SUMMARY

• Incorrect walker is associated with increased fall risk in older adults, but little is being done to correct the issue.
• Our product, the StrideTech GO, measures the two most common methods of incorrect walker use: 

1. Excessive weight through the handles (measured as left- and right-hand force on the left- and right-hand handles)
2. Excessive distance between the user and the device (measured as distance between the user’s hip and the frame of the walker) 

• With StrideTech GO, we can decrease average weight through the handles and average distance between the user and their device over 11 weeks
• With StrideTech GO, we can visually and mathematically detect weekly patterns of mobility behavior
• With StrideTech GO, we can visually and mathematically detect daily patterns of mobility behavior

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INTRODUCTION

Stride Tech Medical Inc.’s mission is to prevent falls. Seniors widely use walkers to maintain mobility while reducing the risk of falls. Despite the benefits, habitually poor walker use, marked by excessive weight on the walker handles and/or excessive distance between the user and the walker, can lead to muscle atrophy, poor posture, and falls. A widely publicized investigation in 2009 showed that over 87% of severe falls with an assistive device occurred with a walker. They recommended increased time devoted to fitting and education on proper use. Eleven years later, most seniors still do not receive individualized fitting or training on how to use their walkers.

Our product, the StrideTech GO (STG), is an attachable walker accessory that integrates sensors and biofeedback onto existing walkers to correct common misuses in real time. Grip covers embedded with sensors Velcro over the handles of a walker. An additional sensor is mounted to the frame which measures the distance from the user’s hip to the walker frame. The grip covers vibrate if the sensors detect either of the two primary indicators of walker misuse:

• Excessive weight through the handles
• Excessive distance between the frame of the walker and the use

StrideTech GO is the first commercial product to help fill the urgent need for long term training in walker use. This white paper will outline the technical background and testing that has been done to establish efficacy, as well as briefly outline next steps and improvements. 

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PROTOCOL

StrideTech defines long-term efficacy as the ability to see changes in STG measures of walker use over the course of at least six weeks. This time period is the minimum recommendation of long-term testing from various physical therapist advisors to the team. The data presented was collected from a volunteer, Barbara, who agreed to attach StrideTech GO to her personal walker for six weeks. (After six weeks of use, she wished to continue using the product, so the team extended the testing trial an additional five weeks.) The threshold levels to initiate vibratory and visual feedback were set at the standard 18 in. for hip-distance feedback, and 7 lbs. for weight-bearing feedback. 

On a weekly basis, the StrideTech team would meet with Barbara to download the previous week’s data from the StrideTech GO, replace the device’s SD card, display walker use data, and get feedback on how well the device was functioning. 

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RESULTS

Case Study 1 – Decreased hip distance, weight-bearing, and % misuse over 11 weeks of using StrideTech GO

In previous short-term testing sessions, StrideTech has been able to observe significant decreases in the hip distance and weight-bearing on the walker due to vibrational and/or visual feedback provided by the StrideTech GO. Long-term testing aims to assess if similar outcomes can be seen, measured, and maintained over multiple weeks. 

Below is Barbara’s average daily hip-distance over 60 days.

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As expected, her daily average hip-distance varied from day to day. After speaking with Barbara and physical therapists about this,, we were reassured this was normal for her. Energy levels, back pain, and previous days of mobility all influenced how attuned to feedback and posture Barbara felt she could be throughout a day. However, looking at the average of her hip distance over Week 1 vs. Week 11, which went from 10.2 in. to 7.5 in., respectively, we saw a reduction in hip distance over time. 

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Below is the average daily weight-bearing on the left (blue) and right (pink) handles over 60 days.

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On average, Barbra rarely triggered weight bearing feedback. On average, she tended to stay below the 7 lbs. threshold for feedback. Notably, over time the team noticed daily and weekly trends that indicated Barbara would favor one side over the other, and then switch. This was previously unobserved by the team, as most testers usually either put equal weight through both handles of the walker, or heavily favored one side of the walker. When the team asked her about her tendency to switch between left and right hand weight bearing dominance, she explained it was due to residual pain from back surgery she underwent several years earlier. Accordingly, she would switch which side she leaned on more heavily depending on her back pain on a given day.

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While it is a goal of StrideTech to give feedback and reports on left and right hand weight bearing symmetry, this situation was interesting to see reflected in the data. 

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Another key metric the team looked at was Misuse Rate (%) for Hip Distance and Force over time. This metric looked at the daily number of hip distance and force misuses as a percentage of the amount of activity logged that day. (Ex. for a day of 100 registered Hip Distance measurements, with 5 measurements over the thresholds for feedback, a user would have a hip-distance misuse rate of 5% for that day.) Below is Barbara’s hip distance and force misuse rate over 60 days.

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Excitingly, a huge decrease in misuse rate can be seen for both hip distance and weight-bearing over time. For the last twenty days of the trial, Barbara was misusing her walker less than 10% of the time she was using it. That was an over 30% decrease in walker misuse from her starting week. 

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Overall, the team, Barbara, and her physical therapists were all excited to see such promising results. When asked about her experience using the StrideTech GO, Barbara explained the StrideTech GO made her feel more confident in walking knowing 1. She was improving and 2. She would get immediate feedback if she did start slipping back into unsafe walker behaviors. 

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FUTURE WORK 

More data and more testing are needed to explore the exciting potential of the StrideTech GO. Because long-term testing is no longer under a controlled scenario, the weekly check-ins were vital for data validation. At this time, activity time was calculated by culminating the time non-zero hip distance and non-zero force values were detected. Since the end of this trial, new firmware algorithms utilizing accelerometer data have been tested and implemented, allowing for more finely tuned activity detection. 

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Stay tuned for next week’s White Paper, Long Term Testing Pt. 2, to see how the team was able to discern weekly and daily mobility patterns from the StrideTech GO system.

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