The Comparison Of Proprioception And Hoffmann Reflex In Functional Instability And Normal Ankles

Abstract

Purpose It is demonstrated that recurrent ankle sprain might impair nerve conduction or neuron pathway surrounding the ankle joint. However, none of any study examines the influences of FI symptoms on motoneuron excitability. The purpose of this study was to compare the difference in proprioception and Hoffmann reflex between FI and normal ankles. Methods Twenty-two subjects (10 with health normal ankles, 3 with unilateral FI ankle, and 10 with bilateral FI ankles) were recruited as subjects. The proprioception was measured by BIODEX III dynamometer as ankle active/passive reposition sense. The Hoffmann reflex was measured by DANTEC Keypoint ® as H-reflex and M wave maximal amplitude. Independent t-test and Pearson correlation analysis were used to exam the difference and relationship between FI and normal ankles. The significant level was set atα=0.05. Results The results of this study showed that: 1) FI ankle had significant bigger absolute reposition error angle. 2) FI ankle had significant smaller H-reflex maximal amplitudes and the Hmax/Mmax ratio. Conclusions This study demonstrated that FI ankle had significant poor proprioception and lower motoneuron excitability. It is believed that impaired mechanoreceptors in functional instability ankle would decrease the sensitivity of ankle proprioception. Moreover, these diminished afferent signals seemed to be in relation to lower the maximal amplitude of soleus Hoffmann reflex. Supported by NSC92-2413-H-179-012, Taiwan, R.O.C