The effect of reduced somatosensation on standing balance: a systematic review

Deterioration of Vestibular Motion Perception: A Risk Factor for Postural Instability and Falls in Elderly With Type 2 Diabetes

AIMS

To assess whether impaired vestibular perception of self-motion is a risk factor for unsteadiness and falls in elderly patients with type 2 diabetes (T2D).

MATERIALS AND METHODS

113 participants (65-75 years old) with T2D underwent tests of roll and pitch discrimination, postural stability (Berg Balance Scale, Modified Romberg Test, and quantitative posturography), clinical examination and blood chemistry analyses. Falls 1-year after enrolment were self-reported. We performed cluster analysis based on the values of the vestibular motion thresholds, and logistic stepwise regression to compare the clinical-biochemical parameters between clusters.

RESULTS

We identified two clusters (VC1 n = 65 and VC2 n = 48 participants). VC2 had significantly (p < 0.001) higher (poorer) thresholds than VC1: mean pitch threshold 1.62°/s (95% CI 1.48-1.78) in VC2 and 0.91°/s (95% CI 0.84-0.98) in VC1, mean roll threshold 1.34°/s (95% CI 1.21-1.48) in VC2 and 0.69°/s (95% CI 0.64-0.74) in VC1. Diabetes duration was significantly (p = 0.024) longer in VC2 (11.96 years, 95% CI 9.23-14.68) than in VC1 (8.37 years, 95% CI 6.85-9.88). Glycaemic control was significantly (p = 0.014) poorer in VC2 (mean HbA1c 6.74%, 95% CI 6.47-7.06) than in VC1 (mean HbA1c 6.34%, 95% CI 6.16-6.53). VC2 had a significantly higher incidence of postural instability than VC1, with a higher risk of failing the Modified Romberg Test C4 (RR = 1.57, χ2 = 5.33, p = 0.021), reporting falls during follow-up (RR = 11.48, χ2 = 9.40, p = 0.002), and greater postural sway in the medio-lateral direction (p < 0.025).

CONCLUSIONS

Assessing vestibular motion thresholds identifies individuals with T2D at risk of postural instability due to altered motion perception and guides vestibular rehabilitation.

Stochastic resonance in the sensory systems and its applications in neural prosthetics

Noise is generally considered to be detrimental. In the right conditions, however, noise can improve signal detection or information transmission. This counterintuitive phenomenon is called stochastic resonance (SR). SR has generated significant interdisciplinary interest, particularly in physics, engineering, and medical and environmental sciences. In this review, we discuss a growing empirical literature that suggests that noise at the right intensity may improve the detection and processing of auditory, sensorimotor, and visual stimuli. We focus particularly on applications of SR in sensory biology and investigate whether SR-based technologies present a pathway to improve outcomes for individuals living with sensory impairments. We conclude that there is considerable evidence supporting the application of SR in developing sensory prosthetics. However, the progression of SR-based technologies is variable across the sensory modalities. We suggest opportunities for further advancements in each modality, considering the best approaches to maximise benefits and capitalise on progress already made. Overall, SR can offer opportunities to improve existing technologies or to motivate innovations.

Smartphone Usage and Postural Stability in Individuals With Forward Head Posture: A Nintendo Wii Balance Board Analysis

OBJECTIVE

To assess postural stability, specifically center of body sway during single-leg standing balance, among individuals with and without forward head posture (FHP) during smartphone use.

METHODS

The research recruited 53 healthy smartphone users, aged 18-25, and categorized them into FHP group comprising 26 subjects and the normal (control) group with 27 subjects. Participants were assigned the task of maintaining balance while engaged in smartphone typing during single-leg standing. The experiment involved four specific conditions according to neck posture and stable of surface. The study meticulously quantified body center of pressure (COP) sway amplitudes using the Nintendo Wii Balance Board.

RESULTS

The research revealed that individuals with FHP exhibited significantly greater body sway compared to the control group when using smartphones. Notably, distinct variations were observed in path length sway, anteroposterior (AP), and mediolateral (ML) sway amplitude, particularly evident when maintaining flexed neck positions on a soft surface while engaged with smartphones.

CONCLUSION

These findings strongly suggest that individuals with FHP encounter deteriorated postural stability during smartphone use, particularly in challenging head positions.

Effects of individually optimized rocker midsoles and self-adjusting insoles on dynamic stability in persons with diabetes mellitus and neuropathy

BACKGROUND

Persons with diabetic peripheral neuropathy (DPN) may face challenges such as balance issues due to reduced somatosensory feedback and an increased risk of developing diabetic foot ulcers (DFUs) due to increased plantar pressure. Pressure reducing footwear is thought to further impair balance. We introduced 3D-printed rocker midsoles and self-adjusting insoles that are able to reduce elevated plantar pressure values and aimed to prevent balance deterioration. However, their effect on the balance during walking (dynamic stability) is not analyzed yet.

RESEARCH QUESTION

Is dynamic stability of persons with DPN impaired compared to healthy individuals and what is the effect of the 3D-printed rocker midsoles and self-adjusting insoles on the dynamic stability in this population?

METHODS

Dynamic stability, specifically the margins of stability (MOS) in the anterior-posterior (AP) and medio-lateral (ML) direction, was measured in ten healthy and nineteen persons with DPN. Independent-samples t-test was applied to analyze the difference in the MOS between groups. One-way repeated measures analyses of variance (ANOVA) was conducted to test the difference between the therapeutic footwear combinations within the DPN group.

RESULTS

There is no significant difference between the healthy and DPN group in MOS-AP. MOS-ML is significantly larger in DPN compared to the healthy participants. Using the self-adjusting insole shows a significantly lower (negative) MOS-AP compared to when using a rocker shoe within the DPN group.

SIGNIFICANCE

This study provides valuable information on whether DPN and our therapeutic footwear have a negative effect on the dynamic stability. DPN does not have a negative effect on dynamic stability in the AP direction. For the ML direction, DPN seems to cause larger MOS-ML by likely using a compensation strategy (e.g., wider steps) while our experimental footwear does not further impair the MOS-ML.

The Effect of Resistance Exercises Using an Elastic Band on Balance and Fear of Falling in Older Adults With Diabetic Peripheral Neuropathy: A 16-week Randomized Controlled Trial

OBJECTIVE

The current study aimed to investigate the effect of resistance training using an elastic band on balance and fear of falling in older adults with diabetic peripheral neuropathy.

DESIGN

The study was a clinical controlled trial with a repeated measure design.

SETTING

Iranian Diabetes Foundation of Mashhad.

PARTICIPANTS

The participants were 51 older adults with diabetic peripheral neuropathy and balance impairment (N=51).

INTERVENTIONS

Participants were randomly assigned to 2 groups; 1 group received balance training using an elastic band and the other group just received balance training.

MAIN OUTCOME MEASURES

The main outcomes were balance and fear of falling that were measured using Berg Balance Scale and a short version of the Fall Efficiency Scale-International, respectively.

RESULTS

The results showed that balance resistance training with and without using an elastic band significantly enhances balance and reduces fear of falling in diabetic older adults suffering from balance issues. However, balance resistance training using an elastic band had a significantly better effect on the balance and fear of falling in the participants. The best results were obtained after week 12 (48 sessions of balance training).

CONCLUSION

Balance rehabilitation programs may include an elastic band in balance resistance training for 12 weeks (3-4 sessions a week) for enhancing balance in diabetic older adults suffering from balance impairment.

Association of Symptomatic Dizziness With All-Cause and Cause-Specific Mortality

Importance

Dizziness is a highly prevalent complaint with wide-ranging causes and resultant morbidity. Whether symptomatic dizziness and its various manifestations are associated with all-cause and cause-specific mortality is unknown.

Objective

To examine the associations of symptomatic dizziness and its manifestations with all-cause and cause-specific mortality.

Design, Setting, and Participants

This cohort study is a mortality follow-up study based on the 1999-2004 National Health and Nutrition Examination Survey. The study cohort included adults 40 years and older who completed questions about symptomatic dizziness, including problems with dizziness, balance, falling, and positional dizziness, within the past 12 months. Respondents were linked to mortality data through December 31, 2019. Data were analyzed from February to August 2023.

