Computing Density of States of One-Dimensional Photonic Crystal under P-Polarized Incident Wave

Volume 2 Issue 3 (March 2014

Restoring Independent Living after Disability Using a Wearable Device: A Synergistic Physio-Neuro Approach to Leverage Neuroplasticity

The number of people living with various grades of disability is now in excess of 1 billion. A significant portion of this population is dependent on caregivers and unable to access or afford therapy. This emerging healthcare challenge coincides with new knowledge about the self-learning, self-organizing, neuroplastic nature of the brain, offering hope to those trying to regain independence after disability. As conditions such as stroke and dementia begin to affect more and more people in the younger age groups, there is an urgent, global need for a connected rehabilitation solution that leverages the advantages of neuroplasticity to restore cognitive and physical function. This chapter explains a novel approach using a Synergistic Physio-Neuro learning model (SynPhNe learning model), which mimics how babies learn. This learning model has been embedded into a wearable, biofeedback device that can be used to restore function after stroke, injury, the degenerative effects of aging or a childhood learning disability. This chapter enumerates the clinical studies conducted with adult stroke patients in two scenarios—with therapist supervision and with lay person supervision. The results indicate that such a learning model is effective and promises to be an accessible and affordable solution for patients striving for independence

Study of enhanced upper extremity rehabilitation with active feedback using SEMG

Most stroke patients are discharged from care in hospitals once they learn to walk. This usually leaves a large gap in upper extremity rehabilitation, and more so in recovery of fine motor skills. On the other hand, several interviews with stroke patients have revealed that they desire recovery of hand functions first, so that they can perform the activities of daily living, such as feeding, bathing and clothing themselves, as well as going to the toilet on their own. They consider these important for living a life of independence and dignity. pioneers of brain plasticity have pointed out that the patient must be engaged completely and intensely in the activity for such plasticity to occur. This study attempts to develop a wearable robotic brace which can assist patients with minimal functions in upper extremities, translating non-functional movements to functional use. The device will engage the patients through surface electromyographic signals (SEMG) and visual feedback of muscle contraction and movement, using the bodies existing neural pathways. A hand and wrist orthosis was designed to suit the simulation of pinch, cylindrical grasp and wrist movement of a hemiplaegic right hand, using the above SEMG triggers. In order to engage the patient early enough and intensely enough to bring about rapid brain plasticity, several new directions in the future design of such orthosis was proposed such as Human-Machine-Human Interface Alternative Natural Positions for Rehabilitation Devices Multiple Trigger Selection using electromyographic and electroencephalographic signals Some preliminary studies were done on such new directions on healthy subjects.Master of Science (Biomedical Engineering

A synergistic physio-neuro rehabilitation platform to accelerate recovery of hand function after stroke

