Prolonged activity of knee extensors and dorsal flexors is associated with adaptations in gait in diabetes and diabetic polyneuropathy

Muscle synergies are largely unaffected in individuals with diabetes who do not have diabetic neuropathy

BACKGROUND

Impaired neuromuscular function in individuals with diabetes can adversely affect gait kinematics, kinetics, and electromyography, potentially increasing the risk of serious complications such as plantar ulcers and amputations. However, it remains unclear whether these changes are associated with alterations in muscle synergies. This study aims to examine muscle synergies in individuals with diabetes.

METHODS

Surface electromyography recordings were obtained from seven lower extremity muscles (vastus lateralis, rectus femoris, biceps femoris, semitendinosus, lateral gastrocnemius, soleus, and tibialis anterior) during 20 trials of barefoot walking. Eleven individuals with type 2 diabetes without diabetic neuropathy and ten age-matched controls were recruited. Variations in synergy complexity were assessed by the number of synergies needed to account for >90 % of the total variance in the electromyography data, total variance accounted for by one synergy, and total variance accounted for by four synergies. Synergy weights and activations for a four-synergy solution were compared using cosine similarity. An electromyography co-contraction index was computed for agonist and antagonist pairs of muscles.

FINDINGS

Those with diabetes did not significantly differ from controls in the number of synergies, total variance accounted for by one synergy, total variance accounted for by four synergies, or synergy composition. However, they demonstrated higher levels of variability in synergy composition similarity.

INTERPRETATION

These results indicate that, at the group level, individuals with diabetes without neuropathy employ largely similar motor control strategies as their healthy counterparts while walking, and previously reported variations in gait biomechanics in this population may be attributed to peripheral neuromuscular dysfunction.

Balance and gait in individuals with diabetic peripheral neuropathy

BACKGROUND

Diabetic Peripheral Neuropathy (DPN) causes various physical problems such as the increased risk of falling, loss of balance and coordination while standing or walking, susceptibility to injuries due to sensory loss.

AIMS

The aim of the study was to evaluate and compare the effects of neuropathic pain (NP) in individuals with DPN on balance and gait.

METHODS

This prospective controlled study was conducted on 42 adults aged between 40-65 years. The participants were divided into three groups; individuals with DPN and NP (DPN+NP/n = 14), individuals with DPN without NP (DPN-NP/n = 14), and the control group (n = 14), respectively. The Force Plate system and Core Balance System measured static and dynamic postural balance and stability limits. Gait and dynamic plantar pressure distribution analyses were performed with a computerized gait evaluation system.

RESULTS

The score of LANSS, and VAS during gait were higher in DPN+NP group than in DPN-NP (p < 0.05). No significant difference was observed between the groups in balance parameters (p > 0.05). The right-left heel maximum forces were lower in both groups with DPN compared to the control group (p < 0.05). In terms of spatiotemporal parameters of the gait, there was a difference between the groups only in step width and left single support line parameters (p < 0.05).

CONCLUSIONS

The results of this study indicate that the individuals with DPN have an increased step width, their left single support line was shortened, and the maximum force on the heel decreased. The NP did not cause any change in balance and gait parameters.

Compromised neuromuscular function of walking in people with diabetes: a narrative review

AIM

This review summarizes recent studies that have investigated the neuromuscular dysfunction of walking in people with diabetes and its relationship to ulcer formation.

METHODS

A comprehensive electronic search in the database (Scopus, Web of Science, PsycINFO, ProQuest, and PubMed) was performed for articles pertaining to diabetes and gait biomechanics.

RESULTS

The Achilles tendon is thicker and stiffer in those with diabetes. People with diabetes demonstrate changes in walking kinematics and kinetics, including slower self-selected gait speed, shorter stride length, longer stance phase duration, and decreased ankle, knee, and metatarsophalangeal (MTP) joint range of motion. EMG is altered during walking and may reflect diabetes-induced changes in muscle synergies. Synergies are notable because they provide a more holistic pattern of muscle activations and can help develop better tools for characterizing disease progression.

CONCLUSION

Diabetes compromises neuromuscular coordination and function. The mechanisms contributing to ulcer formation are incompletely understood. Diabetes-related gait impairments may be a significant independent risk factor for the development of foot ulcers.

The Effects of a 12-Week-Long Sand Exercise Training Program on Neuromechanical and Functional Parameters in Type II Diabetic Patients with Neuropathy

Studies have proven the effectiveness of different weight-bearing exercise interventions for diabetic patients with neuropathy; however, several adverse effects were reported using solid surfaces. Thus, in the present study, we investigated the effects of a novel sand exercise training intervention on biomechanical and functional parameters in seven diabetic patients (age = 62.7 ± 9.7 years) with neuropathy. Patients underwent a 12-week sand exercise training program, using strengthening, stretching, balance, and gait exercises. They were tested for ankle plantar- and dorsiflexion peak torque, active range of motion (ROM), timed up and go (TUG), and bilateral static balance. EMG activity of tibialis anterior (TA), gastrocnemius medialis (GM), and lateralis (GL) muscles were measured during unilateral isometric contraction in plantar- and dorsiflexion. In the intervention period, plantarflexion peak torque improved significantly (p = 0.033), while dorsiflexion torque remained unchanged. Plantar- and dorsiflexion ROM increased (p = 0.032) and (p = 0.021), respectively. EMG activity of GM (p = 0.005) and GL (p = 0.002) measured during dorsiflexion and postural sway in the balance test, as well as time to complete the TUG test, decreased significantly (p = 0.021) and (p = 0.002), respectively. No adverse effect was reported during the intervention period. We concluded that sand exercise training can be a safe and effective method to improve plantarflexion strength, ankle flexibility, and balance, which is reflected in better gait function in patients with diabetic peripheral neuropathy (DPN).

