Prescribed footwear, such as Removable Cast Walkers, are used to reduce harmful pressures on the bottom of the foot for prevention and treatment of diabetic foot ulceration (DFU). Although a key component to the healing and prevention of DFU, patient adherence with these devices is excessively poor as determined by patient interviews and initial objective assessments. The use of """"""""off the shelf"""""""" activity monitors for objective monitoring of adherence has provided some valuable information regarding adherence and wound healing, however, the methodology used to date has had several significant restraints and is not suitable for use outside of the research setting. This methodology is limited to the assessment of foot loading during walking and thereby ignores the significant loading of feet that occurs while standing. Also there is no means of identifying whether sensors were worn, allowing for significantly underreported activity/adherence values. Lastly, the calculation of adherence from these devices is quite labor intensive and cannot be done in real time. In this proposal, we develop an innovative and low cost technology that could help improve patient adherence via both an alarm notification to the patient and valuable data logger information provided to clinician. The proposed system combines a widely available inexpensive device with innovative physical activity monitoring technology for improving patients'adherence to wearing prescribed footwear. The device consists of an active RFID tag (Radio-frequency identification) integrated in the subject's footwear, together with a body worn sensor that includes an RFID tag reader and motion sensors based on micro-electro-mechanical systems (MEMS) technology for monitoring spontaneous daily physical activity. The RFID tag will act as a proximity sensor, with the range limited to the length of the patient's body. Therefore for physical activity to be classified as adherent with the prescribed footwear, the MEMS sensor recording the activity must concurrently detect the footwear as being within sensor range (e.g. being worn). The suggested technology is an extension of our work in monitoring spontaneous daily physical activities in real-time using unobtrusive body wearable technology. The body worn sensor measures specific body postures in real-time, such as sitting, walking, standing, and lying down and is also capable of measuring patients'compliance in wearing the sensor by monitoring chest movement due to respiration. The software algorithm is sensitive and specific enough to integrate an alarm, should the subject ambulate unsafely without their RFID tagged footwear. (e.g., walk more than five steps). In case that the RFID tag is out of range (i.e. subject didn't wear the footwear), the sensor unit will notify an alarm (via sound or vibration) and will mark the time of the alarm in the on-board memory system. In the clinical part of the study, two different tests are designed to address its validity as well as its application in (a) quantification of patient adherence as compared to previous measures of adherence to prescribed footwear (e.g. face-to-face interview) while ambulating at home and in the community and (b) investigating changes in patients'footwear behavior in response to commonly used practices, such as addressing patient preferences, patient education;and use of alarm. The suggested technology could make an immediate difference in diabetic foot care management and enable clinicians to better manage diabetic wound care. It may also lead to smart foot ulcer prevention strategies via improving subjects'adherence to prescribed footwear and allowing for dosage of daily physical activity. Lastly this device and the data gathered by it may also serve as a valuable patient education tool.

Public Health Relevance

The use of specialized footwear that limits physical stress to the feet during weight bearing activities is a key factor in the prevention and treatment of diabetic foot wounds (ulcers);however, patients generally wear the footwear for only a small fraction of their daily activities. This project seeks to develop an unobtrusive monitor that will identify patients'use of their footwear during their daily physical activity. This device may be used to provide clinicians valuable information regarding patient compliance and also may be used as a tool to directly improve compliance by providing a warning alert to patients when they are active while not wearing their footwear.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Small Business Innovation Research Grants (SBIR) - Phase I (R43)
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Special Emphasis Panel (ZRG1-MOSS-F (15))
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Arreaza-Rubin, Guillermo
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Biosensics, LLC
United States
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