Sleep problems and their implications from preschool to school age

Sleep plays a significant role in human functioning and wellbeing. It is of particular importance for young children, whose brains undergo significant developmental changes. This dissertation focuses on sleep problems among preschool-age children, the persistence of these problems until school age, and how they relate in establishing a behaviour and emotional wellbeing at school age. The importance of sleep quality to neural basis of sensory information processing and attention regulation among school age children was also assessed. According to the results of a population-based survey, sleep problems are very common in preschool-age children. Parents of almost half of the children surveyed reported frequent sleep problems most typically resistance to going to bed and difficulties falling asleep, followed by snoring, bruxism and sleep talking. Frequent bedtime resistance and difficulties falling asleep were also reported in a follow-up study of school-age children, as well as difficulty getting out of bed in the morning and early morning fatigue. Overall, the frequency of sleep difficulties decreased at school age. However, more than a third of the preschool-age children with sleep difficulties continued to have such problems at school age, when they were at the highest risk of experiencing comorbid emotional and behavioural problems. On the other hand, only a few children developed sleep problems at school age. Sleep quality among school-age children, measured objectively by means of actigraphy was associated with eventrelated brain potentials reflecting auditory information processing and attention regulation. Children with lower sleep quality had enhanced N2 and mismatch negativity responses, presumably reflecting hypersensitive reactivity to sounds, compared with children who sleep well. Sleep problems, therefore, appear to be a major challenge for the wellbeing of children at preschool and school-age. It appears from the results of this study that such problems are more common in younger age group, and that few children develop them later on. Therefore, preschool-age children and their families should be a major target group in identifying and treating sleep problems. It is essential to attend to such problems at preschool-age so as to prevent them from persisting over the longer term and adversely affecting the development of brain functions and behavioural and socioemotional regulation.