Inhibition of soleus Hoffmann reflex by ankle-foot orthosis application in healthy volunteers.

Autor:	Larsen LE; Laboratory for Clinical and Experimental Neurophysiology, Department of Neurology, Ghent University Hospital, Ghent, Belgium., Jakobsen LA; Department of Health Science and Technology, Medical Faculty, Aalborg University, Aalborg, Denmark., Jensen A; Department of Health Science and Technology, Medical Faculty, Aalborg University, Aalborg, Denmark., Lambden BM; Hull York Medical School, University of Hull, Hull, UK., Sørensen MR; Department of Health Science and Technology, Medical Faculty, Aalborg University, Aalborg, Denmark., Ellrich J; Department of Health Science and Technology, Medical Faculty, Aalborg University, Aalborg, Denmark jellrich@hst.aau.dk.
Jazyk:	angličtina
Zdroj:	Prosthetics and orthotics international [Prosthet Orthot Int] 2015 Dec; Vol. 39 (6), pp. 444-53. Date of Electronic Publication: 2014 Jun 04.
DOI:	10.1177/0309364614535621
Abstrakt:	Background: An ankle-foot orthosis is suggested to actively assist dorsiflexion of the foot by induction of a positive proprioceptive impact to ankle dorsiflexor muscles. However, an objective proof is missing. Objectives: To assess the proprioceptive impact of an ankle-foot orthosis application by Hoffmann reflex recordings of the soleus muscle under static conditions. It was hypothesized that the use of an ankle-foot orthosis facilitated dorsiflexor motor function and thus a decreased the soleus Hoffmann reflex. Study Design: Experimental study in healthy volunteers, pre-post test design. Methods: In all, 20 healthy volunteers were enrolled in order to assess the proprioceptive impact of orthosis application. The Hoffmann reflex was recorded before, during, and after orthosis application. Results: Under orthosis application, the Hoffmann reflex significantly decreased as compared to before (p < 0.05) and after application (p < 0.05). Conclusions: Findings indicate an inhibition of plantarflexors probably induced by facilitation of ankle dorsiflexors under static conditions. At first glance, it seems that foot orthoses primarily have a stabilizing effect on ankle joints in terms of simple mechanical bandages. However, the present results suggest an additional active impact on proprioceptive control. Clinical Relevance: The putative neuromodulatory effect on motor control may support the application of such ankle-foot orthoses in, for example, drop foot. Furthermore, the objective assessment of a neurophysiological mode of action of orthoses by Hoffmann reflex recordings might be an appropriate primary outcome parameter in clinical trials. (© The International Society for Prosthetics and Orthotics 2014.)
Databáze:	MEDLINE
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