Exposure

Self-reported symptomatic dizziness.

Main Outcomes and Measures

All-cause and cause-specific (cardiovascular disease, diabetes, cancer, and unintentional injuries) mortality. Cox proportional hazard regression models were used to examine associations between symptomatic dizziness and all-cause and cause-specific mortality while adjusting for demographics and medical history.

Results

In this nationally representative cohort of 9000 middle-aged and older US adults (mean [SD] age, 61.8 [13.8] years; 4570 [50.8%] female), prevalence of symptomatic dizziness was 23.8%. Specifically, 18.3% reported problems with dizziness, 14.5% reported problems with balance, 5.7% reported problems with falling, and 3.8% reported dizziness when turning in bed (positional dizziness). At a median (range) of 16.2 (0.1-20.6) years of follow-up, all-cause mortality for adults with symptomatic dizziness was higher than for those without (45.6% vs 27.1%). Symptomatic dizziness was associated with elevated risk for cause-specific mortality from diabetes (hazard ratio [HR], 1.66; 95% CI, 1.23-2.25), cardiovascular disease (HR, 1.33; 95% CI, 1.12-1.55), and cancer (HR, 1.21; 95% CI, 0.99-1.47) but not unintentional injuries (HR, 0.98; 95% CI, 0.51-1.88). Reporting problems with balance or falling was associated with increased all-cause mortality (balance: HR, 1.27; 95% CI, 1.17-1.39; and falling: HR, 1.52; 95% CI, 1.33-1.73), cardiovascular disease-specific mortality (balance: HR, 1.41; 95% CI, 1.20-1.66; and falling: HR, 1.49; 95% CI, 1.15-1.94), and diabetes-specific mortality risks (balance: HR, 1.74; 95% CI, 1.26-2.39; and falling: HR, 2.01; 95% CI, 1.26-3.18). There was no association between positional dizziness and mortality (HR, 0.98; 95% CI, 0.82-1.19).

Conclusions and Relevance

In this cohort study, symptomatic dizziness was associated with increased risk for all-cause and diabetes-, cardiovascular disease-, and cancer-specific mortality. The imprecision of the effect size estimate for cancer-specific mortality prevents making a definitive conclusion. Future studies are needed to determine whether symptomatic dizziness indicates underlying health conditions contributing to mortality or if early intervention for imbalance and falls can reduce mortality risk.

Modern smartphone usage can negatively impact postural balance while standing on dynamically challenging grounds

BACKGROUND

While several studies have explored the impacts of smartphone usage on postural balance, their tasks are limited to texting or calling, and the studies were performed on rigid ground.

RESEARCH QUESTIONS

METHODS: Sixteen healthy young adults were recruited to perform two smartphone tasks: taking selfies and posting statuses on social media; participants were standing on four different grounds: rigid, foam-based compliant, robot-simulated compliant, and robot-simulated oscillatory grounds. The center-of-pressure (CoP) under each foot was recorded via force plates and the net CoP was calculated. Temporal, spatial, and control aspects of postural balance were analyzed by virtual time-to-contact (VTC), CoP path length (PL) and sway area (SA), and switching rate (SR), respectively. Two-way repeated measures analysis of variance (ANOVA) tests were performed for each dependent variable to compare the mean differences between smartphone tasks and ground conditions and their interaction effect. Paired t-tests with Bonferroni correction were used to determine significant differences in post-hoc analyses.

RESULTS

VTC decreased significantly whereas CoP PL and SA increased significantly during smartphone usage (all p-values <0.001). Interaction effects between task and ground condition (all p-values <0.001) were observed in all measures but SR, implying that the effect of smartphone usage on postural balance can significantly change depending on the ground condition.

SIGNIFICANCE

These results highlight the potential fall risks due to the impact of modern smartphone usage on standing balance. Understanding the effect of smartphone usage on standing balance and the interaction effect with various ground conditions opens the door for potential balance assistive devices and mobile phone applications to minimize falls.

Effects of individually optimized rocker midsoles and self-adjusting insoles on plantar pressure in persons with diabetes mellitus and loss of protective sensation

INTRODUCTION

Rocker shoes and insoles reduce peak pressure (PP) in persons with diabetes (DM) and loss of protective sensation (LOPS). However, they are handmade, leading to inconsistent effectiveness. If foot structure changes over time, high PP-locations also change. To address this, individualized algorithm based 3D-printed rockers and self-adjusting pressure-reducing insoles are applied.

METHODS

PP across seven foot regions was analyzed in 21 persons with DM and LOPS. Regions with PP < 200 kPa were considered not at risk (RnoR); regions with PP ≥ 200 kPa at risk (RaR). The aim was to offload RaR, while remaining PP < 200 kPa in RnoR.

RESULTS

Individualized rockers and self-adjusting insoles combined successfully reduce PP < 200 kPa (on average 24 % - 48 %) in all feet with toes, central and lateral forefoot identified as RaR. Same intervention reduces PP in 68 % of the feet with medial forefoot identified as RaR. With the heel as RaR, no intervention reduces PP successfully in all feet.

CONCLUSIONS

Individualized 3D-printed rockers combined with self-adjusting insoles reduce PP (< 200 kPa) in toes, central and lateral forefoot, but not in heels. Alternative insoles with medial arch support, heel cup and compliant midsole materials might enhance success rate across entire foot.

A Physically Active Lifestyle Can Protect against Age-Related Decline in Ankle Proprioception

This study examined whether physically active middle-aged (50-64 years) and older adults (65-80 years) demonstrate age-related ankle proprioceptive decline relative to younger counterparts. Empirical data indicate that ankle proprioception declines with aging and such sensory decline negatively affects balance. Using a passive motion apparatus, we employed a psychophysical forced-choice paradigm in which the ankle was passively plantarflexed to a reference position (15° or 25°) and a comparison position that was always smaller than the reference. Subsequently, participants indicated which position was more plantarflexed. As outcome measures of ankle position sense acuity, a just-noticeable-difference (JND) threshold and the uncertainty area (UA) were derived from the psychometric stimulus-response difference function for each participant. The JND threshold is a measure of proprioceptive bias and UA constitutes a measure of precision. The main results are: First, at the 15° reference, most middle-aged (74%) and older adults (71%) had thresholds within the range of the young adults. The respective median JND threshold of young adults was statistically lower when compared to both older groups. Second, no differences between age groups were observed at the 25° reference. Third, no age-related differences were found for UA at either reference. These data indicate that physically active aging adults may be spared from age-related decline in ankle position sense and that age-related differences emerge for small ankle displacements. The findings underscore the importance of remaining active during aging.

Sensory Restoration for Improved Motor Control of Prostheses

Somatosensory neuroprostheses are devices with the potential to restore the senses of touch and movement from prosthetic limbs for people with limb amputation or paralysis. By electrically stimulating the peripheral or central nervous system, these devices evoke sensations that appear to emanate from the missing or insensate limb, and when paired with sensors on the prosthesis, they can improve the functionality and embodiment of the prosthesis. There have been major advances in the design of these systems over the past decade, although several important steps remain before they can achieve widespread clinical adoption outside the lab setting. Here, we provide a brief overview of somatosensory neuroprostheses and explores these hurdles and potential next steps towards clinical translation.

Comparison of the immediate effects of plantar vibration of both feet with the plantar vibration of the affected foot on balance in patients with stroke: Preliminary findings

OBJECTIVE

Plantar vibration is one of the strategies to enhance balance in stroke patients. This study compared the effects of the plantar vibration of both feet and the plantar vibration of the most affected side in patients with stroke.

METHODS

This study was a single-blind clinical trial. Post-stroke patients with balance impairment were enrolled in the study and underwent two treatment sessions with a one-week interval. They received both feet's plantar vibration in one session and plantar vibration of the most affected side in the other session (frequency 100 Hz, 5 min). Mini-BESTest, Modified Modified Ashworth Scale (MMAS), and Semmes-Weinstein monofilament examination (SWME) were used to evaluate balance, spasticity, and plantar sensation, before and after the treatment sessions.

