Action w software

For activity and sleep measurement we used actigraphy, as previously described^{17 (link)}. Actigraphy employs a miniature wristwatch-like accelerometer which is attached to the wrist, ankle or waist and continuously records movement for an extended period. The actigraphy device used in the present study was the Actigraph (Micro-mini RC, Ambulatory Monitoring Inc., NY, USA). The parents were asked to attach an Actigraph to their child’s waist with an adjustable elastic belt for 7 consecutive days. Waist attachment was chosen as we found it less disturbing than wrist or ankle attachment. Previous studies have also demonstrated that a minimum of 7 nights was necessary to obtain reliable data^{36 (link)}. The actigraphs were removed from the toddlers only for bathing—the average time of which was 29.7 ± 14.2 min.
Motility levels were sampled in the zero-crossing mode in 1-min epochs. The resolution of the Actigraphs was set at 0.01 G/s. The activity data recorded by the Actigraphs was later downloaded using ActMe software (ver. 3.10.0.3, Ambulatory Monitoring Inc.), and then sleep measurements were analyzed with Sadeh’s algorithm^{37 (link),38 (link)}, using Action-W software (ver. 2.4.20, Ambulatory Monitoring Inc.).

For activity and sleep measurement we used actigraphy. Actigraphy is based on a miniature wristwatch-like accelerometer which is attached to the wrist, ankle or waist and continuously records movement for an extended period. The actigraphy device used in the present study was the Actigraph (Micro-mini RC, Ambulatory Monitoring Inc., NY, USA). The parents were asked to attach the Actigraphs to their child’s waist with an adjustable elastic belt for 7 consecutive days. Waist attachment was chosen as we found it less disturbing than wrist or ankle attachment and actigraphic data has been reported to be reliable at various attachment locations, including the wrist, ankles, and waist. Previous studies have also demonstrated that a minimum of 7 nights was necessary to obtain reliable data15 (link).
Motility levels were sampled in the zero-crossing mode in 1-min epochs. The resolution of the Actigraph was set at 0.01 G/s. The activity data recorded by the Actigraph was later downloaded using ActMe software (ver. 3.10.0.3,Ambulatory Monitoring Inc.), and then sleep measurements were analyzed using Action-W software (ver. 2.4.20, Ambulatory Monitoring Inc.). During the study, time intervals when the device was removed, for example, during bathing, were recorded in a sleep diary by parents.

For activity and sleep assessment we used actigraphy and sleep diaries, as previously described^{1 (link)}. Briefly, the parents were instructed to attach Actigraphs (Micro-mini RC, Ambulatory Monitoring Inc., NY, USA) to their child’s waist with an adjustable elastic belt for 7 consecutive days^{1 (link)}. The activity data recorded by the Actigraph were later downloaded using ActMe software (ver. 3.10.0.3, Ambulatory Monitoring Inc., NY, USA), and then sleep measurements were analyzed using Action-W software (ver. 2.4.20, Ambulatory Monitoring Inc., NY, USA). Time intervals during the study when the Actigraph was removed, for example, during bathing, were recorded by parents in a sleep diary^{1 (link)}. The sleep diary was composed of seven 24-h single-sheet schedules, on which parents were asked to record details such as time of nap, going in/out of bed, bathing and night wakings of which they were aware. Sleep diary data were used to define the scoring interval for actigraphic sleep measurement, according to the procedure outlined by Acebo and colleagues^{4 (link)}.