A model of irregular sleep–wake pattern in autistic children aged 4 or older

Autistic children often experience sleep problems, such as large fluctuations in sleep onset time and frequent awakenings at night. Those symptoms change for the better with age. Naps, however, remain after the age of 4 in autistic children. Previously, we proposed piecewise-linear circle maps of irregular sleep–wake patterns in autistic children under the age of 4, but not for autistic children aged 4 or older. In the present study, we repropose piecewise-linear circle maps which reproduce irregular sleep–wake patterns in autistic children both under the age of 4, and age 4 and above. For the purpose of the reproduction, fluctuations in nap onset times were limited, and the time range of the sleep in early evening was adjusted. Those parameters were varied by age of child. As a result, the present circle map reproduced irregular sleep–wake patterns in autistic children not only under the age of 4, but also aged 4 and older. Furthermore, the circle map showed regular sleep–wake patterns in control children.