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

Tretriluxana J, Kantak S, Tretriluxana S, Wu AD, Fisher BE - Stroke Res Treat (2015)

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Physical Therapy, Mahidol University, Nakhon Pathom 73170, Thailand.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus

Representative data for grasp aperture during reach-to-grasp actions to the small object (a) and the large object (b) following sham (left) and real rTMS conditions (right). The thinner trajectories represent baseline performance; the thick trajectories represent performance after each TMS condition.
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fig4: Representative data for grasp aperture during reach-to-grasp actions to the small object (a) and the large object (b) following sham (left) and real rTMS conditions (right). The thinner trajectories represent baseline performance; the thick trajectories represent performance after each TMS condition.

Mentions: Figure 4 illustrates representative subject data showing the effect of sham and real rTMS on the temporal evolution of grasp aperture as the participant reached to grasp the small and large objects. The most prominent effect was an increase in the maximum grasp aperture for the small object following real LF-rTMS applied over the nonlesioned hemisphere. Figure 5 shows the data for maximum grasp aperture averaged across all participants. While there was little effect of real rTMS for the larger object RTG (Figure 5(b)), real rTMS significantly enhanced maximum grasp aperture while reaching to a smaller object compared to sham stimulation (Figure 5(a), TMS condition (real, sham) × time (pre, post) interaction, F(1,16) = 5.706, p = 0.034). There was no significant effect of rTMS on time to peak aperture for either object size.


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

Tretriluxana J, Kantak S, Tretriluxana S, Wu AD, Fisher BE - Stroke Res Treat (2015)

Representative data for grasp aperture during reach-to-grasp actions to the small object (a) and the large object (b) following sham (left) and real rTMS conditions (right). The thinner trajectories represent baseline performance; the thick trajectories represent performance after each TMS condition.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4664821&req=5

fig4: Representative data for grasp aperture during reach-to-grasp actions to the small object (a) and the large object (b) following sham (left) and real rTMS conditions (right). The thinner trajectories represent baseline performance; the thick trajectories represent performance after each TMS condition.
Mentions: Figure 4 illustrates representative subject data showing the effect of sham and real rTMS on the temporal evolution of grasp aperture as the participant reached to grasp the small and large objects. The most prominent effect was an increase in the maximum grasp aperture for the small object following real LF-rTMS applied over the nonlesioned hemisphere. Figure 5 shows the data for maximum grasp aperture averaged across all participants. While there was little effect of real rTMS for the larger object RTG (Figure 5(b)), real rTMS significantly enhanced maximum grasp aperture while reaching to a smaller object compared to sham stimulation (Figure 5(a), TMS condition (real, sham) × time (pre, post) interaction, F(1,16) = 5.706, p = 0.034). There was no significant effect of rTMS on time to peak aperture for either object size.

Bottom Line: 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.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Physical Therapy, Mahidol University, Nakhon Pathom 73170, Thailand.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus