Motor Deficits in the Ipsilesional Arm of Severely Paretic Stroke Survivors Correlate With Functional Independence in Left, but Not Right Hemisphere Damage (original) (raw)
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Frontiers in Human Neuroscience
The ipsilesional arm of stroke patients often has functionally limiting deficits in motor control and dexterity that depend on the side of the brain that is lesioned and that increase with the severity of paretic arm impairment. However, remediation of the ipsilesional arm has yet to be integrated into the usual standard of care for upper limb rehabilitation in stroke, largely due to a lack of translational research examining the effects of ipsilesional-arm intervention. We now ask whether ipsilesional-arm training, tailored to the hemisphere-specific nature of ipsilesional-arm motor deficits in participants with moderate to severe contralesional paresis, improves ipsilesional arm performance and generalizes to improve functional independence. We assessed the effects of this intervention on ipsilesional arm unilateral performance [Jebsen–Taylor Hand Function Test (JHFT)], ipsilesional grip strength, contralesional arm impairment level [Fugl–Meyer Assessment (FM)], and functional ind...
Contralesional motor deficits after unilateral stroke reflect hemisphere-specific control mechanisms
Brain, 2013
We have proposed a model of motor lateralization, in which the left and right hemispheres are specialized for different aspects of motor control: the left hemisphere for predicting and accounting for limb dynamics and the right hemisphere for stabilizing limb position through impedance control mechanisms. Our previous studies, demonstrating different motor deficits in the ipsilesional arm of stroke patients with left or right hemisphere damage, provided a critical test of our model. However, motor deficits after stroke are most prominent on the contralesional side. Post-stroke rehabilitation has also, naturally, focused on improving contralesional arm impairment and function. Understanding whether contralesional motor deficits differ depending on the hemisphere of damage is, therefore, of vital importance for assessing the impact of brain damage on function and also for designing rehabilitation interventions specific to laterality of damage. We, therefore, asked whether motor deficits in the contralesional arm of unilateral stroke patients reflect hemisphere-dependent control mechanisms. Because our model of lateralization predicts that contralesional deficits will differ depending on the hemisphere of damage, this study also served as an essential assessment of our model. Stroke patients with mild to moderate hemiparesis in either the left or right arm because of contralateral stroke and healthy control subjects performed targeted multi-joint reaching movements in different directions. As predicted, our results indicated a double dissociation; although left hemisphere damage was associated with greater errors in trajectory curvature and movement direction, errors in movement extent were greatest after right hemisphere damage. Thus, our results provide the first demonstration of hemisphere specific motor control deficits in the contralesional arm of stroke patients. Our results also suggest that it is critical to consider the differential deficits induced by right or left hemisphere lesions to enhance post-stroke rehabilitation interventions.
Direction-specific Disruption of Paretic Arm Movement in Post-stroke Patients
Progress in Rehabilitation Medicine, 2020
This study aimed to characterize reaching movements of the paretic arm in different directions within the reachable workspace in post-stroke patients. Methods: A total of 12 poststroke patients participated in this study. Each held a ball with a tracking marker and performed back-and-forth reaching movements from near the middle of the body to one of two targets in front of them located on the ipsilateral and contralateral sides of the arm performing the movement. We recorded and analyzed the trajectories of the tracking marker. The stability of arm movements was evaluated using areas and minimum Feret diameters to assess the trajectories of both the paretic and non-paretic arms. The speed of the arm movement was also calculated. Results: For the paretic arm, contralateral movement was more impaired than ipsilateral movement, whereas for the non-paretic arm, no difference was observed between the directions. The maximum speed of the contralateral movement was significantly slower than that of the ipsilateral movement in both the paretic and non-paretic arms. Conclusion: The paretic arm shows direction-specific instability in movement toward the contralateral side of the arm.
Contralesional Hemisphere Control of the Proximal Paretic Upper Limb following Stroke
Cerebral Cortex, 2012
Cathodal transcranial direct current stimulation (c-tDCS) can reduce excitability of neurons in primary motor cortex (M1) and may facilitate motor recovery after stroke. However, little is known about the neurophysiological effects of tDCS on proximal upper limb function. We hypothesized that suppression of contralesional M1 (cM1) excitability would produce neurophysiological effects that depended on the severity of upper limb impairment. Twelve patients with varying upper limb impairment after subcortical stroke were assessed on clinical scales of upper limb spasticity, impairment, and function. Magnetic resonance imaging was used to determine lesion size and fractional anisotropy (FA) within the posterior limbs of the internal capsules indicative of corticospinal tract integrity. Excitability within paretic M1 biceps brachii representation was determined from motor-evoked potentials during selective isometric tasks, after cM1 sham stimulation and after c-tDCS. These neurophysiological data indicate that c-tDCS improved selective proximal upper limb control for mildly impaired patients and worsened it for moderate to severely impaired patients. The direction of the neurophysiological after effects of c-tDCS was strongly related to upper limb spasticity, impairment, function, and FA asymmetry between the posterior limbs of the internal capsules. These results indicate systematic variation of cM1 for proximal upper limb control after stroke and that suppression of cM1 excitability is not a ''one size fits all'' approach.
