The effects of Vibro-medical insole on vibrotactile sensation in diabetic patients with mild-to-moderate peripheral neuropathy

Acute Effects of Vibrating Insoles on Dynamic Balance and Gait Quality in Individuals With Diabetic Peripheral Neuropathy: A Randomized Crossover Study

OBJECTIVE

This study investigated the effects of vibrating insoles on dynamic balance and gait quality during level and stair walking and explored the influence of vibration type and frequency in individuals with diabetic peripheral neuropathy (DPN).

RESEARCH DESIGN AND METHODS

Twenty-two men with DPN were assessed for gait quality and postural and dynamic balance during walking and stair negotiation using a motion capture system and force plates across seven vibratory insole conditions (Vcs) versus a control (Ctrl) condition (insole without vibration). Vibration was applied during standing and walking tasks, and 15-min rest-stop periods without vibration were interposed between conditions. Repeated measures test conditions were randomized. The primary outcomes were gait speed and dynamic balance.

RESULTS

Gait speed during walking significantly improved in all Vcs compared with Ctrl (P < 0.005), with Vc2, Vc4, and Vc6 identified as the most effective. Gait speed increased (reflecting faster walking) during stair ascent and descent in Vc2 (Ctrl vs. Vc2 for ascent 0.447 ± 0.180 vs. 0.517 ± 0.127 m/s; P = 0.037 and descent 0.394 ± 0.170 vs. 0.487 ± 0.125 m/s; P = 0.016), Vc4 (Ctrl vs. Vc4 for ascent 0.447 ± 0.180 vs. 0.482 ± 0.197 m/s; P = 0.047 and descent 0.394 ± 0.170 vs. 0.438 ± 0.181 m/s; P = 0.017), and Vc6 (Ctrl vs. Vc6 for ascent 0.447 ± 0.180 vs. 0.506 ± 0.179 m/s; P = 0.043 and descent 0.394 ± 0.170 vs. 0.463 ± 0.159 m/s; P = 0.026). Postural balance improved during quiet standing with eyes closed in Vc2, Vc4, Vc6, and Vc7 (P < 0.005).

CONCLUSIONS

Vibrating insoles are an effective acute strategy for improving postural balance and gait quality during level walking and stair descent in individuals with DPN. These benefits are particularly evident when the entire plantar foot surface is stimulated.

Retention of Improved Plantar Sensation in Patients with Type II Diabetes Mellitus and Sensory Peripheral Neuropathy after One Month of Vibrating Insole Therapy: A Pilot Study

Sensory peripheral neuropathy is a common complication of diabetes mellitus and the biggest risk factor for diabetic foot ulcers. There is currently no available treatment that can reverse sensory loss in the diabetic population. The application of mechanical noise has been shown to improve vibration perception threshold or plantar sensation (through stochastic resonance) in the short term, but the therapeutic use, and longer-term effects have not been explored. In this study, vibrating insoles were therapeutically used by 22 participants, for 30 min per day, on a daily basis, for a month by persons with diabetic sensory peripheral neuropathy. The therapeutic application of vibrating insoles in this cohort significantly improved VPT by an average of 8.5 V (p = 0.001) post-intervention and 8.2 V (p < 0.001) post-washout. This statistically and clinically relevant improvement can play a role in protection against diabetic foot ulcers and the delay of subsequent lower-extremity amputation.

Subthreshold white noise vibration alters trembling sway in older adults

BACKGROUND

Somatosensory deficit is a significant contributor to falls in older adults. Stochastic resonance has shown promise in recent studies of somatosensation-based balance disorders, improving many measures of stability both inside and outside of the clinic. However, our understanding of this effect from a physiological perspective is poorly understood. Therefore, the primary goal of this study is to explore the influence of subthreshold vibratory stimulation on sway under the rambling-trembling framework.

METHODS

10 Healthy older adults (60-65 years) volunteered to participate in this study. Each participant underwent two randomized testing sessions on separate days, one experimental and one placebo. During each session, the participants' baseline sway was captured during one 90-s quiet standing trial. Their sensation threshold was then captured using a custom vibratory mat and 4-2-1 vibration perception threshold test. Finally, participants completed another 90-s quiet standing trial while the vibratory mat vibrated at 90% of their measured threshold (if experimental) or with the mat off (if placebo). While they completed these trials, an AMTI force plate collected force and moment data in the anteroposterior (AP) and mediolateral (ML), from which the center of pressure (COP), rambling (RM), and trembling (TR) time series were calculated. From each of these time series, range, variability (root-mean-square), and predictability (sample entropy) were extracted. One-tailed paired t-tests were used to compare baseline and during-vibration measures.

