Sensomotor development, the first six years.

By Sander Kales, D.O.-MRO, M.Sc.

1. Growth Movements precedes Motor Development.
There are two new important insights in Sensomotor development.

The first is that development also has an Outside In direction and not just Inside-Out i.e. from Central Nervous System (CNS) towards the outside world. For us Osteopaths this implies that the Foetal surroundings are very important for later development. So for the pregnant mom, her well being, motor and sensory behaviour is of the utmost importance for the development of the child.
Within Morphodynamics the principles of Neoteny and Parcellation sculpt the development of tissue. These principles also govern the Sensor motor development: the environment sculpts the patterns, first of growth and later of movement.

The second insight is when development is always in relation to its environment, the timing of development in relation to its surroundings is important. This is why motor development coincides with hormonal development or sensory development, but also with the development of other organs. So the timeline of development of the sensory motor system but also of its surroundings is important. Here lies for us Osteopaths a new line of research. Van den Heede has already pointed out the importance of the timeline in development between Liver - Heart - Brain.

1.a. Growth and parcellation.
To understand the first insight on Outside In development, we have to begin with how do motor patterns develop. It is now possible to prove that all patterns of behaviour have embryonic developmental processes as their precursors. What we call instincts are the direct consequences of prenatal developmental events, which are really the prenatal performances of the embryo (Blechschmidt). This growth movement is the intrinsic force of life (see 1).
On the other hand we have the parcellating effect of the environment, In this case the Uterus and the Mother (see 2).

1.a.1. Growth as an intrinsic force and precursor to motor behaviour.

In fetal development, the cephalocaudal growth pattern determines the overall proportions of the head, torso, and limbs, while the limbs’ internal proportions are characterized primarily by the opposite, distoproximal pattern. Thus we see that two opposing growth tendencies are active in the developing human body. Growth ceases earlier in the legs than in the arms and later still in the torso, as many researchers confirm. (Verhulst)
This cephalocaudal growth can also be seen in the development of the Reflexes.

1.a.2. Embryonic growth directions.
Embryonic tissue development follows the information transmitted by the oscillation (Korpiun):
The first phase of an inward, centripetal motion, or inward oscillation, occurs when egg and sperm cells come together in the first week of the ovum’s development. The ovum does not grow in size as a morula and blastocyst, instead dividing itself inward in a downswing phase.
The first phase of an outward, centrifugal motion, or outward oscillation, occurs during implantation into the uterine wall and formation of the embryonic disk’s trilaminar form, with the ectoderm, mesoderm, and endoderm; this is an upswing phase.
The second phase of an inward, centripetal motion, or inward oscillation, occurs at the beginning of the third week. This is the phase in which the heart and the head find their place through inward curling, The lower end folds inward to form the umbilical cord, a downswing phase.
The second phase of an outward motion begins centrifugally in the seventh week, with the body moving from the embryonic phase to the fetal period. The extremities begin to sprout from the body, and all main organs of the body are present in the embryo. This continues in gradual motions until birth, an upswing phase. This process is the reversal of process 1 and concludes development from conception to entry into the physical world on earth.

Besides the Outward and Inward directions of growth, there is also a left right development (as well as front to back).

Also what appears to be a symmetrical growth of the cerebral hemispheres is really an oscillating process between the right and left sides of the head. This alternating and reciprocal growth process ushers in the subsequent reciprocal transmission of nerve impulses from one hemisphere to the other.
As an example, we recall the analysis of the child’s suckling reflex let us remind ourselves that if the lips of the young embryo had never rolled in as part of an early growth movement, then the newborn child would never be able to suckle instinctively.
Indeed, preceding growth movements are found for all so-called instinctive reflexes. (Blechschmidt)

