Another set of sleep disorders are behavioural. They are more common than obstructive sleep apnoea, but generally milder. They include sleep onset association disorders, which occur when the baby or toddler becomes overly reliant on certain actions or objects, like a pacifier, to fall asleep. These affect 25 to 50 per cent of babies aged six to 12 months and 15 to 20 per cent of toddlers. About 10 to 30 per cent of preschoolers develop limit-setting sleep disorder and delay bedtime.
Parents are taught to train their children to sleep without help and to enforce a fixed bedtime. Preschoolers may also develop night-time fears, such as of loud noises or being alone, but usually outgrow these. In the meantime, parents should reassure them and teach them coping skills, say, by using a night light. Almost a third of Dr Tang’s patients have behavioural sleep problems, up from less than 10 per cent a year ago. Parents are now more aware that these are treatable problems, rather than behavior that they have to wait for the child to outgrow, she said. But the incidence of behavioural sleep disorders may also be rising, as children put off sleep to spend more time on computers and mobile phones, suggested Dr Teoh.