Problems in the Development of the Sleep-Wake Rhythm Influence Neurodevelopmental Disorders in Children

Abstract

Development of the sleep-wake rhythm has a significant effect on the physical and mental development of children. The sleep-wake rhythm is controlled by aminergic neurons in the brainstem's ascending reticular activating system, which is associated with synaptogenesis and the promotion of brain development. The sleep-wake rhythm develops rapidly within the first year after birth. At 3-4 months of age, the framework of the circadian rhythm is established. The objective of the present review is to assess a hypothesis concerning problems in the development of the sleep-wake rhythm and their effect on neurodevelopmental disorders. Autism spectrum disorder is characterised by a delay in the development of sleep rhythms at 3-4 months of age and also insomnia and night-time awakenings, as supported by several reports. Melatonin may shorten the sleep latency in ASD. Rett syndrome sufferers kept awake during the daytime were analysed by the Sleep-wake Rhythm Investigation Support System (SWRISS) (IAC, Inc., (Tokyo, Japan)), and the cause was found to be the dysfunction of aminergic neurons. Children and adolescents with attention deficit hyperactivity disorder show sleep problems such as resistance to bedtime, difficulty falling asleep, sleep apnoea, and restless legs syndrome. Sleep deprivation syndrome in schoolchildren is deeply influenced by Internet use, games, and smartphones, and this syndrome affects emotion, learning, concentration, and executive functioning. Sleep disorders in adults are strongly considered to affect not only the physiological/autonomic nervous system but also neurocognitive/psychiatric symptoms. Even adults cannot avoid serious problems, much less children, and the impact of sleep problems is considerably greater in adults. Paediatricians and nurses should be aware of the significance, from birth, of sleep development and sleep hygiene education for carers and parents. This research was reviewed and approved by the ethical committee of the Segawa Memorial Neurological Clinic for Children (No. SMNCC23-02).

Keywords: 3–4 months of age; autism spectrum disorder; circadian rhythm; development of sleep–wake rhythm; sleep deprivation syndrome.

Figure 1

The development of sleep rhythms in a normal boy from the time of birth recorded by his mother with a day-by-day plot. Development of sleep (bold) and psychomotor development details are shown on the right. Circadian rhythms begin to distinguish between day and night by 3–4 months of age; head sitting and smiling to others become possible in normal development. Between 6–12 months of age, amplitude of sleep varies to decrease napping and night wakening. Psychomotor developments also vary. Around 12–18 months, the biphasic sleep–wake rhythm is largely established [8].

Figure 2

The accuracy and weight of each rating of sleep rhythm ((1), (2), and (3)) before the age of one year in predicting the subsequent diagnosis of ASD were examined. The statistical analysis on prediction used quantification theory II. Using quantification theory II to analyse the prediction equation with each rating of sleep rhythm ((1), (2), and (3)) up to age one as independent variables and the presence or absence of an ASD diagnosis as the dependent variable, not only the discriminant accuracy, but also the degree to which the judgment of each rating contributes to the prediction of diagnosis was determined. The higher the category score, the greater the contribution of each rating to prediction. These analyses were conducted using R (3.3.0). The discrimination accuracy of ASD diagnosis using category scores for each factor was 76.9%, and the contribution of each factor revealed that (3) “rhythm of sleep at age 1” had a significant impact on prediction. See Ref. [21].

Figure 3

Sleep disorders in ASD. (a) He could not sleep easily and showed an irregular sleep rhythm. He kept awake in the middle of the night frequently. (b) She had severe ASD clinical features and suffered from a severe sleep disorder with free-running rhythm for one month. Her sleep rate was low in the middle of the night and high during the day. Her amplitude of the sleep–wake cycle was low. (c) She kept awake during midnight every night, even if she could sleep at a regular time. Her sleep rate at 2–3 am was decreased.

Figure 4

Day sleep in Rett syndrome. (a) Case 16y0m F and (b) Case 6y0m F.

Figure 5

A 9-month-old boy improved not only his sleep rhythm, but his mood swings and developmental delays after two weeks of sleep hygiene education.