Igwegbe I.,Parexel International |
Fadojutimi-Akinsiku M.O.,Howard University |
Hirsh A.M.,University Hospitals |
Park N.J.,Boston University |
And 2 more authors.
Advances in Skin and Wound Care | Year: 2015
Objective: Refractory leg ulcerations are common in homozygous sickle cell anemia. In this case series, patients were treated with transdermal continuous oxygen therapy (TCOT), based on the hypothesis that oxygen deprivation caused by arteriovenous shunting may be remedied by providing oxygen directly to the wound bed. The authors believe this is the first attempt to treat sickle cell ulcers with TCOT. Case Presentation: Five patients with long histories of recurring sickle cell disease ulcers that would not heal with various conventional and/or other adjunctive wound healing modalities were treated with TCOT. The patients had recurring nonhealing wounds for 30, 21, 20, 20, and 15 years, respectively. All 5 patients healed or showed substantial improvement in the treatment periods of 3 to 36 weeks. Conclusion: The authors conclude that TCOT may be a novel, effective, and inexpensive modality in treating patients with sickle cell disease ulcers. Improvement was typically noticeable within 2 weeks. Further clinical trials may be considered to evaluate the efficacy of TCOT in sickle cell ulcers. © 2015 Wolters Kluwer Health, Inc. All rights reserved.
Zhang F.,University of Rhode Island |
D'andrea S.E.,Center for Restorative and Regenerative Medicine |
D'andrea S.E.,Brown University |
Nunnery M.J.,North Technologies |
And 2 more authors.
IEEE Transactions on Neural Systems and Rehabilitation Engineering | Year: 2011
Recent advances in design of powered artificial legs have led to increased potential to allow lower limb amputees to actively recover from stumbles. To achieve this goal, promptly and accurately identifying stumbles is essential. This study aimed to 1) select potential stumble detection data sources that react reliably and quickly to stumbles and can be measured from a prosthesis, and 2) investigate two different approaches based on selected data sources to detect stumbles and classify stumble types in patients with transfemoral (TF) amputations during ambulation. In the experiments, the normal gait of TF amputees was perturbed by a controllable treadmill or when they walked on an obstacle course. The results showed that the acceleration of prosthetic foot can accurately detect the tested stumbling events 140-240 ms before the critical timing of falling and precisely classify the stumble type. However, the detector based on foot acceleration produced high false alarm rates, which challenged its real application. Combining electromyographic (EMG) signals recorded from the residual limb with the foot acceleration significantly reduced the false alarm rate but sacrificed the detection response time. The results of this study may lead to design of a stumble detection system for instrumented, powered artificial legs; however, continued engineering efforts are required to improve the detection performance and resolve the challenges that remain for implementing the stumble detector on prosthetic legs. © 2011 IEEE.
Chadwick E.K.,Case Western Reserve University |
Chadwick E.K.,Aberystwyth University |
Blana D.,Case Western Reserve University |
Blana D.,Aberystwyth University |
And 14 more authors.
Journal of Neural Engineering | Year: 2011
Functional electrical stimulation (FES), the coordinated electrical activation of multiple muscles, has been used to restore arm and hand function in people with paralysis. User interfaces for such systems typically derive commands from mechanically unrelated parts of the body with retained volitional control, and are unnatural and unable to simultaneously command the various joints of the arm. Neural interface systems, based on spiking intracortical signals recorded from the arm area of motor cortex, have shown the ability to control computer cursors, robotic arms and individual muscles in intact non-human primates. Such neural interface systems may thus offer a more natural source of commands for restoring dexterous movements via FES. However, the ability to use decoded neural signals to control the complex mechanical dynamics of a reanimated human limb, rather than the kinematics of a computer mouse, has not been demonstrated. This study demonstrates the ability of an individual with long-standing tetraplegia to use cortical neuron recordings to command the real-time movements of a simulated dynamic arm. This virtual arm replicates the dynamics associated with arm mass and muscle contractile properties, as well as those of an FES feedback controller that converts user commands into the required muscle activation patterns. An individual with long-standing tetraplegia was thus able to control a virtual, two-joint, dynamic arm in real time using commands derived from an existing human intracortical interface technology. These results show the feasibility of combining such an intracortical interface with existing FES systems to provide a high-performance, natural system for restoring arm and hand function in individuals with extensive paralysis. © 2011 IOP Publishing Ltd.