RESULTS

No significant differences were found during the placebo session. For the experimental session, significant increases were found in AP TR range, ML TR RMS, AP COP predictability, and AP & ML TR predictability. The TR time series was particularly sensitive to vibration, suggesting a strong influence on peripheral/spinal mechanisms of postural control.

SIGNIFICANCE

Though it is unclear whether observed effects are indicative of "improvements" or not, it does suggest that there was a measurable effect of subthreshold vibration on sway. This knowledge should be utilized in future studies of stochastic resonance, potentially acting as a mode of customization, tailoring vibration location, duration, magnitude, and frequency content to achieve the desired effect. One day, this work may aid in our ability to treat somatosensation-based balance deficits, ultimately reducing the incidence and severity of falls in older adults.

Immediate effects of footwear with vibration applied to the swing phase of the gait cycle on dynamic balance in patients with diabetic peripheral neuropathy

Sensory and sub-sensory foot vibration have beneficial effects on the static and dynamic balance of patients with diabetic peripheral neuropathy (DPN). Previous foot vibration during walking was applied at sub-sensory threshold in both stance and swing phases of the gait cycle in DPN. This study aimed to investigate the effects of footwear with vibration above the sensory threshold applied to the swing phase of the gait cycle on the dynamic balance of DPN. Fifteen patients with DPN and 10 matched healthy control participants were enrolled in this study. Dynamic balance assessment was investigated by the sit to stand and turn tests while electromyography activity (root mean square, RMS) of the vastus lateralis (VL), tibialis anterior (TA), and peroneus longus (PL) muscles were recorded at baseline, after 10 min of wearing the vibratory sandal without vibration, and after 10 min of wearing the sandal with vibration. Repeated measure analysis of variance was conducted for data analysis. Wearing the vibratory sandal slightly increased the speed of weight transfer in both groups and COP sway in DPN (P > 0.05), and close to significant decrease of turn sway (P = 0.07) in both groups. There were significant differences of the PL RMS in turn test (P = 0.03) in DPN and peak RMS of the PL after 10 min of wearing the sandal with vibration in both groups (P < 0.05). The results of the present study demonstrated that PL activity was significantly influenced by the vibratory sandal as its tendon passing across the sole and in direct contact with the source of the vibration.

Efficacy and tolerability of DPP4 inhibitor, teneligliptin, on autonomic and peripheral neuropathy in type 2 diabetes: an open label, pilot study

BACKGROUND

Diabetic neuropathy increases risk of cardiovascular disease, peripheral artery disease, foot amputation and overall mortality. Not only hyperglycaemia induced nerve damage is harder to repair using currently approved medications, but also, the use of these agents is often limited by the extent of pain relief provided and side effects.

METHODOLOGY

In this prospective, open-label, pilot study, 20 type-2 diabetes mellitus patients (male/female=13/7, mean age- 56.1±8.04 years), meeting inclusion/exclusion criteria, were treated with dipeptidyl peptidase-4 (DPP-4) inhibitor, Teneligliptin, 20mg once a day for three months. Efficacy parameters: Sudomotor function (Sudoscan score); parasympathetic dysfunction assessed using Ewing's criteria i.e. heart rate response to -standing (HRS), -valsalva (HRV) and -deep breath (HRD); sympathetic dysfunction assessed as blood pressure response to -standing (BPS) and -handgrip (BPH); ankle brachial index (ABI), vibration perception threshold (VPT), C-reactive protein, glycemic profile and health related quality of life (HRQoL); and, tolerability parameters: complete blood count, liver function tests, serum creatinine, thyroid stimulating hormone, QT- interval and serum vitamin B12 levels, were measured.

RESULTS

There was no statistical difference in BMI, SBP, DBP, HRD, BPH and all safety parameters. After 12 weeks treatment, there was improvement in HRS (p<0.01) and HRV (p<0.01), but not in HRD (p=0.12). BPS was significantly lowered (p <0.01), but not the BPH (p =0.06). Sudoscan score was increased, while VPT was significantly decreased (both p<0.01).

CONCLUSION

Teneligliptin not only improves the glycemic status but also improves sudomotor function, peripheral and autonomic neuropathy, and reduces vascular inflammation in type 2 diabetes.

Designing and fabricating a novel medical insole with universal fluid layer with auto-customizability

Medical insoles play a significant role in pressure reduction, proper stress-strain distribution, and correcting some deformities in the foot. The aim of the present research is to design and fabricate new medical insoles with universal fluid layer. After fabricating two types of insoles including flat silicone insole with shore 17 and flat silicone insole with universal fluid layer (medical silicone with shore 17 and silicone gel with shore 0), PEDAR test using one person in two standing and walking positions in three conditions comprised without the use of medical insole, using of flat medical silicone insole, and flat silicone insole with universal fluid layer was performed. These insoles were also modeled and solved in Abacus software according to the results obtained from mechanical properties testing of silicone and PEDAR test. The results of the finite element analysis showed that absorption of stress and strain in the static state by the silicone insoles with universal fluid layer was 63% and 63%, and in the dynamic state was 84% and 89% more than those obtained by the flat silicone insoles, respectively. The experimental results of the PEDAR system also showed that in the standing state, the silicone insoles with universal fluid layer and the flat silicone insoles had 58% and 30% pressure reduction, respectively, in comparison with without insole condition. Also, in the gait state, the silicone insoles with fluid layer and the flat silicone insole showed 37% and 9% pressure reduction, respectively, in comparison with without insole condition. Eventually, it was found out that the silicone insoles with fluid layer reduce plantar pressure well in comparison to the flat silicone insoles.

