responsible for up to 50% of the total positive work needed to maintain forward gait [56]; therefore, weakness of the paretic plantarflexors is especially debilitating, and as a result, the paretic ankle is often a specific target of stroke rehabilitation [78910]. In recent years, ankle exoskeletons have emerged as a technology capable of improving ankle power output by applying torque at the ankle joint during walking in clinical populations [78] and healthy controls [11121314]. Myoelectric exoskeletons offer a user-controlled approach to stroke rehabilitation by measuring and adapting to changes in the user’s soleus electromyography (EMG) when generating torque profiles applied at the ankle [15]. For example, a proportional myoelectric ankle exoskeleton was shown to increase the paretic plantarflexion moment for persons post-stroke walking at 75% of their comfortable overground (OVG) speed [8]; despite these improvements, assistance did not reduce the metabolic cost of walking or improve percent paretic propulsion. The authors suggested exoskeleton performance could be limited because the walking speed was restricted to a pace at which exoskeleton assistance was not needed.

Exoskeleton design for improved function following a stroke would benefit from understanding the interaction among exoskeleton assistance, changes in walking speed, and measured walking performance. Increases in walking speed post-stroke are associated with improvements in forward propulsion and propulsion symmetry [16], trailing limb posture [1718], step length symmetries [1719], and greater walking economies [1719]. This suggests that assistive technologies need to account for variability in walking speeds to further improve post-stroke walking outcomes. However, research to date has evaluated exoskeleton performance at only one walking speed, typically set to either the participant’s comfortable OVG speed or a speed below this value [78]. At constant speeds, ankle exoskeletons have been shown to improve total ankle power in both healthy controls [11] and persons post-stroke [8], suggesting the joint powers and joint power symmetries could be improved by exoskeleton technology. Additionally, an exosuit applying assistance to the ankle was able to improve paretic propulsion and metabolic cost in persons post-stroke walking at their comfortable OVG speed [7]. Assessing the impact of exoskeleton assistance on walking performance across a range of speeds is the next logical step toward developing exoskeleton intervention strategies targeted at improving walking performance and quality of life for millions of persons post-stroke.

In order to assess the impact of exoskeleton assistance across a range of walking speeds in persons post-stroke, we developed a novel, speed-adaptive exoskeleton controller that automatically modulates the magnitude of ankle torque with changes in walking speed and soleus EMG. We hypothesized that: 1) Our novel speed-adaptive controller will scale exoskeleton assistance with increases in walking speed as intended. 2) Exoskeleton assistance will lead to increases in total average net paretic ankle power and limb power at all walking speeds. 3) Exoskeleton assistance will lead to metabolic benefits associated with improved paretic average net ankle and limb powers.

Methods

Exoskeleton hardware

We implemented an exoskeleton emulator comprised of a powerful off-board actuation and control system, a flexible Bowden cable transmission, and a lightweight exoskeleton end effector [20]. The exoskeleton end effector includes shank and foot carbon fiber components custom fitted to participants and hinged at the ankle. The desired exoskeleton torque profile was applied by a benchtop motor (Baldor Electric Co, USA) to the carbon-fiber ankle exoskeleton through a Bowden-cable transmission system. An inline tensile load cell (DCE-2500 N, LCM Systems, Newport, UK) was used to confirm the force transmitted by the exoskeleton emulator during exoskeleton assistance.

Speed-adaptive proportional myoelectric exoskeleton controller

Our exoskeleton controller alters the timing and magnitude of assistance with the user’s soleus EMG signal and walking speed (Fig. 1). The exoskeleton torque is determined from Eq. 1, in which participant mass (mparticipant) is constant across speeds, treadmill speed (V) is measured in real-time, the speed gain (Gspeed) is constant for all subjects and across speeds, the adaptive gain (Gadp) is constant for a gait cycle and calculated anew for each gait cycle, and the force-gated and normalized EMG (EMGGRFgated) is a continuously changing variable.