Lo A.C.,Brown University |
Lo A.C.,Center for Restorative and Regenerative Medicine |
Lo A.C.,Saint Francis Hospital
American Journal of Physical Medicine and Rehabilitation | Year: 2012
Rehabilitation robots are increasingly being tested and promoted for clinical neurorehabilitation. Compared with conventional and manual methods, robots allow for a variety of advantages, particularly in the areas of interventional control and the ability to provide a high volume of facilitated movement. Since 1997, there have been more than 60 clinical trials reporting the use of two dozen different robots for neurorehabilitation. Although there are a number of smaller pilot studies, there are only few larger clinical trials. There may be a number of reasons why pilot robot studies do not materialize into larger studies. Beyond devices that failed to perform as intended, what are the clinical design issues that have limited these studies? Some basic considerations include randomization, inclusion of a control group, power calculation based on a clinically meaningful outcome, and finally, reproducible descriptions of the intervention being tested. Although many of these issues are general challenges presented for all rehabilitation studies, there are clinical design features that would likely greatly improve interpretation of results and better position robot devices toward the next clinical trial step. On the other hand, the absence of these elements, even in the setting of a pilot study, may significantly hamper the interpretation of results and not yield sufficient information on treatment effects, adverse event rates, dropout rate, and so on, to allow further testing to proceed to follow-up Food and Drug Administration phase II and III studies. Development of rehabilitation robots for clinical use needs to occur hand in hand with well-conducted clinical trials to provide evidence of efficacy while also taking into account costs. Copyright © 2012 by Lippincott Williams & Wilkins.
Lieberman D.E.,1 Divinity Avenue |
Venkadesan M.,1 Divinity Avenue |
Venkadesan M.,Harvard University |
Werbel W.A.,University of Michigan |
And 7 more authors.
Nature | Year: 2010
Humans have engaged in endurance running for millions of years, but the modern running shoe was not invented until the 1970s. For most of human evolutionary history, runners were either barefoot or wore minimal footwear such as sandals or moccasins with smaller heels and little cushioning relative to modern running shoes. We wondered how runners coped with the impact caused by the foot colliding with the ground before the invention of the modern shoe. Here we show that habitually barefoot endurance runners often land on the fore-foot (fore-foot strike) before bringing down the heel, but they sometimes land with a flat foot (mid-foot strike) or, less often, on the heel (rear-foot strike). In contrast, habitually shod runners mostly rear-foot strike, facilitated by the elevated and cushioned heel of the modern running shoe. Kinematic and kinetic analyses show that even on hard surfaces, barefoot runners who fore-foot strike generate smaller collision forces than shod rear-foot strikers. This difference results primarily from a more plantarflexed foot at landing and more ankle compliance during impact, decreasing the effective mass of the body that collides with the ground. Fore-foot-and mid-foot-strike gaits were probably more common when humans ran barefoot or in minimal shoes, and may protect the feet and lower limbs from some of the impact-related injuries now experienced by a high percentage of runners. © 2010 Macmillan Publishers Limited. All rights reserved.
Malik W.Q.,Massachusetts General Hospital |
Malik W.Q.,Brown University |
Malik W.Q.,Massachusetts Institute of Technology |
Truccolo W.,Brown University |
And 6 more authors.
IEEE Transactions on Neural Systems and Rehabilitation Engineering | Year: 2011
The Kalman filter is commonly used in neural interface systems to decode neural activity and estimate the desired movement kinematics. We analyze a low-complexity Kalman filter implementation in which the filter gain is approximated by its steady-state form, computed offline before real-time decoding commences. We evaluate its performance using human motor cortical spike train data obtained from an intracortical recording array as part of an ongoing pilot clinical trial. We demonstrate that the standard Kalman filter gain converges to within 95% of the steady-state filter gain in 1.5±0.5 s (mean ± s.d.). The difference in the intended movement velocity decoded by the two filters vanishes within 5 s, with a correlation coefficient of 0.99 between the two decoded velocities over the session length. We also find that the steady-state Kalman filter reduces the computational load (algorithm execution time) for decoding the firing rates of 25±3 single units by a factor of 7.0±0.9. We expect that the gain in computational efficiency will be much higher in systems with larger neural ensembles. The steady-state filter can thus provide substantial runtime efficiency at little cost in terms of estimation accuracy. This far more efficient neural decoding approach will facilitate the practical implementation of future large-dimensional, multisignal neural interface systems. © 2010 IEEE.
