Jarugool Tretriluxana

Manual asymmetries in grasp pre-shaping and transport-grasp coordination.

Few studies have directly compared the visuo-motor transformation of grasp pre-shaping or transport–grasp coordination of reach-to-grasp movements between the two hands. Our objective was to determine if there are manual asymmetries in right-handed adults as a foundation to investigate hemispheric specialization in individuals post-stroke. Twelve non-disabled right-handed adults performed rapid reach-to-grasp movements to cylinders of three sizes as vision of the arm and hand was partially occluded. We reasoned that the hand system (left or right) that is superior in anticipatory planning of aperture scaling and movement preparation would be more likely to exhibit early grasp pre-shaping under this experimental manipulation. Movement time, hand path, transport velocity, and aperture were derived from 3D electromagnetic sensor data. The visuo-motor transformation of object sizes into an action of aperture pre-shaping was quantified using the correlations between initial aperture velocity and object diameter, and peak aperture and object diameter. Coordination between hand transport and aperture grasping was quantified using the cross-correlation between transport velocity and aperture size. Peak aperture and object diameter were strongly correlated for both hands. However, early aperture velocity and object diameter were correlated only for left-hand movements. Cross-correlation analyses revealed a strong association between transport velocity and aperture only for right-hand movements. Together, these results suggest earlier anticipatory control for the left hand in the visuo-motor transformation of grasp pre-shaping and a stronger transport–grasp linkage for the right hand. Further, initial aperture velocity was a more sensitive measure of these manual asymmetries than peak aperture. Our findings compliment the specialization previously observed for pointing movements of the dominant and non-dominant hemispheric/limb system and the coordinated control of complex movements and visuo-spatial components, respectively.

Low frequency repetitive transcranial magnetic stimulation to the non-lesioned hemisphere improves paretic arm reach-to-grasp performance after chronic stroke

Purpose: To investigate the effect of inhibitory low frequency repetitive Transcranial Magnetic Stimulation (rTMS) applied to the non-lesioned hemisphere on kinematics and coordination of paretic arm reach-to-grasp (RTG) actions in individuals with stroke. Relevance: This study is designed as a phase I trial to determine the feasibility and efficacy of low frequency rTMS applied to the non-lesioned hemisphere for the recovery of reach-to-grasp actions in individuals with hemiparesis secondary to stroke. The results have important implications for the use of rTMS in parallel with complex paretic arm skill practice. Participants: Nine adults, anterior circulation unilateral stroke. Their average age was 59 years, the average time since stroke was 4.8 years. Method and analysis: Two TMS treatments were performed on two separate days: active rTMS and sham rTMS. Cortico-motor excitability (CE) of the non-lesioned hemisphere as well as RTG kinematics of the paretic hand as participants reached for a dowel of 1.2 cm in diameter was assessed before and after the rTMS treatments. In the active condition, rTMS was applied over the “hot spot” of the extensor digitorum communis muscle (EDC) in primary motor cortex (M1) of the non-lesioned hemisphere at 90% resting motor threshold. TMS pulses were delivered at 1 Hz for 20 min. In the sham condition, a sham coil was positioned similar to the active condition; TMS clicking noise was produced but no TMS pulse was delivered. Dependent measures: CE was measured as peak-to-peak amplitude of the motor evoked potential at 120% of resting motor threshold. RTG kinematics included movement time, peak transport velocity, peak aperture, time of peak transport velocity and time of peak aperture. RTG coordination was captured by cross correlation coefficient between transport velocity and grasp aperture size. Results: While 1 Hz rTMS applied over non-lesioned M1 significantly decreased the MEP amplitude of non-paretic EDC, sham TMS did not have a significant effect on MEP amplitude. Active rTMS significantly decreased total movement time and increased peak grasp aperture. There were no changes in peak transport velocity or the time of peak transport velocity or the time of peak aperture after application of active rTMS. Additionally, the participants completed RTG actions with a more coordinated pattern after undergoing active rTMS. Following sham TMS, there were no changes in CE, RTG kinematics or coordination. While there were no significant correlation between changes in cortico-motor excitability and RTG kinematics, the decrease in cortico-motor excitability of the non-lesioned hemisphere showed a strong correlation with an increase in cross-correlation coefficient. Conclusions and implications: The findings demonstrate the feasibility and efficacy of low frequency rTMS applied to the non-lesioned hemisphere for the recovery of reach-to-grasp actions in individuals with hemiparesis secondary to stroke. The inhibitory effect of low frequency rTMS resulted in improved paretic hand reach-to-grasp performance with faster movement time and more coordinated reach-to-grasp pattern. These results have important implications for the use of rTMS for stroke rehabilitation. Implications for Rehabilitation Low frequency repetitive transcranial magnetic stimulation (LF-rTMS) to the non-lesioned hemisphere improves paretic arm reach-to-grasp performance. The preliminary results have important implications for the use of LF-rTMS as conjunctive intervention for stroke rehabilitation.