RESULTS

Ten patients with a mean age of 52.9 (SD = 5.48) years were enrolled in the study. Mini-BESTest scores of balance and plantar flexor muscle spasticity were significantly improved after both feet plantar vibration and plantar vibration of the more affected side. There was no significant difference between the effectiveness of both sides plantar vibration and the most affected side plantar vibration. There were no significant improvements in SWME sensory scores after plantar vibration of either both sides or the most affected side.

CONCLUSION

Plantar vibration of both sides had no additional benefits in this group of patients with chronic stroke. Plantar vibration of more affected side can be used for improving balance and plantar flexor spasticity post-stroke. The Plantar vibration had no effects on the affected foot sensibility.

The effect of modified optic flow gain on quiet stance

Visual feedback provides critical information to support postural stability. Previous work has shown that magnifying visual feedback, such as by presenting individuals with biofeedback during balance tasks, can improve postural control. When studies manipulate the availability of optic flow directly, the conditions are often restricted to include an absence of visual feedback or sway referenced paradigms. Therefore, the aim of this study was to understand how manipulating the gain of optic flow contributes to quiet standing balance control among healthy adults. Optic flow was amplified or reduced relative to head motion using a virtual reality head-mounted display while participants stood quietly on either a firm or foam surface. Overall, when there was an increased reliance placed on the visual system by standing on foam, a tighter control of upright stance was observed as the gain of optic flow increased. Further, this study provided evidence that visual contributions to balance control may extend to higher frequencies of postural sway than previously theorized (greater than 0.1 Hz).

Immediate effect of textured insoles on the balance in patients with diabetic neuropathy

AIMS/INTRODUCTION

Neuropathy is a common complication of diabetes that reduces balance by disrupting vision, and the sensory and vestibular systems. This is important in older adults who are more at risk of falling. Studies show that improving the sensory mechanisms through insoles can improve balance in people with balance disorders. As textured insoles have recently been considered for improving balance disorders, this study aimed to investigate the immediate effect of textured insoles on the balance of patients with diabetic neuropathy.

MATERIALS AND METHODS

A total of 17 patients with diabetic neuropathy participated in this quasi-experimental study. The studied variables were the general balance index, posterior-anterior balance index and medial-lateral balance index, which were measured in three conditions: (i) soft textured insoles; (ii) hard textured insoles; and (iii) without textured insoles. A Biodex balance device was used for this purpose.

RESULTS

In the general balance index, there was a significant difference between all the studied conditions. In the posterior-anterior balance index, there was a significant difference between without textured insole and hard textured insoles, and also soft and hard textured insoles. In the medial-lateral balance index, there was a significant difference between the hard textured insoles and without textured insoles, and also soft and hard textured insoles (P < 0.05).

CONCLUSIONS

Wearing textured insoles can increase the balance in patients with diabetic neuropathy. This can be due to its effect on the sensory feedback of the soles, improving the proprioception and tactile sensors that are the main sources of balance.

Prospective comparative study between knee alignment-oriented static and dynamic balance exercise in patellofemoral pain syndrome patients with dynamic knee valgus

Exercise therapy has been reported as an effective treatment method for patellofemoral pain syndrome (PFPS). However, there is a lack of studies regarding the effectiveness of balance exercise in the treatment of patients with PFPS. This study aimed to prospectively compare changes in proprioception, neuromuscular control, knee muscle strength, and patient-reported outcomes between patients with PFPS treated with knee alignment-oriented static balance exercise (SBE) and dynamic balance exercise (DBE). The participants were divided into 2 groups: 17 knee alignment-oriented SBE group and 19 knee alignment-oriented DBE group. Proprioception was assessed by dynamic postural stability using postural stabilometry. Neuromuscular control and knee muscle strength were measured for acceleration time and peak torque in quadriceps muscle using an isokinetic device. Patient-reported outcomes were evaluated using a visual analog scale for pain and the Kujala Anterior Knee Pain Scale. There was greater improvement in dynamic postural stability (0.9 ± 0.3 vs 1.2 ± 0.5; 95% confidence interval [CI]: 0, 0.6; Effect size: 0.72; P = .021) and quadriceps AT (40.5 ± 14.3 vs 54.1 ± 16.9; 95% CI: 2.9, 24.2; Effect size: 0.86; P = .014) in the DBE group compared to the SBE group. Knee alignment-oriented DBE can be more effective in improving dynamic postural stability and quadriceps muscle reaction time compared with the knee alignment-oriented SBE in PFPS patients with dynamic knee valgus.

Impact of Sensory Afferences in Postural Control Quantified by Force Platform: A Protocol for Systematic Review

Older adults’ postural balance is a critical domain of research as balance deficit is an important risk factor for falls that can lead to severe injuries and death. Considering the effects of ageing on sensory systems, we propose that posturographic evaluation with a force platform exploring the effect of sensory deprivation or perturbation on balance could help understand postural control alterations in the elderly. The aim of the future systematic review and meta-analysis described in this protocol is to explore the capacity of older adults to maintain their balance during sensory perturbations, and compare the effect of perturbation between the sensory channels contributing to balance. Seven databases will be searched for studies evaluating older adults’ balance under various sensory conditions. After evaluating the studies’ risk of bias, results from similar studies (i.e., similar experimental conditions and posturographic markers) will be aggregated. This protocol describes a future review that is expected to provide a better understanding of changes in sensory systems of balance due to ageing, and therefore perspectives on fall assessment, prevention, and rehabilitation.

Vibration Sensitivity Is Associated With Functional Balance After Unilateral Transtibial Amputation

Objectives

To evaluate differences in vibration perception thresholds between adults with transtibial amputation and age-matched adults without amputation and to examine associations between vibration perception thresholds and balance performance. We hypothesized that adults with transtibial amputation would demonstrate lower thresholds compared with adults without amputation and that lower thresholds would be associated with better functional balance.

Design

Prospective cross-sectional study.

Setting

National conference, clinical practice, and university laboratory.

Participants

Adults (N=34) with a nondysvascular, unilateral, transtibial amputation and 43 age-matched controls without amputation.

Interventions

Participants' vibration perception thresholds were evaluated bilaterally by applying a vibration stimulus to the midpatella and recording their verbal response to conscious perception of stimulus. Functional balance was assessed with the Berg Balance Scale and the Four Square Step Test.

Main Outcome Measures

Residual and sound limb (right and left for controls) vibration perception thresholds, Berg Balance Scale, and Four Square Step Test.

Results

For participants with transtibial amputation and controls, there were no significant between-group (P=.921) or interlimb (P=.540) differences in vibration perception thresholds. Overall, robust regression models explained 35.1% and 19.3% variance in Berg Balance Scale scores and Four Square Step Test times, respectively. Among adults with transtibial amputation, vibration perception thresholds were negatively associated with Berg Balance Scale scores (P=.009) and positively associated with Four Square Step Test times (P=.048). Among controls, average vibration perception thresholds were not significantly associated with functional balance (P>.050).

Conclusions

Adults with nondysvascular, transtibial-level amputation demonstrated similar vibration detection compared with adults with intact limbs, indicating that vibration detection is preserved in the amputated region postamputation. These findings suggest a unique relationship between vibration perception and functional balance post-transtibial amputation.

