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INTRODUCTION The gait characteristic of cadence is commonly presented as step number per unit of time, typically per one minute, and has been found to be applicable to many conditions and interventions (Arch et al., 2017). This measure has been used in a variety of populations including those utilizing orthotic and prosthetic interventions. Cadence has increased value to individuals with LEA as measured ability to vary cadence is currently a necessary criteria for access to advanced prosthetic technology in the United States and has been considered for adoption in other developed countries including Canada, Australia, and Japan. While cadence is regularly measured with 3D kinematic systems as reported in the literature, lack of validated and reliable methods of its determination using observational gait analysis methods and calculation have prevented widespread clinical translation (Handa et al., 2007). The 10-Meter Walk Test (10MWT) and Four Square Step Test (FSST) are commonly used clinical outcome measures with strong psychometric properties. The purpose of this study is to develop a methodology for calculating cadence in from these tests in real time and to determine feasibility using convenient samples of healthy subjects from multiple sites. METHOD This multi-site study protocol was approved by the Institutional Review Board of Loma Linda University (LLU), Loma Linda, CA. Convenient samples of 20 subjects were recruited from the student bodies of LLU and Eastern Michigan University, Ypsilanti, MI, each for a total sample of 40 (n = 40). Each subject was tested in two sessions on the same day in consecutive weeks while being recorded on video and timed by two live raters. Tests were both completed at comfortable and fastest possible speeds. A discrete step timing method was used to determine cadence from each test with live times compared to video. Concurrent validity and inter-rater, intra-rater, and test-retest reliability were determined primarily using ICCs calculated with the Pearson product-moment method and determined secondarily using an analysis of variance. ICCs were also calculated between tests. RESULTS Psychometric properties ranged from adequate to excellent. Direct error of 3.97% and 9.73% for cadence calculation was measured for the 10MWT and FSST, respectively. Percent differences of 43.1% and 33.0% were found for cadence between comfortable and fastest conditions, correspondingly. DISCUSSION The results of this study developed the method of discrete step timing for determining cadence in real-time from the 10MWT and FSST at comfortable and fastest possible walking speeds. The method was found to be feasible when utilizing healthy subjects tested at two university sites in the United States. Healthy subjects have been previously used in cadence validation studies. Since the percent difference between the comfortable and fastest possible conditions for both tests exceeded the direct error, these subjects can be said to have variable cadence. Further, the ICCs between the tests at both speed conditions are less than the ICC between the FSST and FSST-FP, which previously demonstrated the ability to determine variable cadence. This shows, at least preliminarily, that variable cadence can be determined between different tests as well as within the same test. CONCLUSION A method of discrete step timing was used to calculate cadence of patients is real-time while completing the 10MWT and FSST at comfortable and fastest possible speed conditions. Further analysis determined variable cadence can be determined in this matter not only within each test, but between tests using differing constructs. [ABSTRACT FROM AUTHOR]

Purpose: To present population data on standardized measures of dexterity, activity performance, disability, health-related quality of life (HRQoL) and community integration for persons with upper limb amputation (ULA), compare outcomes to normative values, and examine differences by prosthesis type and laterality (unilateral vs. bilateral amputation)., Materials and Methods: Multi-site, cross-sectional design, with in-person evaluations, functional performance, and self-report measures. Descriptive and comparative analyses were performed by amputation level and prosthesis type, data were compared for unilateral and bilateral amputation., Results: One hundred and twenty-seven individuals participated; mean age 57 years, 59% percent body-powered prostheses users. All measures of dexterity differed ( p  < 0.05) by amputation level and by laterality. All measures of activity differed by amputation level with the best scores in transradial (TR) amputation groups. Comparisons of body-powered users with TR amputation found that dexterity was better for those with bilateral compared to unilateral amputation., Conclusions: Dexterity is markedly impaired in persons with ULA. Individuals with more proximal ULA levels are most impacted. HRQoL and community participation are less impacted and more equivalent to unimpaired persons. Further research is needed to examine differences by terminal device type and determine how best to match persons with ULA to the optimal prosthesis type and componentry, based on individual characteristics.Implications for RehabilitationThis study provides population-based, comparative data on dexterity, activity performance, disability, quality of life, and independence in upper limb prosthesis users.The study provides preliminary analyses comparing the effectiveness of body-powered devices, myoelectric devices with single degree of freedom and multi-degree of freedom terminal devices.The data presented in this study can be used to benchmark outcomes in patients who are upper limb prosthesis users.The data will also be useful to inform comparative evaluations of existing and emerging prosthetic technology.

