Figure 2
Exemplary description of non-wear time (NWT) validation using a minute-by-minute evaluation for calculation of overlap in length (minutes) of NWT detected based on accelerometry (accelero.) as compared to diary (black rectangles, wear time based on 24 h-accelerometry or diary data, respectively; white rectangles, NWT based on 24 h-accelerometry or diary data, respectively). As an example, in the original diary data (panel I), five NWT periods during waking were reported being 30, 30, 115, 130, and 30 minutes, respectively. When applying the 60-min NWT algorithm (panel II) to both accelerometry and diary data two of all NWT periods in diary (115 and 130 minutes, respectively), and three NWT periods in accelerometry were detected (75, 65, and 140 minutes, respectively). When applying the 60-min NWT algorithm (panel III) to accelerometry data only while any NWT regardless of a minimal length reported in the diary was assessed, still three NWT periods in accelerometry (75, 65, and 140 minutes, respectively) but all five ‘original’ NWT periods in diary (30, 30, 115, 130, and 30 minutes, respectively) were detected. For each NWT algorithm and both approaches (panel II and III), NWT minutes detected by accelerometry only, in diary only and in both accelerometry and diary were assessed. We then calculated the relative contribution of each of these to the potential total NWT (i.e., NWT detected in either diary, accelerometry, or both). Overlap was defined as the NWT detected in both accelerometry and diary.