Neurorehabilitation using a voluntary driven exoskeletal robot improves trunk function in patients with chronic spinal cord injury: a single-arm study

Body weight-supported treadmill training with the voluntary driven exoskeleton (VDE-BWSTT) has been shown to improve the gait function of patients with chronic spinal cord injury. However, little is known whether VDE-BWSTT can effectively improve the trunk function of patients with chronic spinal cord injury. In this open-label, single-arm study, nine patients with chronic spinal cord injury at the cervical or thoracic level (six males and three females, aged 37.8 ± 15.6 years, and time since injury 51.1 ± 31.8 months) who underwent outpatient VDE-BWSTT training program at Keio University Hospital, Japan from September 2017 to March 2019 were included. All patients underwent twenty 60-minute gait training sessions using VDE. Trunk muscular strength, i.e., the maximum force against which patient could maintain a sitting posture without any support, was evaluated in four directions: anterior, posterior, and lateral (right and left) after 10 and 20 training sessions. After intervention, lateral muscular strength significantly improved. In addition, a significant positive correlation was detected between the change in lateral trunk muscular strength after 20 training sessions relative to baseline and gait speed. The change in trunk muscular strength after 20 training sessions relative to baseline was greatly correlated with patient age. This suggests that older adult patients with chronic spinal cord injury achieved a greater improvement in trunk muscle strength following VDE-BWSTT. All these findings suggest that VDE-BWSTT can improve the trunk function of patients with chronic spinal cord injury and the effect might be greater in older adult patients. The study was approved by the Keio University of Medicine Ethics Committee (IRB No. 20150355-3) on September 26, 2017.

Auditory and Vestibular Assessment of Patients with Type Two Diabetes Mellitus: A Case-Control Study

Introduction

Type two diabetes mellitus may relate to auditory and vestibular dysfunction. This relationship was frequently observed in elders. The present study aimed to evaluate the auditory and vestibular function of diabetic patients and compare the results with those of a healthy adult control group.

Materials and Methods

Patients were asked to complete demographic characteristics form. Moreover, fasting blood sugar, as well as hemoglobin A1C tests, were carried out on them. Both the patients and control group were evaluated using several auditory and vestibular tests including Pure Tone Audiometry (PTA), video Head Impulse Test (v-HIT), ocular Vestibular Evoked Myogenic Potential (o-VEMP), and cervical Vestibular Evoked Myogenic Potential (c-VEMP).

Results

The PTA showed a significant difference in some frequencies between the two groups. These differences were minimal in lower frequencies and become greater at 8000Hz. The v-HIT was abnormal for some patients and also showed a significant difference between the two groups. The o-VEMP and c-VEMP results were normal in most patients.

Conclusion

Based on the obtained results, auditory and vestibular dysfunctions are related to Diabetes. Patients with type two diabetes mellitus showed mild auditory and vestibular dysfunctions compared to the healthy control group.

Strength exercise for balance and gait in HIV-associated distal symmetrical polyneuropathy: A randomised controlled trial

BACKGROUND

HIV-associated peripheral neuropathy (PN) is a common neurological complication associated with HIV infection. Distal symmetrical polyneuropathy (DSPN) is the most commonly occurring type, which is associated with symptoms such as numbness, unsteady gait and, in some cases, muscle atrophy and weakness when myelinated nerve fibres are affected. If unmyelinated nerve fibres are affected, a painful neuropathy and autonomic symptoms may occur.

OBJECTIVES

This research study assessed the effects of a strength exercise intervention on balance impairment and gait disturbance amongst individuals living with HIV-associated DSPN.

METHOD

The study was a single-blinded, randomised controlled trial (RCT) with participants sourced from four HIV centres in Kano metropolis, Nigeria. The intervention was supervised and included progressive resistance exercise (PRE) (three 40-min sessions per week for 12 weeks) using a quadriceps bench (n = 44). The control group (CG) included the non-exercise group (n = 47). The two groups continued to receive routine care. Data were summarised and analysed using inferential statistics (SPSS version 20 program) with the alpha level set at < 0.05.

RESULTS

At 12 weeks, the results revealed significant improvement with regard to balance performance (p = 0.001) and walking ability (p = 0.001) in the training group. In contrast, no significant differences in balance (P = 0.677) or gait (P = 0.578) were observed in the CG.

CONCLUSION

The findings suggest that PRE is beneficial for balance impairment and gait disturbance caused by neuropathy in persons living with HIV and receiving antiretroviral drugs.

Association of Balance Function With All-Cause and Cause-Specific Mortality Among US Adults

Importance

Difficulty maintaining balance is common among individuals aged 40 years or older and increases the risk of falls. However, little is known about the association of balance function with long-term mortality outcomes in adults.

Objective

To investigate the association of balance function with all-cause and cause-specific mortality among US adults.

Design, Setting, and Participants

A prospective, population-based cohort study of a nationally representative sample of 5816 adults (weighted population, 92 260 641) from the US National Health and Nutrition Examination Survey was conducted from 1999 to 2004. Individuals aged 40 years or older who completed the modified Romberg Test of Standing Balance on Firm and Compliant Support Surfaces were included. Participants were linked to mortality data from the test date through December 31, 2015. Data analysis was conducted from February 1 to June 1, 2020.

Exposures

The modified Romberg Test of Standing Balance on Firm and Compliant Support Surfaces was used to measure balance function and define balance disorder according to sensory input.

Main Outcomes and Measures

Mortality associated with all causes, cardiovascular disease (CVD), and cancer.

Results

A total of 5816 adults (weighted mean [SE] age, 53.6 [0.2] years; 2897 [49.8%] women) were included in this cohort study. During up to 16.8 years of follow-up (median, 12.5 years; 68 919 person-years), 1530 deaths occurred, including 342 associated with CVD and 364 associated with cancer. Participants with balance disorder were at a higher risk of death from all causes, CVD, and cancer. After adjusting for sociodemographic characteristics, lifestyle factors, and chronic conditions, the hazard ratios (HRs) among participants with balance disorder compared with those without balance disorder were 1.44 (95% CI, 1.23-1.69) for all-cause mortality, 1.65 (95% CI, 1.17-2.31) for CVD mortality, and 1.37 (95% CI, 1.03-1.83) for cancer mortality. Furthermore, vestibular balance disorder was associated with increased mortality from all causes (HR, 1.31; 95% CI, 1.08-1.58), CVD (HR, 1.59; 95% CI, 1.12-2.27), and cancer (HR, 1.39; 95% CI, 1.04-1.86).

Conclusions and Relevance

In this nationally representative sample of US adults, balance disorder was associated with an increased risk of all-cause, CVD, and cancer mortality. Further studies are needed to confirm these findings and evaluate whether the observed associations represent a causal biological phenomenon and, if so, whether the effect is modifiable with a multicomponent exercise program.

Cutaneous and muscular afferents from the foot and sensory fusion processing: Physiology and pathology in neuropathies

The foot-sole cutaneous receptors (section 2), their function in stance control (sway minimisation, exploratory role) (2.1), and the modulation of their effects by gait pattern and intended behaviour (2.2) are reviewed. Experimental manipulations (anaesthesia, temperature) (2.3 and 2.4) have shown that information from foot sole has widespread influence on balance. Foot-sole stimulation (2.5) appears to be a promising approach for rehabilitation. Proprioceptive information (3) has a pre-eminent role in balance and gait. Reflex responses to balance perturbations are produced by both leg and foot muscle stretch (3.1) and show complex interactions with skin input at both spinal and supra-spinal levels (3.2), where sensory feedback is modulated by posture, locomotion and vision. Other muscles, notably of neck and trunk, contribute to kinaesthesia and sense of orientation in space (3.3). The effects of age-related decline of afferent input are variable under different foot-contact and visual conditions (3.4). Muscle force diminishes with age and sarcopenia, affecting intrinsic foot muscles relaying relevant feedback (3.5). In neuropathy (4), reduction in cutaneous sensation accompanies the diminished density of viable receptors (4.1). Loss of foot-sole input goes along with large-fibre dysfunction in intrinsic foot muscles. Diabetic patients have an elevated risk of falling, and vision and vestibular compensation strategies may be inadequate (4.2). From Charcot-Marie-Tooth 1A disease (4.3) we have become aware of the role of spindle group II fibres and of the anatomical feet conditions in balance control. Lastly (5) we touch on the effects of nerve stimulation onto cortical and spinal excitability, which may participate in plasticity processes, and on exercise interventions to reduce the impact of neuropathy.

Foot and ankle somatosensory deficits in children with cerebral palsy: A pilot study

PURPOSE

To investigate foot and ankle somatosensory function in children with cerebral palsy (CP).

