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Tyrell CM, Helm E, Reisman DS. Learning the spatial features of a locomotor task is slowed after stroke. J Neurophysiol 112: 480 -489, 2014. First published April 30, 2014 doi:10.1152/jn.00486.2013The capacity for humans to learn a new walking pattern has been explored with a split-belt treadmill during single sessions of adaptation, but the split-belt treadmill can also be used to study longer-term motor learning. Although the literature provides some information about motor learning after stroke, existing studies have primarily involved the upper extremity and the results are mixed. The purpose of this study was to characterize learning of a novel locomotor task in stroke survivors. We hypothesized that the presence of neurological dysfunction from stroke would result in slower learning of a locomotor task and decreased retention of what was learned and that these deficits would be related to level of sensorimotor impairment. Sixteen participants with stroke and sixteen neurologically intact participants walked on a split-belt treadmill for 15 min on 5 consecutive days and during a retention test.Step length and limb phase were measured to capture learning of the spatial and temporal aspects of walking. Learning the spatial pattern of split-belt treadmill walking was slowed after stroke compared with neurologically intact subjects, whereas there were no differences between these two groups in learning the temporal pattern. During the retention test, poststroke participants demonstrated equal retention of the split-belt treadmill walking pattern compared with those who were neurologically intact. The results suggest that although stroke survivors are slower to learn a new spatial pattern of gait, if given sufficient time they are able to do so to the same extent as those who are neurologically intact. stroke; locomotion; learning; adaptation MOTOR LEARNING is traditionally defined as a persistent change in a movement that occurs over long-term practice and experience and that results in stable performance (Schmidt 1988;Schmidt and Wrisberg 2000). The process of learning begins with exposure to the task, followed by consolidation, which is a set of processes that involve changes in the central nervous system leading to a long-term memory that is resistant to disruption or interference by other motor activity (Krakauer and Shadmehr 2006;Stickgold and Walker 2007). These processes ultimately lead to the ability to recall the newly learned motor skill in the appropriate context or environment.The capacity for humans to learn a new walking pattern has been explored with a split-belt treadmill (Malone et al. 2011) and a rotating treadmill (Earhart et al. 2001). During walking on a rotating treadmill, subjects adapt their walking pattern while walking in place on the perimeter of a rotating disk. After ϳ30 min of exposure, when the subjects are blindfolded and asked to walk under normal conditions they demonstrate an involuntary and significant curvature of their walking trajectory. The split-belt treadmill is a trea...

Brain-derived neurotrophic factor (BDNF) has been directly related to exercise-enhanced motor performance in the neurologically injured animal model; however literature concerning the role of BDNF in the enhancement of motor learning in the human population is limited. Previous studies in healthy subjects have examined the relationship between intensity of an acute bout of exercise, increases in peripheral BDNF and motor learning of a simple isometric upper extremity task. The current study examined the role of high intensity exercise on upregulation of peripheral BDNF levels as well as the role of high intensity exercise in mediation of motor skill performance and retention of a novel locomotor task in neurologically intact adults. In addition, the impact of a single nucleotide polymorphism in the BDNF gene (Val66Met) in moderating the relationship between exercise and motor learning was explored. It was hypothesized that participation in high intensity exercise prior to practicing a novel walking task (split-belt treadmill walking) would elicit increases in peripheral BDNF as well as promote an increased rate and magnitude of within session learning and retention on a second day of exposure to the walking task. Within session learning and retention would be moderated by the presence or absence of Val66Met polymorphism. Fifty-four neurologically intact participants participated in two sessions of split-belt treadmill walking. Step length and limb phase were measured to assess learning of spatial and temporal parameters of walking. Serum BDNF was collected prior to and immediately following either high intensity exercise or 5 minutes of quiet rest. The results demonstrated that high intensity exercise provides limited additional benefit to learning of a novel locomotor pattern in neurologically intact adults, despite increases in circulating BDNF. In addition, presence of a single nucleotide polymorphism on the BDNF gene did not moderate the magnitude of serum BDNF increases with high intensity exercise, nor did it moderate the relationship between high intensity exercise and locomotor learning.

Background and Purpose In rehabilitation, examining how variables change over time can help to define the minimal number of training sessions required to produce a desired change. The purpose of this study was to identify the time course of changes in gait biomechanics and walking function in persons with chronic stroke. Methods Thirteen persons > 6 months post-stroke participated in 12 weeks of fast treadmill training combined with plantar- and dorsi-flexor muscle functional electrical stimulation (FastFES). All participants completed testing before the start of intervention, after 4, 8 and 12 weeks of FastFES locomotor training. Results Peak limb paretic propulsion, paretic limb propulsive integral, peak paretic limb knee flexion, (p<0.05 for all) and peak paretic trailing limb angle (p<0.01) improved from pre-training to 4 weeks but not between 4 and 12 weeks. Self-selected walking speed and 6-minute walk test distance improved from pre-training to 4 weeks and from 4 to 12 weeks (p<0.01 and p<0.05, respectively for both). Timed Up & Go test time did not improve between pre-training and 4 weeks, but improved by 12 weeks (p=0.24 and p<0.01, respectively). Discussion and Conclusions The results demonstrate that walking function improves with a different time course compared to gait biomechanics in response to a locomotor training intervention in persons with chronic stroke. Thirty-six training sessions were necessary to achieve an increase in walking speed that exceeded the MCID. These finding should be considered when designing locomotor training interventions after stroke. Video Abstract available (see Video, Supplemental Digital Content 1) for more insights from the authors.