Archives of Physical Medicine and Rehabilitation, 2004
Objectives: To characterize fine motor control through finger tapping in both arms of 10 patients with chronic stroke, to make baseline comparisons with matched controls, and to examine the responsiveness of deficits seen in stroke patients after 6 weeks of bilateral arm-based training. Design: Nonrandomized controlled, cohort before-after trial. Setting: Research institution. Participants: Ten people from the community with chronic unilateral ischemic stroke and 10 age-and sex-matched healthy controls. Participants with hemiparesis had completed all conventional care and were more than 6 month poststroke. Inclusion criteria were at least 6 months since a unilateral stroke, ability to follow simple instructions and 2-step commands, volitional control of the nonparetic arm, and at least minimal antigravity movement in the shoulder of the paretic arm. Interventions: Not applicable. Main Outcome Measures: Measurements included rate and timing consistency of unilateral tapping at a preferred and a maximal rate and the accuracy and stability of interlimb coordination in bilateral simultaneous (inphase) and alternating (antiphase) tapping at a preferred rate. Results: Nonparetic finger control was similar to that of the nondisabled participants except under bilateral conditions, where it was less consistent. A subgroup with residual paretic finger function, had slower and less consistent paretic finger tapping, as well as less accurate and more variable interlimb coordination; however, basic bilateral coupling relationships were preserved. Bilateral arm-based training improved bilateral nonparetic consistency but slowed unilateral preferred tapping. Training also improved paretic fine motor control in 2 of 4 participants with mild stroke severity. The 2 responders, with dominant hemisphere lesions, indicated a possible recovery advantage with bilateral training for such lesions. Conclusions: In general, nonparetic finger control for tapping was preserved but paretic finger control was compromised. Disruption of nonparetic control of tapping, particularly consistency of tapping, occurred during bilateral tapping tasks but was responsive to 6 weeks of bilateral arm-based training. Despite the apparent lack of training specificity, the generalizable effects of bilateral arm training to fine motor interlimb coordination may reflect central motor control mechanisms for upper-extremity coordination, which may be accessed and may influence the recovery of arm function after stroke.
Recovery of Ipsilateral Dexterity After Stroke
Stroke, 2000
Background and Purpose —Previous work indicated that patients within 1 month of parietal or posterior frontal damage are often abnormally slow or clumsy when using the ipsilateral hand for dexterity tasks. This article reports a 6-month follow-up study to assess recovery and the impact on functional outcome. Methods —Twenty-four patients (80%) were available for follow-up. They used the ipsilateral hand on a dexterity test that simulated everyday hand function. Weakness and ideomotor apraxia were also assessed. Performance was compared with that of healthy age-matched control subjects using the same hand. Rating scales for self-care and dexterity in everyday life were completed by patients and carers. Results —Significant recovery had occurred on all measures, but patients with left hemisphere damage remained impaired on the dexterity test, with 7 patients (58%) scoring below the normal range. Five of these were apraxic. Reports of everyday functioning did not reflect this impairmen...
Consistency of Paretic Upper Extremity Motor Performance Soon After Stroke
Journal of Physical Therapy Science, 1995
The consistency of seven measures of paretic upper extremity motor performance was examined in 10 patients who experienced a stroke a mean 6.3 days before entering the study. Motor performance was measured using dynamometers, the Motricity Index, and timed alternating movement. All motor performance measures correlated significantly with one another on the first and fifth assessment days (r s ≥0.707). Within day Cronbach's alphas were high (≥0.9116). The measures were correlated strongly across days. Only the Motricity Index score for shoulder abduction differed significantly between days. The results showed that the measures investigated were consistent within and between days. As they appear to be measuring the same construct, there is little need to employ all if the intent is to characterize motor performance of the paretic upper extremity soon after stroke. A select few measures should be sufficient for such a characterization.
Motor Recovery of the Ipsilesional Upper Limb in Subacute Stroke
Archives of Physical Medicine and Rehabilitation, 2013
Objective: To investigate the time-related changes in motor performance of the ipsilesional upper limb in subacute poststroke patients by using clinical and kinematic assessments. Design: Observational, longitudinal, prospective, monocentric study. Setting: Physical medicine and rehabilitation department. Participants: Stroke patients (nZ19; mean age, 62.9y) were included less than 30 days after a first unilateral ischemic/hemorrhagic stroke. The control group was composed of age-matched, healthy volunteers (nZ9; mean age, 63.1y).
Ipsilesional Arm Aiming Movements After Stroke: Influence of the Degree of Contralesional Impairment
Journal of Motor Behavior, 2017
The authors examined the effects of the degree of impairment of the contralesional upper limb and the side of the hemispheric damage on ipsilesional upper limb performance in chronic stroke individuals. Right-and left-side stroke resulting in mild-to-severe impairment and healthy participants took part in simple and choice reaction time tasks involving aiming movements. The stroke individuals performed the aiming movements with the ipsilesional upper limb using a digitizing tablet to ipsi-or contralateral targets presented in a monitor. The global performance of the group with severe right hemispheric damage was worse than that of the other groups, indicating that the side of hemispheric damage and degree of motor impairment can adversely affect aiming movement performance.