Department of Brain Science and Engineering, Graduate school of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu-ku, Kitakyushu, 808-0196, Japan.
Cogn Neurodyn. 2008 Sep;2(3):221-8. doi: 10.1007/s11571-008-9051-3. Epub 2008 May 28.
The two-process model is a scheme for the timing of sleep that consists of homeostatic (Process S) and circadian (Process C) variables. The two-process model exhibits abnormal sleep patterns such as internal desynchronization or sleep fragmentation. Early infants with autism often experience sleep difficulties. Large day-by-day changes are found in the sleep onset and waking times in autistic children. Frequent night waking is a prominent property of their sleep. Further, the sleep duration of autistic children is often fragmented. These sleep patterns in infants with autism are not fully understood yet. In the present study, the sleep patterns in autistic children were reproduced by a modified two-process model using nonlinear analysis. A nap term was introduced into the original two-process model to reproduce the sleep patterns in early infants. The nap term and the time course of Process S are mentioned in the present study. Those parameters led to bifurcation of the sleep-wake cycle in the modified two-process model. In a certain range of these parameter sets, a small external noise was amplified, and an irregular sleep-wake cycle appeared. The short duration of sleep led to another irregular sleep onset or waking. Consequently, an irregular sleep-wake cycle appeared in early infantile autism.
双过程模型是睡眠定时的一种方案，由内稳态（过程 S）和昼夜节律（过程 C）变量组成。双过程模型表现出异常的睡眠模式，如内部失同步或睡眠碎片化。自闭症早期婴儿经常经历睡眠困难。自闭症儿童的入睡和醒来时间每天都有很大的变化。频繁的夜间醒来是他们睡眠的一个突出特征。此外，自闭症儿童的睡眠持续时间通常是碎片化的。这些自闭症婴儿的睡眠模式尚未完全理解。在本研究中，使用非线性分析，通过修改的双过程模型再现了自闭症儿童的睡眠模式。在原始的双过程模型中引入了小睡项，以再现早期婴儿的睡眠模式。本研究提到了小睡项和过程 S 的时间过程。这些参数导致了修改后的双过程模型中睡眠-觉醒周期的分岔。在这些参数集的某个范围内，小的外部噪声被放大，出现不规则的睡眠-觉醒周期。睡眠时间短导致另一个不规则的入睡或醒来。因此，在婴儿期自闭症中出现了不规则的睡眠-觉醒周期。
