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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

Grasp aperture for the small object (a) and the large object (b) pre (●) and post (○) each TMS condition. ∗ indicates a significant interaction between the TMS condition and time. Error bar = SD.
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fig5: Grasp aperture for the small object (a) and the large object (b) pre (●) and post (○) each TMS condition. ∗ indicates a significant interaction between the TMS condition and time. Error bar = SD.

Mentions: At baseline, collapsing across TMS condition, peak grasp aperture was significantly greater for the larger object compared to the smaller object (Wilcoxon Signed Ranks Test, z(8) = −2.599; p = 0.009) (Figure 5). Additionally, compared to the smaller object, the participants reached and grasped the larger object with a more coordinated pattern as evidenced by a greater maximum cross-correlation coefficient (Wilcoxon Signed Ranks Test, z(8) = −2.244; p = 0.025, Figure 6(a)) and shorter time lag (Wilcoxon Signed Ranks Test, z(8) = −2.497; p = 0.013, Figure 6(b)).


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)

Grasp aperture for the small object (a) and the large object (b) pre (●) and post (○) each TMS condition. ∗ indicates a significant interaction between the TMS condition and time. Error bar = SD.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig5: Grasp aperture for the small object (a) and the large object (b) pre (●) and post (○) each TMS condition. ∗ indicates a significant interaction between the TMS condition and time. Error bar = SD.
Mentions: At baseline, collapsing across TMS condition, peak grasp aperture was significantly greater for the larger object compared to the smaller object (Wilcoxon Signed Ranks Test, z(8) = −2.599; p = 0.009) (Figure 5). Additionally, compared to the smaller object, the participants reached and grasped the larger object with a more coordinated pattern as evidenced by a greater maximum cross-correlation coefficient (Wilcoxon Signed Ranks Test, z(8) = −2.244; p = 0.025, Figure 6(a)) and shorter time lag (Wilcoxon Signed Ranks Test, z(8) = −2.497; p = 0.013, Figure 6(b)).

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