τexo (t)=mparticipant×V×Gspeed×Gadp×EMGGRFgatedτexo (t)=mparticipant×V×Gspeed×Gadp×EMGGRFgated
(1)
Fig. 1
Fig. 1

Novel speed-adaptive myoelectric exoskeleton controller measures and adapts to users’ soleus EMG signal as well as their walking speed in order to generate the exoskeleton torque profile. Raw soleus EMG signal is filtered and rectified to create an EMG envelope, and the created EMG envelope is then gated by anterior GRFs to ensure assistance is only applied during forward propulsion. The adaptive EMG gain is calculated as a moving average of peak force-gated EMG from the last five paretic gait cycles. The pre-speed gain control signal is the product of the force-gated EMG and the adaptive EMG gain. The speed gain is determined using real-time walking speed and computed as 25% of the maximum biological plantarflexion torque at that given walking speed. Exoskeleton torque is the result of multiplying the speed gain with the pre-speed gain control signal

[…]

Continue —> Mechanics and energetics of post-stroke walking aided by a powered ankle exoskeleton with speed-adaptive myoelectric control | Journal of NeuroEngineering and Rehabilitation | Full Text

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[ARTICLE] Elements virtual rehabilitation improves motor, cognitive, and functional outcomes in adult stroke: evidence from a randomized controlled pilot study – Full Text

 

Abstract

Background

Virtual reality technologies show potential as effective rehabilitation tools following neuro-trauma. In particular, the Elements system, involving customized surface computing and tangible interfaces, produces strong treatment effects for upper-limb and cognitive function following traumatic brain injury. The present study evaluated the efficacy of Elements as a virtual rehabilitation approach for stroke survivors.

Methods

Twenty-one adults (42–94 years old) with sub-acute stroke were randomized to four weeks of Elements virtual rehabilitation (three weekly 30–40 min sessions) combined with treatment as usual (conventional occupational and physiotherapy) or to treatment as usual alone. Upper-limb skill (Box and Blocks Test), cognition (Montreal Cognitive Assessment and selected CogState subtests), and everyday participation (Neurobehavioral Functioning Inventory) were examined before and after inpatient training, and one-month later.

Results

Effect sizes for the experimental group (d = 1.05–2.51) were larger compared with controls (d = 0.11–0.86), with Elements training showing statistically greater improvements in motor function of the most affected hand (p = 0.008), and general intellectual status and executive function (p ≤ 0.001). Proportional recovery was two- to three-fold greater than control participants, with superior transfer to everyday motor, cognitive, and communication behaviors. All gains were maintained at follow-up.

Conclusion

A course of Elements virtual rehabilitation using goal-directed and exploratory upper-limb movement tasks facilitates both motor and cognitive recovery after stroke. The magnitude of training effects, maintenance of gains at follow-up, and generalization to daily activities provide compelling preliminary evidence of the power of virtual rehabilitation when applied in a targeted and principled manner.

Trial registration

this pilot study was not registered.

Introduction

Stroke is one of the most common forms of acquired brain injury (ABI), with around 60,000 new and recurrent strokes occurring every year in Australia alone [1]. The clinical outcome of stroke is variable but often includes persistent upper-limb motor deficits, including weakness, discoordination, and reduced speed and mobility [2], and cognitive impairments in information processing and executive function [34]. Not surprisingly, stroke is a leading cause of disability worldwide, and the burden of stroke across all levels of the International Classification of Functioning (ICF) – body structures/function, activity, and participation – underlines the importance of interventions that can impact multiple domains of functioning [56].

Recovery of functional performance following stroke remains a significant challenge for rehabilitation specialists [78], but may be enhanced by innovation in the use of new technologies like virtual reality [9101112]. A critical goal is to find compelling ways of engaging individuals in their therapy by creating meaningful, stimulating and intensive forms of training [13]. The term, virtual rehabilitation (VR), is used to describe a form of training wherein patients interact with virtual or augmented environments, presented with the aid of technology [1415]. The technologies can be either commercial systems (e.g. Nintendo Wii, Xbox Kinect) or those customised specifically for rehabilitation. VR offers a number of advantages over traditional therapies, including the ability to engage individuals in the simulated practice of functional tasks at higher doses [1617], automated assessment of performance over time, flexibility in the scaling of task constraints, and a variety of reward structures to help maintain compliance [18].

While evaluation research is still in its infancy, recent systematic reviews and meta-analyses show that VR can enhance upper-limb motor outcomes in stroke [101119], yielding treatment effects of medium-to-large magnitude [1011], and complementing conventional approaches to rehabilitation. VR has been shown to engender high levels of engagement in stroke patients undergoing physical therapy [2021] and training of even moderate intensity can afford functional benefits at the activity/skill level [919]. In the specific case of upper-limb VR, however, there is little available evidence that these benefits transfer to participation [9]. Furthermore, most available data is on patients in chronic stages of recovery, with less on acute stroke [9]. Notwithstanding this, use of VR has begun to emerge in clinical practice, recommended in Australian and international stroke guidelines as a viable adjunct in therapy to improve motor and functional outcomes [222324].

