Development of an inertial measurement-based assessment of disease severity in Chronic Fatigue Syndrome, by Turner Palombo, Suzanne Vernon, Shad Roundy in Digital Commons (Utah Space Grant Consortium grant) 2020 Paper 11. Published May 2021


Research abstract: 

While myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is relatively new and poorly understood, a recent upsurge in research has identified the disease’s core symptoms, including post-exertional malaise and orthostatic intolerance. The FDA has yet to approve any treatments for ME/CFS, partially due to a lack of validated efficacy

The central focus of this research is to develop ME/CFS efficacy endpoints using a non-invasive, inertial measurement-based approach. Accessible endpoints will provide a way to properly evaluate potential treatments for ME/CFS. Using a Kalman filter, inertial measurement unit (IMU) data can be converted to optimized leg angle estimates. These
angle estimates can then be converted to personalized daily measurements of upright activity, referred to as uptime.

In a six-day, case-control study conducted by the Bateman Horne Center, uptime was measured for 15 subjects (five controls, five moderate-level ME/CFS, and five severe-level ME/CFS).  Analysis of these uptime scores indicated that each group spends different proportions of their days upright and active. This result shows that uptime can accurately
determine disease severity and is, therefore, a reliable endpoint for evaluating ME/CFS treatment efficacy.


This research proves the value of uptime as an objective replacement for HUA. Analysis of collected uptime data indicates that disease groups spend different proportions of the
day upright and active. Healthy individuals are expected to have weekly uptime scores above 30%, subjects with moderate ME/CFS are expected to have weekly uptime scores between 20% and 30%, and subjects with severe ME/CFS are expected to have weekly uptime scores below 20%.

Another objective of our study was to evaluate the effects of PEM brought on by the NASA Lean Test. Our results showed no change in uptime after the NASA Lean Test. Although this contradicts our expectations, we have confirmed that this test is humane; patients with ME/CFS do what they can to avoid stress-causing exertion, but we have seen that this test does not cause a drastic decrease in uptime—indicating that they aren’t significantly hurt by the test. Future studies should incorporate home-visits to reduce the stress caused by participation, thereby ensuring that PEM is only induced by researchers during the
Lean Test.

Accurate uptime measurements will become invaluable for healthcare providers in assisting ME/CFS patients. Furthermore, uptime provides a method for pharmaceutical companies and independent researchers to prove the efficacy of their treatments—a critical step towards receiving FDA-approval. The BHC’s data shows that patients with severe ME/CFS are limited to a bed or reclining chair for all but five hours each day; increasing this number would be life-changing.

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