Determination of pathological clonus characteristics using a haptic ankle manipulator

Carel G.M. Meskers, Erwin De Vlugt, Jurriaan H. De Groot, Wessel H.J. Wisman, J. Hans Arendzen, Frans C.T. Van Der Helm

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

Abstract

Clonus is a self sustained oscillatory movement of the extremities often seen after lesions of the central nervous system. There is still controversy about the origin of clonus whether it is i) an autonomous pacemaker-like oscillator, ii) a reflexive mediated feedback property or iii) a combination of both. With the use of a haptic robot we were able to initiate clonus in patients (n=7). We would conclude the underlying mechanism to be autonomous when the frequency of movement would not change with additional external damping and inertia. Results however showed distinct changes in frequency of movement, varying the peripheral conditions. Furthermore, when the clonus was suddenly stopped by a controlled increase of a huge external damper, clear bursting was observed in the triceps EMG while there was no rotation of the ankle. In conclusion, i) clonus is initiated by spinal reflexes (probably Ia or Ib afferents), ii) also during clonus the same spinal reflexes are likely to contribute to the maintenance of ankle rotation and iii) the after bursting directs to self sustained firing of neural circuitry. These conclusions implicate the existence of a reflexive controlled oscillator. Future research will be performed using detailed model simulations to test different gains between reflexive feedback and neural oscillations, e.g. from the alpha-motorneurons.

Original languageEnglish
Title of host publication2007 IEEE 10th International Conference on Rehabilitation Robotics, ICORR'07
Pages626-630
Number of pages5
DOIs
Publication statusPublished - 1 Dec 2007
Event2007 IEEE 10th International Conference on Rehabilitation Robotics, ICORR'07 - Noordwijk, Netherlands
Duration: 12 Jun 200715 Jun 2007

Publication series

Name2007 IEEE 10th International Conference on Rehabilitation Robotics, ICORR'07

Conference

Conference2007 IEEE 10th International Conference on Rehabilitation Robotics, ICORR'07
CountryNetherlands
CityNoordwijk
Period12/06/200715/06/2007

Cite this