Sound asleep: sensory decoupling during sleep depends on an infant’s sensory profile

Why Some Babies Can’t Sleep Through the Noise: The Link Between Sensory Sensitivity and Deep Sleep. The Core Question: Why do some infants wake at the slightest sound while others sleep through a storm? Researchers at the University of East Anglia (UEA) investigated whether a baby’s "sensory profile"—how they react to sights and sounds while awake—predicts how their brain filters out noise during sleep. The Study: Families visited a specialized sleep lab where infants took two naps:. 1. The Quiet Condition: A standard, peaceful sleeping environment., 2. The Noisy Condition: A room where gentle beeps (at the volume of a normal conversation) were played periodically. Using EEG to monitor brainwaves, researchers measured "sensory decoupling"—the brain's ability to disconnect from the outside world to protect deep sleep. Key Findings:. "Shallow" Deep Sleep: Infants with high sensory sensitivity (often seen in those with an increased likelihood of autism) didn't necessarily sleep for less time, but their deep sleep was shallower. The slow brain waves that define restorative sleep were weaker and smaller., The Noise Impact: When exposed to noise, these sensitive infants experienced a significant disruption in their brain's ability to filter out the environment. Their brains remained "too alert" to the sounds around them., Intrinsic Wiring: Surprisingly, even in the quiet room, sensitive infants still had shallower sleep than their less-sensitive peers. This suggests that the difficulty in getting "good" sleep is partly due to the baby's internal biological wiring, not just the environment.