[Note: It sounds like they have enough participants].
This is about a pilot study the Bateman Horne Center (in Utah, USA) has organised:
It is using a ring:
Initial pilot study involves 20 ME/CFS patients.
https://batemanhornecenter.org/empowered-research-while-you-sleep
This is about a pilot study the Bateman Horne Center (in Utah, USA) has organised:
It is using a ring:
"Ōura is a ring-sized computer designed to assess sleep. It measures total sleep time and amount of deep and REM sleep each night and during the day it measures energy expenditure and activity."
Initial pilot study involves 20 ME/CFS patients.
https://batemanhornecenter.org/empowered-research-while-you-sleep