Modulation of the ipsilateral and contralateral H reflexes following ipsilateral mechanical pressure of the foot in normal subjects.
OBJECTIVE
Mechanoreceptors from the foot sole likely contribute in the reflex regulations. Therefore, it was hypothesized that repetitive low threshold afferents stimulation would have an inhibitory effect on the soleus H-reflexes.


METHODS
Sixteen normal subjects voluntarily, participated in the study and were randomly allocated. Subjects were remained in prone position. The Cutaneous Mechanical Pressure (CMP equal to 50% of leg and foot weight) was applied to the ipsilateral lateral and Medial plantar surface by a designed instrument through a square plate (30 x 30 mm). H reflex as an indicator for excitability of motoneurones was bilaterally elicited before and after the application of the CMP. The H-reflex parameters were estimated.


RESULTS
Mechanical pressure significantly depressed soleus H-reflex excitability in ipsilateral and contralateral feet in all subjects.


CONCLUSIONS
The demonstration of a decrease in H-reflex excitability as a result of applied pressure to the foot sole suggests that the change in reflex excitability is the result of a common spinal mechanism. The results highlight the modulatory effects that natural stimulation of afferents can have on reflex excitability.


CONCLUSIONS
The placement of a small flat plate, in order to apply pressure to the plantar eminence, may be useful for modulation of muscle tone. In addition, these findings might be useful for reducing spasticity; because spasticity is at least partially caused by hyperexcitability of the motorneuron pool.
Bastani
A
A
Tehran University of Medical Sciences, Faculty of Rehabilitation, Pich-Shemiran, Tehran, Iran. andisheh_bas@yahoo.com
Hadian
M R
MR
Talebian
S
S
Bagheri
H
H
Olyaie
G R
GR
D000328:Adult; D004576:Electromyography; D005260:Female; D005528:Foot / Q000294:innervation*; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology*; D009128:Muscle Spasticity / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000502:physiology*; D011312:Pressure; D016684:Prone Position; D011795:Surveys and Questionnaires