Childhood Development

Childhood development starts from conception, and moves through implantation in the womb, through foetal growth, birth and then newborn development. A brief description of the development is outlined below, with comments on potential problems, and signs of abnormal or delayed development.

Fertilisation and implantation

Conceptually speaking from the time that the sperm fertilizes the egg, implantation occurs and growth starts in the womb, the fertilized ovary is exposed to both genetic selection and environmental selection. Thus, ovaries that are formed that contain non-functional gene products are discarded and will not implant. Those that will not grow in the nutrient conditions of the womb also will not develop into a viable embryo. There is, however, the potential for an embryo, created by in vitro fertilization to grow in the well-defined tissue culture medium in which it has been created, but upon implantation into the mother the embryo may not survive, due to the genetics of the embryo not being suited to the different nutritional environment in the womb. Problems in a woman becoming pregnant with the need for in vitro fertilization are potential signs that all is not right either genetically or nutritionally in the womb. Nutritional selection also plays a part not only on the development of the baby, but on which genetic combinations survive. Evidence suggests that there is a significant genetic shift in genetic variants that are selected for in children with autism (see the section on Genetics). Inadequate preconception nutrition is directly related to a woman's fertility and ability to conceive, and many women who have given birth to autistic children report that they had problems in becoming pregnant.

Growth in the womb

During the time of foetal growth in the womb, many additional stresses are placed on the developing foetus, including a drop in nutrients during the time of pregnancy. Whilst it is well known that low folate levels can affect the foetal development, the requirement for nutrients such as iron, vitamin B12, vitamin B2 and biotin, all of which reduce in the mother during pregnancy are less well appreciated. Potential signs of nutritional stress may include frequent mis-carriages, low birth weight babies and premature birth. Notable amongst the nutrients in the womb is the extensive "loading" of the brain with vitamin B12 that occurs in the foetus and up to 17% of the transplacentally acquired vitamin B12 is taken up by the brain. This appears to be the most important time for "brain" loading with vitamin B12, and very little further loading occurs following parturition even during breast feeding. Autistic children are known to have much lower levels of all vitamin B12 analogues in their brain than normal individuals, and insufficient "loading" of the brain in utero, is the most obvious reason for this. Apart from vitamin B12 there are some other factors of note. Melatonin, an important hormone that is now known to regulate sleep and wake cycles, and to induce the survival, development and function of neurons in the brain, and also to affect gut maturation, is produced exclusively by the mother while the baby is in utero. There are melatonin receptors present in the fetal brain, and alterations in the levels of maternal melatonin have been associated with disrupted brain development and long term sequelae. During foetal development, neuromuscular synapses form throughout the foetus, however, these synapses are "immature", and are covered by a loose, unmyelinated sheath produced by the Schwann cells. The majority of myelination happens after birth in humans. Myelination starts in the fourth month of human development and continues until the third and forth decade of life. Myelination is very nutrient dependent relying heavily on iron, vitamin B12 and biotin, as well as on stimulation via vitamin D. Deficiency in any or all of these results in delayed myelination, such as observed in autism.

Birth

At birth the child is still dependent upon the mother for additional nutrient support which must continue until the baby's own organs are able to produce hormones such as melatonin. Thus, the neonate does not have a functioning pineal gland and so must rely upon melatonin from the mother until around 9-12 weeks after birth. If the mother is deficient in functional B12 either during pregnancy or during lactation the child will be deficient in melatonin. This can have serious implications in both brain and gut development in the new-born.

Newborn Development

The development of the child after birth is dependent upon myelination of the nerves (the production of the insulatory sheath on the nerves), and the production of successful synapses between nerves, muscles and various proprioceptors. Myelination is critical for development as myelination speeds up the conduction rate in the nerves and reinforces "important" pathways and as such is critical in learning.

The first 2 months. The child starts to lift and turn its head, whilst lying on its back, however it is not able to support its head when lifted or placed in a sitting position. The hands appear to be fisted, yet the arms are flexible. The child is responsive to touch and the toes will fan outwards if the sole of the foot is stroked and the touched leg may extend. The child may try to step and walk if the body is supported and both feet are placed on a surface. When the child turns its head to the left the left arm extends, while the right arm and leg flex inwards, and vice-versa. The child is alert to voices.

3 to 4 months. The development of the eye-muscle control allows the infant to track objects such as people. The child tries to grasp objects by swiping at them. Can rise up shoulders and head with arms when lying on tummy. The child can now keep its head up. The child starts to "coo". The development of vision is essential for the child in order for their brains to use the visual information in order to understand the world around them and to react/interact appropriately to it. Visual problems are very common in ASD, with conditions such as astigmatism, anisometropia, and strabismus being more common.