Machine Learning-Based Diabetic Neuropathy and Previous Foot Ulceration Patients Detection Using Electromyography and Ground Reaction Forces during Gait

Diabetic neuropathy (DN) is one of the prevalent forms of neuropathy that involves alterations in biomechanical changes in the human gait. Diabetic foot ulceration (DFU) is one of the pervasive types of complications that arise due to DN. In the literature, for the last 50 years, researchers have been trying to observe the biomechanical changes due to DN and DFU by studying muscle electromyography (EMG) and ground reaction forces (GRF). However, the literature is contradictory. In such a scenario, we propose using Machine learning techniques to identify DN and DFU patients by using EMG and GRF data. We collected a dataset from the literature which involves three patient groups: Control (n = 6), DN (n = 6), and previous history of DFU (n = 9) and collected three lower limb muscles EMG (tibialis anterior (TA), vastus lateralis (VL), gastrocnemius lateralis (GL)), and three GRF components (GRFx, GRFy, and GRFz). Raw EMG and GRF signals were preprocessed, and different feature extraction techniques were applied to extract the best features from the signals. The extracted feature list was ranked using four different feature ranking techniques, and highly correlated features were removed. In this study, we considered different combinations of muscles and GRF components to find the best performing feature list for the identification of DN and DFU. We trained eight different conventional ML models: Discriminant analysis classifier (DAC), Ensemble classification model (ECM), Kernel classification model (KCM), k-nearest neighbor model (KNN), Linear classification model (LCM), Naive Bayes classifier (NBC), Support vector machine classifier (SVM), and Binary decision classification tree (BDC), to find the best-performing algorithm and optimized that model. We trained the optimized the ML algorithm for different combinations of muscles and GRF component features, and the performance matrix was evaluated. Our study found the KNN algorithm performed well in identifying DN and DFU, and we optimized it before training. We found the best accuracy of 96.18% for EMG analysis using the top 22 features from the chi-square feature ranking technique for features from GL and VL muscles combined. In the GRF analysis, the model showed 98.68% accuracy using the top 7 features from the Feature selection using neighborhood component analysis for the feature combinations from the GRFx-GRFz signal. In conclusion, our study has shown a potential solution for ML application in DN and DFU patient identification using EMG and GRF parameters. With careful signal preprocessing with strategic feature extraction from the biomechanical parameters, optimization of the ML model can provide a potential solution in the diagnosis and stratification of DN and DFU patients from the EMG and GRF signals.

Gait Parameters and Peripheral Neuropathy in Patients With Diabetes: A Meta-Analysis

OBJECTIVE

To investigate the relationship between diabetic peripheral neuropathy (DPN) and gait abnormality in diabetic patients.

METHODS

Related research concerning the gait of diabetic patients with and without DPN was collected and analyzed by searching PubMed, Embase, and Web of Science. Statistical analysis was performed by using RevMan 5.3 software.

RESULTS

Twenty-one studies were included in this meta-analysis, consisting of 499 diabetic neuropathy patients and 467 diabetes controls without neuropathy. Meta-analysis results showed lower gait velocity, shorter stride length, longer stride time, longer stance time, and higher maximum knee extension moment in the DPN group, compared with their counterparts.

CONCLUSION

Among diabetic patients, those complicated with DPN possess lower gait velocity, shorter stride length, longer stride time, longer stance time, and higher maximum knee extension moment.

Wearable Sensor for Assessing Gait and Postural Alterations in Patients with Diabetes: A Scoping Review

Background and Objectives: Diabetes mellitus is considered a serious public health problem due to its high prevalence and related complications, including gait and posture impairments due to neuropathy and vascular alterations and the subsequent increased risk of falls. The gait of patients with diabetes is characterized by alterations of the main spatiotemporal gait parameters such as gait velocity, cadence, stride time and length, which are also known to worsen with disease course. Wearable sensor systems can be used for gait analysis by providing spatiotemporal parameters and postural control (evaluated from the perspective of body sway), useful for investigating the disease progression. Thanks to their small size and low cost of their components, inertial measurement units (IMUs) are easy to wear and are cheap tools for movement analysis. Materials and Methods: The aim of this study is to review articles published in the last 21 years (from 2000 to 2021) concerning the application of wearable sensors to assess spatiotemporal parameters of gait and body postural alterations in patients with diabetes mellitus. Relevant articles were searched in the Medline database using PubMed, Ovid and Cochrane libraries. Results: One hundred and four articles were initially identified while searching the scientific literature on this topic. Thirteen were selected and analysed in this review. Wearable motion sensors are useful, noninvasive, low-cost, and objective tools for performing gait and posture analysis in diabetic patients. The IMUs can be worn at the lumber levels, tibias or feet, and different spatiotemporal parameters of movement and static posture can be assessed. Conclusions: Future research should focus on standardizing the measurement setup and selecting the most informative spatiotemporal parameters for gait and posture analysis.

Ankle-Brachial Index Is a Good Determinant of Lower Limb Muscular Strength but Not of the Gait Pattern in PAD Patients

The aim of this study was to evaluate the relationship of the ankle-brachial index (ABI) level with kinetic and kinematic parameters of the gait pattern and force-velocity parameters generated by lower limb muscles. Methods: The study group consisted of 65 patients with peripheral arterial disease (PAD). The ABI value, kinetic and kinematic parameters of gait and force-velocity parameters of knee and ankle extensors and flexors were determined in all subjects. The values obtained for right and left limbs as well as the limbs with higher and lower ABI were compared. Results: Regardless of the method of analysis, the values of the gait’s kinematic and kinetic parameters of both lower limbs did not differ significantly. However, significant differences were noted in the values of peak torque, work and power of the extensor muscles of the knee and the flexor muscles of the ankle with the higher and lower ABI. Conclusion: This study demonstrated that a higher degree of ischemia worsened the level of strength, endurance, and performance of ankle flexors and extensors of the knee joint. ABI is not related to the gait pattern. The above-mentioned relationship should be taken into account in the rehabilitation process and methodological assessment.

