Papers by Carolee Winstein
Neuroscience Research, May 1, 2007
We estimated the trial-to-trial variability and the test-retest reliability of several intracorti... more We estimated the trial-to-trial variability and the test-retest reliability of several intracortical and corticomotor excitability parameters for the upper extremity in chronic stroke patients. Nine patients with hemiparesis of the upper extremity were enrolled 8-17 months after a unilateral stroke. Transcranial magnetic stimulation was used to obtain repeated measures over a two week interval of motor evoked potential (MEP) recruitment curves and cortical silent periods in the first dorsal interosseus muscle of each hand. Five trials would have provided accurate estimates of the MEP amplitude and silent period duration for the unlesioned side in all patients, but 25% of the datasets from the lesioned side provided poor estimates of MEP amplitude even with 10 trials. Intraclass correlations were >0.70 for all parameters obtained from the lesioned side and for the MEP amplitude, slope of the recruitment curve, silent period, and silent period slope from the unlesioned side. MEP amplitude varied across sessions within subject by 20% on both sides, whereas other parameters showed less variability on the unlesioned side relative to the lesioned side. The Fugl-Meyer upper extremity motor score and the time to complete the 6 fine-motor items from the Wolf Motor Function Test (WMFT) were also found to be highly reliable over this interval. We conclude that the functional and most of the excitability parameters are reliable across time in patients with variable lesions due to stroke. Due to high intrasubject variability, the use of some excitability parameters as indicators of functional neuroplasticity in response to treatment may be limited to interventions with large effect sizes.
The Journals of Gerontology: Series B, Mar 1, 1996
Prolonged movement times in elderly persons have been well documented; however, the locus of this... more Prolonged movement times in elderly persons have been well documented; however, the locus of this slowing is uncertain. Kinematic analysis of discrete aiming has revealed deficits primarily in the target approach phase, suggesting inefficient feedback processing. This study investigated age-related movement slowing in a continuous aiming task, for which movements are mediated by feedforward and on-line sensory processes. Two-dimensional video-recordings were made of young and elderly adults performing reciprocal tapping using the right and left hands under three different accuracy conditions. The elderly subjects exhibited more discrete adjustments in the trajectories coupled with longer times in this period. Further, the elderly spent more time reversing direction between target hits, especially in the high accuracy condition. Longer time on target was seen in the left-hand performance of the elderly. Results suggest that the locus of age-related slowing in the performance of continuous aiming may reflect a greater dependence on slower feedback processes instead of rapid, on-line, and feedforward sensory processes. Age-related differences in hand performance may provide further insight into central processing deficits.
Neurorehabilitation and Neural Repair, Mar 16, 2007
Background-Previous studies report that motor recovery after partial destruction of the primary m... more Background-Previous studies report that motor recovery after partial destruction of the primary motor cortex (M1) may be associated with adaptive functional reorganization within spared M1. Objective-To test feasible methodologies for evaluating relationships between behavioral gains facilitated by rehabilitative training and functional adaptations in perilesional M1 and the cerebellum. Methods-Four patients with hemiparesis for more than 3 months after a cortical lesion partially within M1 and 12 healthy volunteers participated. Functional magnetic resonance imaging (fMRI) using a finger-tapping task and concurrent behavioral assessments, including the Fugl-Meyer Motor Assessment of the upper extremity and the Wolf Motor Function Test, were conducted before and after 2 weeks of arm-focused training; 2 patients were further examined 6 and 12 months later to evaluate long-term persistence of brain-behavior adaptations. Results-All patients showed higher activation magnitude in perilesional M1 than healthy controls before and after therapy. Further long-term functional gains paralleled the decrease of activation magnitude in perilesional M1 in the 2 more impaired cases. Conclusion-The evolution of suggestive correlations between serial scans of fMRI adaptive activity within the primary motor cortex and the cerebellum in relation to relevant behavioral changes over the course of 2 weeks of task-specific therapy and then no formal therapy suggests that repeated assessments may be best for monitoring therapy-induced neuroplasticity. This approach may help develop optimal rehabilitation strategies to maximize poststroke motor recovery as well as improve the search for brain-behavior correlations in functional neuroimaging research.
