With a four-month-old of my own, I read the POEM on Getting an Infant to Sleep in the November 1 issue of AFP with more interest than I might have before becoming a parent. Prior studies have not found one sleep strategy to be superior to another. This latest study adds to the mix by finding that graduated extinction and sleep fading are not only effective but are well-tolerated by babies and parents alike.
Graduated extinction involves placing the infant down for bedtime while drowsy but still awake. Parents then wait a progressively increasing amount of time (2 minutes, then 4 minutes, then 6 minutes) before checking on the child. With sleep fading, parents progressively move bedtime later until the child falls asleep within 15 minutes of being laid down. The POEM study compared these two interventions in 6-month-olds with sleep difficulties to a control group and found that the time it took to fall asleep shortened with both methods. Infant and maternal stress also improved with both interventions. After 12 months, parent-child attachments were unaffected, and there was no change in the risk of emotional or behavioral problems.
An AFP article from 2015 includes graduated extinction among other recommended strategies from the American Academy of Sleep Medicine such as unmodified extinction ("cry it out") and scheduled awakenings (awakening babies 15 minutes prior to expected overnight awakenings). "Camping out" has also been shown to be equivalent to graduated extinction. With camping out, parents initially sit close by as the baby falls asleep and then gradually, over several nights, move further away from the crib until they are outside of the baby's room.
Once infants are old enough to consider implementing a sleep strategy (usually around 4-6 months of age), having several to suggest allows family physicians to work with parents to find an agreeable starting point. I especially appreciate being able to reassure families that, whatever they do, most babies will be sleeping through the night by 1 year of age. There's an AFP By Topic on Sleep Disorders in Children if you'd like to read more.