Sensory-Motor Mechanisms Increasing Falls Risk in Diabetic Peripheral Neuropathy

Diabetic peripheral neuropathy (DPN) is associated with peripheral sensory and motor nerve damage that affects up to half of diabetes patients and is an independent risk factor for falls. Clinical implications of DPN-related falls include injury, psychological distress and physical activity curtailment. This review describes how the sensory and motor deficits associated with DPN underpin biomechanical alterations to the pattern of walking (gait), which contribute to balance impairments underpinning falls. Changes to gait with diabetes occur even before the onset of measurable DPN, but changes become much more marked with DPN. Gait impairments with diabetes and DPN include alterations to walking speed, step length, step width and joint ranges of motion. These alterations also impact the rotational forces around joints known as joint moments, which are reduced as part of a natural strategy to lower the muscular demands of gait to compensate for lower strength capacities due to diabetes and DPN. Muscle weakness and atrophy are most striking in patients with DPN, but also present in non-neuropathic diabetes patients, affecting not only distal muscles of the foot and ankle, but also proximal thigh muscles. Insensate feet with DPN cause a delayed neuromuscular response immediately following foot–ground contact during gait and this is a major factor contributing to increased falls risk. Pronounced balance impairments measured in the gait laboratory are only seen in DPN patients and not non-neuropathic diabetes patients. Self-perception of unsteadiness matches gait laboratory measures and can distinguish between patients with and without DPN. Diabetic foot ulcers and their associated risk factors including insensate feet with DPN and offloading devices further increase falls risk. Falls prevention strategies based on sensory and motor mechanisms should target those most at risk of falls with DPN, with further research needed to optimise interventions.

Study protocol for a randomized controlled trial on the effect of the Diabetic Foot Guidance System (SOPeD) for the prevention and treatment of foot musculoskeletal dysfunctions in people with diabetic neuropathy: the FOotCAre (FOCA) trial I

BACKGROUND

This study is part of a series of two clinical trials. Taking into account the various musculoskeletal alterations of the foot and ankle in people with diabetic peripheral neuropathy (DPN) and the need for self-care to avoid more serious dysfunctions and complications, a self-manageable exercise protocol that focuses on strengthening the foot muscles is presented as a potentially effective preventive method for foot and gait complications. The aim of this trial is to investigate the effect of a customized rehabilitation technology, the Diabetic Foot Guidance System (SOPeD), on DPN status, functional outcomes and gait biomechanics in people with DPN.

METHODS/DESIGN

Footcare (FOCA) trial I is a randomized, controlled and parallel two-arm trial with blind assessment. A total of 62 patients with DPN will be allocated into either a control group (recommended foot care by international consensus with no foot exercises) or an intervention group (who will perform exercises through SOPeD at home three times a week for 12 weeks). The exercise program will be customized throughout its course by a perceived effort scale reported by the participant after completion of each exercise. The participants will be assessed at three different times (baseline, completion at 12 weeks, and follow-up at 24 weeks) for all outcomes. The primary outcomes will be DPN symptoms and severity classification. The secondary outcomes will be foot-ankle kinematics and kinetic and plantar pressure distribution during gait, tactile and vibration sensitivities, foot health and functionality, foot strength, and functional balance.

DISCUSSION

As there is no evidence about the efficacy of rehabilitation technology in reducing DPN symptoms and severity or improving biomechanical, clinical, and functional outcomes for people with DPN, this research can contribute substantially to clarifying the therapeutic merits of software interventions. We hope that the use of our application for people with DPN complications will reduce or attenuate the deficits caused by DPN. This rehabilitation technology is freely available, and we intend to introduce it into the public health system in Brazil after demonstrating its effectiveness.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04011267. Registered on 8 July 2019.

The influence of peripheral arterial disease on lower limb surface myoelectric signals in patients living with type II diabetes mellitus

BACKGROUND

The aim of this study was to evaluate whether there are any significant differences in muscle activity between individuals living with type II diabetes mellitus (T2DM) and individuals living with T2DM and peripheral arterial disease (PAD), during gait at a self-selected speed. The influence of different stages of PAD on muscle activity during gait was also assessed with the use of surface electromyography (EMG).

RESEARCH QUESTION

Does PAD affect lower limb muscle activity during gait in the presence of T2DM?

METHODS

This quantitative study involves a prospective, comparative, non-experimental subject design. Ninety participants were divided into three groups namely Group A (thirty participants living with T2DM), Group B(i) (thirty participants living with T2DM and mild PAD) and Group B(ii) (thirty participants living with T2DM and severe PAD). Surface electrode sensors were placed according to SENIAM guidelines, on six main lower limb muscles on both limbs. Muscle activity was recorded using a wireless system, where participants were instructed to walk at a self-selected speed on a 10-m walkway. Average Burst RMS was performed and the amplitude (mV) and the duration of muscle activation (s) was analysed.

RESULTS

There was a significant increase in muscle amplitude and duration of activation in the presence of lower limb ischaemia during gait. The largest significant difference (p = <0.05) in EMG amplitude and duration of activation when looking at the twelve muscles in general was found between participants living with T2DM and participants living with T2DM and severe PAD.