METHODS

Ten children with spastic diplegia (age 15 ± 5 y; GMFCS I-III) and 11 typically developing (TD) peers (age 15 ± 10 y) participated in the study. Light touch pressure and two-point discrimination were assessed on the plantar side of the foot by using a monofilament kit and an aesthesiometer, respectively. The duration of vibration sensation at the first metatarsal head and medial malleolus was tested by a 128 Hz tuning fork. Joint position sense and kinesthesia in the ankle joint were also assessed.

RESULTS

Children with CP demonstrated significantly higher light touch pressure and two-point discrimination thresholds compared to their TD peers. Individuals with CP perceived the vibration stimulus for a longer period compared to the TD participants. Finally, the CP group demonstrated significant impairments in joint position sense but not in kinesthesia of the ankle joints.

CONCLUSIONS

These findings suggest that children with CP have foot and ankle tactile and proprioceptive deficits. Assessment of lower extremity somatosensory function should be included in clinical practice as it can guide clinicians in designing more effective treatment protocols to improve functional performance in CP.

Test-retest reliability of the two-point discrimination test on the sole of the foot in people with multiple sclerosis

BACKGROUND

Two-point discrimination (TPD) is an assessment of tactile acuity. People with multiple sclerosis (MS) can have reduced foot sole tactile acuity, which has been linked to impaired balance.

OBJECTIVE

To quantify the test-retest reliability of TPD on the sole of the foot in people with MS.

APPROACH

41 participants (32 females), with mean (SD) age of 60 (9) years, and Expanded Disability Status Scale of <7.5, had their TPD measured at the head of the first metatarsal and the heel on two occasions, 2-14 d apart. Mean systematic change, within-subjects SD, limits of agreement (LOA), coefficient of variation and the intraclass correlation coefficient (ICC) were quantified as point estimates (95% CI).

MAIN RESULTS

Systematic learning effects were evident. The within-subjects SD at the metatarsal and the heel was 6.7 mm (5.5-8.6) and 8.3 mm (6.7-10.8), and the LOAs were 18.6 mm (15.2-24.) and 23.7 mm (18.7-30.1), respectively. ICCs for metatarsal and heel was 0.87 (0.76-0.93) and 0.90 (0.80-0.95), respectively, but these were likely inflated by sample heterogeneity.

SIGNIFICANCE

In people with MS, TPD on the sole of the foot has an adequate test-retest reliability for research purposes, but there is substantial measurement variability for individual patients.

Mechanical Plantar Foot Stimulation in Parkinson's Disease: A Scoping Review

Background: Parkinson′s disease (PD) is the second most prevalent neurodegenerative disease in older individuals. Neurorehabilitation-based interventions such as those improving gait are crucial for a holistic approach and to limit falls. Several studies have recently shown that mechanical plantar foot stimulation is a beneficial intervention for improving gait impairment in PD patients. The objective of this scoping review is to evaluate the beneficial effects of this stimulation on gait parameters, and to analyse protocols of foot stimulation and other effects in non-motor symptoms. Relevant articles were searched in the Medline database using Pubmed and Scopus, using the primary search terms ‘foot stimulation’ OR ‘plantar stimulation’ AND ‘Parkinson’s disease*’. Several protocols have been used for mechanical plantar foot stimulation (ranging from medical devices to textured insoles). The gait parameters that have been shown to be improved are stride length and walking speed. The beneficial effects are achieved after both acute and repeated plantar foot stimulation. Beneficial effects are observed in other organs and systems, such as muscle activation, brain connectivity, cardiovascular control in the central nervous system, and the release of brain-derived neurotrophic factor and cortisol in blood added evidence about this intervention’s impact on brain function. Mechanical plantar foot stimulation is a safe and effective add-on treatment able for improving gait impairments in PD patients during the L-dopa off state. Randomized and controlled clinical trials to study its eventual potentiating effect with different pharmacotherapy regimens are warranted.

Evaluation of Plantar Foot Sensation, Balance, Physical Performance, and Fear of Movement in Substance Use Disorders

BACKGROUND

Neuropathologic changes may occur in the nervous system due to long-term substance use, leading to functional disability with altering of balance. We know little about substance-related mechanisms that can cause movement disorders. This study investigated the effects of plantar foot sensation and balance on physical performance as an effect of substance use in detoxified patients.

METHODS

Twenty-three users of cannabis, volatile agents, or narcotic/stimulant agents alone or in combination for at least 1 year (mean age, 27.6 years) and 20 healthy volunteers (mean age, 24.6 years) were included. Participant evaluations were implemented immediately after the detoxification process with psychiatrist approval. Depression, state-trait anxiety, and fear of movement levels were evaluated with the Beck Depression Inventory, State-Trait Anxiety Inventory, and Tampa Scale for Kinesiophobia, respectively. Plantar foot sensations were evaluated with light touch, two-point discrimination, and vibration examinations. Balance was assessed with balance software and a balance board and force platform. Balance path, balance path distance, and center of pressure were recorded. Physical performance was evaluated with the Timed Up and Go (TUG) test in the final step.

RESULTS

There was a significant difference in two-point discrimination of patients versus controls (P < .05). Significant differences were also found in balance values, particularly in the sagittal direction (P < .05). TUG test results of patients compared with controls showed a negative influence on physical function (P < .05).

CONCLUSIONS

Detailed examination should be performed to understand movement disorders in substance users. Herein, substance users had impaired two-point discrimination and sagittal balance reciprocally. Thus, customized physiotherapy approaches to substance users should be considered to improve their movement disorders.

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.

Foot and Ankle Somatosensory Deficits Affect Balance and Motor Function in Children With Cerebral Palsy

Sensory dysfunction is prevalent in cerebral palsy (CP). Evidence suggests that sensory deficits can contribute to manual ability impairments in children with CP, yet it is still unclear how they contribute to balance and motor performance. Therefore, the objective of this study was to investigate the relationship between lower extremity (LE) somatosensation and functional performance in children with CP. Ten participants with spastic diplegia (Gross Motor Function Classification Scale: I-III) and who were able to stand independently completed the study. Threshold of light touch pressure, two-point discriminatory ability of the plantar side of the foot, duration of cutaneous vibration sensation, and error in the joint position sense of the ankle were assessed to quantify somatosensory function. The balance was tested by the Balance Evaluation System Test (BESTest) and postural sway measures during a standing task. Motor performance was evaluated by using a battery of clinical assessments: (1) Gross Motor Function Measure (GMFM-66-IS) to test gross motor ability; (2) spatiotemporal gait characteristics (velocity, step length) to evaluate walking ability; (3) Timed Up and Go (TUG) and 6 Min Walk (6MWT) tests to assess functional mobility; and (4) an isokinetic dynamometer was used to test the Maximum Volitional Isometric Contraction (MVIC) of the plantar flexor muscles. The results showed that the light touch pressure measure was strongly associated only with the 6MWT. Vibration and two-point discrimination were strongly related to balance performance. Further, the vibration sensation of the first metatarsal head demonstrated a significantly strong relationship with motor performance as measured by GMFM-66-IS, spatiotemporal gait parameters, TUG, and ankle plantar flexors strength test. The joint position sense of the ankle was only related to one subdomain of the BESTest (Postural Responses). This study provides preliminary evidence that LE sensory deficits can possibly contribute to the pronounced balance and motor impairments in CP. The findings emphasize the importance of developing a thorough LE sensory test battery that can guide traditional treatment protocols toward a more holistic therapeutic approach by combining both motor and sensory rehabilitative strategies to improve motor function in CP.

Does isolated somatosensory impairment affect the balance and ambulation of patients with supratentorial stroke after the acute phase?

