Exploring the receptor origin of vibration-induced reflexes

Abstract

Study Design An experimental design.Objectives The aim of this study was to determine the latencies of vibration-induced reflexes in individuals with and without spinal cord injury (SCI), and to compare these latencies to identify differences in reflex circuitries. SettingA tertiary rehabilitation centre in Istanbul Methods Seventeen individuals with chronic SCI (SCI group) and 23 participants without SCI (Control group) were included in this study. Latency of tonic vibration reflex (TVR), and whole body vibration-induced muscular reflex (WBV-IMR) of the left soleus muscle were tested for estimating the reflex origins. The local tendon vibration was applied at six different vibration frequencies (50, 85, 140, 185, 235 and 265 Hz), each lasting for 15 s with 3-s rest intervals. The whole body vibration was applied at six different vibration frequencies (35, 37, 39, 41, 43 and 45 Hz), each lasting for 15 s with 3-s rest intervals.Results Mean (SD) TVR latency was 39.7 (5.3) milliseconds in the SCI group and 35.9 (2.7) milliseconds in the Control group with a mean (95% CI) difference of -3.8 (-6.7 to -0.9) milliseconds. Mean (SD) WBV-IMR latency was 45.8 (7.4) milliseconds in the SCI group and 43.3 (3.0) milliseconds in the Control group with a mean (95% CI) difference of -2.5 (-6.5 to 1.4) milliseconds. There were significant differences between TVR latency and WBV-IMR latency in both the groups (mean (95% CI) difference; -6.2 (-9.3 to -3.0) milliseconds p = 0.0001 for SCI group and -7.4 (-9.3 to -5.6) milliseconds p = 0.011 for Control group). ConclusionsThe results suggests that the receptor of origin of TVR and WBV-IMR may be different.

Whole body vibration activates the tonic vibration reflex during voluntary contraction

“…An electronic reflex hammer (Elcon, Germany) was used to determine the T-reflex latency. The T-reflex and TVR latencies are almost the same; both are spindle-based reflexes 19 ) . Thus, we used the T-reflex latency to describe the TVR reflex.…”

“…If the latency of the WBV-induced reflex in the semi-squat position was at least 1 MSD shorter than that of the BMR, the short-latency reflex (i.e., TVR) was considered activated. BMR latency is longer than the muscle spindle-based reflex (i.e., TVR, T-reflex) latency 9 , 16 , 17 , 18 , 19 ) . If the difference between the latencies of the WBV-induced reflex and BMR was within ± 1 MSD in the semi-squat position, it was accepted that the latency did not change and that BMR was activated in the semi-squat position.…”

“…Two spinal reflex mechanisms have been proposed to explain the neuromuscular effects of WBV 4 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ) . The primary findings of the present study were that simultaneous WBV application and voluntary contraction activated TVR, whereas WBV application alone activated BMR in all participants.…”

High-frequency whole-body vibration activates tonic vibration reflex

“…When the body or body segment is subjected to these externally applied forces, skeletal muscle activity reflexively increases. [ 1 - 5 ] However, the neuronal circuitry and receptors of the WBV-induced muscula reflex (WBV-IMR) pathway are not definitively defined. It has been suggested by some authors that the neuromuscular effect of WBV can be explained by the tonic vibration reflex (TVR).…”

A new method to determine stretch reflex latency

“…Hitherto, the methods measuring the stretch reflex (SR) latency used a sensor (eg, accelerometer, load cell) placed either on a mechanical stimulator (eg, hammer, vibration platform) or a body site (eg, skin overlying tendon or muscle belly) and used the output of these sensors to estimate the onset time point of mechanical stimulation. [1][2][3][4][5][6][7] However, the muscle spindles are not stimulated exactly at the time of application of the mechanical stimulus.…”