June 2019

To Improve Patient Outcomes, Measure What Matters

By Michael Rowling, BS

Mobility and balance deficits in patients with lower extremity impairments are significant factors for decreased quality of life. To improve outcomes for these patients, clinicians need measures that are evidence-based and scientifically validated; in other words, there is a need to measure things that matter.  For LER readers, that means capturing the components of gait and balance that relate to activities of daily living with the correct tools and in a properly conceived and systematic manner.

The US Food and Drug Administration (FDA) and the Mobility Saves Project of the American Orthotic and Prosthetic Association summarize why validated measures are needed:

  • Real-world data (RWD) and real-world evidence (RWE) play an increasingly important role in healthcare decision-making.1
  • The FDA uses RWD and RWE to monitor post-marketing safety and adverse events and to make regulatory decisions.2

The healthcare community is using these data to support coverage decisions and to develop guidelines and decision-support tools for use in clinical practice. Namely:

  • “Medical product developers are using RWD and RWE to support clinical trial designs (eg, large simple trials, pragmatic clinical trials) and observational studies to generate innovative, new treatment approaches.”1
  • “Lower extremity and spinal orthotic and prosthetic devices and related clinical services are designed to provide stability and mobility to patients with lower limb loss or impairment and spinal injury. Supplying bracing or support… where needed or a new artificial limb… when necessary saves our healthcare system significant future costs. Medicare’s own data show this to be the case. Timely treatment that preserves or helps regain mobility not only makes sense, it also saves dollars.”2

These quotations illustrate (1) the current and future importance of measuring RWD and (2) why facilitating and optimizing patient-centered mobility performance is a win–win for all stakeholders: industry, payers, providers, and patients. An informed and engaged patient has the opportunity to gain maximum benefit from his/her care plan.

To achieve these goals, validated measures are still needed. Preliminary results suggest that wearables have the potential to alter the course of drug and device development and eventually they may become part of routine clinical care. Consider how Holter monitors changed the assessment of cardiac arrhythmias over 50 years ago; will wearable sensors be able to change the clinical assessment of gait and balance in a similar way? I believe so; however, please use caution when choosing devices for specific clinical populations.

Many algorithms and measurements used in today’s Inertial Measurement Units (IMUs) have not yet achieved robust and reliable levels. The specificity and sensitivity of these algorithms may provide false positives/negatives for different populations characterized by altered gait patterns because they have not been validated during walking or other transitional movements such as turning. Also, from the clinician’s point of view: Protocols designed to assess gait using IMUs are many and the plethora of quantified outcomes is an obstacle for a comprehensive overview of pathological gaits, which can be highly confusing.3 Furthermore, according to a recent panoramic review, only 6% of sensors (including IMUs and magnetometers) used to assess Parkinson’s disease are precise and efficient enough for clinical testing.4 To avoid these challenges, many researchers utilize gold standard systems (pressure walkways) for measurements of the gait events (heel strike and toe off) to improve IMUs’ accuracy.5

To understand the effectiveness of interventions and accurately portray the patient’s mobility in, and capacity for, activities of daily living, clinicians need to appropriately measure the necessary components of gait and balance. At ProtoKinetics, we believe that outcome measures beyond only straight-line walking can be improved by including obstacle avoidance, change of direction, and dynamic balance. In other words, validated measurements and methodologies are what matter!

Managing and synthesizing accurate gait and balance data are essential to realizing the promise of outcomes-driven healthcare. To do so will require the continued innovation of vendor-partners who develop unique products that help researchers and clinicians answer critical performance-based questions. It’s also incumbent upon you, the informed LER reader, to implement these important findings and innovations to improve patient outcomes.

Michael Rowling, BS, is Chief Operating Officer and Director of Business Development, ProtoKinetics, Havertown, Pennsylvania.


  1. Real-world evidence. US Food and Drug Administration. May 9, 2019. www.fda.gov/science-research/science-and-research-special-topics/real-world-evidence. Accessed July 9, 2019.
  2. About Mobility Saves. Mobility Saves Project of the American Orthotic and Prosthetic Association. www.mobilitysaves.org/about/. Accessed July 9, 2019.
  3. Vienne A, Barrois, RP, Buffat S, Ricard D, Vidal PP. Inertial sensors to assess gait quality in patients with neurological disorders/ a systematic review of technical and analytical challenges. Front. Psychol. 2017.8/817.
  4. Sánchez-Ferro Á, Elshehabi M, Godinho C, et al. New methods for the assessment of Parkinson’s Disease (2005 to 2015): a systematic review. Mov. Disord. 2016;31:1283–1292.
  5. Bertoli M, Cereatti A, Trojaniello D, et al. Estimation of spatio-temporal parameters of gait from magneto-inertial measurement units: multicenter validation among Parkinson, mildly cognitively impaired and healthy older adults. BioMed Eng OnLine. 2018;17:58.

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