Background: No previous studies have followed prosthesis users with upper limb loss or limb deficiency using their own prostheses to assess change over time., Objectives: (1) To describe prostheses and terminal device types used at baseline and 1-year follow-up; (2) to examine changes in functional outcomes and device satisfaction over time; and (3) to examine whether changes in outcomes varied across level of amputation and type of prosthesis used., Study Design: Multisite, observational time series design with in-person functional performance and self-report data collected at baseline and 1-year follow-up., Methods: Baseline and follow-up outcome scores were compared using Wilcoxon signed-rank tests. Analyses were stratified by amputation level, time since amputation, prosthesis type, and change in device type. Published minimal detectable change (MDC) values were used to determine whether detectable change in outcome measures occurred., Results: The longitudinal cohort consisted of 64 participants (mean age 64 years, 56% body-powered users). The only significant differences in outcome measures between baseline and follow-up (after adjustment for false discovery) were hours/day of prosthesis use, which increased from 6.0 (4.4) to 7.3 (5.3) hours (P = 0.0022). Differences in prosthesis use intensity remained significant in analyses stratified by amputation level, time since amputation, prosthesis type, and change in device type. Between 14 and 20% of the sample had change in one or more outcome measures that was greater than the known MDC., Conclusions: Most participants had stable outcomes over a year's time, whereas 14-20% experienced either improvement or decline in one or more tests indicating the importance of annual follow-up visits., (Copyright © 2021 International Society for Prosthetics and Orthotics.)

Background: The most crucial aspect of a prosthesis is the socket, as it will directly determine gait stability and quality. The current standard of care ischial ramus containment socket is reported to increase coronal stability through gait; however, socket discomfort is the primary complaint among prosthetic users., Objectives: The purpose of this study is to compare ischial ramus containment to alternatives in the transfemoral amputee population. All subjects were fit with three different sockets: traditional ischial ramus containment, a dynamic socket, and a sub-ischial. In this study, authors hypothesized socket skeletal motion would be equivalent across interventions., Study Design: Single-blind, repeated-measures, three-period randomized crossover clinical trial., Methods: Outcome measures were socket comfort score and skeletal motion, viewed coronally with X-ray measuring the position of the skeleton in relationship to the socket in full weight-bearing and full un-loading., Results: The mean age was 38.2 and mean Amputee Mobility Predictor score was 40. Mean vertical movement, horizontal movement, single limb prosthetic stance, mean femoral adduction in swing and stance, and median socket comfort score were not statistically different., Conclusion: The socket design did not significantly effect skeletal motion and socket comfort. All socket designs are suitable depending on the patient-centric preferences and prosthetist skill set., Clinical Relevance: The comfort of the standard of care transfemoral amputation socket has been widely reported as problematic. A comparison of alternative designs in a controlled clinical trial environment will assist the clinician in understanding the impact of design regarding skeletal motion and comfort. Users could benefit from alternatives applied in clinical practice.

Study Design: A nonrandomized, two-armed prospective study., Objective: Water-tight dural closure is paramount to the prevention of cerebrospinal fluid (CSF) leakage and associated complications. Synthetic polyethylene glycol (PEG) hydrogel has been used as an adjunct to sutured dural repair; however, its expansion postoperatively is a concern for neurological complications. A low-swell formulation of PEG sealant was introduced as DuraSeal Exact Spine Sealant System (DESS). A Post-Approval Study was performed primarily to evaluate the safety and efficacy of DESS for spinal dural repair compared to current alternatives, in a large patient population, reflecting a real-world practice., Methods: A total of 36 sites in the United States enrolled 429 patients treated with DESS as an adjunct to dural repair in the spinal sealant group and 406 patients treated with all other modalities in the control arm, from October 2011 to June 2016. The primary endpoint was the incidence of CSF leak within 90 days of operation. The secondary endpoints evaluated were deep surgical site infection and neurological serious adverse events., Results: The CSF leakage in the DESS group (6.6%) was not significantly different from the control group (6.5%) ( p = .83), and there was no significant difference in the time to first leak. The two groups had no significant differences in deep surgical site infection (1.6% versus control 2.1%, p = .61) or proportion of subjects with neurological serious adverse events (2.9% versus control 1.6%, p = .516)., Conclusions: DuraSeal Exact Spinal Sealant is safe when compared to current alternatives for spinal dural repair., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: The device is approved by the Food and Drug Administration. Although the authors have not received or will receive benefits for person or professional use from a commercial party related directly or indirectly to the subject of this manuscript, benefits have been or will be received but are directed solely to a research fund, foundation, educational institution, or other nonprofit organization with which the authors have been associated. The study and the preparation of the manuscript was supported by a commercial party related to the subject of the manuscript.