Until recently, most VR systems have been designed to improve motor functions, with cognitive outcomes often a secondary consideration in evaluation studies [91011]. Notwithstanding this, treatments that target both motor and cognitive functions are indicated for stroke, given evidence that cognitive and motor systems overlap at a structural and functional level [2526], and work synergistically in a “perception-action cycle” [27] in stroke patients undergoing rehabilitation [28]. Recent studies provide preliminary evidence of improved attention and memory in stroke patients following motor-oriented VR [29303132], amounting to a small-to-medium effect on cognition [9]. When designed to address aspects of cognitive control and planning, VR has the potential to enhance dual-task control, resulting in better generalization of trained skills to daily functioning [33].

While evaluation research is still in its infancy, several recent customized systems (like Elements, the system evaluated here) have been deliberately designed to exploit factors known to enhance training intensity and motor learning. Informed by neuroscience and learning theory [for a recent review see 12], the Elements VR system was designed to enhance neuro-plastic recovery processes via: (1) an enriched therapeutic environment affording a natural form of user interaction via tangible computing and surface displays [34], which engage both the cognitive attention of participants and their motivation to explore training tasks; (2) concurrent augmented feedback (AF) on performance [35] offering participants additional information on the outcome of their actions to assist in re-building a sense of body position in space (aka body schema) and ability to predict/plan future actions; and (3) scaling of task challenges to the current level of motor and cognitive function [36], ensuring dynamic scaffolding of participants’ information processing and response capabilities. The Elements system, described in detail below and in earlier publications [3738], consists of a large (42 in.) tabletop surface display, tangible user interfaces, and software for presenting both goal-directed and exploratory virtual environments. Previous evaluations of the system in patients with traumatic brain injury showed improvements in both motor and cognitive performance, with transfer to activities of daily living [3739]. However, the impact of Elements in other forms of ABI, such as stroke, has not been evaluated.

The broad aim of current study was to evaluate the efficacy of the Elements VR interactive tabletop system for rehabilitation of motor and cognitive functions in sub-acute stroke, compared with treatment as usual (TAU). We were particularly interested in motor and cognitive outcomes, their relationship, and the transfer and maintenance of treatment effects. Training-related changes at the activity/skill level on standardized measures of motor and cognitive performance were investigated, together with functional changes. By offering an engaging, principled and customized form of interaction, we predicted that the Elements system would effect (i) greater changes on both motor and cognitive outcomes than with TAU alone; (ii) sustained benefits, as assessed over a short follow-up period, and (iii) transfer to everyday functional performance (i.e. participation).[…]

 

Continue —> Elements virtual rehabilitation improves motor, cognitive, and functional outcomes in adult stroke: evidence from a randomized controlled pilot study | Journal of NeuroEngineering and Rehabilitation | Full Text

Fig. 1

 

Fig. 1

Examples of the Elements (a) goal-directed Bases task with visual augmented feedback, and (b) exploratory Squiggles task

 

 

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[ARTICLE] Compliant lower limb exoskeletons: a comprehensive review on mechanical design principles – Full Text

Abstract

Exoskeleton technology has made significant advances during the last decade, resulting in a considerable variety of solutions for gait assistance and rehabilitation. The mechanical design of these devices is a crucial aspect that affects the efficiency and effectiveness of their interaction with the user. Recent developments have pointed towards compliant mechanisms and structures, due to their promising potential in terms of adaptability, safety, efficiency, and comfort. However, there still remain challenges to be solved before compliant lower limb exoskeletons can be deployed in real scenarios. In this review, we analysed 52 lower limb wearable exoskeletons, focusing on three main aspects of compliance: actuation, structure, and interface attachment components. We highlighted the drawbacks and advantages of the different solutions, and suggested a number of promising research lines. We also created and made available a set of data sheets that contain the technical characteristics of the reviewed devices, with the aim of providing researchers and end-users with an updated overview on the existing solutions.

Background

Robotic wearable exoskeletons1 have potential impact in several application domains, like industry [1], space [2] and healthcare [3]. In the healthcare sector, this technology is expected to contribute by reducing the clinical costs associated with the assistance and rehabilitation of people with neurological and age-related disorders [3456]. Research in this area is clearly shifting toward the inclusion of compliant elements (i.e. actuators, structure2, etc.) as a way to overcome the main drawbacks of rigid exoskeletons, in terms of adaptability, comfort, safety and efficiency [7].

