Early intervention approach to facilitate speech development in children with Down syndrome with emphasis on stimulation and correction of cranial nerve function

Down syndrome is a genetic disorder that is caused by trisomy of chromosome 21 in children. The effect of this extra chromosome on the entire body system and especially on the central nervous system (CNS) causes major disorders in these children, the most important of which is undoubtedly the delay in motor and mental development of the child. (7)

One of the most important mental and motor abilities of humans, which is the result of the natural functioning of the cortex, is "language and speech".

The functional unit of the brain is the "synapse" (3), so the CNS function is based on synaptogenesis, the creation of synapses between neurons, and as a result, extensive and complex connections between cortex and subcortex neurons (7). Many parts of the brain produce a large amount of neurons during the first weeks, months, or even about the first 2-3 years of life, and the neurons create numerous branching branches of axon that communicate with other neurons through the creation of synapses.

If the new axons cannot communicate with the next suitable neurons, muscle cells or glandular cells, they will decay within a few weeks, moreover, if sufficient connections are not established, the entire neuron that sent the axon branches will be destroyed, so shortly after the birth of a human baby, the principle governing the number of neurons and their connections in the relevant parts of the brain is that if they are not used, they will be destroyed.

Therefore, 50% or more of the primary neurons will be lost in many areas of the cerebral cortex (3). Therefore, if this axonal and synaptic growth in the baby's brain does not take place well for some reason, as a result, the CNS will suffer a functional decline and learning will not take place in a normal way.

In the investigation of Down syndrome, two basic and important factors that are involved in the growth and development of the brain are:

1-Genetic Code

2-External Stimulation

In children with Down syndrome, disruption in the genetic code leaves 3 major negative effects (8), 9) and (10), which are:

-reduction of dendritic branches

-decreased synapse formation

-Disturbance in myelination

These problems occur throughout the CNS, especially in the cerebellar cortex and brainstem. There are documented evidences of the mentioned effects in the entire level of the brain stem, especially the basal ganglia of the vestibular system (equilibrium and pons) (8, 9, 10, 23, 24, and 25)

Our assumption is that by using timely, accurate and continuous external stimulations on the cranial nerves, with the cognitive perspective and the effect we have on the cerebellum and cortex, we are able to facilitate the process of myelination of axons, branching of dendrites and finally synaptogenesis, which is the main cause of the neuropathology of Down syndrome.

Therefore, our goal in this research is to correct the function of the brain stem and the function of the cerebellum and cortex in the first step through the cranial nerves on the CNS with external stimulations with the above-mentioned characteristics (6) and in this way bring the Down syndrome child to the level of normal children in terms of language and speech development. Of course, it should be noted that in this intervention program, we will also use the pre-lingual and language intervention program indirectly (consultative) in addition to correcting the cranial nerve function.

Considering that the human brain doubles in the first 6 months of life and reaches 3 to 4 times the size of birth by the age of 3 (7) Therefore, the human brain has the highest flexibility ability in the first years of life, and this confirms the importance of exposing young children to wide and numerous learning experiences, and in this case, the child has the best possible basis for further education in (3) On this basis and according to extensive studies that have shown the importance of early intervention 4 and 11 to 22, we are of the opinion that as soon as a child's genetic disorder is diagnosed, treatment intervention should be started and delay in this field even for one day can cause the child's lack of growth and optimal brain development.

Therefore, it is recommended to start direct therapeutic intervention on Down children under 6 months.

Author:

Dr. Majid Oriyadi Zanjani, supervisor Dr. Hossein Karimi

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