The Reduced Adaptability of H-Reflex Parameters to Postural Change With Deficiency of Foot Plantar Sensitivity

Mengzi Sun; Kelsey Lewis; Jung Hun Choi; Fangtong Zhang; Feng Qu; Li Li

doi:10.3389/fphys.2022.890414

The Reduced Adaptability of H-Reflex Parameters to Postural Change With Deficiency of Foot Plantar Sensitivity

Front Physiol. 2022 Jun 29:13:890414. doi: 10.3389/fphys.2022.890414. eCollection 2022.

Authors

Mengzi Sun^{1

2}, Kelsey Lewis², Jung Hun Choi³, Fangtong Zhang¹, Feng Qu¹, Li Li²

Affiliations

¹ Biomechanics Laboratory, Beijing Sport University, Beijing, China.
² Department of Health Sciences and Kinesiology, Georgia Southern University, Statesboro, GA, United States.
³ Department of Mechanical Engineering, Georgia Southern University, Statesboro, GA, United States.

Abstract

Purpose: The project was to examine the influence of peripheral neuropathy (PN) severity on the relationship between Hoffmann-reflex (H-reflex) and postures. Methods: A total of 34 participants were recruited. H-reflex (H/M ratio and H-index) during prone, standing, and the heel-contact phase of walking was tested, along with foot sole sensitivity. Results: The participants were divided into three groups based on the severity of the foot sole sensitivity deficit: control, less (LA), and more (MA) affected with both feet 5.07 monofilament test scores ranging 10, 0-5, and 6-9, respectively. A significant group by the posture interaction was observed in the H/M ratio (F_{3.0, 41.9} = 2.904, p = 0.046, η _p ² = 0.172). In the control group, the H/M ratio of prone (22 ± 7%) was greater than that of the standing (13 ± 3%, p = 0.013) and heel-contact phase (10 ± 2%, p = 0.004). In the MA group, the H/M ratio of standing (13 ± 3%) was greater than that of the heel-contact phase (8 ± 2%, p = 0.011). The H-index was significantly different among groups (F_2,28 = 5.711, p = 0.008, and η _p ² = 0.290). Post hoc analysis showed that the H-index of the control group (80.6 ± 11.3) was greater than that of the LA (69.8 ± 12.1, p = 0.021) and MA groups (62.0 ± 10.6, p = 0.003). Conclusion: In a non-PN population, the plantar sensory input plays an important role in maintaining standing postural control, while as for the PN population with foot sole sensitivity deficiency, type Ⅰ afferent fibers reflex loop (H-reflex) contributes more to the standing postural control. The H-index parameter is an excellent method to recognize the people with and without PN but not to distinguish the severity of PN with impaired foot sole sensitivity.

Keywords: H-reflex; heel-contact; peripheral neuropathy; prone; standing.