More people are surviving stroke than ever before due to advances in emergency care. However, the numbers of stroke patients that have not fully regained their ability to perform activities of daily living (ADL) have also increased. As the stroke survivor population grows, healthcare institutions and families are finding it increasingly difficult to restore disabled patients to independent living and provide adequate treatment and rehabilitation time. Recovery of functional use of the hand is a key factor in regaining independence post-stroke. Engineering and robotics solutions proposed for regaining hand function have so far not had the widespread success that was expected. The ability to reach out to the majority of stroke patients using robotic rehabilitation solutions is also not viable due to high cost and infrastructure requirements. In addition, a major reason, as discovered in this work, has been the traditional pre-occupation with the disability and augmentation of lost function and insufficient research into utilizing the patient’s residual abilities and innate, natural learning mechanisms during the course to recovery. This PhD research proposes a paradigm shift in rehabilitation strategy. It envisions a learning model and technology solution which would harness and leverage the intuitive learning abilities that exist in human beings as an integral part of therapy. Bio-signals from the muscles and brain are used as a universal language to assess and train patients to re-learn key mind-body strategies which enable accelerated improvement in functional abilities. Such strategies include self-regulating the musculoskeletal and brain responses to the demands of motor activities, which is a must before proceeding to extended repetitive practice. The human learning model which drives the strategy of SYNergistic PHysio-NEuro rehabilitation platform or “SynPhNe”, is explained in this report along with innovative hardware and software architectures. The assessment and rehabilitation capabilities of this platform are described, with a focus on hand function recovery. Technical feasibility studies with healthy and stroke patients were conducted as an initial stage proof-of-concept, which included observing patient responses to a video imitation and biofeedback routine over a single session, using a Phase I prototype. Short term improvements in function and ability to activate and inhibit muscles were seen. Subsequently, a clinical feasibility trial was conducted with a more wearable, user friendly Phase II clinical prototype. This was clinically supervised at the largest public rehabilitation centre in Singapore. The subjects were long term, “plateaued” chronic patients who underwent therapy over four weeks, along with pre and post clinical assessment. The data for five subjects is presented and specific case studies discussed to illustrate how patients with different challenges may adopt different pathways to function recovery. Three hypotheses were tested: • Biofeedback integrated with mirror image video-based imitation (as a feedforward) supports accelerated re-learning of hand function after stroke. • It is technologically feasible to deliver this form of training via a safe, low cost, wearable, automated device, particularly to stroke patients whose recovery had “plateaued” with little hope for further improvement. • It is feasible to track obvious and non-obvious (sub-clinical) improvements using novel, bio-signal based real-time brain and muscle metrics which can help to personalize therapy and make it more meaningful to patients. The data showed that the ability to successfully perform repetitive actions was as much associated with the ability to volitionally relax muscles as it was with the ability to contract muscles. Those who could achieve such relaxation-activation balance for both the muscles and the brain achieved the best results. The SynPhNe training resulted in functional improvement as per clinical scales, better manipulation of objects, lower self-reported pain, and better intra-limb co-ordination. More severely affected subjects seemed to progress proportionately faster as compared to less impaired subjects. Subjects with lower impairments, however, improved functional status faster over 12 sessions as expected although their recovery had reached a “plateau” prior to this trial. Incremental changes in performance that could not be captured by typical clinical scales were successfully displayed by the bio-signal parameters being tracked. This study showed that patients unconsciously train hitherto unseen, maladaptive brain-muscle reactions repetitively along with desired actions and tasks, thus making brain plasticity a double edged sword. If patients are made aware of these unconscious, non-obvious reactions, it is possible for them to self-correct and inhibit these reactions to overcome recovery “plateaus”. This is an important adjunct to standard care and potentially applicable to sub-acute and chronic stroke patients, including those with co-morbidities such as ataxia, sensory deficit, attention difficulties, high muscle tone, intra-limb muscle coupling and pain.Doctor of Philosophy (MAE

Using neuroplasticity principles to delay or reverse effects of chronic disease, disability and ageing: A new look at disease biology

Unconscious adaptations in posture and muscle use take place in the course of ageing, progression of chronic conditions or a sudden incident like stroke resulting in physical disability. In many cases, the person is unable or prefers not to use the affected limbs as before even after prolonged therapy either due to weakness, fatigue, pain or loss of control. This results in neuroplastic changes in the brain which may get retrained with compensatory and maladaptive muscle strategies over time, for simple everyday tasks. Such maladaptation leads to still further deterioration and permanent, progressively worsening disability leading to loss of dependence as a person ages. Research data from studies conducted on humans with an automated physio-neuro rehabilitation device, SynPhNe, show that the brain can be retrained to elicit favourable changes in long term maladaptive strategies at both brain and muscle levels. This can be achieved by training the brain and muscle as ONE system, by self-correcting unconscious brain-muscle responses in real time while performing simple tasks and actions. Most of this self-correction revolves around achieving a better activation-relaxation balance in the agonist and antagonist muscle groups during movement, as well as in the two brain hemispheres. The self-correction is effected using posture correction with augmented, time locked brain-muscle biofeedback. Trials in long term stroke patients in Singapore and India resulted in up to 70% recovery of hand use within four weeks as compared to starting baseline. Muscle tone and spasticity improved and uncontrolled tremors reduced allowing subjects to use their affected hands for activities like dressing, using chopsticks, object manipulation and playing the guitar. Secondary pain also reduced or disappeared. Such a self-correction rehabilitation protocol having a significant guided relaxation component may help children and adults with chronic disability to modify symptoms sufficiently to lead an independent and higher quality of life while improving alertness levels, muscle quality and oxygenation. Future trials with cerebral palsy children and traumatic brain injury adults are being planned

An Automated Physio-neuro Recovery Tool For Enhancing Muscle And Brain Co-ordination And Recovery After Sports Related Trauma And Injuries

