How to interpret the Off Head metric

Dreem Research Team
Written by Dreem Research Team
Last update

Definition 

Every 2 seconds of the signal is tested for on head or off head. When the recording is completed, the % of the record with off head is displayed as ‘off head’ metric. This first metric you should look at when reviewing a recording.

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How to read it

Values from 0 to 10% are acceptable, and the Record Quality metric should be inspected next. Any values above 10 should be considered substantial record loss, and interventions should be advised to  the participant to minimize durations EEG signal loss.

 

Color coding

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If you see values over 10, it means that the headband didn't stay properly on the head for more than 10% of the recording. We advise you to help the participant on optimizing headband fit. It can be through positioning tips or using the right adjusters.