Acute effects of high-frequency microfocal vibratory stimulation on the H reflex of the soleus muscle. A double-blind study in healthy subjects

Enrico Alfonsi, Paolo Paone, Cristina Tassorelli, Roberto De Icco, Arrigo Moglia, Elena Alvisi, Lucky Marchetta, Mauro Fresia, Alessandra Montini, Marzia Calabrese, Vittorio Versiglia, Giorgio Sandrini

Funct Neurol, Oct.-Dec. 2015

1. This study in healthy subjects examined the effects of a system delivering focal microvibrations at high frequency (Equistasi®) on tonic vibration stimulus (TVS)-induced inhibition of the soleus muscle H reflex. Highfrequency microvibrations significantly increased the inhibitory effect of TVS on the H reflex for up to three minutes. Moreover, Equistasi® also significantly reduced alpha-motoneuron excitability, as indicated by the changes in the ratio between the maximumamplitude H reflex (Hmax reflex) and the maximumamplitude muscle response (Mmax response); this effect was due to reduction of the amplitude of the H reflex because the amplitude of muscle response remained unchanged.

2. The present findings indicate that Equistasi® has a modulatory effect on proprioceptive reflex circuits. Therefore, Equistasi® might interfere with some mechanisms involved in both physiological and pathophysiological control of movement and of posture.