The H-reflex to Magnetic Stimulation of Lower-Limb Nerves

Soleus H-reflex to S1 nerve root stimulation

“…Table 3 The sensory fiber and motor nerve fiber conduction velocity in the S1 nerve root within the spinal canal Length of S1 nerve root (cm) 17.5 a (SD = 0. reflexes to tibial nerve stimulation lengthened out-of-proportion to the M wave changes during the ischemia. These findings complement earlier studies of the possible clinical feasibility of S1 nerve root stimulation for H-reflexes using magnetic (Zhu et al, 1992;Maccabee et al, 1996) and electrical stimulation (Ertekin et al, 1996). The application of S1 nerve root stimulation methods for eliciting H-reflexes provides a method for distinguishing between proximal and distal lesion sites of the S1 nerve root and its peripheral pathway subserving soleus H-reflexes.…”

“…The mean H-M interval was 6.8 ms which includes one ms for monosynaptic activation of the motor neurons, leaving 5.8 ms as the travel time in the dorsal and ventral sacral roots. Our earlier data (Zhu et al, 1992) suggested that the conduction velocity of the Ia afferents was approximately 18% faster than motor efferents in the proximal segment of the sciatic nerve, giving the travel time of 2.6 ms and a motor efferent travel time of 3.2 ms. The travel time in each of the roots divided by the length of the root (8.75 cm) gives a Ia afferents conduction velocity of 67.3 m/s and a motor efferents conduction velocity of 54.7 ms (Table 3).…”

“…Recent studies have documented that soleus H-reflex can be elicited by magnetic or electrical stimulation of the S1 nerve root and proximal portions of the sciatic nerve (Zhu et al, 1992;Ertekin et al, 1996;Maccabee et al, 1996). The ability to elicit the soleus H-reflex from stimulation of several different sites (S1 nerve root, sciatic nerve, tibial nerve) will be of help in distinguishing between proximal and distal involvement of the reflex pathway.…”

Single measurement reliability and reproducibility of volitional and magnetically-evoked indices of neuromuscular performance in adults

“…Barker et al, 1987;Chokroverty et al, 1993;Evans et al, 1988;Polkey et al, 1996;Vivodtzev et al, 2005;Zhu et al, 1992) and in the diagnosis of neurological abnormality (Benecke, 1996;Murray, 1991). Magnetic stimulation of a peripheral motor nerve activates the fast motor units (Maertens de Noordhout, 1991) and has become popular as a painless alternative to electrical stimulation for assessing true maximal neuromuscular performance (Gleeson, 2001;Hopkins and Ingersoll, 2000;Zhou et al, 1995).…”

Proximally evoked soleus H-reflex to S1 nerve root stimulation in sensory neuronopathies (ganglionopathies)

“…Zhu et al reported that the soleus H‐reflex can be elicited by magnetic or high‐voltage electrical stimulation of the S1 nerve root at the S1 foramen. The peak interval between H‐ and M‐waves (HMI, H‐M interval) represents the intraspinal conduction time of the reflex which could differentiate proximal nerve or root lesions from distal lesions . Jin et al demonstrated that the S1 H‐reflex was more sensitive than the tibial H‐reflex for detecting S1 nerve root lesions .…”