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Background: Individuals with diabetic peripheral neuropathy frequently experience concomitant impaired proprioception and postural instability. Conventional exercise training has been demonstrated to be effective in improving balance but does not incorporate visual feedback targeting joint perception, which is an integral mechanism that helps compensate for impaired proprioception in diabetic peripheral neuropathy. Methods: This prospective cohort study recruited 29 participants (mean ± SD: age, 57 ± 10 years; body mass index [calculated as weight in kilograms divided by height in meters squared], 26.9 ± 3.1). Participants satisfying the inclusion criteria performed predefined ankle exercises through reaching tasks, with visual feedback from the ankle joint projected on a screen. Ankle motion in the mediolateral and anteroposterior directions was captured using wearable sensors attached to the participant’s shank. Improvements in postural stability were quantified by measuring center of mass sway area and the reciprocal compensatory index before and after training using validated body-worn sensor technology. Results: Findings revealed a significant reduction in center of mass sway after training (mean, 22%; P = .02). A higher postural stability deficit (high body sway) at baseline was associated with higher training gains in postural balance (reduction in center of mass sway) (r = −0.52, P < .05). In addition, significant improvement was observed in postural coordination between the ankle and hip joints (mean, 10.4%; P = .04). Conclusions: The present research implemented a novel balance rehabilitation strategy based on virtual reality technology. The method included wearable sensors and an interactive user interface for real-time visual feedback based on ankle joint motion, similar to a video gaming environment, for compensating impaired joint proprioception. These findings support that visual feedback generated from the ankle joint coupled with motor learning may be effective in improving postural stability in patients with diabetic peripheral neuropathy. (J Am Podiatr Med Assoc 103(6): 498–507, 2013)

Background: Individuals with diabetes have a higher risk of falls and fall-related injuries. People with diabetes often develop peripheral neuropathy (DPN) as well as nerve damage throughout the body. In particular, reduced lower extremity proprioception due to DPN may cause a misjudgment of foot position and thus increase the risk of fall. Objective: An innovative virtual obstacle-crossing paradigm using wearable sensors was developed in an attempt to assess lower extremity position perception damage due to DPN. Methods: 67 participants (age 55.4 ± 8.9, BMI 28.1 ± 5.8) including diabetics with and without DPN as well as aged-matched healthy controls were recruited. Severity of neuropathy was quantified using a vibratory perception threshold (VPT) test. The ability of perception of lower extremity was quantified by measuring obstacle-crossing success rate (OCSR), toe-obstacle clearance (TOC), and reaction time (TR) while crossing a series of virtual obstacles with heights at 10% and 20% of the subject’s leg length. Results: No significant difference was found between groups for age and BMI. The data revealed that DPN subjects had a significantly lower OCSR compared to diabetics with no neuropathy and controls at an obstacle size of 10% of leg length (p < 0.05). DPN subjects also demonstrated longer TR compared to other groups and for both obstacle sizes. In addition, TOC was reduced in neuropathy groups. Interestingly, a significant correlation between TR and VPT (r = 0.5, p < 10–3) was observed indicating a delay in reaction with increasing neuropathy severity. The delay becomes more pronounced by increasing the size of the obstacle. Using a regression model suggests that the change in TR between obstacle sizes of 10% and 20% of leg length is the most sensitive predictor for neuropathy severity with an odds ratio of 2.70 (p = 0.02). Conclusion: The findings demonstrate proof of a concept of virtual-reality application as a promising method for objective assessment of neuropathy severity, however a further study is warranted to establish a stronger relationship between the measured parameters and neuropathy.