Currently, there is a large variety of designs of lower limb compliant exoskeletons aimed at gait rehabilitation or assistance. However, there is a lack of detailed information about the mechanical components of these devices, which has been largely overlooked by previous reviews (e.g. [789]). These variety and lack of information makes it difficult for developers to identify which design choices are most important for a specific application, user’s need or pathology. For this reason, we aimed to bring together available literature into a comprehensive review focused on existing lower limb wearable exoskeletons that contain compliant elements in their design.

In this work, we refer to ‘compliant exoskeleton’ as a system that includes compliant properties derived from non-rigid actuation system and/or structure. Our review focused on three particular aspects: the actuation technology, the structure of the exoskeleton and the interface attachment components3.

We have gathered the mechanical and actuation characteristics of 52 devices into standardized data sheets (available at Additional file 1), to facilitate the process of comparison of the different solutions under a unified and homogeneous perspective. We consider that such a comprehensive summary will be vital to researchers and developers in search for an updated design reference.

Methodology

We applied the following search query on the Scopus database: TITLE-ABS-KEY(“actuat*” AND (“complian*” OR “elastic*” OR “soft”) AND (“exoskeleton*” OR “rehabilitat*” OR “orthotic*” OR “orthos*” OR (“wearable” AND “robot*”)) OR “exosuit” OR “exo-suit”), which returned 1131 studies. We excluded: publications focusing on upper limb robots; non-actuated compliant exoskeletons; solutions where compliance was achieved through control; studies that did not report any mechanical information on the robot; and studies not related to either assistance or rehabilitation. The above process resulted in a total of 105 publications, which covered 52 different lower limb exoskeletons.

To simplify and structure the information, we classified the compliant exoskeletons according to the mechanical component that results in their intrinsic compliant performance: (i) exoskeletons with compliant actuators (i.e. series elastic, variable stiffness and pneumatic actuators) and rigid structure; (ii) exoskeletons with soft structure (soft exoskeletons4) and rigid actuators; (iii) exoskeletons with compliant actuators and soft structure. The review describes the different design choices of the exoskeletons, i.e. actuation system, structure and interfacing attachment components to connect the actuators with the human body.

A glossary with the most commonly used terms in this article has been added at the end of the document. Some definitions have been readapted from the literature.

Results

As shown in Fig. 1, 85% of the reviewed articles (corresponding to 44 exoskeletons) used compliant actuators and a rigid structure. Soft exoskeletons represent 11% of the reviewed articles (6 exoskeletons). Two exoskeletons (4%) belong to the intersection of previous groups, this is, exoskeletons integrating both soft structure and compliant actuation5. We refer to the latter as “fully compliant exoskeletons”.

Fig. 1
Fig. 1

Classification of the 52 lower limb exoskeletons according to their compliant mechanical component

 

Continue —>  Compliant lower limb exoskeletons: a comprehensive review on mechanical design principles | Journal of NeuroEngineering and Rehabilitation | Full Text

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[NEWS] Anti-Tremor Function is One of this Mouse Adapter’s Cool Features

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AMAneo BTi

Inclusive Technology releases the AMAneo BTi, an adapter designed to enable people with disabilities to operate an iPad or iPhone directly with any mouse or assistive mouse, including track ball, joystick, head mouse, thumb mouse, and more.

Previously, the most common iPad or iPhone operation method was using Switch Control of the iOS.

However, to use this adapter, simply plug in the mouse and connect it to the iPhone, iPad, or iPad Mini using Bluetooth. A touch pointer then automatically appears on the device’s screen enabling full control over the iPad. There are no additional apps to install, according to a media release from UK-based Inclusive Technology. Its US distributor is located in Waxhaw, NC.

Other interaction options include click and drag, auto click and click delay. Two switch ports are also provided, enabling the option of controlling the left and right mouse button with two external switches.

Additional features include instant access to Apple’s AssistiveTouch Menu, which gives users access to several iPad controls such as volume control and the Home button, as well as an innovative anti-tremor function to filter out any shaking of the hand or head and ensure that the on-screen cursor moves smoothly, according to a media release.

The AMAneo BTi charges using a Micro USB and lasts for up to 20 hours of operation.

[Source: Inclusive Technology]

 

via Anti-Tremor Function is One of this Mouse Adapter’s Cool Features – Rehab Managment

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