That sounds about right.
This guy did a year long study and came up with 65% accuracy compared to PSG.
His main points were:
Where I was wrong, where I was right
Over two years ago36 I wrote:
The NeuroOn sleep mask cannot work exactly as advertised - it cannot utilize a proper EEG signal. While it can detect a REM phase in sleep very roughly, it's very far from reliable sleep analysis. The majority of the population isn't able to achieve polyphasic sleep, since their brains aren't capable of that. A similar thing goes with lucid dreaming. NeuroOn at its best would be not too useful of a gadget to be put away after several uses.
WRONG Looking at the spectral analysis of NeuroOn's signal above it seems that I have been wrong in saying that it's impossible to reliably discern sleep stages from 3 electrodes located on the forehead. It looks like it should be possible, but requires much more research than IntelClinic has put in NeuroOn.
RIGHT It holds true that NeuroOn can conduct only a rough (not medical-grade) analysis of the sleep phases.
RIGHT Polyphasic Sleep isn't supported by NeuroOn, as confirmed by the IntelClinic.
? We don't know much about lucid dreaming yet, but the research required to change that might be quite costly.
Apparently the new device is supposed to be more accurate.