Lo A.,Brown University |
Lo A.,Center for Restorative and Regenerative Medicine |
Lo A.,Saint Francis Hospital
Topics in Spinal Cord Injury Rehabilitation | Year: 2011
Gait dysfunction is an area of considerable disability for people with multiple sclerosis (MS) and Parkinson's disease (PD). The use of robot-assisted gait training is a potential technology-based intervention to treat gait impairment. Twenty-five people with MS and PD were enrolled in separate clinical studies and treated with up to 16 sessions of robot-assisted gait training. Outcomes collected included quantitative temporal-spatial gait data, as well as patient self-reported quality of life. Our findings show that robot-assisted gait training can result in positive improvements in gait and quality of life in the MS population and reduce freezing of gait in the PD population. © 2011 Thomas Land Publishers, Inc.
Herr H.M.,Massachusetts Institute of Technology |
Herr H.M.,Center for Restorative and Regenerative Medicine |
Grabowski A.M.,Massachusetts Institute of Technology |
Grabowski A.M.,Center for Restorative and Regenerative Medicine
Proceedings of the Royal Society B: Biological Sciences | Year: 2012
Over time, leg prostheses have improved in design, but have been incapable of actively adapting to different walking velocities in a manner comparable to a biological limb. People with a leg amputation using such commercially available passive-elastic prostheses require significantly more metabolic energy to walk at the same velocities, prefer to walk slower and have abnormal biomechanics compared with non-amputees. A bionic prosthesis has been developed that emulates the function of a biological ankle during level-ground walking, specifically providing the net positive work required for a range of walking velocities. We compared metabolic energy costs, preferred velocities and biomechanical patterns of seven people with a unilateral transtibial amputation using the bionic prosthesis and using their own passiveelastic prosthesis to those of seven non-amputees during level-ground walking. Compared with using a passive-elastic prosthesis, using the bionic prosthesis decreased metabolic cost by 8 per cent, increased trailing prosthetic leg mechanical work by 57 per cent and decreased the leading biological leg mechanical work by 10 per cent, on average, across walking velocities of 0.75-1.75 m s -1 and increased preferred walking velocity by 23 per cent. Using the bionic prosthesis resulted in metabolic energy costs, preferred walking velocities and biomechanical patterns that were not significantly different from people without an amputation. © 2011 The Royal Society.
Yao M.,VA New England Health Care Division |
Yao M.,Boston University |
Yao M.,Center for Restorative and Regenerative Medicine |
Fabbi M.,VA New England Health Care Division |
And 14 more authors.
International Wound Journal | Year: 2014
The purpose of this study was to evaluate the efficacy of negative pressure wound therapy (NPWT) compared with standard of care on wound healing in high-risk patients with multiple significant comorbidities and chronic lower extremity ulcers (LEUs) across the continuum of care settings. A retrospective cohort study of 'real-world' high-risk patients was conducted using Boston University Medical Center electronic medical records, along with chart abstraction to capture detailed medical history, comorbidities, healing outcomes and ulcer characteristics. A total of 342 patients, 171 NPWT patients with LEUs were matched with 171 non-NPWT patients with respect to age and gender, were included in this cohort from 2002 to 2010. The hazard ratios (HRs) were estimated by COX proportional hazard models after adjusting for potential confounders. The NPWT patients were 2·63 times (95% CI = 1·87-3·70) more likely to achieve wound closure compared with non-NPWT patients. Moreover, incidence of wound closure in NPWT patients were increased in diabetic ulcers (HR = 3·26, 95% CI = 2·21-4·83), arterial ulcers (HR = 2·27, CI = 1·56-3·78) and venous ulcers (HR = 6·31, 95% CI = 1·49-26·6) compared with non-NPWT patients. In addition, wound healing appeared to be positively affected by the timing of NPWT application. Compared with later NPWT users (1 year or later after ulcer onset), early NPWT users (within 3 months after ulcer onset) and intermediate NPWT users (4-12 months after ulcer onset) were 3·38 and 2·18 times more likely to achieve wound healing, respectively. This study showed that despite the greater significant comorbidities, patients receiving NPWT healed faster. Early use of NPWT demonstrated better healing. The longer the interval before intervention is with NPWT, the higher the correlation is with poor outcome. © 2012 Medicalhelplines.com Inc and John Wiley & Sons Ltd.