A combination of sensory stimuli can help soothe crying babies, study reveals

A frequently crying infant can have a major impact on both the infant itself and its parents. Parents of excessively crying infants are often exhausted and experience symptoms of depression. Excessive crying is even associated with infant hospitalization and shaken baby syndrome. There are, however, no proven effective prompt soothing methods for excessively crying infants under the age of 6 months. Child development experts Eline Möller, Wieke de Vente and Roos Rodenburg from SEIN and the UvA wanted to change this. They therefore investigated whether the combination of swaddling (wrapping the baby in a swaddle sack), sound (shushing) and movement (swinging) induce a spontaneous calming response when parents soothe their baby or when a 'smart crib' soothes the baby. They also examined whether the age of the baby influences the calming response. To do so, Möller, De Vente and Rodenburg looked at 69 babies aged 0 to 6 months. Each baby and one of its parents came to the UvA Family Lab. The researchers did a so-called counterbalanced experiment that consisted of two conditions: the parent and the smart crib. Each of the two conditions involved three two-minute phases: baseline (to be able to determine the baseline value), laying on the back, and soothing. Möller explains: 'During the baseline the baby sat on the parent's lap. We then induced fussiness by putting the baby on the back, followed by parental soothing - the parent shushed and rocked the swaddled baby. We went through the same phases with the smart crib as a comforter. The smart crib also swings the baby and also makes a shushing sound.' The researchers recorded the level of fussiness in the babies through observation; the baby's heart rate and heart rate variability were also measured to record physiological fussiness. If, while soothing the baby, the observed fussiness and heart rate decrease and the heart rate variability increases (compared to lying on the back), the infant reacts with a calming response.