Injuries are common in high intensity sports such as rugby, martial arts, motor sports and the like. These sports result in not just limb injuries but also brain injuries affecting cognitive and motor function. One of the problems with long term neuro-muscular rehabilitation is that access to supervised therapy is difficult on a daily basis and family resources such as time and money can be severely strained. SynPhNe is a wearable, portable, connected rehabilitation device which trains the brain and muscle as one system, rather than two distinct elements. It can highlight a person’s unconscious musclebrain reactions after injury and trauma which may be hampering recovery. These reactions are then self-corrected in real time using a dynamic relaxation protocol. The person trains to perform various exercises and tasks in an environment of dynamic activation-relaxation balance which helps not just muscle isolation but also outcomes based tasks. SynPhNe was first tested among the stroke population. Stroke is considered a severe form of trauma affecting brain and muscle function. One outcome was that using SynPhNe requires substantially fewer repetitions to obtain results, as compared to conventional repetitive practice therapy. It was also possible for a non-medical person to use the device to administer guided therapy. Being automated with easy-to-build exercise options for different types of sports specific training schedules, it presents a promising option to help sports persons recover not just movement but also co-ordination and control in a safe, fast and low cost manner. This paper describes how the SynPhNe method could impact the sports injury and performance enhancement challenges of the future.Published versio

Evidence for inefficient contraction and abnormal mitochondrial activity in sarcopenia using magnetic resonance spectroscopy

Abstract Background Mitochondrial dysfunction has been implicated in sarcopenia. 31P magnetic resonance spectroscopy (MRS) enables non‐invasive measurement of adenosine triphosphate (ATP) synthesis rates to probe mitochondrial function. Here, we assessed muscle energetics in older sarcopenic and non‐sarcopenic men and compared with muscle biopsy‐derived markers of mitochondrial function. Methods Twenty Chinese men with sarcopenia (SARC, age = 73.1 ± 4.1 years) and 19 healthy aged and sex‐matched controls (CON, age = 70.3 ± 4.2 years) underwent assessment of strength, physical performance, and magnetic resonance imaging. Concentrations of phosphocreatine (PCr), ATP and inorganic phosphate (Pi) as well as muscle pH were measured at rest and during an interleaved rest–exercise protocol to probe muscle mitochondrial function. Results were compared to biopsy‐derived mitochondrial complex activity and expression to understand underlying metabolic perturbations. Results Despite matched muscle contractile power (strength/cross‐sectional area), the ATP contractile cost was higher in SARC compared with CON (low‐intensity exercise: 1.06 ± 0.59 vs. 0.57 ± 0.22, moderate: 0.93 ± 0.43 vs. 0.58 ± 0.68, high: 0.70 ± 0.57 vs. 0.43 ± 0.51 mmol L−1 min−1 bar−1 cm−2, P = 0.003, <0.0001 and <0.0001, respectively). Post‐exercise mitochondrial oxidative synthesis rates (a marker of mitochondrial function) tended to be longer in SARC but did not reach significance (17.3 ± 6.4 vs. 14.6 ± 6.5 mmol L−1 min−1, P = 0.2). However, relative increases in end‐exercise ADP in SARC (31.8 ± 9.9 vs. 24.0 ± 7.3 mmol L−1, P = 0.008) may have been a compensatory mechanism. Mitochondrial complex activity was found to be associated with exercise‐induced drops in PCr [citrate synthetase activity (CS), Spearman correlation rho = −0.42, P = 0.03] and end‐exercise ADP (complex III, rho = −0.52, P = 0.01; CS rho = −0.45, P = 0.02; SDH rho = −0.45, P = 0.03), with CS also being strongly associated with the PCr recovery rate following low intensity exercise (rho = −0.47, P = 0.02), and the cost of contraction at high intensity (rho = −0.54, P = 0.02). Interestingly, at high intensity, the fractional contribution of oxidative phosphorylation to exercise was correlated with activity in complex II (rho = 0.5, P = 0.03), CS (rho = 0.47, P = 0.02) and SDH (rho = 0.46, P = 0.03), linking increased mitochondrial complex activity with increased ability to generate energy through oxidative pathways. Conclusions This study used 31P MRS to assess ATP utilization and resynthesis in sarcopenic muscle and demonstrated abnormal increases in the energy cost during exercise and perturbed mitochondrial energetics in recovery. Associations between mitochondrial complex activity and the fractional contribution to energy requirement during exercise indicate increased ability to generate energy oxidatively in those with better mitochondrial complex activity