Balance and ambulation are the result of a multicomponent control process through the interaction of the sensory and motor information. Despite the clinical relevance of the somatosensory system, its role has not drawn much attention from clinical researchers in that motor impairment is considered a major cause of dysfunction. There is little research on how somatosensory impairment alone affects functional disability after stroke. The purpose of this study was to investigate the effects of isolated somatosensory deficit on the balance and ambulation ability in patients with stroke. P38 latency of the SSEP was used to evaluate the integrity of the dorsal column-medial lemniscus pathway and the SSEP reference value was derived from the formula considering individual height and age. According to the SSEP latency, subjects were classified into 'normal', 'abnormal', and 'no response' group. A total of 110 supratentorial stroke patients with at least grade 4 of the Medical Research Council scale of lower extremity on the affected side were enrolled. Berg balance scale (BBS) and functional ambulatory categories (FAC) showed significant differences among the groups (P < 0.05). In post-hoc analysis, the BBS and FAC was significantly different between the 'normal' and 'abnormal SSEP' group (P = 0.013 for BBS, P = 0.004 for FAC) and the 'normal' and 'no response SSEP' group (P = 0.015 for BBS, P = 0.006 for FAC). We found that isolated somatosensory impairment has a negative effect on the balance and ambulation ability in patients with supratentorial stroke after the acute phase.

Human Balance in Response to Continuous, Predictable Translations of the Support Base: Integration of Sensory Information, Adaptation to Perturbations, and the Effect of Age, Neuropathy and Parkinson’s Disease

This short narrative review article moves from early papers that described the behaviour of healthy subjects balancing on a motorized platform continuously translating in the antero-posterior direction. Research from the laboratories of two of the authors and related investigations on dynamic balancing behaviour are briefly summarized. More recent findings challenging time-honoured views are considered, such as the statement that vision plays a head-in-space stabilizing role. The time interval to integrate vision or its withdrawal in the balancing pattern is mentioned as well. Similarities and differences between ageing subjects and patients with peripheral or central disorders are concisely reported. The muscle activities recorded during the translation cycles suggest that vision and amplitude changes of the anticipatory postural activities play a predominant role in controlling dynamic balance during prolonged administration of the predictable perturbation. The potential of this paradigm for rehabilitation of balance problems is discussed.

An MRI-Compatible Foot-Sole Stimulation System Enabling Characterization of the Brain Response to Walking-Related Tactile Stimuli

Foot-sole somatosensory impairment is a main contributor to balance decline and falls in aging and disease. The cortical networks involved in walking-related foot sole somatosensation, however, remain poorly understood. We thus created and tested a novel MRI-compatible device to enable study of the cortical response to pressure stimuli applied to the foot sole that mimic those stimuli experienced when walking. The device consists of a dual-drive stimulator equipped with two pneumatic cylinders, which are separately programed to apply pressure waveforms to the entire foot sole. In a sample of nine healthy younger adults, the pressure curve applied to the foot sole closely correlated with that experienced during over ground walking (r = 0.811 ± 0.043, P < 0.01). MRI compatibility testing indicated that the device has no or negligible impact on MR image quality. Gradient-recalled echo-planar images of nine healthy young adults using a block-designed 3.5-min walking-related stimulation revealed significant activation within the supplementary motor area, supramarginal gyrus, paracingulate gyri, insula, precentral gyrus, middle temporal gyrus, and hippocampus (uncorrected P < 0.001, k ≥ 10). Together, these results indicate that this stimulation system is MRI-compatible and capable of mimicking walking-related pressure waveforms on foot sole. It may thus be used as a research tool to identify cortical targets for interventions (e.g., non-invasive brain stimulation) aimed at enhancing this important source of input to the locomotor control system.

Balance impairment in pediatric charcot-marie-tooth disease

INTRODUCTION

Balance impairment contributes to gait dysfunction, falls, and reduced quality of life in adults with Charcot-Marie-Tooth disease (CMT) but has been minimally examined in pediatric CMT.

METHODS

The CMT Pediatric Scale (CMTPedS) was administered to 520 children with CMT. Associations between balance function (Bruininks-Oseretsky Test of Motor Proficiency [BOT-2]) and sensorimotor and gait impairments were investigated.

RESULTS

Daily trips/falls were reported by 42.3% of participants. Balance (BOT-2) varied by CMT subtype, was impaired in 42% of 4-year-olds, and declined with age (P < 0.001). Vibration (P < 0.001), pinprick (P < 0.004), ankle dorsiflexion strength (P < 0.001), and foot alignment (P < 0.004) were associated with BOT-2 balance (adjusted R2 = 0.28). The visual dependence of balance increased with age.

DISCUSSION

Balance impairment occurs from a young age in children with CMT. Balance intervention studies are required in pediatric CMT and should consider the degree of sensorimotor impairment, foot malalignment, and visual dependence. Muscle Nerve, 2019.

The immediate effect of plantar stimulation on dynamic and static balance: A randomized controlled trial

OBJECTIVE

To examine the immediate effect on dynamic and static balance of a manual protocol of plantar stimulation in healthy subjects.

MATERIALS AND METHOD

Of the 144 healthy and physically active volunteers recruited, 98 subjects participated. Subjects were randomly assigned and allocated to the experimental group (EG) (n= 50), in which a 10-min manual protocol of plantar stimulation was applied on the right foot, or to the control group (CG) (n= 48). The change scores of the modified Star Excursion Balance Test (mSEBT) and the Unipedal Stance Test (UPST) were used to assess the immediate effect of the protocol on dynamic and static balance, respectively.

RESULTS

In the dynamic balance, a group effect was found in the anterior direction, posteromedial direction and composite scores of the mSEBT when groups were compared by limb. Changes in the posteromedial direction of both limbs (right limb: p= 0.002, left limb: p= 0.05) and composite score of the right limb (p= 0.009) were significantly greater in the EG versus the CG. Non-significant results were found in the static balance (UPST time).

CONCLUSIONS

The application of a 10-minute manual stimulation protocol without joint mobilization, addressed to stimulate the plantar cutaneous mechanoreceptors, could elicit benefits on dynamic balance. This improvement was observed bilaterally even though only one plantar surface was stimulated. As balance deficits may impair functional movements and regular training in sports, this intervention aims to ameliorate dynamic balancing ability could improve the functional recovery of sport gestures.

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.

EFFECT OF WEARING INSOLE WITH DIFFERENT DENSITY ON STANDING AND WALKING PLANTAR PRESSURE DISTRIBUTION

Diabetic ulcers can lead to infection and amputation. Using insole can help to reduce and prevent foot ulceration and amputation in a diabetic patient. The aim of this study was to analyze the effect of wearing an insole with different density on standing and walking plantar pressure distribution. Methods: A group of 10 diabetic patients participated in this one-grouped before-after trial. Plantar pressure distribution was measured during walking and standing. Repeated Measure was used to test differences. Results: Repeated measure test showed that use of insole decreased foot pressure while walking significantly ([Formula: see text]). Pairwise comparison showed that wearing shoe insole with shore 30 decreased pressure compared to wearing shoe insole with shore 50 ([Formula: see text]) and walking without insole respectively ([Formula: see text]). Conclusion: The insole has more effect on plantar pressure during walking than standing, it also concluded that insole with shore 30 decreased pressure during walking more than that of the insole with shore 50. It could be said that patients who suffer from pain and discomfort on hind and forefoot may benefit insole with shore 30 to relieve from plantar pressure on the hindfoot and forefoot regions during standing and walking.

Is there a relationship between plantar foot sensation and static balance, physical performance, fear of falling, and quality of life in hemodialysis patients?

INTRODUCTION

This study was conducted to investigate the relationship between plantar foot sensation and static balance, physical performance, fear of falling, and quality of life in hemodialysis patients.

MATERIALS AND METHODS

The study involved 24 hemodialysis patients and 20 healthy volunteers. Light touch-pressure sensation (Semmes Weinstein Monofilament test kit), two-point discrimination sensation (esthesiometer) and vibration sensation (128 Hz diapason) were used to evaluate plantar foot sensation. Static balance was assessed by the one-leg standing balance test, physical performance by the Timed Up and Go test, fear of falling with the Fall Efficacy Scale, and quality of life with the Ferrans and Powers Quality of Life Index Dialysis Version.