SIGNIFICANCE

The increase in muscle activity indicates that there are musculoskeletal and biomechanical changes in the lower limb musculature with increasing severity of PAD. Higher muscle exertion demands are required during gait which may result in earlier fatigue. EMG tests would be beneficial for detecting muscle dysfunction objectively and non-invasively in T2DM and PAD.

A review of gait disorders in the elderly and neurological patients for robot-assisted training

Purpose: Ambulation is an important objective for people with pathological gaits. Exoskeleton robots can assist these people to complete their activities of daily living. There are exoskeletons that have been presented in literature to assist the elderly and other pathological gait users. This article presents a review of the degree of support required in the elderly and neurological gait disorders found in the human population. This will help to advance the design of robot-assisted devices based on the needs of the end users.Methods: The articles included in this review are collected from different databases including Science Direct, Springer Link, Web of Science, Medline and PubMed and with the purpose to investigate the gait parameters of elderly and neurological patients. Studies were included after considering the full texts and only those which focus on spatiotemporal, kinematic and kinetic gait parameters were selected as they are most relevant to the scope of this review. A systematic review and meta-analysis were conducted.Results: The meta-analysis report on the spatiotemporal, kinematic and kinetic gait parameters of elderly and neurological patients revealed a significant difference based on the type and level of impairment. Healthy elderly population showed deviations in the gait parameters due to age, however, significant difference is observed in the gait parameters of the neurological patients.Conclusion: A level of agreement was observed in most of the studies however the review also noticed some controversies among different studies in the same group. The review on the spatiotemporal, kinematics and kinetic gait parameters will provide a summary of the fundamental needs of the users for the future design and development of robotic assistive devices.Implications for rehabilitationThe support requirements provide the foundation for designing assistive devices.The findings will be crucial in defining the design criteria for robot assistive devices.

Foot function and strength of patients with diabetes grouped by ulcer risk classification (IWGDF)

BACKGROUND

The stratification system from the International Working Group on the Diabetic Foot (IWGDF) was used to classify the participants as to the ulcer risk. However, it is not yet known what the classification groups' individual deficits are regarding sensitivity, function, and musculoskeletal properties and mechanics. This makes it difficult to design proper ulcer prevention strategies for patients. Thus, this study aimed to investigate the foot function, foot strength and health of people with diabetes mellitus (DM)-with or without DPN-while considering the different ulcer risk classifications determined by the IWGDF.

METHODS

The subject pool comprised 72 people with DM, with and without DPN. The patients were divided into three groups: Group 0 (G0), which comprised diabetic patients without DPN; Group 1 (G1), which comprised patients with DPN; and Group 2 (G2), which comprised patients with DPN who had foot deformities. The health and foot function of the subjects' feet were assessed using a foot health status questionnaire (FHSQ-BR) that investigated four domains: foot pain, foot function, footwear, and general foot health. The patients' foot strength was evaluated using the maximum force under each subject's hallux and toes on a pressure platform (emed q-100, Novel, Munich, Germany).

RESULTS

Moderate differences were found between G0 and G1 and G2 for the foot pain, foot function, general foot health, and footwear. There was also a small but significant difference between G0 and G2 in regards to hallux strength.

CONCLUSION

Foot health, foot function and strength levels of people with DM and DPN classified by the ulcer risk are different and this must be taken into account when evaluating and developing treatment strategies for these patients.

Kinetics and kinematics of diabetic foot in type 2 diabetes mellitus with and without peripheral neuropathy: a systematic review and meta-analysis

Background

Diabetes mellitus patients are at increased risk of developing diabetic foot with peripheral neuropathy, vascular and musculoskeletal complications. Therefore they are prone to develop frequent and often foot problems with a relative high risk of infection, gangrene and amputation. In addition, altered plantar pressure distribution is an important etiopathogenic risk factor for the development of foot ulcers. Thus the review on study of foot kinematic and kinetic in type 2 diabetes mellitus to understand the biomechanical changes is important.

Methodology

Scientific articles were obtained using electronic databases including Science Direct, CINAHL, Springer Link, Medline, Web of Science, and Pubmed. The selection was completed after reading the full texts. Studies using experimental design with focus on biomechanics of diabetic foot were selected.

Results

The meta-analysis report on gait velocity (neuropathy = 128 and non-diabetes = 131) showed that there was a significantly lower gait velocity in neuropathy participants compared to non-diabetes age matched participants at a high effect level (−0.09, 95 % CI −0.13 to 0.05; p < 0.0001). Regarding knee joint flexion range there was a significant difference between neuropathy and non-diabetes group (4.75, 95 % CI, −7.53 to 1.97, p = 0.0008).

Conclusions

The systematic review with meta-analysis reported significant difference in kinematic and kinetic variables among diabetic with neuropathy, diabetic without neuropathy and non-diabetes individuals. The review also found that the sample size in some studies were not statistically significant to perform the meta-analysis and report a strong conclusion. Therefore a study with higher sample size should be done.

Muscle fiber conduction velocity in different gait phases of early and late-stage diabetic neuropathy

We investigated the muscle fiber conduction velocity (MFCV) during gait phases of the lower limb muscles in individuals with various degrees of diabetic peripheral neuropathy (DPN). Forty-five patients were classified into severity degrees of DPN by a fuzzy model. The stages were absent (n=11), mild (n=14), moderate (n=11) and severe (n=9), with 10 matched healthy controls. While walking, all subjects had their sEMG (4 linear electrode arrays) recorded for tibialis anterior (TA), gastrocnemius medialis (GM), vastus lateralis (VL) and biceps femoris (BF). MFCV was calculated using a maximum likelihood algorithm with 30ms standard deviation Gaussian windows. In general, individuals in the earlier stages of DPN showed lower MFCV of TA, GM and BF, whilst individuals with severe DPN presented higher MFCV of the same muscles. We observed that mild patients already showed lower MFCV of TA at early stance and swing, and lower MFCV of BF at swing. All diabetic groups showed a markedly reduction in MFCV of VL, irrespective of DPN. Severe patients presented higher MFCV mainly in distal muscles, TA at early and swing phases and GM at propulsion and midstance. The absent group already showed MFCV of VL and GM reductions at the propulsion phase and of VL at early stance. Although MFCV changes were not as progressive as the DPN was, we clearly distinguished diabetic patients from controls, and severe patients from all others.

