I forgot to comment on the following important point:
> the pulse seems to reliably predict when I get to sleep but nothing else, not even when I am awake vs. sleeping
My experience with the Zeo made me realize that predicting sleep vs wake is hard to do. The modern multi-sensor devices tend to use the accelerometer derived movement together with historical sleep times to predict this. The early Fitbit devices tracked sleep with the motion sensor alone. In the middle of my normal sleep cycles, if I listen to a podcast or read from a smartphone/eReader while remaining mostly motionless, both the Zeo EEG and the Garmin PPG derived EEG will interpret that time as REM sleep.
I wonder if the professional sleep labs can accurately detect the difference? The true test will be when sensors/algorithms in casual activity trackers can detect when we nod off or nap during normal waking hours.
> the pulse seems to reliably predict when I get to sleep but nothing else, not even when I am awake vs. sleeping
My experience with the Zeo made me realize that predicting sleep vs wake is hard to do. The modern multi-sensor devices tend to use the accelerometer derived movement together with historical sleep times to predict this. The early Fitbit devices tracked sleep with the motion sensor alone. In the middle of my normal sleep cycles, if I listen to a podcast or read from a smartphone/eReader while remaining mostly motionless, both the Zeo EEG and the Garmin PPG derived EEG will interpret that time as REM sleep.
I wonder if the professional sleep labs can accurately detect the difference? The true test will be when sensors/algorithms in casual activity trackers can detect when we nod off or nap during normal waking hours.