5 to 6 months. The child gradually develops the ability to sit alone and is able to roll from back to stomach. When on tummy the child can raise up the head and shoulders and "look around" for objects. The child progresses to making vowel sounds such as "oo" and "ah".

6 to 9 months. The child starts to crawl and is able to walk while holding onto an adult's hand, or the side of the cot. The child is able to sit down from a standing position, and may be able to pull up to stand while holding onto furniture. The child often starts to babble incoherently and blows bubbles, and may laugh, particularly when tickled.

9 to 12 months. The child starts primitive walking, may balance while standing unsupported and may take a few steps alone. The child becomes more vocal, imitating sounds and may say its first words, such as "mama" and "Dada". At this stage the child can respond to simple commands such as "no". A delay in this phase is one of the earliest signs of potential autism.

Sleep disorders. Sleep disorders are relatively rare in children with normal development, however up to 80% of children with ASD may have disorders that progress through early childhood and this can lead to behavioural problems. Melatonin is the main sleep hormone, and production of melatonin requires sufficient methyl B12. Melatonin production in the new-born is delayed by 3 to 4 months, and before this time, melatonin is supplied by the mother's milk. A deficiency of vitamin B12 in the mothers will therefore reduce the availability of melatonin to the neonate. Sleep disorders in children are associated with academic problems, ADHD-type symptoms, memory problems and emotional and behavioural issues.

Myelination of the nervous system. The speed at which a message is sent along nerves is greatly increased by adding a layer of insulation to the outside of the nerves. This layer, the myelin sheath, is progressively added, outwards from the brain, and complete myelination can take up to 18 years. Myelination is noticeably delayed in ASD. Lack or delay in myelination will affect the development of speech, the development of continence and factors such as development of balance, standing, walking, etc. Depending upon the level of myelination and the type of nerve fibre, conduction speeds are increased from around 2 meters per second to 150 meters per second. Delay in myelination, seen in ASD, would result in much lower and slower responses of the child to external stimulus and also to delays in physical co-ordination.

Development of continence. Urination occurs involuntarily in children until the age of 3 to 5 years, and depends upon myelination of the pelvic and hypogastric nerves. A delay in myelination, such as occurs in ASD delays the ability of the child to control urination.

Development of speech.. Development of expressive speech follows myelination of an area in the brain called Broca's region, it appears that such myelination is delayed in ASD.

Development of visual working memory. The ability of a child to understand maths concepts, to solve simple problems, to read body language, and to process non-verbal clues depends upon visual working memory. Children with autism perform less well on measures of immediate memory, working memory, visual working memory and long-term memory, than developmentally normal children.

Development of attention, emotions and executive functions in the child.

Myelination of the prefrontal region of the brain is necessary for the synchronizing communication in areas of the brain associated with attention, emotions, and executive (thinking) functions. Delayed myelination will therefore affect these functions, and give rise to the delays, which are characteristic of ASD.

Development in Autistic children.

Nearly every process outlined above is delayed to a greater or lesser degree in autistic children and creates the "Spectrum" of symptoms associated with ASD and may account for the "deficits in social interaction and communication" and the "repetitive, stereotypical sensory behaviours" associated with the condition.

Deficits in social interaction include:

Poor eye contact
Lack of response to name
Lack of pointing
Reduced gestures
Lack of imitation
Pretend play
Shared attention

Stereotypical behaviours include:

Spinning
Lining up
Hand flapping
Walking on tip toes
Stiff walking (propping)

Assessment tools for childhood development.

There are many different modes of assessing development of children. Two forms can be found on this site.

1. Visual symptoms associated with ASD

2. Visual assessment for ASD

There is also a down-loadable App for assessment at Early Autism Detection

Helping childhood development.

There are many Institutions that have been established to help children with learning difficulties and improving social behaviour, etc. As we become aware of them or hear good reports about them, we will add them to the site.

References/ Useful links.

Skills

Skills Development Programme www.skillsforautism.com

Media

Autism Media Channel www.autismmediachannel.com

Behaviour

Centre for Autism and Related Disorders www.centerforautism.com

Vision

American Optometric Association https://www.aoa.org/patients-and-public/good-vision-throughout-life/childrens-vision/infant-vision-birth-to-24-months-of-age

Check list for development

https://cdn.ymaws.com/www.covd.org/resource/resmgr/ovd40-3/article_understandingvisuals.pdf

Help with Development

https://www.brainbalancecenters.com/