Hemisphere Specific Impairments in Reach-to-Grasp Control After Stroke: Effects of Object Size

Background and objective. The authors investigated hemispheric specialization for the visuomotor transformation of grasp preshaping and the coordination between transport and grasp in individuals poststroke. Based on a bilateral model, the authors hypothesized that after unilateral stroke there would be hemisphere-specific deficits revealed by the ipsilesional limb. Methods. Right or left stroke and age- and limb-matched nondisabled participants performed rapid reach-to-grasp of 3 sized objects. The authors quantified grasp preshaping as the correlation between initial aperture velocity and peak aperture, and peak aperture and object diameter. A cross correlation analysis using transport velocity and aperture size was performed to quantify transport-grasp coordination. All statistical tests for hemisphere-specific deficits involved comparisons between each stroke group and the matched nondisabled group. Results. Overall, the right stroke group, but not left stroke group, demonstrated prolonged movement time. For grasp preshaping there was a higher correlation between initial aperture velocity and peak aperture for the right stroke group and a lower correlation between peak aperture and object diameter for the left stroke group. For transport-grasp coordination the correlation between transport velocity and aperture size was higher for the left stroke group and lower for the right stroke group, which also demonstrated a higher standard deviation of time lag. Conclusions. After left stroke, there was deficient scaling of grasp preshaping and stronger transport-grasp coordination. In contrast, after right stroke, grasp preshaping began earlier and transport-grasp coordination was weaker. Together, these hemisphere-specific deficits suggest a left hemisphere specialization for the visuomotor transformation of grasp preshaping and a right hemisphere specialization for transport-grasp coordination.

Feasibility investigation of the Accelerated Skill Acquisition Program (ASAP): insights into reach-to-grasp coordination of individuals with postacute stroke.

Abstract Background: Skill acquisition, capacity building, and motivational enhancements are the basis of the Accelerated Skill Acquisition Program (ASAP) and form the foundation for effective incorporation of the paretic upper extremity into life activities. This is the first phase I trial to deliver ASAP during the postacute interval in mildly to moderately impaired stroke survivors and to include an assessment of paretic reach-to-grasp (RTG) coordination using RTG task and cross-correlation analyses. Methods: Two baseline and posttreatment evaluations consisted of RTG actions, the Wolf Motor Function Test (WMFT), and the Stroke Impact Scale (SIS). An individualized arm therapy program using ASAP principles was administered for a total of 30 hours, 2 hours per day, for 2 to 4 days per week over 5 weeks. Dependent measures were kinematics of RTG actions, RTG coordination, total time score of WMFT, and stroke recovery score of SIS. Results: All participants tolerated ASAP well, and none reported any adverse effects during or after the protocol. When the 2 baseline evaluations were compared, there were no changes in any RTG kinematics or RTG coordination. In contrast, after 30 hours of ASAP, total movement time and deceleration time of RTG actions markedly decreased, maximum reach (transport) velocity strikingly increased, and time of maximum aperture was accomplished later. Additionally, the maximal RTG correlation coefficient increased with a shorter associated time lag. A similar pattern was observed for the clinical outcome measures of WMFT and SIS. Conclusions: The findings demonstrate the feasibility of using an ASAP protocol for patients 1 to 3 months post stroke. Under ASAP, WMFT tasks and RTG actions were performed faster with higher peak transport velocity and a more coordinated RTG pattern. The next step is to determine whether the immediate gains in the skilled RTG actions persist 6 months alter.