Background & Objectives: Charcot neuroarthropathy (CN) is a devastating complication of diabetes. It has two-fold higher rate of major amputation compared to those without CN. Unfortunately, to date, there is no pathological marker or diagnostic criterion for it and diagnosis relies on pattern recognition and clinical intuition. Not surprisingly, the diagnosis can be missed up to 95% of the time and the average diagnostic delay has been estimated at almost 7 months. Recent studies reported asymmetric plantar temperature differences secondary to inflammation as a hallmark for the diagnosis and treatment response of Charcot foot syndrome. However, little attention has been given to temperature response to activity. Methods: Fifteen individuals with acute CN and 17 age-matched non-CN participants with type 2 diabetes and peripheral neuropathy were recruited. All participants walked for two predefined paths of 50 and 150 steps. A thermal image was acquired at baseline after acclimatization and immediately after each walking trial. The plantar temperature (PT) response as a function of number of steps was examined using a validated wearable sensor technology. A custom image processing toolbox was designed to characterize the plantar temperature response to activity. Results: During initial activity, the PT was reduced in all participants, but the temperature drop for the non-affected foot was 1.9 times greater than the affected side in CN group (p=0.04). Interestingly, the PT in CN was sharply increased after 50 steps for both feet, while no difference was observed in non-CN between 50 and 200 steps. Conclusions: The observed differential thermal response to walking initiation between Charcot and non-Charcot feet warrants future investigation to provide further insight into the correlation between activity dosing and thermal response. It may also lead to a valuable insight into identifying an "inflammatory trigger" that may ultimately provide an early warning sign or increased sensitivity for subsequent unilateral or bilateral CN development or clinical expression of foot ulcer. These results also support that managing modulating duration of continuous steps and or prolonged standing during daily activity could be helpful for reducing the trauma in patients with CN or patients at risk of diabetic foot ulcer.

Background: Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes that affects nerve functions and may occur in 25% of patients with 10 or more years of diabetes and up to 50% with 20 years of diabetes. Patients with DPN experience a high incidence of injuries while walking and have a low level of perceived safety. In certain cases the impaired judgment - mainly due to impaired proprioceptive feedback - can cause obstacle collision leading to falls and injuries. The subtle early findings that are indicative of postural instability are difficult to accurately assess from a clinical examination, and gait laboratory assessment is not currently available or practical. Thus, unfortunately, many patients that are "at risk for falls" are undiagnosed. Objectives: An innovative virtual obstacle crossing (VOC) paradigm using wearable sensors was developed in attempts to detect lower extremity nerve damage due to DPN. Methods: Sixty-eight participants including diabetes with no, moderate and severe neuropathy and aged-matched healthy controls were recruited. Severity of neuropathy was quantified using vibratory perception threshold (VPT) values. The ability of perception of lower extremity was quantified by measuring the rate of obstacle crossing success (OCS), reaction time (TR), and foot position while crossing a series of virtual obstacles with various heights. Results: Results suggest VOC test allows separating between groups. All proposed parameters were significantly deteriorated by increasing neuropath severity (p

Background: People with diabetes-related peripheral neuropathy (DPN) frequently suffer from concomitant postural instability that can lead to falls, fractures, depression, anxiety, and decreased quality of life. Exercise has been demonstrated to be effective in improving balance. However, high demands of conventional balance programs might overtax DPN patients' ability to perform exercises correctly. This might in turn reduce motivation or increase risk of diabetic foot ulcers. In addition, conventional training regimes do not incorporate visual feedback, which is of key importance for compensating the impaired proprioceptive feedback due to DPN. In this study, we examined the effectiveness of an innovative ankle exercise program based on virtual reality for improving postural control among DPN patients. Methods: A novel ankle reaching exercise program was developed based on virtual reality and body worn sensors. Twenty-nine eligible DPN subjects (Age:57±10 years; BMI: 55.9±11.1 kg/m2) were asked to perform a set of point-to-point ankle reaching tasks while receiving real-time video game style feedback from ankle joint motion. The ankle motion in medial-lateral and anterior-posterior was measured using a set of wearable sensors attached to the subject's shank. To evaluate the benefit of this paradigm for improving postural control, a validated technology based on body worn sensors was used to examine balance at baseline and after training. Postural control was quantified by measuring the area of center of mass sway (COM) and reciprocal compensatory index (RCI). Results: Our findings revealed a significant reduction in COM post-training in average by 16% (p= 0.03). A negative correlation (r= -0.46; p< 0.05) was observed between baseline COM and the magnitude of COM reduction post-training suggesting a larger exercise benefit for those who have higher postural control deficit. A similar association was observed between neuropathy severity and magnitude of exercise benefit. In addition, a significant improvement was observed in RCI in average by 11.3% (p< 0.005). Conclusions: The current research has implemented a novel balance training paradigm that provides real-time visual feedback from ankle joint motion in order to incorporate joint proprioception in balance training. Our findings support that motor learning based on real-time feedback from ankle joint motion is effective in improving postural stability among DPN patients.