Related Experiment Video
Updated: Aug 15, 2026
Measuring Neural Mechanisms Underlying Sleep-Dependent Memory Consolidation During Naps in Early Childhood
Published on: October 2, 2019
Actigraphy correctly predicts sleep behavior in infants who are younger than six months, when compared with
Kevin So1, Pat Buckley, T Michael Adamson
1Department of Paediatrics, Monash University, Melbourne, Victoria, Australia.
Insights
Actigraphy is a valid tool for monitoring infant sleep. This study validated actigraphy against polysomnography (PSG), finding high agreement rates in infants under six months old.
Area of Science:
- Pediatrics
- Sleep Medicine
- Biomedical Engineering
Background:
- Actigraphy is commonly used for sleep studies in adults and children.
- Previous infant actigraphy validation often relied on behavioral observation, not polysomnography (PSG).
Purpose of the Study:
- To validate actigraphy against PSG for sleep/wake detection in infants younger than six months.
- To assess the impact of different activity thresholds and postconceptional age on actigraphy accuracy.
Main Methods:
- Twenty-two healthy infants (13 term, 9 preterm) were studied at matched postconceptional ages.
- Actigraphy data were compared with PSG recordings using 1-minute epochs.
- Agreement rate (AR), sensitivity, specificity, and predictive values were calculated and analyzed.
Main Results:
- High overall agreement rates (AR) between actigraphy and PSG were observed: 93.7% at 2-4 weeks and 91.6% at 5-6 months with a low activity threshold.
- The auto activity threshold showed the best agreement (AR 89.3%) at 2-4 months.
- Sensitivity values were consistently high, ranging from 91.2% to 96.2% across age groups.
Conclusions:
- Actigraphy is a valid and reliable method for monitoring sleep and wake states in infants under six months of age.
- Accuracy is not significantly affected by age within this developmental period.
- While predictive values for wakefulness and specificity were lower, overall agreement supports actigraphy's utility.
Abstract:
Actigraphy has been widely used in adults and children. In infants, validation of actigraphy has typically used a comparison with behaviorally determined sleep state classification rather than polysomnography (PSG). This study validated actigraphy against PSG for determining sleep and waking states in infants who were younger than 6 mo. Twenty-two healthy infants, 13 term and 9 preterm, were studied at three different matched postconceptional ages. Actigraph data were compared with PSG recordings in 1-min epochs. Agreement rate (AR), predictive value for sleep, predictive value for wake, sensitivity. and specificity were calculated and compared between activity thresholds and across ages with two-way ANOVA for repeated measures. Thirty-two validation studies were analyzed. Overall AR with PSG of 93.7 +/- 1.3 and 91.6 +/- 1.8 were obtained at 2-4 wk and 5-6 mo, respectively, at the low activity threshold setting, whereas the auto activity threshold gave the best agreement with PSG at 2-4 mo (AR 89.3 +/- 1.3%). Sensitivity values of 96.2 +/- 1.1% at 2-4 wk, 91.2 +/- 1.5% at 2-4 mo, and 94.0 +/- 1.9% were obtained at these same settings. There was no difference across ages in AR or sensitivity. PVW and specificity values were low in this study. We conclude that actigraphy is a valid method for monitoring sleep in infants who are younger than 6 mo.