Postural Control and Gait Performance in the Diabetic Peripheral Neuropathy: A Systematic Review

Purpose. The aim of this paper is to review the published studies on the characteristics of impairments in the postural control and gait performance in diabetic peripheral neuropathy (DPN). Methods. A review was performed by obtaining publication of all papers reporting on the postural control and gait performance in DPN from Google Scholar, Ovid, SAGE, Springerlink, Science Direct (SD), EBSCO Discovery Service, and Web of Science databases. The keywords used for searching were “postural control,” “balance,” “gait performance,” “diabetes mellitus,” and “diabetic peripheral neuropathy.” Results. Total of 4,337 studies were hit in the search. 1,524 studies were screened on their titles and citations. Then, 79 studies were screened on their abstract. Only 38 studies were eligible to be selected: 17 studies on postural control and 21 studies on the gait performance. Most previous researches were found to have strong evidence of postural control impairments and noticeable gait deficits in DPN. Deterioration of somatosensory, visual, and vestibular systems with the pathologic condition of diabetes on cognitive impairment causes further instability of postural and gait performance in DPN. Conclusions. Postural instability and gait imbalance in DPN may contribute to high risk of fall incidence, especially in the geriatric population. Thus, further works are crucial to highlight this fact in the hospital based and community adults.

Altered joint moment strategy during stair walking in diabetes patients with and without peripheral neuropathy

AIM

To investigate lower limb biomechanical strategy during stair walking in patients with diabetes and patients with diabetic peripheral neuropathy, a population known to exhibit lower limb muscular weakness.

METHODS

The peak lower limb joint moments of twenty-two patients with diabetic peripheral neuropathy and thirty-nine patients with diabetes and no neuropathy were compared during ascent and descent of a staircase to thirty-two healthy controls. Fifty-nine of the ninety-four participants also performed assessment of their maximum isokinetic ankle and knee joint moment (muscle strength) to assess the level of peak joint moments during the stair task relative to their maximal joint moment-generating capabilities (operating strengths).

RESULTS

Both patient groups ascended and descended stairs slower than controls (p<0.05). Peak joint moments in patients with diabetic peripheral neuropathy were lower (p<0.05) at the ankle and knee during stair ascent, and knee only during stair descent compared to controls. Ankle and knee muscle strength values were lower (p<0.05) in patients with diabetic peripheral neuropathy compared to controls, and lower at knee only in patients without neuropathy. Operating strengths were higher (p<0.05) at the ankle and knee in patients with neuropathy during stair descent compared to the controls, but not during stair ascent.

CONCLUSION

Patients with diabetic peripheral neuropathy walk slower to alter gait strategy during stair walking and account for lower-limb muscular weakness, but still exhibit heightened operating strengths during stair descent, which may impact upon fatigue and the ability to recover a safe stance following postural instability.

Intralimb Coordination Patterns in Absent, Mild, and Severe Stages of Diabetic Neuropathy: Looking Beyond Kinematic Analysis of Gait Cycle

AIM

Diabetes Mellitus progressively leads to impairments in stability and joint motion and might affect coordination patterns, mainly due to neuropathy. This study aims to describe changes in intralimb joint coordination in healthy individuals and patients with absent, mild and, severe stages of neuropathy.

METHODS

Forty-seven diabetic patients were classified into three groups of neuropathic severity by a fuzzy model: 18 without neuropathy (DIAB), 7 with mild neuropathy (MILD), and 22 with moderate to severe neuropathy (SVRE). Thirteen healthy subjects were included as controls (CTRL). Continuous relative phase (CRP) was calculated at each instant of the gait cycle for each pair of lower limb joints. Analysis of Variance compared each frame of the CRP time series and its standard deviation among groups (α = 5%).

RESULTS

For the ankle-hip CRP, the SVRE group presented increased variability at the propulsion phase and a distinct pattern at the propulsion and initial swing phases compared to the DIAB and CTRL groups. For the ankle-knee CRP, the 3 diabetic groups presented more anti-phase ratios than the CTRL group at the midstance, propulsion, and terminal swing phases, with decreased variability at the early stance phase. For the knee-hip CRP, the MILD group showed more in-phase ratio at the early stance and terminal swing phases and lower variability compared to all other groups. All diabetic groups were more in-phase at early the midstance phase (with lower variability) than the control group.

CONCLUSION

The low variability and coordination differences of the MILD group showed that gait coordination might be altered not only when frank evidence of neuropathy is present, but also when neuropathy is still incipient. The ankle-knee CRP at the initial swing phase showed distinct patterns for groups from all degrees of neuropathic severity and CTRLs. The ankle-hip CRP pattern distinguished the SVRE patients from other diabetic groups, particularly in the transitional phase from stance to swing.

Quantitative assessment of early biomechanical modifications in diabetic foot patients: the role of foot kinematics and step width

BACKGROUND

Forefoot ulcers (FU) are one of the most disabling and relevant chronic complications of diabetes mellitus (DM). In recent years there is emerging awareness that a better understanding of the biomechanical factors underlying the diabetic ulcer could lead to improve the management of the disease, with significant socio-economic impacts. Our purpose was to try to detect early biomechanical factors associated with disease progression.