An acute high-intensity exercise bout that could be incorporated into a neurorehabilitation learning-specific session and results in substantial exercise-induced responses is feasible post-stroke.

Background: Cancer rehabilitation often includes manual assessment and interventions to address cancer treatment–related side effects. The effect of reduced access to rehabilitative care due to COVID-19 is currently unknown. Objective/Purpose: To assess distress and quality of life (QOL) for women receiving care for breast cancer–related impairments during closure of rehabilitation services due to COVID-19. Methods: Preexisting patients returning to rehabilitation services after a COVID-19–associated interruption of treatment were asked to complete a survey regarding their distress, function, and QOL levels at the suspension of rehabilitation services and at the resumption of those services. Setting and Patients: Outpatient cancer rehabilitation clinic treating breast cancer survivors at an accredited cancer center. Measurements: Distress thermometer, FACT-G (Functional Assessment of Cancer Therapy–General) survey, and visual analog scale questions regarding sleep, fatigue, and physical activity as part of reassessment by the clinician. Utility of telehealth was also explored. Results: Fifteen women (age range, 38-76 years) with primary complaints of shoulder stiffness, pain, and lymphedema completed surveys, and 33% received telehealth. Reported distress levels at the time of closure were significantly higher than self-reported levels at reopening (t 14 = 4.69, P = .000). Increases in distress at the time of closure were correlated with reduced physical activity (r = −0.602, P = .018). Reduced levels of distress following return to rehabilitation were correlated with reduced levels of fatigue (r = 0.575, P = .025). No statistically significant relationships between distress and sleep quality were found. Limitations: Self-report via surveys, recall bias, and the multifactorial characteristics of distress limit study findings. Conclusion: Closure of rehabilitation services during COVID-19 created distress, resulting in reduced physical activity and QOL in breast cancer survivors. Cancer survivorship communities will need to assess the effect of disrupted service across cancer rehabilitation centers. Further research is needed to validate optimal interventions including telehealth best practice to manage distress and QOL in a COVID-19 context.

Stroke survivors without cerebellar involvement retain the ability to adapt to the split-belt treadmill, however it has been suggested that their rate of adaptation may be slowed compared to those who are neurologically intact. Depending on limb placement, the split-belt treadmill can be configured to either exaggerate baseline asymmetry, or reduce it, which may affect the behavior of adaptation or de-adaptation. The objectives of this study were to characterize the rate and magnitude of locomotor (de)adaptation in chronic stroke survivors compared to healthy matched subjects, and to evaluate whether exaggeration or reduction of baseline asymmetry impact the responses. Seventeen stroke survivors and healthy subjects completed 10 minutes of split-belt treadmill walking, then 5 minutes of tied-belt walking. Stroke survivors completed this once with each leg on the fast belt. Magnitude and rate of (de)adaptation were evaluated for step length and limb phase asymmetry. There were no differences between the groups with the exception of the reduced step length asymmetry configuration, in which case there was a significantly reduced magnitude (p=<0.000) and rate (p=0.011) of adaptation when compared to controls. There was a similar trend observed during post-adaptation for the exaggerated asymmetry group. The rate and magnitude of locomotor (de)adaptation is similar between chronic stroke survivors and neurologically intact controls, except when the adaptation or de-adaptation response would take the stroke survivors away from a symmetric step length pattern. This suggests that there may be some benefit to symmetry that is recognized by the system.

Induction of neural plasticity through motor learning has been demonstrated in animals and humans. Brain derived neurotrophic factor (BDNF), a member of the neurotrophin family of growth factors, is thought to play an integral role in modulation of central nervous system plasticity during learning and motor skill recovery. Thirty percent of humans possess a single nucleotide polymorphism on the BDNF gene (Val66Met), which has been linked to decreased activity dependent release of BDNF. Presence of the polymorphism has been associated with altered cortical activation, short term plasticity and altered skill acquisition, and learning in healthy humans. The impact of the Val66Met polymorphism on motor learning post-stroke has not been explored. The purpose of this study was to examine the impact of the Val66Met polymorphism in learning of a novel locomotor task in subjects with chronic stroke. It was hypothesized that subjects with the polymorphism would have an altered rate and magnitude of adaptation to a novel locomotor walking paradigm (the split-belt treadmill), compared to those without the polymorphism. The rate of adaptation was evaluated as the reduction in gait asymmetry during the first 30 (early adaptation) and last 100 (late adaptation) strides. Twenty-seven individuals with chronic stroke participated in a single session of split-belt treadmill walking and tested for the polymorphism. Step length and limb phase were measured to assess adaptation of spatial and temporal parameters of walking. The rate of adaptation of step length asymmetry differed significantly between those with and without the polymorphism, while the amount of total adaptation did not. These results suggest that chronic stroke survivors, regardless of presence or absence of the polymorphism, are able to adapt their walking pattern over a period of trial and error practice, however the presence of the polymorphism influences the rate at which this is achieved.