Behavioral sleep stage classification methods need further development

To properly compare and reproduce sleep behavioral sleep studies in preterm infants, new behavioral sleep stage classification methods (BSSCs) must be developed, or the current methods must receive further validation studies, according to a recent review.

BSSCs are used to record sleep stages in preterm infants born with a gestational age of less than 37 weeks. As sleep is essential for infant brain development, these studies hope to more deeply research sleep in infants. Current studies however rely on different criteria, creating less options for comparing the data between different studies.

In a recent review, researchers sought to identify current BSSCs used for preterm infants ranging from 23 to 37 weeks postmenstrual age, along with analyzing the usefulness of these studies and the criteria which they use for different age groups. To do this, they created a 3-step plan, where they would search peer-reviewed scientific literature on BSSCs, trace back the studies, and finally use the reference lists in the BSSCs to find additional studies which introduced BSSCs.

Studies were divided into 3 categories: ones which introduced a new BSSC, ones which used an existing BSSC, and other literature on BSSCs. These studies were then analyzed on how they divided the stages of sleep, the criteria they used to identify each stage, and how valid and reliable they were when used in preterm infants.

Active sleep (AS) was classified in preterm infants and was shown to have characteristics of rapid eye movements (REM). AS was stated to be “considered important for the endogenous stimulation of sensorimotor processing areas of the brain, facilitating activity-dependent development.”

A total of 36 BSSCs were identified, withbody movements, eyes, respiratory pattern, facial movements, and sounds being the most common criteria that they used. The behavioral stages of these criteria differed in a state of sleep compared to a state of wakefulness.

Less than half of the BSSCS were given consistent reporting of age ranges, validity, or reliability. Also, the BSSCs identified were used on infants of all ages, even those which the BSSCs were not developed for.

Reference:

Bik A, Sam C, De Groot ER, Visser SSM, Wang X, Tataranno ML. A scoping review of behavioral sleep stage classification methods for preterm infants. Sleep Medicine. 2022 (90); 74-82. doi:10.1016/j.sleep.2022.01.006