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Objective. Many physical therapist interventions provided to individuals with chronic stroke can lead to gains in gait speed or endurance (eg, 6-Minute Walk Test [6MWT]), although changes in objective measures of participation are not often observed. The goal of this study was to determine the influence of different walking interventions on daily stepping (steps per day) and the contributions of demographic, training, and clinical measures to these changes. Methods. In this secondary analysis of a randomized clinical trial, steps per day at baseline and changes in steps per day following 1 of 3 locomotor interventions were evaluated in individuals who were ambulatory and >6 months after stroke. Data were collected on 58 individuals who received [less than or equal to]30 sessions of high-intensity training (HIT) in variable contexts (eg, tasks and environments; n = 19), HIT focused on forward walking (n = 19), or low-intensity variable training (n = 20). Primary outcomes were steps per day at baseline, at post-training, and at a 3-month follow-up, and secondary outcomes were gait speed, 6MWT, balance, and balance confidence. Correlation and regression analyses identified demographic and clinical variables associated with steps per day. Results. Gains in steps per day were observed across all groups combined, with no between-group differences; post hoc within-group analyses revealed significant gains only following HIT in variable contexts. Both HIT groups showed gains in endurance (6MWT), with increases in balance confidence only following HIT in variable contexts. Changes in steps per day were associated primarily with gains in 6MWT, with additional associations with baseline 6MWT, lower-extremity Fugl-Meyer scores, and changes in balance confidence. Conclusion. HIT in variable contexts elicited gains in daily stepping, with changes primarily associated with gains in gait endurance. Impact. Providing HIT in variable contexts appears to improve measures of participation (eg, daily stepping) that may be associated with clinical measures of function. Gains in multiple measures of mobility and participation with HIT in variable contexts may improve the efficiency and value of physical therapy services. Keywords: Community Mobility, Locomotion, Physical Activity, Rehabilitation, Introduction Most individuals with chronic (>6 months) stroke recover some degree of locomotor function, (1) although persistent neurologic deficits result in decreased gait speed and endurance as well as reduced [...]

Background. The 6-Minute Walk Test (6MWT) is a common clinical assessment used to evaluate locomotor function in patients after stroke. Previous work suggests the 6MWT can estimate peak metabolic capacity [...]

Background. High-intensity stepping practice may be a critical component to improve gait following motor incomplete spinal cord injury (ISCI). However, such practice is discouraged by traditional theories of rehabilitation that suggest high-intensity locomotor exercise degrades gait performance. Accordingly, such training is thought to reinforce abnormal movement patterns, although evidence to support this notion is limited. Objective. The purposes of this study were: (1) to evaluate the effects of short-term manipulations in locomotor intensity on gait performance in people with ISCI and (2) to evaluate potential detrimental effects of high-intensity locomotor training on walking performance. Design, a single-day, repeated-measures, pretraining-posttraining study design was used. Methods. Nineteen individuals with chronic ISCI performed a graded-intensity locomotor exercise task with simultaneous collection of lower extremity kinematic and electromyographic data. Measures of interest were compared across intensity levels of 33%, 67%, and 100% of peak gait speed. A subset of 9 individuals participated in 12 weeks of high-intensity locomotor training. Similar measurements were collected and compared between pretraining and posttraining evaluations. Results. The results indicate that short-term increases in intensity led to significant improvements in muscle activity, spatiotemporal metrics, and joint excursions, with selected improvements in measures of locomotor coordination. High-intensity locomotor training led to significant increases in peak gait speed (0.64-0.80 m/s), and spatiotemporal and kinematic metrics indicate a trend for improved coordination. Limitations. Measures of gait performance were assessed during treadmill ambulation and not compared with a control group. Generalizability of these results to overground ambulation is unknown. Conclusions. High-intensity locomotor exercise and training does not degrade, but rather improves, locomotor function and quality in individuals with ISCI, which contrasts with traditional theories of motor dysfunction following neurologic injury., Spinal cord injury (SCI) results in profound deficits in sensorimotor function, which can contribute to the loss of functional mobility. Following motor incomplete spinal cord injury (ISCI), indicating partial sparing [...]

