Assessment of knee flexion in young children with prosthetic knee components using dynamic time warping

Introduction: Analysis of human locomotion is challenged by limitations in traditional numerical and statistical methods as applied to continuous timeseries data. This challenge particularly affects understanding of how close limb prostheses are to mimicking anatomical motion. This study was the first to apply a technique called Dynamic Time Warping to measure the biomimesis of prosthetic knee motion in young children and addressed the following research questions: Is a combined dynamic time warping/root mean square analysis feasible for analyzing pediatric lower limb kinematics? When provided at an earlier age than traditional protocols dictate, can children with limb loss utilize an articulating prosthetic knee in a biomimetic manner? Methods: Warp costs and amplitude differences were generated for knee flexion curves in a sample of ten children five years of age and younger: five with unilateral limb loss and five age-matched typically developing children. Separate comparisons were made for stance phase flexion and swing phase flexion via two-way ANOVAs between bilateral limbs in both groups, and between prosthetic knee vs. dominant anatomical knee in age-matched pairs between groups. Greater warp costs indicated greater temporal dissimilarities, and a follow-up root mean square assessed remaining amplitude dissimilarities. Bilateral results were assessed by age using linear regression. Results: The technique was successfully applied in this population. Young children with limb loss used a prosthetic knee biomimetically in both stance and swing, with mean warp costs of 12.7 and 3.3, respectively. In the typically developing group, knee motion became more symmetrical with age, but there was no correlation in the limb loss group. In all comparisons, warp costs were significantly greater for stance phase than swing phase. Analyses were limited by the small sample size. Discussion: This study has established that dynamic time warping with root mean square analysis can be used to compare the entirety of time-series curves generated in gait analysis. The study also provided clinically relevant insights on the development of mature knee flexion patterns during typical development, and the role of a pediatric prosthetic knee

Effects of Two Exercise Programs on Neck Proprioception in Patients with Chronic Neck Pain: A Preliminary Randomized Clinical Trial

Background: The purpose of this study was to compare the effects of specific neck muscle training and general neck-shoulder exercises on neck proprioception, pain, and disability in patients with chronic non-specific neck pain. Methods: Twenty-five patients with chronic non-specific neck pain were recruited into this preliminary single-blinded randomized clinical trial. They were randomly assigned to either a specific neck exercise (n = 13, mean aged 24 years) or a general neck exercise group (n = 12, mean aged 25 years). Specific neck exercises included eye-head coordination and isometric deep neck muscle exercises. General neck exercises included neck and shoulder free range of motion and shoulder shrug. Pain, disability, and neck proprioception, which was determined using the joint repositioning error, were measured at baseline and after eight weeks of training in both groups. Results: Both training groups showed significant improvements in joint repositioning error (p \u3c 0.001, F = 24.144, ES = 0.8), pain (p \u3c 0.001, F = 61.118, ES = 0.31), and disability (p = 0.015, F = 6.937, ES = 0.60). However, the specific neck exercise group showed larger variability in joint repositioning error (p = 0.006, F = 0.20, F critical = 0.36). Conclusions: Either specific neck exercise or a general neck-shoulder range of motion exercise could be effective in improving neck proprioception. Therefore, exercises could be recommended based on patient comfort and patients’ specific limitations

The Murchison Widefield Array: The Square Kilometre Array Precursor at Low Radio Frequencies

The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a location chosen for its extremely low levels of radio frequency interference. The MWA operates at low radio frequencies, 80–300 MHz, with a processed bandwidth of 30.72 MHz for both linear polarisations, and consists of 128 aperture arrays (known as tiles) distributed over a ~3-km diameter area. Novel hybrid hardware/software correlation and a real-time imaging and calibration systems comprise the MWA signal processing backend. In this paper, the as-built MWA is described both at a system and sub-system level, the expected performance of the array is presented, and the science goals of the instrument are summarised

Pediatric Prosthetic Knee Angle Dataset for Dynamic Time Warping

Non-time-normalized knee joint angles from children with unilateral lower limb loss requiring a prosthetic knee joint (LL) and age-matched controls (C), in stance (first column per side) and swing (second column per side). Collected at the Biomechanics Laboratory at Georgia State University in Atlanta, GA

Do Cognitive Biases Result in Altered User Outcomes with Advanced Orthopedic Devices?