Study Design: Prospective, multicenter, randomized, and controlled Investigational Device Exemption clinical trial., Objective: To compare the clinical safety and effectiveness of the selectively constrained SECURE-C (Globus Medical, Audubon, PA) Cervical Artificial Disc to anterior cervical discectomy and fusion (ACDF)., Summary of Background Data: Cervical total disc replacement has been developed as an alternative to ACDF by allowing segmental motion. Current cervical total disc replacement designs incorporate constrained and unconstrained metal-on-metal or metal-on-polymer articulating designs with various means of fixation., Methods: A total of 380 patients from 18 investigational sites were prospectively enrolled in the study. Patients were randomized, treated surgically, and evaluated postoperatively at 6 weeks, 3 months, 6 months, 12 months, and 24 months. Clinical outcomes include overall success, visual analogue scale pain (right arm, left arm, and neck), neck disability index, neurological status, Short Form 36 (SF-36) Health Status Survey questionnaires, range of motion, and adverse events. Bayesian statistical methods were used to analyze the outcomes., Results: Overall success results demonstrated statistical superiority of the randomized SECURE-C group compared with the randomized ACDF group at 24 months, with a posterior probability of 100% using the protocol-specified criteria and 98.1% using Food and Drug Administration-defined criteria. At 24 months postoperatively, SECURE-C demonstrated clinically significant improvement in pain and function in terms of neck disability index, visual analogue scale, and 36-Item Short Form Health Survey. At 24 months, the percentage of patients experiencing secondary surgical interventions at the index level was statistically lower for the SECURE-C group (2.5%) than the ACDF group (9.7%). At 24 months, 84.6% of as-treated SECURE-C patients were range-of-motion successes. Satisfaction was high among SECURE-C patients., Conclusion: The selectively constrained SECURE-C Cervical Artificial Disc is as safe and effective as the standard of care, an anterior cervical discectomy and fusion. SECURE-C is statistically superior in terms of overall success, index-level subsequent surgical procedures, and patient satisfaction, making it an attractive surgical option for patients with symptomatic cervical disc disease., Level of Evidence: 1.

Attention is important for sufficient performance on many visual tasks. This has been shown using achromatic steady-state and pattern-reversal VEPs. Waveform characteristics typically attenuate when attending to distractor stimuli and ignoring VEP stimuli. Chromatic pattern-onset responses have not been tested under conditions of selective attention: as they can be used in clinical settings to test color vision, it is important to know what effects attentional shifts would have on this response. In the present study chromatic pattern-onset VEPs were recorded using spatially divided and spatially contiguous VEP and distractor stimuli. VEP stimuli were 1 cycle.deg(-1) horizontal sine wave patterns (onset mode 100 ms on/400 ms off) used to selectively modulate the L-M and S-(L+M) visual pathways. Distracter stimuli were letters. Subjects attended to either the letters or the gratings and pressed a button when a predetermined stimulus appeared. In Experiment one, VEP and distractor stimuli were superimposed and spatially contiguous. In Experiment two, stimuli were presented to different hemifields. No significant changes in waveform amplitude and latency were found between VEP and distractor attention conditions for either visual pathway. For the chromatic pattern-onset response, modulation of attention does not change responses either with spatially contiguous or spatially separate selective attention manipulations. Consequently, it may not be necessary to monitor attention during recording of this response., (© 2010 The Authors, Ophthalmic and Physiological Optics © 2010 The College of Optometrists.)

Purpose: Intra-ocular pressure (IOP) increases to double that of its normal level under full-body inversion, in part simulating high IOPs found in glaucoma and ocular hypertension. Inversion also simulates negative g-forces experienced in aerobatic maneuvers such as those produced during aerial combat. Studies using achromatic pattern-reversal visual evoked potentials (VEPs) have shown losses in response amplitude when subjects are inverted and IOP is increased. In other studies, chromatic, pattern-onset VEPs have been shown to be a sensitive and objective indicator of ocular and systemic pathology. Thus, chromatic pattern-onset VEPs may also show changes in amplitude and/or latency when subjects are subjected to full-body inversion., Methods: In this study we employed chromatic, pattern-onset VEPs to determine if there were changes in response latency for the different visual pathways with healthy subjects during full-body inversion. Stimuli were 1 cpd horizontal sine-wave patterns presented in an onset mode (100 ms on/400 ms off). Subjects (n = 7) were tested at low to medium contrast levels, which were subjectively equated across chromatic pathways (S, LM, and achromatic). Patterns were presented using LCD goggles., Results: All subjects showed a small but statistically significant increase in latency in the large negative component (CII) for both L - M and S - (L + M) pathways during inversion. The achromatic pathway also showed a statistically significant increase in latency to the positive component (CI) during inversion., Conclusions: These results demonstrate that changes in ocular and/or systemic physiology during full-body inversion can result in increased latencies of chromatic and achromatic pattern-onset VEPs.

X-linked incomplete achromatopsia (XIA), also called blue-cone monochromacy (BCM), is a rare cone disorder that most commonly results either from one of two conditions. The first condition is a deletion of the locus control region (LCR) which is a critical DNA element that lies upstream of the L and M photopigment gene array on the X-chromosome and is necessary for expression of the photopigment genes. The second condition is an inactivating point mutation within the coding sequence of the remaining photopigment gene in an array from which all but one gene has been deleted. Many previous studies have concluded that affected individuals either have only rods and S-cones (Blackwell & Blackwell, 1957, 1961; Daw & Enoch, 1973; Hess et al., 1989) or have rods, S-cones, and another cone type that contains the rod pigment (Pokorny et al., 1970; Alpern et al., 1971). However, Smith et al. (1983) described individuals with XIA who had residual L-cone function. Here we report results for a subject with XIA who appears to have residual M-cone function. Genetic analysis revealed that he had apparently normal genes for M-cone photopigment thus leaving open the possibility that he has a contribution to vision based on expression of these genes at a very low level.