bioRxiv (Cold Spring Harbor Laboratory), May 12, 2023
Background: Walking patterns in stroke survivors are highly heterogeneous, which poses a challeng... more Background: Walking patterns in stroke survivors are highly heterogeneous, which poses a challenge in systematizing treatment prescriptions for walking rehabilitation interventions. Objective: We used bilateral spatiotemporal and force data during walking to create a multi-site research sample to: 1) identify clusters of walking behaviors in people post-stroke and neurotypical controls, and 2) determine the generalizability of these walking clusters across different research sites. We hypothesized that participants post-stroke will have different walking impairments resulting in different clusters of walking behaviors, which are also different from control participants. Methods: We collected data from 81 post-stroke participants across four research sites and included data from 31 control participants. Using sparse K-means clustering, we identified walking clusters based on 17 spatiotemporal and force variables. We analyzed the biomechanical features within each cluster to characterize cluster-specific walking behaviors. We also assessed the generalizability of the clusters using a leave-one-out approach. Results: We identified five clusters: a fast and asymmetric cluster, a moderate speed and symmetric cluster with short stance times, a moderate speed and asymmetric cluster, a slow cluster with frontal plane force asymmetries, and a slow and symmetric cluster. The moderate speed and asymmetric cluster did not generalize across sites. Conclusions: Although post-stroke walking patterns are heterogenous, these patterns can be systematically classified into distinct clusters based on spatiotemporal and force data. Future interventions could target the key features that characterize each cluster to increase the efficacy of interventions to improve mobility in people post-stroke. .
Journal of Motor Behavior, Sep 16, 2015
Context-dependent learning is a phenomenon in which people demonstrate superior performance in th... more Context-dependent learning is a phenomenon in which people demonstrate superior performance in the context in which they originally learned a skill but perform less well in a novel context. This study investigated context-dependent learning in people with Parkinson's disease (PD) and age-matched nondisabled adults. All participants practiced 3 finger sequences, each embedded within a unique context (colors and locations on a computer screen). One day after practice, the participants were tested either under the sequence-context associations remained the same as during practice, or the sequence-context associations were changed (SWITCH). Compared with nondisabled adults, people with PD demonstrated significantly greater decrement in performance (especially movement time) under the SWITCH condition, suggesting that individuals with PD are more context dependent than nondisabled adults.
Neurorehabilitation and Neural Repair, Dec 24, 2021
Lesion load of the corticospinal tract (CST-LL), a measure of overlap between a stroke lesion and... more Lesion load of the corticospinal tract (CST-LL), a measure of overlap between a stroke lesion and the CST, is one of the strongest predictors of motor outcomes following stroke. CST-LL is typically calculated by using a probabilistic map of the CST originating from the primary motor cortex (M1). However, higher-order motor areas also have projections that contribute to the CST and motor control. In this retrospective study, we examined whether evaluating CST-LL from additional motor origins is more strongly associated with post-stroke motor severity than using CST-LL originating from M1 only. We found that lesion load to both the ventral premotor (PMv) cortex and M1 were more strongly related to stroke motor severity indexed by Fugl-Meyer Assessment cut-off scores than CST-LL of M1 alone, suggesting that higher-order motor regions add clinical relevance to motor impairment.
Cambridge University Press eBooks, Oct 28, 2010
Journal of Neurologic Physical Therapy, Dec 1, 2006
Journal of Neurologic Physical Therapy, Dec 1, 2004
Journal of Neurologic Physical Therapy, Dec 1, 2005
... Subjects stood with their right leg on a force platform with weight equally distributed and w... more ... Subjects stood with their right leg on a force platform with weight equally distributed and were ... is available on the strategies used by the elderly to control the knee during dynamic activ-ities ... Currently we are determining the application of these findings to the human condition. ...
Journal of Motor Behavior, Dec 14, 2017
A framework is presented of how theoretical predictions can be tested across the expert athlete t... more A framework is presented of how theoretical predictions can be tested across the expert athlete to disabled patient skill continuum. Common-coding theory is used as the exemplar to discuss sensory and motor system contributions to perceptual-motor behavior. Behavioral and neural studies investigating expert athletes and patients recovering from cerebral stroke are reviewed. They provide evidence of bi-directional contributions of visual and motor systems to perceptual-motor behavior. Majority of this research is focused on perceptual-motor performance or learning, with less on transfer. The field is ripe for research designed to test theoretical predictions across the expert athlete to disabled patient skill continuum. Our view has implications for theory and practice in sports science, physical education, and rehabilitation.
Experimental Brain Research, May 5, 2006
The specific motor control processes supported by the cerebellum and impaired with cerebellar dam... more The specific motor control processes supported by the cerebellum and impaired with cerebellar damage remain unclear. The cerebellum has been implicated in both planning and updating of accurate movements. Previously, we used a statistical model to parcel aiming performance that was constrained by a timed-response paradigm into contributions attributed to a specified plan and feedforward updating. Here, we apply this procedure to determine the putative role of the cerebellum in planning and updating goal-directed aiming by comparing the performance of subjects with unilateral cerebellar stroke to controls. Subjects rapidly moved to targets in predictable or unpredictable conditions and cerebellar subjects used the contralesional limb to control for ipsilesional motor execution deficits. Displacement-derived movement velocity was used in the statistical model to determine the effect of planning and updating on accuracy. Compared to controls, the cerebellar group demonstrated errors in final position that were primarily determined by planning deficits. This finding is manifest in four ways: Cerebellar subjects (1) were less accurate than controls in both predictable and unpredictable conditions; (2) they showed minimal benefit from increased preparation time for target amplitude specification; (3) with ample time to plan direction, wrong direction response frequency was greater; and (4) final position was minimally determined by the plan. Because these deficits were found contralesional to the moving limb, the cerebellum's role in planning is not lateralized to one hemisphere but rather our findings suggest that cerebellar output affects motor planning for both upper limbs. Indeed, a lesion analysis showed that the dentate nucleus, an area implicated in planning motor strategies and the primary cerebellar output nucleus, was the only common region affected by our patient group with contralateral cerebellar strokes.
