Human-Computer Interaction Institute
School of Computer Science, Carnegie Mellon University


Exploring in-home monitoring of rehabilitation and creating an authoring tool for physical therapists

Kevin Huang

October 2015

Ph.D. Thesis


Keywords: NA

Physiotherapy is a key part of treatment for neurological and musculoskeletal disorders, which affect millions in the U.S. each year. Physical therapy treatments typically consist of an initial diagnostic session during which patients' impairments are assessed and exercises are prescribed to improve the impaired functions. As part of the treatment program, exercises are often assigned to be performed at home daily. Patients return to the clinic weekly or biweekly for check-up visits during which the physical therapist reassesses their condition and make further treatment decisions, including readjusting the exercise prescriptions.

Most physical therapists work in clinics or hospitals. When patients perform their exercises at home, physical therapists cannot supervise them and lack quantitative exercise data reflecting the patients' exercise compliance and performance. Without this information, it is difficult for physical therapists to make informed decisions or treatment adjustments. To make informed decisions, physical therapists need to know how often patients exercise, the duration and/or repetitions of each session, exercise metrics such as the average velocities and ranges of motion for each exercise, patients' symptom levels (e.g. pain or dizziness) before and after exercise, and what mistakes patients make.

In this thesis, I evaluate and work towards a solution to this problem. The growing ubiquity of mobile and wearable technology makes possible the development of "virtual rehabilitation assistants." Using motion sensors such as accelerometers and gyroscopea that are embedded in a wearable device, the "assistant" can mediate between patients at home and physical therapists in the clinic. Its functions are to:

  • use motion sensors to record home exercise metrics for compliance and performance and report these metrics to physical therapists in real-time or periodically;
  • allow physical therapists and patients to quantify and see progress on a fine-grain level;
  • record symptom levels to further help physical therapists gauge the effectiveness of exercise prescriptions;
  • offer real-time mistake recognition and feedback to the patients during exercises
One contribution of this thesis is an evaluation of the feasibility of this idea in real home settings. Because there has been little research on wearable virtual assistants in patient homes, there are many unanswered questions regarding their use and usefulness:

Q1. What patient in-home data could wearable virtual assistants gather to support physical therapy treatments?

Q2. Can patient data gathered by virtual assistants be useful to physical therapists?

Q3. How is this wearable in -home technology received by patients?

I sought to answer these questions by implementing and deploying a prototype called "SenseCap." SenseCap is a small mobile device worn on a ball cap that monitors patients' exercise movements and queries them about their symptoms. A technology probe study showed that the virtual assistant could gather important compliance, performance, and symptom data to assist physical therapists' decision-making, and that this technology would be feasible and acceptable for in-home use by patients. Another contribution of this thesis is the development of a tool to allow physical therapists to create and customize virtual assistants. With current technology, virtual assistants require engineering and programming efforts to design, implement, configure and deploy them. Because most physical therapists do not have access to an engineering team they and their patients would be unable to benefit from this technology. With the goal of making virtual assistants accessible to any physical therapist, I exploredthe following research questions:

Q4. Would a user-friendly rule-specification interface make it easy for physical therapists to specify correct and incorrect exercise movements directly to a computer? What are the limitations of this method of specifying exercise rules?

Q5. Is it possible to create a CAD-type authoring tool, based on a usable interface, that physical therapists could use to create their own customized virtual assistant for monitoring and coaching patients? What are the implementation details of such a system and the resulting virtual assistant?

Q6. What preferences do PTs have regarding the delivery of coaching feedback for patients?

Q7. What is the recognition accuracy of a virtual rehabilitation assistant created by this tool?

This dissertation research aims to improve our understanding of the barriers to rehabilitation that occur because of the invisibility of home exercise behavior,to lower these barriers by making it possible for patients to use a widely-available and easily-used wearable device that coaches and monitors them while they perform their exercises, and improve the ability of physical therapists to create an exercise regime for their patients and to learn what patients have done to perform these exercises. In doing so, treatment should be better suited to each patient and more successful.

71 pages

Thesis Committee:
Sara Kiesler (Co-Chair)
Daniel P. Siewiorek (Co-Chair)
Asim Smailagic
Anind Dey
Patrick J. Sparto (University of Pittsburgh)

Anind K. Dey, Head, Human-Computer Interaction Institute
Andrew W. Moore, Dean, School of Computer Science

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