METHODS

Thirty subjects (M/F: 22/8; mean age ± SD: 61,84 ± 10 years) with diagnosis of type II DM were included. The participants were divided into 3 groups (10 subjects per group) according to the stage of evolution of the disease: Group 1, subjects with newly diagnosed type II DM, without clinical or instrumental diabetic peripheral neuropathy (DPN) nor FU (group called "DM"); Group 2, with DPN but without FU (group called "DPN"); Group 3, with DPN and FU (group called "DNU"). All subjects underwent 3-D Gait Analysis during walking at self-selected speed, measuring spatio-temporal, kinematic and kinetic parameters and focusing on ankle and foot joints. The comparative analysis of values between groups was performed using 1-way ANOVA. We also investigated group to group differences with Tukey HSD test. The results taken into consideration were those with a significance of P < 0,05. 95 % confidence interval was also calculated.

RESULTS

A progressive and significant trend of reduction of ROM in flexion-extension of the metatarso-phalangeal joint (P = 0.0038) and increasing of step width (P = 0.0265) with the advance of the disease was evident, with a statistically significant difference comparing subjects with recently diagnosed diabetes mellitus and subjects with diabetic neuropathy and foot ulcer (P = 0.0048 for ROM and P = 0.0248 for step width at Tukey's test).

CONCLUSIONS

The results provide evidence that foot segmental kinematics, along with step width, can be proposed as simple and clear indicators of disease progression. This can be the starting point for planning more targeted strategies to prevent the occurrence and the recurrence of a FU in diabetic subjects.

Balance and ankle muscle strength predict spatiotemporal gait parameters in individuals with diabetic peripheral neuropathy

AIMS

The aims of this study were to evaluate aspects of balance, ankle muscle strength and spatiotemporal gait parameters in individuals with diabetic peripheral neuropathy (DPN) and verify whether deficits in spatiotemporal gait parameters were associated with ankle muscle strength and balance performance.

MATERIALS AND METHODS

Thirty individuals with DPN and 30 control individuals have participated. Spatiotemporal gait parameters were evaluated by measuring the time to walk a set distance during self-selected and maximal walking speeds. Functional mobility and balance performance were assessed using the Functional Reach and the Time Up and Go tests. Ankle isometric muscle strength was assessed with a handheld digital dynamometer. Analyses of variance were employed to verify possible differences between groups and conditions. Multiple linear regression analysis was employed to uncover possible predictors of gait deficits.

RESULTS

Gait spatiotemporal, functional mobility, balance performance and ankle muscle strength were affected in individuals with DPN. The Time Up and Go test performance and ankle muscle isometric strength were associated to spatiotemporal gait changes, especially during maximal walking speed condition.

CONCLUSION

Functional mobility and balance performance are damaged in DPN and balance performance and ankle muscle strength can be used to predict spatiotemporal gait parameters in individuals with DPN.

Diabetic foot and exercise therapy: step by step the role of rigid posture and biomechanics treatment

Lower extremity ulcers represent a serious and costly complication of diabetes mellitus. Many factors contribute to the development of diabetic foot. Peripheral neuropathy and peripheral vascular disease are the main causes of foot ulceration and contribute in turn to the growth of additional risk factors such as limited joint mobility, muscular alterations and foot deformities. Moreover, a deficit of balance, posture and biomechanics can be present, in particular in patients at high risk for ulceration. The result of this process may be the development of a vicious cycle which leads to abnormal distribution of the foot's plantar pressures in static and dynamic postural conditions. This review shows that some of these risk factors significantly improve after a few weeks of exercise therapy (ET) intervention. Accordingly it has been suggested that ET can be an important weapon in the prevention of foot ulcer. The aim of ET can relate to one or more alterations typically found in diabetic patients, although greater attention should be paid to the evaluation and possible correction of body balance, rigid posture and biomechanics. Some of the most important limitations of ET are difficult access to therapy, patient compliance and the transitoriness of the results if the training stops. Many proposals have been made to overcome such limitations. In particular, it is important that specialized centers offer the opportunity to participate in ET and during the treatment the team should work to change the patient's lifestyle by improving the execution of appropriate daily physical activity.

Effect of diabetic neuropathy severity classified by a fuzzy model in muscle dynamics during gait

Background

Electromyography (EMG) alterations during gait, supposedly caused by diabetic sensorimotor polyneuropathy, are subtle and still inconsistent, due to difficulties in defining homogeneous experimental groups with a clear definition of disease stages. Since evaluating these patients involve many uncertainties, the use of a fuzzy model could enable a better discrimination among different stages of diabetic polyneuropathy and lead to a clarification of when changes in muscle activation start occurring. The aim of this study was to investigate EMG patterns during gait in diabetic individuals with different stages of DSP severity, classified by a fuzzy system.

Methods

147 subjects were divided into a control group (n = 30) and four diabetic groups: absent (n = 43), mild (n = 30), moderate (n = 16), and severe (n = 28) neuropathy, classified by a fuzzy model. The EMG activity of the vastus lateralis, tibialis anterior, and gastrocnemius medialis were measured during gait. Temporal and relative magnitude variables were compared among groups using ANOVA tests.

Results

Muscle activity changes are present even before an established neural involvement, with delay in vastus lateralis peak and lower tibialis anterior relative magnitude. These alterations suggest an impaired ankle shock absorption mechanism, with compensation at the knee. This condition seems to be more pronounced in higher degrees of neuropathy, as there is an increased vastus lateralis activity in the mild and severe neuropathy groups. Tibialis anterior onset at terminal stance was anticipated in all diabetic groups; at higher degrees of neuropathy, the gastrocnemius medialis exhibited activity reduction and peak delay.