Background. During the physical rehabilitation of individuals poststroke, therapists are challenged to provide sufficient amounts of task-specific practice in order to maximize outcomes of multiple functional skills within limited visits. Basic and applied studies have suggested that training of one motor task may affect performance of biomechanically separate tasks that utilize overlapping neural circuits. However, few studies have explicitly investigated the impact of training one functional task on separate, nonpracticed tasks. Objective. The purpose of this preliminary study was to investigate the potential gains in specific nonlocomotor assessments in individuals poststroke following only stepping training of variable, challenging tasks at high aerobic intensities. Methods. Individuals with locomotor deficits following subacute and chronic stroke (n=22) completed a locomotor training paradigm using a repeated-measures design. Practice of multiple stepping tasks was provided in variable environments or contexts at high aerobic intensities for [greater than or equal to] 40 sessions over 10 weeks. The primary outcome was timed Five-Times Sit-to-Stand Test (5XSTS) performance, with secondary measures of sit-to-stand kinematics and kinetics, clinical assessment of balance, and isometric lower limb strength. Results. Participants improved their timed 5XSTS performance following stepping training, with changes in selected biomechanical measures. Statistical and clinically meaningful improvements in balance were observed, with more modest changes in paretic leg strength. Conclusions. The present data suggest that significant gains in selected nonlocomotor tasks can be achieved with high-intensity, variable stepping training. Improvements in nonpracticed tasks may minimize the need to practice multiple tasks within and across treatment sessions., More than 80% of survivors of stroke have motor impairments that contribute to limitations in performance of many functional tasks. (1) Therapists often utilize multiple interventions during clinical sessions to [...]

Background. Robotic-assisted locomotor training has demonstrated some efficacy in individuals with neurological injury and is slowly gaining clinical acceptance. Both exoskeletal devices, which control individual joint movements, and elliptical devices, which control endpoint trajectories, have been utilized with specific patient populations and are available commercially. No studies have directly compared training efficacy or patient performance during stepping between devices. Objective. The purpose of this study was to evaluate kinematic, electromyographic (EMG), and metabolic responses during elliptical- and exoskeletal-assisted stepping in individuals with incomplete spinal cord injury (SCI) compared with therapist-assisted stepping. Design. A prospective, cross-sectional, repeated-measures design was used. Methods. Participants with incomplete SCI (n=11) performed 3 separate bouts of exoskeletal-, elliptical-, or therapist-assisted stepping. Unilateral hip and knee sagittal-plane kinematics, lower-limb EMG recordings, and oxygen consumption were compared across stepping conditions and with control participants (n=10) during treadmill stepping. Results. Exoskeletal stepping kinematics closely approximated normal gait patterns, whereas significantly greater hip and knee flexion postures were observed during elliptical-assisted stepping. Measures of kinematic variability indicated consistent patterns in control participants and during exoskeletal-assisted stepping, whereas therapist- and elliptical-assisted stepping kinematics were more variable. Despite specific differences, EMG patterns generally were similar across stepping conditions in the participants with SCI. In contrast, oxygen consumption was consistently greater during therapist-assisted stepping. Limitations. Limitations included a small sample size, lack of ability to evaluate kinetics during stepping, unilateral EMG recordings, and sagittal-plane kinematics. Conclusions. Despite specific differences in kinematics and EMG activity, metabolic activity was similar during stepping in each robotic device. Understanding potential differences and similarities in stepping performance with robotic assistance may be important in delivery of repeated locomotor training using robotic or therapist assistance and for consumers of robotic devices., Current evidence supports the use of repetitive, task-specific practice in patients with neurological injury to improve locomotor function. Gait training, or locomotor training (LT), (1,2) provided to patients with neurological [...]

Background. In individuals with motor incomplete spinal cord injury (SCI), ambulatory function determined in the clinical setting is related to specific measures of body structure and function and activity limitations, although few studies have quantified the relationship of these variables with daily stepping (steps/day). Objective. The aim of this study was to quantify daily stepping in ambulatory individuals with SCI and its relationship with clinical walking performance measures and specific demographics, impairments, and activity limitations. Design. A cross-sectional study was performed to estimate relationships among clinical variables to daily stepping in serf-identified community versus non-community (household) walkers. Methods, Average daily stepping was determined in 50 people with chronic, motor incomplete SCI. Data for clinical and serf-report measures of walking performance also were collected, and their associations with daily stepping were analyzed using correlation and receiver operating characteristic (ROC) analyses. Relationships between daily stepping and the measures of demographics, impairments, and activity limitations were identified using correlation and regression analyses. Results. The ROC analyses revealed a significant discriminative ability between self-reported community and non-community walkers using clinical gait measures and daily stepping. Stepping activity generally was low throughout the sample tested, however, with an average of approximately 2,600 steps/day. Knee extension strength (force-generating capacity) and static balance were the primary variables related to daily stepping, with metabolic efficiency and capacity and balance confidence contributing to a lesser extent. Limitations. The small sample size and use of specific impairment-related measures were potential limitations of the study. Conclusions. Daily stepping is extremely limited in individuals with incomplete SCI, with a potentially substantial contribution of impairments in knee extension strength and balance., Spinal cord injury (SCI) is a common cause of disability, with an incidence rate of more than 12,000 cases per year in the United States alone. (1) The incidence of [...]