FINDINGS

There was a significant difference in plantar foot sensation, static balance, and physical performance of the patients compared to the healthy controls (P < 0.05). There was a strong correlation between static balance and physical performance with foot sensation in the hemodialysis patients (P < 0.05). There was also a strong correlation between static balance, physical performance, and fear of falling in hemodialysis patients (P < 0.05). The correlation between static balance, physical performance, and quality of life in the hemodialysis patients was strong (P < 0.05).

DISCUSSION

The most important result of this study is that light touch-pressure sensation, vibration sensation, two-point discrimination sensation, static balance, and physical performance, all of which involve the activity of cutaneous sensory receptors on the sole of the foot, are reduced in individuals who undergo hemodialysis. The findings of this study suggest potential rehabilitation strategies that could be applied to this patient group.

An altered spatiotemporal gait adjustment during a virtual obstacle crossing task in patients with diabetic peripheral neuropathy

This study investigates spatiotemporal gait adjustments that occur while stepping over virtual obstacles during treadmill walking in people with/without diabetic peripheral neuropathy (DPN). Eleven adults with Type 2 diabetes mellitus, ten DPN, and 11 age-matched healthy adults (HTY) participated in this study. They stepped over forthcoming virtual obstacles during treadmill walking. Outcomes such as success rate, spatiotemporal gait characteristics during obstacle crossing, and correlations between these variables were evaluated. The results partially supported our hypotheses that when comparing with HTY and DM, people with DPN adopted a crossing strategy which decreased obstacle crossing success rate and maximal toe elevation, and increased stride time and stance time during virtual obstacle crossing. This might be due to the compromised somatosensory functions of their lower extremity which may increase the risk of falling. This study also found an inter-leg relationship which may be applied to future stepping or obstacle crossing training that incorporates both legs as a means for improving outcomes of the trailing leg during daily obstacle negotiation.

Transcranial direct current stimulation modulates the brain's response to foot stimuli under dual-task condition: A fMRI study in elderly adults

Previous behavioral studies have shown that high-intensity cognitive tasks weaken balance control in elder adults. Moreover, age-related loss of plantar sensation is considered to be an important contributing factor to the occurrence of falls. Recently, we have realized that transcranial direct current stimulation (tDCS) can effectively improve the balance of the elderly under the dual-task, but its underlying regulatory mechanism is not clear. In this study, task functional Magnetic Resonance Imaging (fMRI) was used to study the brain's response to foot stimuli under foot stimuli or dual-task (foot stimuli and cognitive task) conditions to explain the effect of the addition of cognitive tasks during balance in 16 healthy elderly adults. To study whether tDCS would counteract the effect of the added cognitive task, we further compared the differences in activity of the cerebral cortices of dual-task and tDCS-dual-task conditions. The results suggested added cognitive tasks significantly attenuated the response of the brain to foot stimuli in elderly adults. Moreover, the cortex excitability weakened by cognitive tasks was significantly promoted after 20 min of tDCS. In conclusion, a portion of the resources originally used for plantar sensory processing may be assigned to the processing of the cognitive task when the cognitive tasks are added, which results in insufficient resources for plantar sensory processing. tDCS improves the ability of the brain to respond to foot stimuli by modulating the excitability of the cognitive cortex and reverses the effects of cognitive tasks.

Effects of sensory deficits on balance, functional status and trunk control in patients diagnosed with guillain-barre syndrome

Objectives:

To investigate the effects of sensory deficits on balance, functional status and trunk control in patients diagnosed with Guillain–Barré syndrome (GBS).

Methods:

Twenty patients who were diagnosed with GBS and who were in the neurology department of Mustafa Kemal University in 2017, participated in this descriptive study. There were 11 males and 9 females, and the average age was 41.55 ± 18.49 years. The trunk control of the GBS patients was assessed using the trunk impairment scale (TIS), reaching function was assessed using the functional reaching test (FRT) in the sitting position and body balance assessed using the Berg balance scale (BBS).Light touch was assessed using Semmes–Weinstein monofilament test, proprioception was assessed using the distal proprioception test and disability status was assessed using the Guillain–Barré syndrome disability scale (GBSDS).

Results:

We found a moderate, positive and significant correlation between proprioception scores and the BBS and between proprioception scores and the TIS. The correlation between proprioception and FRT in the sitting position and between proprioception and the GBSDS was not significant. We found a moderate and negative correlation between light touch and the FRT in the sitting position, TIS, BBS, but a moderate and positive correlation between light touch and the GBSDS.

Conclusion:

Neurologists and physiotherapists should both take sensory and motor function into consideration in the assessment and rehabilitation program of patients diagnosed with GBS.

Low efficacy using the 256-Hz tuning fork when evaluating the influence of somatosensation in balance control for relatively healthy elderly

BACKGROUND

Diminished foot somatosensation contributes to balance deficits and increased fall risk. However, it remains unclear if the 256-Hz tuning fork is adequate to measure, in the outpatient clinical setting, somatosensation in relatively healthy elderly.

AIMS/OBJECTIVES

To evaluate the performance of the 256-Hz tuning fork compared to other measures of somatosensation and balance.

MATERIAL AND METHODS

Thirty-six subjects (mean 69.4 ± 5.3 years) were allocated into four 256-Hz tuning fork sensation groups (TFSG) based on their ability to detect vibration at the first metatarsal, malleolus, tibia or no sites. A biothesiometer measured vibration perception thresholds (VPTs) and 20 monofilaments tactile pressure sensation thresholds (TPSTs). Balance was evaluated with posturography, functional balance tests and questionnaires.

RESULTS

There were no significant differences in age, VPTs or TPSTs between the four TFSGs, nor in outcome of functional balance tests, posturography and questionnaires. Very few significant associations were found between TFSGs and VPTs, TPSTs, functional balance tests, posturography and questionnaires.

CONCLUSIONS AND SIGNIFICANCE

Somatosensation measured with a 256-Hz tuning fork seems to be a minor determinant for balance and thus superfluous when evaluating the importance of vibration perception for balance control in relatively healthy elderly.

Cutaneous afferent innervation of the human foot sole: what can we learn from single-unit recordings?

Cutaneous afferents convey exteroceptive information about the interaction of the body with the environment and proprioceptive information about body position and orientation. Four classes of low-threshold mechanoreceptor afferents innervate the foot sole and transmit feedback that facilitates the conscious and reflexive control of standing balance. Experimental manipulation of cutaneous feedback has been shown to alter the control of gait and standing balance. This has led to a growing interest in the design of intervention strategies that enhance cutaneous feedback and improve postural control. The advent of single-unit microneurography has allowed the firing and receptive field characteristics of foot sole cutaneous afferents to be investigated. In this review, we consolidate the available cutaneous afferent microneurographic recordings from the foot sole and provide an analysis of the firing threshold, and receptive field distribution and density of these cutaneous afferents. This work enhances the understanding of the foot sole as a sensory structure and provides a foundation for the continued development of sensory augmentation insoles and other tactile enhancement interventions.

Perceived and Functional Balance Control Is Negatively Affected by Diminished Touch and Vibration Sensitivity in Relatively Healthy Older Adults and Elderly

Background: Severe diminished foot somatosensation, for example, caused by neuropathies and advanced aging, contributes to balance deficits and increased fall risk. However, little is known about somatosensory impairment and functional and subjective balance problems in relatively healthy elderly. Method: Vibration perception thresholds (VPTs) were assessed with a biothesiometer and tactile pressure sensation thresholds (TPSTs) with 20 monofilaments in 34 relatively healthy community-dwelling older adults (M = 69.4 years). Balance was evaluated with functional balance tests and questionnaires. A stepwise regression analysis was performed to determine the extent to which VPTs, TPSTs, and age could explain balance impairments. Results: High VPTs had negative effects on Berg Balance Scale and Dizziness Handicap Inventory scores (p ≤ .011), as did high TPSTs on walking speed and Figure-8 test (p ≤ .001). With visual information available, one-leg standing time (OLST) was significantly affected by ipsilateral VPTs on solid and TPSTs on compliant surface (p ≤ .002). Without visual information, age was the only factor with a main effect on OLST (p < .001). Age had no significant correlations with TPSTs or VPTs. Discussion: Somatosensation appears to be very important for perceived as well as functional balance control in older adults. Our findings have important clinical implications when assessing balance impairment and impending fall risk.

