A new approach to estimation of the number of central synapses included in the H-reflexReportar como inadecuado

A new approach to estimation of the number of central synapses included in the H-reflex - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

BMC Neurology

, 5:13

First Online: 12 July 2005Received: 08 February 2005Accepted: 12 July 2005


BackgroundAmong the main clinical applications of the H-reflex are the evaluation of the S1 nerve root conductivity such as radiculopathy and measurement of the excitability of the spinal motoneurons in neurological conditions. An attempt has been made to reduce the pathway over which H-reflex can be obtained in a hope to localize a lesion to the S1 nerve root, so the S1 central loop has been suggested. The main goal of this study is the estimation of the H-reflex number of synapses for better understanding of the physiology of this practical reflex.

MethodsForty healthy adult volunteers 22 males, 18 females with the mean age of 37.7 ± 10.2 years participated in this study. They were positioned comfortably in the prone position, with their feet off the edge of the plinth. Recording electrodes were positioned at the mid point of a line connecting the mid popliteal crease to the proximal flare of the medial malleolus. Stimulation was applied at the tibial nerve in the popliteal fossa and H, F and M waves were recorded. Without any change in the location of the recording electrodes, a monopolar needle was inserted as cathode at a point 1 cm medial to the posterior superior iliac spine, perpendicular to the frontal plane. The anode electrode was placed over the anterior superior iliac spine, and then M and H waves of the central loop were recorded. After processing the data, sacral cord conduction delay was determined by this formula:

* Sacral cord conduction delay = central loop of H-reflex – delays of the proximal motor and sensory fibers in the central loop.

ResultsThe central loop of H-reflex was 6.77 ± 0.28 msec and the sacral cord conduction delay was 1.09 ± 0.06 msec.

ConclusionThe sacral cord conduction time was estimated to be about 1.09 msec in this study and because at least 1 msec is required to transmit the signal across the synapse between the sensory ending and the motor cell, so this estimated time was sufficient for only one central synapse in this reflex.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2377-5-13 contains supplementary material, which is available to authorized users.

Download fulltext PDF

Autor: Mohammadreza Alavian Ghavanini - Alireza Ashraf - Shahram Sadeghi - Mohammadreza Emad

Fuente: https://link.springer.com/

Documentos relacionados