Anticipatory Planning of Functional Reach-to-Grasp A Pilot Study

Background. Intensive task-oriented training such as constraint-induced movement therapy (CIMT) is thought to engage motor learning and decision-making processes, including anticipatory action planning. Objective. To identify the effects of CIMT on anticipatory hand posture selection and movement time for task-specific reach-to-grasp performance. Methods. Subacute and chronic poststroke participants were recruited into CIMT (n = 10) or non-CIMT (n = 10) groups. Arm and hand functions were assessed before and after 2 weeks with the Wolf Motor Function Test (WMFT), Motor Activity Log (MAL), and a unique skilled reach-to-grasp task designed to test anticipatory hand posture selection. The reach-to-grasp tasks included power and precision grasping in 2 conditions achieved optimally with either a pronated (low difficulty) or supinated (high difficulty) hand posture. Outcome measures included success rate, frequency of optimal strategy selection, and movement time. Results. Between-group comparisons revealed a significant treatment effect for WMFT and MAL scores. The CIMT group showed larger gains in success rate, optimal posture selection (precision grasp only), and faster movement times for the supinated conditions. Conclusion. Together, a faster movement time and greater frequency of optimal hand posture selection in the more difficult task condition highlights a set of novel findings. These results provide evidence for training-induced improvements in upper-extremity function that support neurobehavioral recovery more than compensation. Although these findings are preliminary in view of the small sample size, the authors suggest that they may be useful to design and power larger-scale studies to further the understanding of the fundamental mechanisms induced by task-oriented training interventions in neurorehabilitation.

Effect of speed on the upper and contralateral lower limb coordination during gait in individuals with stroke

The purposes of this study were to investigate the upper and contralateral lower limb coordination and to study the effect of speed on the upper and contralateral lower limb coordination in individuals with stroke and control groups. Thirty individuals with stroke who were able to walk independently without using any assistive devices and 30 control individuals were recruited for the study. Upper and contralateral lower limb coordination was analyzed using the shoulder and contralateral hip displacements in the sagittal plane. All data were analyzed by three‐dimensional gait analysis. Results demonstrated high degrees of coordination in the upper and contralateral lower limbs of the controls and in the unaffected upper and affected lower limbs of individuals with stroke. Gait speed was found to be associated with the upper and contralateral lower limb coordination in individuals with stroke but not in the controls. The findings implied that the affected upper limb plays an important role for improving gait coordination and is necessary for gait performance in individuals with stroke. Thus, health professionals should exercise the affected arm to increase efficiency of walking in individuals with stroke.

Improvement in Paretic Arm Reach-to-Grasp following Low Frequency Repetitive Transcranial Magnetic Stimulation Depends on Object Size: A Pilot Study

Introduction. Low frequency repetitive transcranial magnetic stimulation (LF-rTMS) delivered to the nonlesioned hemisphere has been shown to improve limited function of the paretic upper extremity (UE) following stroke. The outcome measures have largely included clinical assessments with little investigation on changes in kinematics and coordination. To date, there is no study investigating how the effects of LF-rTMS are modulated by the sizes of an object to be grasped. Objective. To investigate the effect of LF-rTMS on kinematics and coordination of the paretic hand reach-to-grasp (RTG) for two object sizes in chronic stroke. Methods. Nine participants received two TMS conditions: real rTMS and sham rTMS conditions. Before and after the rTMS conditions, cortico-motor excitability (CE) of the nonlesioned hemisphere, RTG kinematics, and coordination was evaluated. Object sizes were 1.2 and 7.2 cm in diameter. Results. Compared to sham rTMS, real rTMS significantly reduced CE of the non-lesioned M1. While rTMS had no effect on RTG action for the larger object, real rTMS significantly improved movement time, aperture opening, and RTG coordination for the smaller object. Conclusions. LF-rTMS improves RTG action for only the smaller object in chronic stroke. The findings suggest a dissociation between effects of rTMS on M1 and task difficulty for this complex skill.

Enhanced Upper Extremity Functions with a Single Session of Action-Observation-Execution and Accelerated Skill Acquisition Program in Subacute Stroke

Background Action-observation-execution (AOE) primes physical training. We examined the immediate effect of AOE with accelerated skill acquisition program (ASAP) on dexterity in subacute stroke. Methods Twelve individuals from 1 to 6 months after stroke were allocated into two groups by matching age and side of stroke. After AOE of 30 minutes, the experimental group received ASAP for 60 minutes whereas the control group received dose-equivalent usual care. The movement time (MT) and functional ability (FA) of hand items of the Wolf motor function test (WMFT), hand functions and global recovery of stroke impact scale (SIS), and intrinsic motivation items of stroke rehabilitation motivation scale were assessed at baseline, after training, and during one-week follow-up. Data were analyzed within and between the groups. Results AOE significantly decreased MT of flipping cards of WMFT and hand functions of SIS. Total MT was markedly reduced. AOE with ASAP demonstrated significant group-by-time interactions on MT of lifting pencil of WMFT, total MT, and global recovery. Grip strength, FA, and hand functions were significantly improved only in the experimental group. Both groups improved motivation significantly. Conclusions The AOE with ASAP enhanced dexterity, which persisted for at least a week. This intervention might improve dexterity in subacute stroke. Trial Registration Number This trial is registered with TCTR20161007001.