Cutaneous sensitivity in unilateral trans-tibial amputees

Aim

To examine tactile sensitivity in the leg and foot sole of below-knee amputees (diabetic n = 3, traumatic n = 1), and healthy control subjects (n = 4), and examine the association between sensation and balance.

Method

Vibration perception threshold (VPT; 3, 40, 250Hz) and monofilaments (MF) were used to examine vibration and light touch sensitivity on the intact limb, residual limb, and homologous locations on controls. A functional reach test was performed to assess functional balance.

Results

Tactile sensitivity was lower for diabetic amputee subjects compared to age matched controls for both VPT and MF; which was expected due to presence of diabetic peripheral neuropathy. In contrast, the traumatic amputee participant showed increased sensitivity for VPT at 40Hz and 250Hz vibration in both the intact and residual limbs compared to controls. Amputees with lower tactile sensitivity had shorter reach distances compared to those with higher sensitivity.

Conclusion

Changes in tactile sensitivity in the residual limb of trans-tibial amputees may have implications for the interaction between the amputee and the prosthetic device. The decreased skin sensitivity observed in the residual limb of subjects with diabetes is of concern as changes in skin sensitivity may be important in 1) identification/prevention of excessive pressure and 2) for functional stability. Interestingly, we saw increased residual limb skin sensitivity in the individual with the traumatic amputation. Although not measured directly in the present study, this increase in tactile sensitivity may be related to cortical reorganisation, which is known to occur following amputation, and would support similar findings observed in upper limb amputees.

A Longitudinal Assessment Of Standing Balance In Healthy Adults

Background/Study Context: The study was a longitudinal assessment of age-related changes in standing balance and response strategy usage in healthy adults.

METHODS

Balance of 17 individuals with a mean age of 44.5 years was assessed and then reassessed 19.5 years later. Participants stood on computer-controlled dual-force platforms enclosed by a visual surround and completed six tests in which visual and/or somatosensory information was systematically degraded or eliminated.

RESULTS

Results for each test and a weighted composite balance score revealed no significant change in postural control over the time period studied. However, response strategy scores indicated some significant change with age. Specifically, compensatory movement corrections about the ankle complex increased when standing on a stable support surface with and without vision, and hip-centered corrections were prominent when standing on an unstable surface with eyes open or closed.

CONCLUSION

Increased reliance on response strategy usage with time is interpreted as a compensatory adjustment to age-related increases in postural instability and accounts for the absence of any change in standing balance under different conditions of sensory input.

The firing characteristics of foot sole cutaneous mechanoreceptor afferents in response to vibration stimuli

Single unit microneurography was used to record the firing characteristics of the four classes of foot sole cutaneous afferents [fast and slowly adapting type I and II (FAI, FAII, SAI, and SAII)] in response to sinusoidal vibratory stimuli. Frequency (3-250 Hz) and amplitude (0.001-2 mm) combinations were applied to afferent receptive fields through a 6-mm diameter probe. The impulses per cycle, defined as the number of action potentials evoked per vibration sine wave, were measured over 1 s of vibration at each frequency-amplitude combination tested. Afferent entrainment threshold (lowest amplitude at which an afferent could entrain 1:1 to the vibration frequency) and afferent firing threshold (minimum amplitude for which impulses per cycle was greater than zero) were then obtained for each frequency. Increases in vibration frequency are generally associated with decreases in expected impulses per cycle (P < 0.001), but each foot sole afferent class appears uniquely tuned to vibration stimuli. FAII afferents tended to have the lowest entrainment and firing thresholds (P < 0.001 for both); however, these afferents seem to be sensitive across frequency. In contrast to FAII afferents, SAI and SAII afferents tended to demonstrate optimal entrainment to frequencies below 20 Hz and FAI afferents faithfully encoded frequencies between 8 and 60 Hz. Contrary to the selective activation of distinct afferent classes in the hand, application of class-specific frequencies in the foot sole is confounded due to the high sensitivity of FAII afferents. These findings may aid in the development of sensorimotor control models or the design of balance enhancement interventions.NEW & NOTEWORTHY Our work provides a mechanistic look at the capacity of foot sole cutaneous afferents to respond to vibration of varying frequency and amplitude. We found that foot sole afferent classes are uniquely tuned to vibration stimuli; however, unlike in the hand, they cannot be independently activated by class-specific frequencies. Viewing the foot sole as a sensory structure, the present findings may aid in the refinement of sensorimotor control models and design of balance enhancement interventions.

The clinical and biomechanical effects of subthreshold random noise on the plantar surface of the foot in diabetic patients and elder people: A systematic review

BACKGROUND

Central nervous system receives information from foot mechanoreceptors in order to control balance and perform movement tasks. Subthreshold random noise seems to improve sensitivity of the cutaneous mechanoreceptor.

OBJECTIVES

The purpose of this study was to systematically review published evidence conducted to evaluate the clinical and biomechanical effects of subthreshold random noise on the plantar surface of the foot in diabetic patients and elder people.

STUDY DESIGN

Systematic review.

METHODS

A literature search was performed in PubMed, Scopus, ScienceDirect, Web of Knowledge, CINAHL, and EMBASE databases based on population, intervention, comparison, outcomes, and study method. Quality of studies was assessed using the methodological quality assessment tool, using Physiotherapy Evidence Database scale.

RESULTS

In all, 11 studies were selected for final evaluation based on inclusion criteria. Five studies evaluated the effects of subthreshold random noise in diabetic patients and six in elder people. In seven studies, biomechanical (balance and gait parameters) effects and in four studies clinical (pressure and vibration sensations) effects of subthreshold random noise were investigated. All reviewed studies were scored fair (2) to good (9) quality in terms of methodological quality assessment using Physiotherapy Evidence Database scale.

CONCLUSION

The results indicated that subthreshold random noise improves balance and sensation in diabetic patients and elder people. Also gait variables can be improved in elder people with subthreshold random noise. However, further well-designed studies are needed.

CLINICAL RELEVANCE

The previous studies reported that subthreshold random noise may improve gait, balance, and sensation, but more studies are needed to evaluate the long-term effect of subthreshold random noise in shoe or insole for daily living tasks in diabetic patients and elder people.

Aging, the Central Nervous System, and Mobility in Older Adults: Interventions

BACKGROUND

Research suggests that the central nervous system (CNS) and mobility are closely linked. CNS-mediated mobility impairment may represent a potentially new and prevalent syndrome within the older adult populations. Interventions targeting this group may have the potential to improve mobility and cognition and prevent disability.

METHODS

In 2012, the Gerontological Society of America (GSA) and the National Institute on Aging (NIA) sponsored a 3-year conference workshop series, "Aging, the CNS, and Mobility." The goal of this third and final conference was to (i) report on the state of the science of interventions targeting CNS-mediated mobility impairment among community-dwelling older adults and (ii) partnering with the NIA, explore the future of research and intervention design focused on a potentially novel aging syndrome.

RESULTS

Evidence was presented in five main intervention areas: (i) pharmacology and diet; (ii) exercise; (iii) electrical stimulation; (iv) sensory stimulation/deprivation; and (v) a combined category of multimodal interventions. Workshop participants identified important gaps in knowledge and key recommendations for future interventions related to recruitment and sample selection, intervention design, and methods to measure effectiveness.

CONCLUSIONS

In order to develop effective preventive interventions for this prevalent syndrome, multidisciplinary teams are essential particularly because of the complex nature of the syndrome. Additionally, integrating innovative methods into the design of interventions may help researchers better measure complex mechanisms, and finally, the value of understanding the link between the CNS and mobility should be conveyed to researchers across disciplines in order to incorporate cognitive and mobility measurements into study protocols.