Conclusion

EMG alterations in the vastus lateralis and tibialis anterior occur even in the absence of diabetic neuropathy and in mild neuropathic subjects, seemingly causing changes in the shock absorption mechanisms at the heel strike. These changes increase with the onset of neural impairments, and the gastrocnemius medialis starts presenting altered activity in the later stages of the disease (moderate and severe neuropathy). The degree of severity of diabetic neuropathy must be taken into account when analyzing diabetic patients’ biomechanical patterns of locomotion; we recommend the use of a fuzzy model for classification of disease stages.

Lower leg muscle strengthening does not redistribute plantar load in diabetic polyneuropathy: a randomised controlled trial

Background

Higher plantar pressures play an important role in the development of plantar foot ulceration in diabetic polyneuropathy and earlier studies suggest that higher pressures under the forefoot may be related to a decrease in lower leg muscle strength. Therefore, in this randomised controlled trial we evaluated whether lower-extremity strength training can reduce plantar pressures in diabetic polyneuropathy.

Methods

This study was embedded in an unblinded randomised controlled trial. Participants had diabetes and polyneuropathy and were randomly assigned to the intervention group (n = 48) receiving strength training during 24 weeks, or the control group (n = 46) receiving no intervention. Plantar pressures were measured in both groups at 0, 12, 24 and 52 weeks. A random intercept model was applied to evaluate the effects of the intervention on peak pressures and pressure–time-integrals, displacement of center-of-pressure and the forefoot to rearfoot pressure–time-integral-ratio.

Results

Plantar pressure patterns were not affected by the strength training. In both the intervention and control groups the peak pressure and the pressure–time-integral under the forefoot increased by 55.7 kPa (95% CI: 14.7, 96.8) and 2.0 kPa.s (95% CI: 0.9, 3.2) over 52 weeks, respectively. Both groups experienced a high number of drop-outs, mainly due to deterioration of health status and lower-extremity disabilities.

Conclusions

Plantar pressures under the forefoot increase progressively over time in people with diabetic polyneuropathy, but in this study were not affected by strength training. Future intervention studies should take this increase of plantar pressure into account and alternative interventions should be developed to reduce the progressive lower extremity problems in these patients.

Trial registration

This study was embedded in a clinical trial with trial number NCT00759265.

Biomechanical characteristics of peripheral diabetic neuropathy: A systematic review and meta-analysis of findings from the gait cycle, muscle activity and dynamic barefoot plantar pressure

BACKGROUND

Diabetic peripheral neuropathy is an important cause of foot ulceration and limb loss. This systematic review and meta-analysis investigated the effect of diabetic peripheral neuropathy on gait, dynamic electromyography and dynamic plantar pressures.

METHODS

Electronic databases were searched systematically for articles reporting the effect of diabetic peripheral neuropathy on gait, dynamic electromyography and plantar pressures. Searches were restricted to articles published between January 2000 and April 2012. Outcome measures assessed included spatiotemporal parameters, lower limb kinematics, kinetics, muscle activation and plantar pressure. Meta-analyses were carried out on all outcome measures reported by ≥3 studies.

FINDINGS

Sixteen studies were included consisting of 382 neuropathy participants, 216 diabetes controls without neuropathy and 207 healthy controls. Meta-analysis was performed on 11 gait variables. A high level of heterogeneity was noted between studies. Meta-analysis results suggested a longer stance time and moderately higher plantar pressures in diabetic peripheral neuropathy patients at the rearfoot, midfoot and forefoot compared to controls. Systematic review of studies suggested potential differences in the biomechanical characteristics (kinematics, kinetics, EMG) of diabetic neuropathy patients. However these findings were inconsistent and limited by small sample sizes.

INTERPRETATION

Current evidence suggests that patients with diabetic peripheral neuropathy have elevated plantar pressures and occupy a longer duration of time in the stance-phase during gait. Firm conclusions are hampered by the heterogeneity and small sample sizes of available studies.

Increased forefoot loading is associated with an increased plantar flexion moment

The aim of this study was to identify the cascade of effects leading from alterations in force generation around the ankle joint to increased plantar pressures under the forefoot. Gait analysis including plantar pressure measurement was performed at an individually preferred and a standardized, imposed gait velocity in diabetic subjects with polyneuropathy (n=94), without polyneuropathy (n=39) and healthy elderly (n=19). The plantar flexion moment at 40% of the stance phase was negatively correlated with the displacement rate of center of pressure (r=-.749, p<.001 at the imposed, and r=-.693, p<.001 at the preferred gait velocity). Displacement rate of center of pressure was strongly correlated with forefoot loading (r=-.837, p<.001 at the imposed, and r=-.731, p<.001 at the preferred gait velocity). People with a relatively high plantar flexion moment at 40% of the stance phase, have a faster forward transfer of center of pressure and consequently higher loading of the forefoot. This indicates that interventions aimed at increasing the control of the roll-off of the foot may contribute to a better plantar pressure distribution.

Afferent control of walking: are there distinct deficits associated to loss of fibres of different diameter?

OBJECTIVES

To compare the gait pattern in patients affected by different types of neuropathy.

METHODS

We recruited healthy subjects (HS, n=38), patients with Charcot-Marie-Tooth disease type 1A (CMT1A) (n=10) and patients with diabetic neuropathy (DNP) (n=12). Neuropathy impairment score and neuropathy score were assessed. Body sway during quiet stance, and spatio-temporal gait parameters were recorded.

