The aim is to describe and compare strategies for tracking non-wear time of wearable light loggers used in ambulatory light exposure studies. This can help other researchers to plan their experiments and choose a non-wear time strategy which fits their research requirements.
- Participants N = 26
- Duration: 7 full days (Monday to Monday)
- Wearable device: ActLumus with 10 seconds sampling period, worn centrally on non-prescription spectacles ("light glasses")
Non-wear time information is given by three sources:
- Wear log completed by the participant with following information:
- Timestamp of taking the light glasses off (current/retrospective)
- Timestamp of placing the light glasses back on (current/retrospective)
- Timestamp of taking the light glasses off before bed (current/retrospective)
- Use of black bag during non-wear episode (current/retrospective)
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Button presses done by the participant (logged by ActLumus);
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Light while in black bag (mEDI ≤1 lux during non-wear time)
- Note: this is partly related to the Wear log, as information on whether the black bag was used or not is contained in the Wear log
Each of these three sources can be used individually to detect a non-wear period. However, the Wear log entries were monitored twice a day by the experimenter, and thus considered as the “ground truth” for non-wear detection.
The ovearching RQ is: What is the concordance between different sources of non-wear?