Transcranial static magnetic field stimulation (tSMS) is a novel brain stimulation technique that has been shown to be safe and effective in modifying biological parameters when applied to the cerebral cortex. Its application decreases cortical excitability, regardless of the polarity of the magnetic field, reducing the amplitude of motor evoked potentials (MEP). tSMS is presented as a potentially useful tool in the management of the interhemispheric inhibition, a condition present in neurological pathologies such as stroke or multiple sclerosis. Despite having demonstrated neurophysiological effects in previous studies, the effects of tSMS application on force production and manual dexterity, have not yet been clearly established. The present study aims to evaluate changes in force production, manual dexterity, and fatigue after unilateral application of a tSMS session on the primary motor cortex (M1). It is hypothesized that the application of tSMS will momentarily decrease the parameters of strength and manual dexterity in the upper limb contralateral to the stimulated cortex, without changes in the strength and dexterity of the unstimulated hemibody. These parameters may show an increase in the unstimulated hemibody. If the hypothesis is confirmed, it could be considered a valid treatment for health conditions presenting interhemispheric inhibition.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
HEALTH_SERVICES_RESEARCH
Masking
QUADRUPLE
Enrollment
44
30-minute tSMS application in a comfortable seated position. The material used in the stimulation was a MAGxx1.1 helmet (Neurek Spain Toledo), with a Neodymium (NdFeB) magnet of 60mm diameter and 30mm height with Nickel (Ni-Cu-Ni) coating MAG60r+ (Neurek Spain, Toledo), placed over the primary motor cortex (M1) of the left cerebral hemisphere.
30-minute sham tSMS application in a comfortable seated position. The device used in sham stimulation had the same weight and shape as the real stimulation helmet.
Universidad Rey Juan Carlos
Alcorcón, Madrid, Spain
RECRUITINGFinger Tapping Test (FTT)
was performed for assessment of manual motor skills. This test has been used for many years in the neuropsychological assessment of brain damage, being an indicator of cortical activity, as well as being used in NIBS studies as a measure of manual dexterity.
Time frame: 5 minutes
Nine-Hole Peg Test (9HPT)
Was used to assess finger dexterity; this tool has been used in the assessment of motor activity in a multitude of pathologies, with adequate to excellent inter-rater reliability and excellent inter-rater reliability in healthy adults.
Time frame: 5 minutes
Hand grip strength
Upper extremity force production was assessed by grip testing; a hand-held dynamometer (Jamar Plus+; Sammons Preston, Rolyon, Bolingbrook, IL) was used for this purpose. Greater hand grip strength corresponds with greater activation in M1, premotor area (PMA), and supplementary motor area (SMA) in the dominant hemisphere, and of the SMA in the nondominant hemisphere, and may provide information about the functionality of the human brain.
Time frame: 5 minutes
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