Background. Locomotor training (LT) to improve walking ability in people poststroke can be accomplished with therapist assistance as needed to promote continuous stepping. Various robotic devices also have been developed that can guide the lower limbs through a kinematically consistent gait pattern. It is unclear whether LT with either therapist or robotic assistance could improve kinematic coordination patterns during walking. Objective. The purpose of this study was to determine whether LT with physical assistance as needed was superior to guided, symmetrical, robotic-assisted LT for improving kinematic coordination during walking poststroke. Design. This study was a randomized clinical trial. Methods. Nineteen people with chronic stroke (>6 months' duration) participating in a larger randomized control trial comparing therapist- versus robotic-assisted LT were recruited. Prior to and following 4 weeks of LT, gait analysis was performed at each participant's self-selected speed during overground walking. Kinematic coordination was defined as the consistency of intralimb hip and knee angular trajectories over repeated gait cycles and was compared before and after treatment for each group. Results. Locomotor training with therapist assistance resulted in significant improvements in the consistency of intralimb movements of the impaired limb. Providing consistent kinematic assistance during robotic-assisted LT did not result in improvements in intralimb consistency. Only minimal changes in discrete kinematics were observed in either group. Limitations. The limitations included a relatively small sample size and a lack of quantification regarding the extent of movement consistency during training sessions for both groups. Conclusions. Coordination of intralimb kinematics appears to improve in response to LT with therapist assistance as needed. Fixed assistance, as provided by this form of robotic guidance during LT, however, did not alter intralimb coordination., Locomotor training (LT) using a treadmill with body-weight support (BWS) has been advocated for improving walking in individuals with hemiparesis poststroke. (1) Specific afferent inputs provided during LT, including maximizing [...]

Background and Objective. Evidence for specific physical interventions that improve walking symmetry in individuals with hemiparesis poststroke is limited. The aim of this study was to investigate the rapid and prolonged effects of unilateral step training (UST) on step length asymmetry (SLA) in people with hemiparesis. Subjects and Design. Eighteen individuals with chronic hemiparesis and substantial SLA during overground walking participated in a single-group, pretest-posttest study. The study consisted of 2 phases, with 10 subjects participating in each phase; 2 subjects participated in both phases. Interventions and Measurements. To investigate rapid effects of UST, the participants completed a 20-minute session of UST on a treadmill with their unimpaired limb, with the impaired limb held stationary off the treadmill. Data for spatiotemporal gait parameters during overground walking at self-selected and fastest speeds were collected prior to and following UST, with follow-up measurements at 1 day and 1 week. To investigate the prolonged effects, the participants completed ten 20-minute sessions of UST. Data for spatiotemporal gait parameters were collected prior to training as well as after every third session, with follow-up measurements at 1 and 2 weeks. Results. Immediately following UST, SLA tested during fast-paced overground walking improved by up to 13% (49% reduced to a 36% SLA), with changes retained for up to 24 hours. Following 10 sessions of UST, SLA improved significantly, with changes retained for up to 2 weeks. Limitations. Despite repeated baseline measurements, the absence of a control group was a limitation. Furthermore, stepping characteristics during UST were not quantified. Conclusion. Unilateral step training may improve spatiotemporal patterns in people with substantial gait asymmetry poststroke. Repeated training may be necessary for maintenance of adaptations., Despite substantial recovery of independent ambulation in individuals following unilateral stroke, persistent gait abnormalities are observed in a large percentage of these individuals and are a priority for rehabilitation interventions. [...]

Background and Purpose. Robotic devices that provide passive guidance and stabilization of the legs and trunk during treadmill stepping may increase the delivery of locomotor training to subjects with neurological injury. Lower-extremity guidance also may reduce voluntary muscle activity as compared with compliant assistance provided by therapists. The purpose of this study was to investigate differences in metabolic costs and lower-limb muscle activity patterns during robotic- and therapist-assisted treadmill walking. Subjects. Twelve ambulatory subjects with motor incomplete spinal cord injury participated. Methods. In 2 separate protocols, metabolic and electromyographic (EMG) data were collected during standing and stepping on a treadmill with therapist and robotic assistance. During robotic-assisted walking, subjects were asked to match the kinematic trajectories of the device and maximize their effort. During therapist-assisted walking, subjects walked on the treadmill with manual assistance provided as necessary. Results. Metabolic costs and swing-phase hip flexor EMG activity were significantly lower when subjects were asked to match the robotic device trajectories than with therapist-assisted walking. These differences were reduced when subjects were asked to maximize their effort during robotic-assisted stepping, although swing-phase plantar-flexor EMG activity was increased. In addition, during standing prior to therapist- or robotic-assisted stepping, metabolic costs were higher without stabilization from the robotic device. Discussion and Conclusion. Differences in metabolic costs and muscle activity patterns between therapist- and robotic-assisted standing and stepping illustrate the importance of minimizing passive guidance and stabilization provided during step training protocols. Key Words: Gait training, Locomotion, Robotics., The efficacy of locomotor training performed using a treadmill with body-weight support (BWS) to improve walking ability in people with motor incomplete spinal cord injury (SCI) has been investigated for [...]

