So after some trial and error, as well as a lot of deliberation among the great choices of hardware available to us, we have decided to move forward using a particle board and a well-supported ADXL355. These are both affordable and easy to manage maintain in high quantity.
Our ultimate goal is to be able to produce a final end-product that 1) Easily replicable for personal use by lay people 2) Easily administered, installed, and scaled at any clinic, hospital, or care facility.
Using Particle, we can share code in the cloud and anybody can buy a Particle board and ADXL355 accelerometer and simply flash our code.
If we have 1 or 100 patients to manage, we can easily add more devices as needed.
The small form-factor, cloud-ide, and robust support were deciding factors in our decision.
We are happy to have finalized the hardware and we'll be posting build pictures and code in the coming days and weeks!
*I'll be using a Particle Core since I picked this up years ago when they were first released as Spark Core at Makerfaire. It should be trivial to implement on the newer Particle Photons, and we even have the option of using Particle Electrons for a completely remote monitoring solution using 2g/3g with minimal code changes.