Effects of vibro-medical insoles with and without vibrations on balance control in diabetic patients with mild-to-moderate peripheral neuropathy

The purpose of this study was to investigate the effects of a total-contact insole with and without subthreshold mechanical random noise on the balance control in diabetic patients with mild-to-moderate peripheral neuropathy. Twenty diabetic patients with mild-to-moderate neuropathy was recruited to this study. A total-contact insole was prototyped and vibratory motors were embedded into it. The parameters of the center of pressure (amplitude, velocity, and phase plane portrait) were analyzed after 30-minute walks with the shoe only, the shoe with vibro-medical insole with and without vibrations in eyes open and closed condition. The center of pressure amplitude, velocity, and phase plane portrait in the anterior-posterior and medio-lateral directions were significantly decreased using a vibro-medical insole without vibration in the eyes open condition (p < 0.05), as compared to the shoe, and with vibro- medical insole with vibration in both eyes open and closed conditions (p < 0.05) compared to the shoe. A significant drop was observed in the center of pressure amplitude, velocity and phase plane portrait parameters when the vibro-medical insole with vibration was used compared to vibro- medical insole without vibration in eyes closed condition (p < 0.05). The use of vibro-medical insoles was found to improve the patient's balance control, as compared to the shoe. In the eyes closed condition, an improvement in the balance control was observed only with vibro-medical insole with vibration rather than vibro-medical insole without vibration or the shoe. Current finding suggest that a combination of the total-contact insole with vibration may improve the balance control remarkably in diabetic patients with mild-to-moderate neuropathy.

How can the stimulation of plantar cutaneous receptors improve postural control? Review and clinical commentary

Postural control requires constant and subconscious postural sway to manage balance and achieve postural stability. These movements of regulation are based in particular on cutaneous plantar information. The foot constitutes a functional whole that participates in the mechanisms of postural control and regulation. It represents the direct interface between the body and the ground during quiet standing, and plantar cutaneous information contributes to postural control. Upright balance mechanically depends on the gravitational torque produced by the forces of gravity and reaction of the ground. In this context, the foot behaves like a sensory system for postural regulation whose objective is to maintain a state of stability within a changing and constraining environment. There is a relation between balance improvement and the facilitation of sensory feedback related to the activation of the plantar cutaneous mechanoreceptors. From a clinical point of view, the application of additional tactile cues may have therapeutic benefits in relation to fall prevention, or to improve specific types of chronic pain.

The effects of vibro-medical insole on sensation and plantar pressure distribution in diabetic patients with mild-to-moderate peripheral neuropathy

BACKGROUND

The first aim of this study was to determine the effect of a vibro-medical insole on pressure sensation and the second was to measure the effects of a vibro-medical insole with and without random noise on plantar pressure distribution in diabetic patients with mild-to-moderate peripheral neuropathy.

METHODS

Twenty patients with mild-to-moderate diabetic neuropathy were recruited in the clinical trial pre-test, post-test study. A medical insole was made for each participant and a vibratory system was inserted into it. Pressure sensation was evaluated before and after the 30-min walk using the vibro-medical insole with added random noise by Semmes-Weinstein Monofilaments. Peak pressure data was measured before and after 30-min walking with a vibro-medical insole with and without random noise by the Pedar-x system.

FINDINGS

Pressure sensations showed improvement after 30-min walking with the vibro-medical insole with added random noise at the heel, metatarsophalangeal heads and hallux of both feet in all participants (p < 0.05). Peak pressure decreased significantly in the heel, MTP_2,3, MTP_4,5 and hallux (p < 0.05) and increased in midfoot (p < 0.05) using the vibro-medical insole with and without random noise compared to the shoe only condition. Only the peak pressure of the heel region decreased using the vibro-medical insole with random noise compared to without random noise (p = 0.006).

INTERPRETATION

Thirty minute walking with a vibro-medical insole seems to improve pressure sensation and alter peak pressure in diabetic patients with mild-to-moderate peripheral neuropathy. This work suggests that vibro-medical insoles can be used for daily living activities and possibly decreases the risk of ulceration in diabetic neuropathy patients.