As prosthetic and orthotic components and devices increase in complexity, as well as expense, additional scrutiny has arisen regarding their outcomes and effectiveness. Quality research outcomes, as well as both self-reported and clinician-measured outcome measures, have never been more important. However, increased device complexity carries with it an additional factor that could confound all these vital outcome measures: what if the user shows more favorable outcomes simply because they are aware that a particular device is more advanced, regardless of its actual function? This is an example of a well-established cognitive phenomenon called Confirmation Bias, which occurs when perceptions of a stimulus are affected by an observer’s expectations about the stimulus. This project builds on our ground-breaking prior research to determine if confirmation bias can affect both user-reported outcomes and clinical movement outcomes when healthy older adults are led to believe they are using an advanced, computerized knee orthosis. Participants will take part in the five-repetition sit-to-stand activity in a baseline condition and while fitted with two knee orthoses. The orthoses will be functionally identical, but the participants will not know that. We will alter one set of orthoses to make them appear advanced and computerized. We will explain the enhanced functions to the participants and go through the process of allowing the pseudo-advanced orthosis to “learn” their knee motion so that it can “dynamically adjust” to stabilize and assist the joint. Following the presentation of the unmodified and modified KOs but before use, we will use a survey to assess opinions regarding expected function. Then, participants will complete the sit-to-stand exercise. We will measure standard clinical outcomes as well as literature-based 3D kinematics and kinetics. Following movement trials, we will repeat the survey to measure opinions regarding actual performance. We hypothesize that users will prefer the “advanced” orthosis, both before and after use. Our prior data further indicate that users will increase their preference for the pseudo-advanced orthosis after use, indicating the impact of confirmation bias in a self-reported outcome. In addition, we hypothesize that, while our previous data on walking outcomes showed no differences, these more sensitive outcomes in a different population will reveal altered performance with the “advanced” orthosis. This will indicate that confirmation bias can result in altered movement patterns, even when the orthopedic device offers no differential functional advantage. These results, pending but pilot data is successfully collected on the baseline condition, will have a positive impact because they will establish a critical need for blinding when conducting research with advanced or expensive orthopedic devices, and the need for clinician understanding of the potential impacts of cognitive biases in their patients

Advanced Education & Research Training Initiative [AERTI] 2009

The American Academy of Orthotists and Prosthetists has long recognized the valuable synergy between research and education, and the mutual importance of each in advancing the field. Consequently, a focal point of an Academy grant initiative funded by the U.S. Department of Education has been a systematic analysis of research capacity and advanced education. A grant project in 2004 convened a series of meetings and produced the Advanced Education and Research Training Initiative (AERTI) report. Continuing the initiative, a multidisciplinary and multinational group of experts convened in Chicago July 17-19, 2009 to review the 2004 AERTI Report, evaluate its recommendations in light of the evolution of the profession over the past five years, and to make suggestions for consideration by the field that would accelerate the pace of progress. This group included clinicians, researchers and educators with widely varying backgrounds, training, and experiences. There was broad consensus that the original recommendations from the AERTI, summarized below, remain sound. In addition, noteworthy progress has been made in recent years toward several of the goals defined in the AERTI. Finally, there was broad agreement that the philosophy articulated in the AERTI report remains sound: “Fostering advanced education and research within the field is important because the resulting infrastructure will lead to higher quality, more effective health care that is of better value to society. This would create a culture within the profession that values science and expects clinicians to consume and apply research.

Walking kinematics in young children with limb loss using early versus traditional prosthetic knee prescription protocols

The traditional treatment protocol for young children with congenital or acquired amputations at or proximal to the knee prescribes a prosthesis without a working knee joint, based in part on the assumption that a child learning to walk cannot properly utilize a passively flexing prosthetic knee component. An alternative to this Traditional Knee (TK) protocol is an “Early Knee” (EK) protocol, which prescribes an articulating prosthetic knee in the child’s first prosthesis, during development of crawling and transitioning into and out of upright positions. To date, no study has compared samples of children with limb loss at or proximal to the knee using TK and EK protocols. The purpose of this multi-site study was to examine kinematic outcomes during walking in separate groups of young children in an EK and a TK prosthesis protocol, along with a population of children without lower limb amputations. Eighteen children aged 12 months to five years were recruited for this study at two clinical sites, six in each of the three groups. Children in the two prosthesis groups had unilateral limb loss and had been treated either at one site with the TK protocol or at another with the EK protocol. Children in the EK group achieved swing phase prosthetic knee flexion averaging 59.8±8.4 degrees. Children wearing prosthetic limbs walked slower than age-matched peers. In most instances, walking speed and step length increased with age in the EK group, similar to the control group. However, this trend was not observed in the TK group. Clearance adaptations were present in both limb loss groups. Observed adaptations were twice as prevalent in the TK group versus the EK group; however, the groups differed in age and etiology. Children with limb loss provided with an articulating knee component in their first prosthesis incorporated knee flexion during swing phase and showed fewer gait adaptations than children in the TK protocol

Walking and Balance in Children and Adolescents with Lower-limb Amputation: A Review of Literature

Background Children with lower limb loss face gait and balance limitations. Prosthetic rehabilitation is thus aimed at improving functional capacity and mobility throughout the developmental phases of the child amputee. This review of literature was conducted to determine the characteristics of prosthetic gait and balance among children and adolescents with lower-limb amputation or other limb loss. Methods Both qualitative and quantitative studies were included in this review and data were organized by amputation etiology, age range and level of amputation. Findings The findings indicated that the structural differences between children with lower-limb amputations and typically developing children lead to functional differences. Significant differences with respect to typically developing children were found in spatiotemporal, kinematic, and kinematic parameters and ground-reaction forces. Children with transtibial amputation place significantly larger load on their intact leg compared to the prosthetic leg during balance tasks. In more complex dynamic balance tests, they generally score lower than their typically developing peers. Interpretation There is limited literature pertaining to improving physical therapy protocols, especially for different age groups, targeting gait and balance enhancements. Understanding gait and balance patterns of children with lower-limb amputation will benefit the design of prosthetic components and mobility rehabilitation protocols that improve long-term outcomes through adulthood