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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

Key variables: (a) transport velocity with marked total movement time (TMT) and maximum transport velocity (Vmax), (b) grasp aperture with marked maximum grasp aperture (Amax), and (c) transport-grasp coordination indicated by highest cross-correlation coefficient (upper arrow, rmax) and associated time lag (lower arrow, τmax).
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fig1: Key variables: (a) transport velocity with marked total movement time (TMT) and maximum transport velocity (Vmax), (b) grasp aperture with marked maximum grasp aperture (Amax), and (c) transport-grasp coordination indicated by highest cross-correlation coefficient (upper arrow, rmax) and associated time lag (lower arrow, τmax).

Mentions: All kinematic data were analyzed by JT, who was blinded to the TMS conditions. The data were filtered using a zero-lag Butterworth low-pass filter with 20 Hz cutoff frequency. All kinematic and transport-grasp coordination variables were extracted for each trial using customized automatic computer routines written in MATLAB 7.5.0 (The MathWorks Inc., Natick, MA). Three-dimensional displacement was calculated from the wrist sensor position to derive tangential velocity of transport (Figure 1(a)) using a finite-difference technique [28]. Aperture was derived from the distance between the thumb and index finger sensors. Movement initiation was defined as the first bin of a continuous rise of at least 3 data points in transport velocity. Movement was terminated at the time of object lift-off.


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)

Key variables: (a) transport velocity with marked total movement time (TMT) and maximum transport velocity (Vmax), (b) grasp aperture with marked maximum grasp aperture (Amax), and (c) transport-grasp coordination indicated by highest cross-correlation coefficient (upper arrow, rmax) and associated time lag (lower arrow, τmax).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig1: Key variables: (a) transport velocity with marked total movement time (TMT) and maximum transport velocity (Vmax), (b) grasp aperture with marked maximum grasp aperture (Amax), and (c) transport-grasp coordination indicated by highest cross-correlation coefficient (upper arrow, rmax) and associated time lag (lower arrow, τmax).
Mentions: All kinematic data were analyzed by JT, who was blinded to the TMS conditions. The data were filtered using a zero-lag Butterworth low-pass filter with 20 Hz cutoff frequency. All kinematic and transport-grasp coordination variables were extracted for each trial using customized automatic computer routines written in MATLAB 7.5.0 (The MathWorks Inc., Natick, MA). Three-dimensional displacement was calculated from the wrist sensor position to derive tangential velocity of transport (Figure 1(a)) using a finite-difference technique [28]. Aperture was derived from the distance between the thumb and index finger sensors. Movement initiation was defined as the first bin of a continuous rise of at least 3 data points in transport velocity. Movement was terminated at the time of object lift-off.

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