A Smartphone Application for Improving Powered seat functions usage
Yu-Kuang Wu, MS PT1,2, Brandon Daveler, BS1,2, Hsin-Yi Liu, MS PT1,2, Josh Brown, BS1,2, Annmarie Kelleher, MS OTR/L1,2, Hongwu Wang, PhD1,2, Rory A. Cooper, PhD1,2
1Department of Rehabilitation Sciences and Technology, School of Health and Rehabilitation Sciences, University of Pittsburgh
2Human Engineering Research Laboratories, Department of Veterans Affairs Pittsburgh Healthcare System Pittsburgh, PA, USA
Background
Introduction and Rationale
Powered wheelchairs with powered seat functions are prescribed for wheelchair users who are unable to adjust their postures or manage their seating pressure independently because of motor and/ or sensory impairments. [1] The powered seat functions can (1) provide users with dynamic postural support, (2) help them reposition and redistribute the seating pressure, (3) provide management of secondary complications and (4) improve driving safety and users’ daily function. [1-3] However, going through the activities of daily living while having to appropriately utilize the powered seat functions can be overwhelming for a wheelchair user. For this reaseon, we have been developing and testing the Virtual Seating Coach (VSC) [4, 5], which is a tailored reminder system to facilitate powered wheelchair users to utilize powered seating functions based on clinical recommendations. The concept is that the VSC program compares powered seat function usage data with clinician's recommendations and provides appropriate reminders to the users. The results in our pilot study have shown that VSC increased subjects' compliance of powered seat functions usage, such as increasing the frequency of performing pressure relief. [6] The preliminary findings encourage us to develop an easily installed VSC system to increase the number of individuals who can benefit from this application, since our current VSC system requires a complicated and time-consuming process of sensor installation. In addition, with the increasing number of smartphone users, converting VSC program into a user-friendly smartphone app could be a good idea in terms of widespreading our application.
Methods
Project description
The purpose of this project is to develop a smartphone based VSC by using accelerometers to measure the powered seat function usage. Also, one usability test has been conducting to understand the usability of our smartphone VSC application.
Procedures
Hardware
Four accelerometers are placed on the seat pan, backrest, legrest, and the wheelchair base to detect the tilt, recline, legrest, and wheelchair base angles. The accelerometers’ signal is sent to an Android smartphone via the USB cable after analog to digital conversion by a microcontroller.
Software
Two applications are running in the smartphone. One application keeps requesting the microcontroller board to send the accelerometer data to the phone for data collection, while another application is displaying the information on the smartphone screen.
Usability test
In the usability test, we installed our smartphone VSC system on users’ personal powered wheelchair. After a series of hand on training, we asked these users to answer a questionnaire with respect to the usability of our system.
RESULTS
Figure 1A shows the interface displaying the angles for seat tilt, backrest recline, legrest elevation and the position of the wheelchair base. Figure 1B indicates how the application instructs users to adjust their powered seat function.
Figure 2 shows one part of preliminary results from the usability data of five powered wheelchair users. As can be seen, most users found that the VSC application is easy to learn and use. However, they also reported that it is hard to navigate the application when they got powered seat function usage warning. This might be due to the fact that a warning message appears as a text message, which is easily ignored.
DISCUSSION
CONCLUSION
The goal of the smartphone-based VSC system is to implement our seating coach on a user-friendly mobile app form that requires no additional hardware modifications of the powered wheelchair. We are currently evaluating our prototype by gathering the feedback from the end-users via conducting the usability study.
Significance and Importance
The availability of the VSC app will promote access to this educational tool by users and clinicians and may further advocate the importance of powered seat functions and proper user training.
References
1. Trefler E, S.M., State of The Science White Paper on Seating for Postural Control. 2001.
2. Lange, M., Positioning: it's all in the angles. Advance for Occupational Therapy Practitioners, 2006.
3. Dicianno, B.E., et al., RESNA position on the application of tilt, recline, and elevating legrests for wheelchairs. Assist Technol, 2009. 21(1): p. 13-22; quiz 24.
4. Ding, D., et al., Virtual coach technology for supporting self-care. Phys Med Rehabil Clin N Am, 2010. 21(1): p. 179-94.
5. Liu., H.-y., et al., Seating virtual coach: A smart reminder for power seat function usage. Technology and Diability, 2010. 22: p. 53-60.
6. Liu, H.-y., et al., Case Study: Pilot Test of Virtual Seating Coach Evaluated by Power Seat Function Users., in Rehabilitation Engineering and Assistive Technology Society of North America Conference, Baltimore, MD. 2012.