Research Award Details

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Can Commitment Contracts and Financial Incentives Improve Brace Compliance in the Treatment of Clubfoot? A pilot study

Grant Recipient: John Vorhies, MD

Co-Investigators: Kali Tileston, Jim Policy, Meghan Imrie, Larry Rinsky
Stanford Children's Health
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Can Commitment Contracts and Financial Incentives Improve Brace Compliance in the Treatment of Clubfoot? A Pilot Study

Principal Investigator: John S. Vorhies, MD

Project Summary
Our study aims to understand the effectiveness of financial incentives in promoting bracing compliance among caregivers of congenital clubfoot patients. We plan to administer weekly financial incentives that are determined by caregiver compliance with prescribed bracing guidelines. Accurate and timely allocation of incentives depends on reliable remote measurements of brace wear compliance. The POSNA Micro-Grant has been applied to compensate research coordinators for time spent testing sensor reliability prior to use in patients.

Progress and Outcomes Update
We are still in progress and are not yet able to assess our primary outcomes. We have not yet begun enrolling patients primarily because of issues encountered with sensor reliability beyond what we initially anticipated.

Bracing compliance data must be available real-time to the research team and participants for implementation of the incentive model. We have internally tested two candidate types of Bluetooth-enabled sensors that sync with patients’ mobile devices to allow for real-time updates on brace wear compliance. During in-house testing, research assistants wore the sensors on their arms or legs with direct skin contact and kept detailed logs of actual wear. This log was then compared to the sensor’s measured wear. Initial testing has focused on accuracy of compliance measurement, syncing with patient devices and the user experience, and proper functionality in a clubfoot brace.

1. iLink manufactured by Intellirod
The iLink is a capacitance sensor that uses the ability of the body to hold charge to determine whether or not a brace is being worn. iLink syncs with the iLinkMyBrace app to provide measurement updates directly to the user and through a secure online web portal to the research team. Over the past year we have conducted multiple iterative rounds of internal testing with a total of 12 iLink sensors. Initial testing was designed to show reliable measurements in an ideal environment with skin-sensor contact. Researchers wore the sensors for 135.3 hours. The first generation of sensors measured 168.9 hours of wear (80% accuracy). The first round of testing revealed the sensitivity of the device to calibration errors as well as software errors resulting in inaccurate measurements and syncing failures. This first set of sensors was returned to Intellirod and we continued to iteratively work out bugs in the software.

Recently, Intellirod has updated the iLink and the iLinkMyBrace app to address challenges revealed through our initial testing. In August, we have tested the most recent round of updated iLink sensors in various environments, including direct contact with the skin, connected to a clubfoot brace, and placed in 3D printed dock designed to simulate a scoliosis brace. Sensors were worn in direct contact with skin for 25.2 hours and measured 25.0 hours (99% accuracy). Technical issues remain, however, as one sensor tested in direct contact stopped syncing with the app due to a hardware issue and was returned to Intellirod.

We have tested three different configurations of the sensor on the clubfoot brace (Figure 1).

The portion of the brace attached to the sensor was detached from the rest of the brace and worn around a wrist to simulate brace wear (Figure 2). The most recent configuration of iLink on the clubfoot brace was worn for 11.4 hours and measured 20.5 hours (55% accuracy). We believe that the proximity of the sensor to metal rivets on the brace and the material used to attach the sensor to the brace may be causing inaccuracies in calibration and measurement. Both Intellirod and our research team are conducting further testing necessary to identify ideal placement of iLink on the clubfoot brace.

2. Tempo Disc connected to BraceRite App
Texas Scottish Rite Hospital (TSRH) has developed the BraceRite app to track scoliosis bracing compliance using the Tempo Disc temperature sensor. After the initial round of iLink testing, we decided to investigate other Bluetooth sensor options and tested five Tempo Disc sensors in direct contact with skin. During testing, we encountered errors in measurements and data display. Often, when the sensor synced with the app multiple times, we saw changes in previously recorded data that were inconsistent with our sensor wear logs. We have been unable to resolve these errors to date.  Additionally, the BraceRite app does not yet include temperature cut-offs for use in clubfoot braces. Thus, we are not moving forward with employing the Tempo Disc in our clinical trial at this time. the TSRH team is actively working on product development with clubfoot in mind, which is supported by a separate POSNA grant.

As we have been unable to verify complete functionality of the sensor, we have not yet begun participant enrollment. We are in close communication with Intellirod and we are continuing to evaluate updated versions of the iLink for use in our trial.

While we have been testing sensor reliability we have continued to develop our plan for recruitment strategy and incentive administration, which has been finalized in a protocol. For the pilot study, our team has decided to manage incentive and compliance updates in-house, holding off on our partnership with Way to Health at this time. A research coordinator will track patient incentives, organize automated text message updates, and administer the rewards monthly as gift cards. We have collaborated and established a business agreement with a third-party vendor, Twilio, a cloud-based communications platform, to send secure text message updates to participants. 

Future plans
Based on our experience with sensor reliability testing, we have modified our research protocol to include a measurement reliability check. Once we demonstrate reliability of the sensors with internal testing we will confirm the accuracy of our in vivo data by monitoring bracing compliance using both the iLink and iButton sensors in the same patients. The iButton is a non-bluetooth enabled heat based sensor with a long track record of successful use in orthotic compliance studies. iButton testing conducted by our research team has also shown reliable measurements. Once we begin the pilot, the iLink will provide real-time bracing updates to the participants and research team and at the end of a participant’s study involvement, iButton data will be analyzed to verify accuracy of iLink measurements.

Our study timeline has been adjusted to account for an extended period of sensor reliability testing. In the first week of September, we will receive sensors with updated software from Intellirod. The research team and Intellirod will continue internal testing in the clubfoot brace environment. Once we are confident in our design, we will identify volunteer caregivers of patients with congenital clubfoot to test the sensors in live patients. This field testing will allow us to identify and address technical concerns that may arise prior to trial enrollment. Participant enrollment in our trial will begin when field testing is complete. Enrollment is expected to begin this fall.