Reliability of nerve function assessments for people with peripheral neuropathy

The effect of loss of foot sole sensitivity on H-reflex of triceps surae muscles and functional gait

Objective: To investigate the effects of foot sole insensitivity on the outcomes of the triceps surae muscle H-reflex and functional gait. Material and Methods: People with peripheral neuropathy were recruited and divided into two groups: people with more (n = 13, 73.3 ± 4.3 years old) or less (n = 10, 73.5 ± 5.3) sensitive tactile sensation. Their monofilament testing scores were 9.0 ± 1.5 (range: 7-10) and 2.3 ± 2.4 (range: 0-6) out of 10, respectively. H-reflex of the triceps surae muscles during quiet standing and their relationship with functional gait, 6 min walking distance (6MWD), and timed-up-and-go duration (TUG), were compared between groups. Results: No significant difference was detected for H-reflex parameters between the groups. The less sensitive group showed reduced (p < .05) functional gait capacity compared to the other group, 38.4 ± 52.7 vs. 463.5 ± 47.6 m for 6MWD, and 9.0 ± 1.5 vs. 7.2 ± 1.1s for TUG, respectively. A significant correlation (p < .05), worse functional gait related to greater H/M ratio, was observed in the less sensitive group, not the other group. Conclusion: Although there was no significant H-reflex difference between the groups, more pronounced tactile sensation degeneration affected functional gaits and their relationship with H-reflex.

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

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_p² = 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_p²= 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.

Hoffmann Reflex Measured From Lateral Gastrocnemius Is More Reliable Than From Soleus Among Elderly With Peripheral Neuropathy

Introduction

Peripheral neuropathy (PN) affects up to 20% of the population over the age of 60. Hoffmann reflex (H-reflex) may assess PN adaptation by measuring the function of the peripheral neural system and central nervous system (CNS) modulation. This project aimed to find a reliable muscle among triceps surae muscles during standing and walking among the PN population.

Materials and Methods

Sixteen older adults (> 65 years of age) diagnosed with PN were recruited in this study. The H-reflex test was conducted on the muscle belly of the soleus (SOL), the medial (MG), and lateral gastrocnemius (LG) during standing and walking (heel contact, midstance, and toe-off phases). All measurements were collected on two occasions, separated by at least 7 days. Intraclass correlation coefficients (ICCs) and their confidence intervals (CIs) were used to examine the consistency of the H-reflex outcome variables in the repeated tests for all three tested muscles.

Results

The ICCs of H-index during standing and the three walking phases were poor to moderate in SOL (0.486∼0.737) and MG (0.221∼0.768), and moderate to high in LG (0.713∼0.871). The ICCs of H/M ratio were poor to moderate in SOL (0.263∼0.702) and MG (0.220∼0.733), and high in LG (0.856∼0.958).

Conclusion

The H-reflex of LG was more reliable than SOL and MG during standing and walking among older adults with peripheral neuropathy. It is crucial for future studies in this population to study H-reflex of LG, not SOL and MG, for more reliable results.

The contribution of small and large sensory afferents to postural control in patients with peripheral neuropathy

Peripheral neuropathy (PN) is a multifarious disorder that is caused by damage to the peripheral nerves. Although the symptoms of PN vary with the etiology, most cases are characterized by impaired tactile and proprioceptive sensation that progresses in a distal to proximal manner. Balance also tends to deteriorate as the disorder becomes more severe, and those afflicted are substantially more likely to fall while walking compared with those who are healthy. Most patients with PN walk more cautiously and with greater stride variability than age-matched controls, but the majority of their falls occur when they must react to a perturbation such as a slippery or uneven surface. The purpose of this study was to first describe the role of somatosensory feedback in the control of posture and then discuss how that relationship is typically affected by the most common types of PN. A comprehensive review of the scientific literature was conducted using MEDLINE, and the relevant information was synthesized. The evidence indicates that the proprioceptive feedback that is conveyed primarily through larger type I afferents is important for postural control. However, the evidence indicates that the tactile feedback communicated through smaller type II afferents is particularly critical to the maintenance of balance. Many forms of PN often lead to chronic tactile desensitization in the soles of the feet and, although the central nervous system seems to adapt to this smaller type II afferent dysfunction by relying on more larger type I afferent reflex loops, the result is still decreased stability. We propose a model that is intended both to help explain the relationship between stability and the smaller type II afferent and the larger type I afferent feedback that may be impaired by PN and to assist in the development of pertinent rehabilitative interventions.