How to interpret EEG Channel Quality metrics

Dreem Research Team
Written by Dreem Research Team
Last update


The signal of each EEG channel is analyzed during the recording and labeled accordingly (good or bad quality). Then the proportion of good quality EEG signals is computed and given through this metric.


How to read them

With a Dreem 3 headband, you will have access to three values. These values pertain to sensors: Left Occipital sensor, Right Occipital sensor, and Frontal sensors respectively. 


How it works

Two seconds signal portions of raw data over 35-40 nights have been labeled by our team of sleep specialists (zero for bad quality, one for good quality). We trained our deep learning algorithm to automatically score the signal for each new night. The number displayed for each channel is the cumulative length of portions (i.e. a 2-second raw signal) scored as “of good quality” by the algorithm over the total length of a recording. 


Color coding


A value below 70 is often related to a poor placing of the headband on the participants' head. If the channel quality metrics are < 70, we advise you to review headband placement with the participant and to switch to a smaller adjuster if possible.