RESULTS

Most patients had reduced or absent tendon-tap reflexes. Strength of foot dorsiflexor muscles (p<0.05) and conduction velocity (CV) of leg nerves (p<0.0001) were more impaired in CMT1A than DNP, whereas joint-position sense was more affected (p<0.05) in DNP. Body sway while standing was larger in DNP compared to CMT1A and HS (p<0.01 and p<0.0001 respectively). During gait, the distribution of foot sole contact pressure was abnormal in CMT1A (p<0.05) but not in DNP. Velocity and step length were decreased, and foot yaw angle at foot flat increased, in DNP with respect to CMT1A and HS (both variables, p<0.001). Gait velocity and step length were decreased (p<0.005) also in CMT1A, but to a smaller extent than in DNP, so that the difference between patient groups was significant (p<0.0005). Duration of the double support was protracted in DNP compared to CMT1A and HS (p<0.0005). For DNP only, velocity of gait and duration of single support were correlated (p<0.05) both to sway path and lower limb muscle strength.

CONCLUSIONS

Changes in both body sway and stance phase of gait were larger in DNP than CMT1A, indicating more impaired static and dynamic control of balance when neuropathy affects the small in addition to the large afferent fibres. Diminished somatosensory input from the smaller fibres rather than muscle weakness or foot deformity plays a critical role in the modulation of the support phase of gait.

SIGNIFICANCE

The analysis of balance and gait in patients with neuropathy can offer a tool for understanding the nature and functional impact of the neuropathy and should be included in their functional evaluation.

Reduced plantar cutaneous sensation modifies gait dynamics, lower-limb kinematics and muscle activity during walking

Peripheral neuropathy is the most common long-term complication in diabetes and is involved in changes in diabetic gait and posture. The regression of nerve function leads to various deficits in the sensory and motor systems, impairing afferent and efferent pathways in the lower extremities. This study aimed to examine how reduced plantar-afferent feedback impacts the gait pattern. Cutaneous sensation in the soles of both feet was experimentally reduced by means of intradermal injections of an anaesthetic solution, without affecting foot proprioception or muscles. Ten subjects performed level walking at a controlled velocity before and after plantar anaesthesia. Muscle activity of five leg-muscles, co-contraction ratios for the knee and ankle joint, ground reaction forces (GRF), spatiotemporal characteristics, joint angles and moments of the hip, knee and ankle were analysed. The intervention significantly lowered plantar sensation, reducing it to the level of sensory neuropathy. Spatiotemporal gait characteristics remained unchanged. The ankle joint was more dorsiflexed which coincided with increased tibialis anterior and decreased gastrocnemius medialis muscle activity during foot flat to mid-stance. In addition, the knee joint was more flexed accompanied by increased biceps femoris activity and higher internal knee-extension moment. With regard to gait dynamics, a delay of the first peak of the vertical GRF was observed. Increased soleus and tibialis anterior muscle activity were found during the end of stance. Short-term loss of plantar sensation affects lower-limb kinematics and gait dynamics, particularly during the first half of stance, and contributes to modified muscle-activation patterns during locomotion.

Lower extremity muscle strength is reduced in people with type 2 diabetes, with and without polyneuropathy, and is associated with impaired mobility and reduced quality of life

AIM

The purpose of the present study was to distinguish the effects of both diabetes mellitus type 2 (DM2) and diabetic polyneuropathy (DPN) on mobility, muscle strength and health related quality of life (HR-QoL).

METHODS

DPN patients (n=98), DM2 patients without DPN (DC) (n=39) and healthy subjects (HC) (n=19) performed isometric and isokinetic lower limb muscle strength tests. Mobility was determined by a timed up and go test (TUGT), a 6 min walk test and the physical activity scale for the elderly questionnaire. HR-QoL was determined by the SF36 questionnaire.

RESULTS

DPN patients had moderate polyneuropathy. In both DPN and DC patients leg muscle strength was reduced by 30-50% compared to HC. Muscle strength was correlated with mobility tests, and reduced muscle strength as well as impaired mobility were associated with a loss of HR-Qol (all p<0.05). We did not observe major differences in muscle strength, mobility (except for the TUGT, p<0.01) and HR-QoL between diabetic patients with and without DPN.

CONCLUSION

DM2 patients, with and without DPN, have decreased maximal muscle strength in the lower limbs and impaired mobility. These abnormalities are associated with a loss of HR-QoL. The additional effect of moderate DPN was small in our patients.

The influence of stride-length on plantar foot-pressures and joint moments

PURPOSE

Joint moments have been acknowledged as key factors in understanding gait abnormalities. Gait velocity is further known to affect joint moments and foot pressures. Keeping gait velocity constant is thus a strategy to cancel out the influence of different preferred gait speed between groups. But even if gait velocity is controlled, individuals can choose different stride length-stride frequency combinations to cope with an imposed gait velocity.

SCOPE

To understand the influence of stride frequency-stride length on joint moments and plantar pressures.

METHODS

Twenty healthy young adults had to cross an 8m walkway with a walking speed of 1.3ms(-1). The wooden walkway was equipped with a force and a pressure platform. While walking speed was kept constant each participant walked with five different imposed stride lengths (SL): preferred (SL0); with a decrease of 10% (SL-10); with a decrease of 20% (SL-20); with an increase of 10% (SL+10) and with an increase of 20% (SF+20).

RESULTS

Ankle and knee joint moments significantly decreased with a decrease in SL. A significant (p<.05) lower peak pressure was achieved with a decreased SL under the heel, toes and midfoot.

DISCUSSION/CONCLUSION

The results showed that a change in stride lengths alters both, joint moments and foot pressures with clinically interesting indications. Redistribution of joint moments in the elderly for example might rather result from decreased SL than from age.