Experimental Brain Research, Nov 17, 1999
The effects of predictability of load magnitude on anticipatory and triggered grip-force adjustme... more The effects of predictability of load magnitude on anticipatory and triggered grip-force adjustments were studied as nine normal subjects used a precision grip to lift, hold, and replace an instrumented test object. Experience with a predictable stimulus has been shown to enhance magnitude scaling of triggered postural responses to different amplitudes of perturbations. However, this phenomenon, known as a central-set effect, has not been tested systematically for grip-force responses in the hand. In our study, predictability was manipulated by applying load perturbations of different magnitudes to the test object under conditions in which the upcoming load magnitude was presented repeatedly or under conditions in which the load magnitudes were presented randomly, each with two different pre-load grip conditions (unconstrained and constrained). In constrained conditions, initial grip forces were maintained near the minimum level necessary to prevent pre-loaded object slippage, while in unconstrained conditions, no initial grip force restrictions were imposed. The effect of predictable (blocked) and unpredictable (random) load presentations on scaling of anticipatory and triggered grip responses was tested by comparing the slopes of linear regressions between the imposed load and grip response magnitude. Anticipatory and triggered grip force responses were scaled to load magnitude in all conditions. However, regardless of pre-load grip force constraint, the gains (slopes) of grip responses relative to load magnitudes were greater when the magnitude of the upcoming load was predictable than when the load increase was unpredictable. In addition, a central-set effect was evidenced by the fewer number of drop trials in the predictable relative to unpredictable load conditions. Pre-load grip forces showed the greatest set effects. However, grip responses showed larger set effects, based on prediction, when pre-load grip force was constrained to lower levels. These results suggest that anticipatory processes pertaining to load magnitude permit the response gain of both voluntary and triggered rapid grip force adjustments to be set, at least partially, prior to perturbation onset. Comparison of anticipatory set effects for reactive torque and lower extremity EMG postural responses triggered by surface translation perturbations suggests a more general rule governing anticipatory processes.
Neuroscience Letters, Jul 1, 2022
Springer eBooks, Jun 14, 2018
Stroke, Aug 1, 2013
Background and Purpose-Much recent interest surrounds the use of action observation, which is obs... more Background and Purpose-Much recent interest surrounds the use of action observation, which is observing another individual performing a motor task, in stroke rehabilitation, to promote motor recovery by engaging similar brain regions to action execution. This may be especially useful in individuals with limited mobility. Here, we assess how cortical motor activity during action observation is affected by stroke and by stroke-related motor deficits. Methods-We used functional MRI to compare brain activity during right and left hand action observation in right-handed nondisabled participants and participants who were right-handed before left hemisphere stroke. All participants performed the same actions after their functional MRI. Results-Nondisabled participants show greater bilateral cortical motor activity when observing actions made using the left hand, whereas participants with stroke show greater ipsilesional cortical motor activity when observing actions made using the right (paretic) hand (P<0.05; corrected). For both groups, action processing is modulated by motor capability: cortical motor activity is greater when observing the hand with lower motor scores (P<0.05; corrected). Furthermore, for stroke, the extent of ipsilesional activity correlates with lesion volume (P=0.049), in a pattern that suggests adaptive plasticity. Conclusions-We found that action observation activates specific motor plans in damaged motor circuits after stroke, and this activity is related to motor capability to perform the same actions. Cortical motor activity during action observation may be relevant to motor learning, and to motor relearning in stroke rehabilitation.
Journal of Clinical Medicine, Mar 23, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
European Journal of Neuroscience, 2020
Psychological states can influence motor performance and learning. In Parkinson's disease (PD... more Psychological states can influence motor performance and learning. In Parkinson's disease (PD), placebo effects or expectancies for pharmacological treatment benefits are not uncommon, but little is known about whether self‐efficacy, beliefs about personal performance capabilities, may play a role in this population. To address this question, we investigated whether experimental manipulations designed to enhance self‐efficacy would benefit motor performance and learning in PD. A motor learning paradigm was utilized to determine the short‐term (i.e., practice) and longer‐term (i.e., retention) impact of self‐efficacy enhancement when 44 individuals with PD (Hoehn and Yahr stage I–III) acquired a challenging balance skill. Using stratified randomization by Hoehn and Yahr stage, participants were assigned to a control group or one of two investigational groups: (a) an expectancy‐relevant statement that encouraged an incremental mindset in which the balance skill, though initially c...
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Papers by Carolee Winstein