Short-term effect of electrical nerve stimulation on spinal reciprocal inhibition during robot-assisted passive stepping in humans

• Published in: The European journal of neuroscience 2015-09, Vol.42 (6), p.2283-2288
• Main Authors: Obata, Hiroki, Ogawa, Tetsuya, Kitamura, Taku, Masugi, Yohei, Takahashi, Miho, Kawashima, Noritaka, Nakazawa, Kimitaka
• Format: Article
• Language: English
• Subjects: Adult; Electric Stimulation - methods; Electric Stimulation Therapy - methods; Electromyography; Female; H-Reflex; Humans; Male; Muscle, Skeletal - physiology; Neural Inhibition; passive stepping; peripheral nerve stimulation; Peroneal Nerve - physiology; plasticity; Robotics - methods; spinal cord; spinal reciprocal inhibition; Walking - physiology; Young Adult
• ISSN: 0953-816X; 1460-9568
• DOI: 10.1111/ejn.13000

The purpose of this study was to investigate the effect of electrical stimulation to the common peroneal nerve (CPN) on the spinal reflex and reciprocal inhibition (RI) during robot‐assisted passive ground stepping (PGS) in healthy subjects. Five interventions were applied for 30 min in healthy subjects: PGS alone; strong CPN stimulation [50% of the maximal tibialis anterior (TA) M‐wave, functional electrical stimulation (FES)] alone; weak CPN stimulation [just above the MT for the TA muscle, therapeutic electrical stimulation (TES)] alone; PGS with FES; and PGS with TES. FES and TES were applied intermittently to the CPN at 25 Hz. The soleus (Sol) H‐reflex and RI, which was assessed by conditioning the Sol H‐reflex with CPN stimulation, were investigated before (baseline), and 5, 15 and 30 min after each intervention. The amplitudes of the Sol H‐reflex were not significantly different after each intervention as compared with the baseline values. The amounts of RI were significantly decreased 5 min after PGS with FES as compared with the baseline values, whereas they were significantly increased 5 and 15 min after PGS with TES. The other interventions did not affect the amount of RI. These results suggest that interventions that combined PGS with CPN stimulation changed the spinal RI in an intensity‐dependent manner. We investigated the short‐term effect of electrical simulation to the common peroneal nerve (CPN) during the swing phase of 30‐min robot‐assisted passive ground stepping (PGS) on the spinal reciprocal inhibition (RI). The amounts of RI were significantly decreased after PGS with FES (50% of the TAMmax) as compared with the base line values (i.e., before each intervention), whereas they were significantly increased after PGS with TES (just above the TA motor threshold). The results suggest that interventions that combined PGS with CPN stimulation changed RI in an intensity‐dependent manner.