Rwm. Vandeursen et al., THE ROLE OF MUSCLE-SPINDLES IN ANKLE MOVEMENT PERCEPTION IN HUMAN-SUBJECTS WITH DIABETIC NEUROPATHY, Experimental Brain Research, 120(1), 1998, pp. 1-8
The objective of this study was to develop a quantitative method to as
sess muscle spindle function. Three groups of subjects were studied: t
en young and healthy subjects, 15 older subjects with diabetic neuropa
thy, and 15 age-matched controls. All subjects performed an ankle-move
ment matching task with and without muscle vibration. Input from the p
lantar cutaneous mechanoreceptors was minimized by using a foot-clampi
ng device. The younger subjects tracked the movement very well, but vi
bration had a significant effect on their performance (P < 0.001). Sim
ilar results were seen in the older control subjects, but they were le
ss successful in tracking movement and slightly less affected by vibra
tion. The neuropathic subjects had the most difficulty tracking, and v
ibration had only a small but still significant effect on their perfor
mance. The interaction between the group and the vibration effect was
highly significant (P < 0.001), indicating that the performance of the
control subjects changed to a greater degree in the presence of vibra
tion than the performance of the subjects with diabetic neuropathy. Mu
scle spindles are the primary receptors that are involved in the chang
e in tracking performance when vibration is added during an ankle-move
ment matching task, and we therefore conclude that the procedure descr
ibed provides a quantitative evaluation of muscle spindle function. Th
e results demonstrate that diabetic neuropathy degrades muscle sensory
function, which may contribute to the impaired balance and unsteadine
ss of gait that has been observed in diabetic neuropathy.