4 ms·

How does a pulse oximeter figure out how to guess you are in a REM state which can usually be done by EEG ? (Or the pebble can this be done by a accelerometer ?

How does a pulse oximeter figure out how to guess you are in a REM state which can usually be done by EEG ? (Or the pebble can this be done by a accelerometer ?) I have taken sleep studies where you would have to do at least something like the beddit device but even then I don't understand how they do it?

coredog64 10y ago
REM is characterized by lack of movement and variable respiration rate. So I would imagine the signal is erratic oxygen saturation. You'll get better results if you can correlate that with an accelerometer. Disclosure: I worked on a sleep tracking device that is a competitor to Beddit.
- dchuk 10y ago
  Can you shed light on whether there are a common set of algorithms that sleep trackers use or if they are generally all proprietary?
  - fleetingmoments 10y ago
    There are some common algorithms for sleep/wake classification from accelerometer input, but sleep stages algorithms are all proprietary as far as I know.
    - antisthenes 10y ago
      Which is another way of saying "no way to verify if they're bullshit or not".
      - fleetingmoments 10y ago
        Not true, anyone could take them to a sleep lab and compare to Polysomnograph-based sleep scoring. I'd love to see a large, independent study on this for a couple of the leading trackers.
      - deleted 10y ago
        [deleted]
- fleetingmoments 10y ago
  None of the popular wrist-based trackers have an oximeter. You need red and infrared light for that, and it is really tricky to get accurate measurements at the wrist in any case. You don't measure respiration rate with oximetry in any case, oxygen saturation does not change that fast. The more advanced solutions are mostly based on Heart Rate Variability which shows some correlation to sleep stages. Source: also worked on this.
CardenB 10y ago
I've always been under the impression they do accelerometer heuristics and brand it as sleep tracking. The research is valuable and private, so there's no way to verify the accuracy of their claims.
gumby 10y ago
The apple watch has an accelerometer too -- Sleep++ uses it.

coredog64 10y ago

REM is characterized by lack of movement and variable respiration rate. So I would imagine the signal is erratic oxygen saturation. You'll get better results if you can correlate that with an accelerometer. Disclosure: I worked on a sleep tracking device that is a competitor to Beddit.

dchuk 10y ago
Can you shed light on whether there are a common set of algorithms that sleep trackers use or if they are generally all proprietary?
- fleetingmoments 10y ago
  There are some common algorithms for sleep/wake classification from accelerometer input, but sleep stages algorithms are all proprietary as far as I know.
  - antisthenes 10y ago
    Which is another way of saying "no way to verify if they're bullshit or not".
    - fleetingmoments 10y ago
      Not true, anyone could take them to a sleep lab and compare to Polysomnograph-based sleep scoring. I'd love to see a large, independent study on this for a couple of the leading trackers.
    - deleted 10y ago
      [deleted]
fleetingmoments 10y ago
None of the popular wrist-based trackers have an oximeter. You need red and infrared light for that, and it is really tricky to get accurate measurements at the wrist in any case. You don't measure respiration rate with oximetry in any case, oxygen saturation does not change that fast. The more advanced solutions are mostly based on Heart Rate Variability which shows some correlation to sleep stages. Source: also worked on this.

CardenB 10y ago

I've always been under the impression they do accelerometer heuristics and brand it as sleep tracking. The research is valuable and private, so there's no way to verify the accuracy of their claims.

gumby 10y ago

The apple watch has an accelerometer too -- Sleep++ uses it.