Background and Purpose. Performance of therapist-assisted, body-weight-supported treadmill training (BWSTT) to enhance walking ability of people with neurological injury is an area of intense research. Its application in the clinical setting, however, is limited by the personnel and labor requirements placed on physical therapists. Recent development of motorized ("robotic") rehabilitative devices that provide assistance during stepping may improve delivery of BWSTT. Case Description. This case report describes the use of a robotic device to enhance motor recovery and ambulation in 3 people following motor incomplete spinal cord injury. Interventions. Changes in motor impairment, functional limitations, and locomotor disability were monitored weekly during robotic-assisted BWSTT and following transition to therapist-assisted BWSTT with the assistance of one therapist. Outcomes. Following this training, 2 patients recovered independent over-ground walking and another improved his gait speed and endurance. Discussion. The use of robotic devices may assist physical therapists by providing task-specific practice of stepping in people following neurological injury. Key Words: Gait training, Locomotion, Rehabilitation, Robotics., Statistics indicate that a large proportion of people with spinal cord injury (SCI) who sustain motor incomplete lesions can regain some recovery of over-ground ambulation. (1-3) Although improvements in motor [...]

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A method for temporal prediction of image sequences is proposed. The motion vectors of conventional block-based motion compensation schemes are used to convey a mapping of a selected set of image points, instead of blocks, between the previous and the current image. The prediction is made by geometrically transforming, or 'warping,' the previous image using the point pairs defined by the mapping as fixed points in the transformation. This method produces a prediction image without block artifacts and can compensate for many motion types where conventional block matching fails, such as scaling and rotation. It can also be incorporated in current hybrid video compression systems with little additional complexity and few or no changes in the bit stream syntax. It is shown that a significant subjective improvement in the prediction as well as a consistent reduction in the objectively measured prediction error is obtained.

In this paper, median based predictors for predictive coding of image sequences are presented. Principles of constructing predictors are discussed after which two approaches of constructing multilevel structures are presented. Simulation results on coding gain, prediction signal entropy and transmission error propagation are presented and compared to an adaptive linear predictor.

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For half a century, Peter F. Drucker has influenced senior executives across the globe with his rare insight into socioeconomic forces and practical advice for navigating often turbulent managerial waters. In his latest contribution to HBR, Drucker discusses the impact of the ideas in his latest work, Post-Capitalist Society, on the day-to-day lives and careers of managers. Drucker argues that managers must learn to negotiate a new environment with a different set of work rules and career expectations. Companies currently face downsizing and turmoil with increasing regularity. Once built to last like pyramids, corporations are now more like tents. In addition, businesses in the post-capitalist society grow through many and varied complicated alliances often baffling to the traditional manager. Confronted by these changes, managers must relearn how to manage. In the new world of business, information is replacing authority as the primary tool of the executive. And, Drucker advises, one embarks on the road toward information literacy not by buying the latest technological gadget but by identifying gaps in knowledge. As companies increasingly become temporary institutions, the manager also must begin to take individual responsibility for himself or herself. To that end, the executive must explore what Drucker calls competencies: a person's abilities, likes, dislikes, and goals, both professional and personal. If executives rise to these challenges, a new organizational foundation will be built. While a combination of rank and power supported the traditional organization, the internal structure of the emerging organization will be mutual understanding and trust. [ABSTRACT FROM PUBLISHER]

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Abstract:The venom with which Demosthenes lambasts Meidias suits both the circumstance of their violent private quarrel as well as the contemporary political climate of the Mediterranean world. This article will reevaluate Demonsthenes’ vitriol in his Against Meidiasto show that the characterization of his opponent plays off Athenian fears specific to tyrannical overthrow. I argue that Demosthenes spins his chief criticisms of Meidias into tyrannical attributes similar to those with which he attacked Philip. Demosthenes’ use of literary tyranny calls into question the reliability of the speech as a source for historical analysis of Athenian hubris.

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Individuals with chronic stroke often demonstrate a “plateau,” or deceleration of motor recovery, which may lead to discharge from physical therapy (PT). However, numerous studies report improvements in motor function when individuals are provided intensive practice of motor tasks. We suggest that reduced task-specific walking practice during clinical PT contributes to limited gains in ambulatory function in those with a perceived plateau poststroke, and suggest that further gains can be realized if intensive stepping, or locomotor training (LT) is provided after discharge.

Locomotor training (LT) using a treadmill can improve walking ability over conventional rehabilitation in individuals with hemiparesis, although the personnel requirements often necessary to provide LT may limit its application. Robotic devices that provide consistent symmetrical assistance have been developed to facilitate LT, although their effectiveness in improving locomotor ability has not been well established.