Establishing average values for actigraphy or normal ones?

In “Establishing normal values for pediatric nighttime sleep measured by actigraphy: a systematic review and meta-analysis,” Galland et al. compiled evidence on sleep norms from 87 articles which used actigraphy in youth aged 0 to 18 [1]. The authors suggest that the resulting average actigraphic sleep duration could serve as normative data [1]. Although this effort has enormous value given the dearth of data on sleep duration in children and adolescents and the authors acknowledge that their findings are not “sufficient to guide sleep recommendations,” the implications of their results must be considered with caution. The terms normative and normal can have two distinct meanings. Normal or normative can be descriptive, i.e. characterizing reality, or prescriptive, i.e. informing behavioral objectives or treatment needs. The American Academy of Pediatrics (AAP) recently provided an instructive example of how this distinction can affect clinical practice. The AAP lowered the normal (i.e. prescriptive) blood pressure values in children and adolescents after excluding obese youth from the reference sample [2]. Similarly, guidelines for desirable BMI have not been adjusted upwards despite widespread evidence of increasing population BMI. As sleep scientists and clinicians, we are all aware that sleep cannot be assessed in a vacuum. Optimal sleep durations need to address the issues of functioning, mental health, and, ideally for youth, of development. The American Academy of Sleep Medicine (AASM) released consensus recommendations for pediatric sleep 2 years ago [3]. Galland et al. found significantly shorter sleep durations than those suggested by AASM.