1.b. Evironmental factors in Motor development.
The most important elements of the intrauterine environment consist of the wall of the uterus, the extra-embryonic membranes (amnion and chorion) that envelop the fetus, and amniotic fluid. The myometrium of the uterus is composed of smooth muscle that provides an elastic restraint around the fetus that can suppress some aspects of motor activity while facilitating other forms of coordinated movement.
The environment contributes to the regulation of behavior in two principal ways:
it is a source of sensory stimuli, some of which can elicit specific behavioral responses
it provides a physical context in which behavior occurs."
The view emerging from this and related studies of other patterns of fetal behavior is that organized patterns of behavior are assembled from simple precursors, and that the rules governing this assembly may be quite different than the basic developmental processes that give rise to the elements themselves." (Smotherman, 1996)

Concluding (Verhulst):
The growth of the body is an extremely complicated phenomenon:
The growth patterns of different parts of the body are interdependent.
External circumstances play a role; human beings, for instance, grow faster in summer than in winter. Widen our view to not just the motor behaviour of the foetus/ child, but also what does the environment (mother, etc.) do at different points in time.

Next we will look at the development of movement patterns that follow the growth movements.

2. General movements, the interlude between growth movements and reflexes.

Prechtl, 1982
(1) Just discernible movements
Startle
General movements
This category is applicable if the whole body is moved but no distinctive patterning or sequencing of the body parts can be recognized. When they first appear at 8 and 9 weeks, they are slow and of limited amplitude. At 10-12 weeks general movements become forceful. Movements of the limbs, trunk and head are rapid but smooth in appearance. The movements are of large amplitude and therefore frequently cause a shift in fetal position during this age period. After 12 weeks general movements become more variable in speed and amplitude. They may last from about 1 to 4 min hut wax and wane during this period. However variable these movements are, they are always graceful in character.

After the General Movements, the next steps are more isolated movements of different body parts, which also take place in a Cephalocaudal direction.

(4) Hiccup
(5) Breathing
(6/7) Isolated arm or leg movement
(8) Isolated retroflexion of the head
(9) Isolated rotation of the head
(10) Isolated anteflexion of the head
(11) Jaw movements
(12) Sucking and swallowing
(13) Hand-face-contact
(14) Stretch
(15) Yawn
(16) Rotation of the fetus

Fetal motility in its various components develops early a temporal patterning. The distribution and duration of general movements, for example, changes with age. At 8 weeks, these movements are scattered irregularly over the record, whereas they occur grouped in bursts of several minutes during the following weeks. The occurrence of such bursts becomes obscured after 14 weeks and is replaced by much longer epochs of fluctuating activity.
After Growth and later General movements come the reflexes which develop from Intruterine, towards Primitive than Transitional and concluding with Postural reflexes.

3. Reflex development

3.a. Davies.
Inhibition of over activity is one of the most important functions of the Central Nervous System. Therefore there are a large number of inhibiting tracts in comparison to excitating, both in Brain Stem and Spinal Cord.
The ability to selectively activate normal musculature is a function of motor control on a cortical level, on instigation of proprioceptieve feedback.
Children are born with a great deal of anarchy and overactivity in their motor control. As they get older, this disappears.
Reflex patterns are the foundation of movement. By repeating these reflex patterns during childhood, the child learns how to move. Movement only becomes purposeful when the child is able to excite the right movement patterns and at the same time the unwanted components in these reflex patterns are being inhibited.
At birth the body is unhibitaly controled by the lower centra of the CNS, which mostly generate unvoluntary reflex movements and postures.

3.b. Feldenkrais
The unconditioned reflexes are innate and characteristic of a whole class of animals; they are transmitted by heredity and are independent of the experience of the individual animal. The conditioned reflexes are not inherited and depend on the surrounding conditions of each individual. The unborn unconditioned reflex does not require the presence of the cortex. It is present in the decerebrated animal.

We see, therefore, that a sensory experience of teleceptor origin is, in fact, always a sensory-motor-vegetative disturbance. The righting function is purely reflective. Thus, in the higher animals there is a voluntary element involved in attitude and posture. The higher corticaI centres have overriding control over other centres. Sherrington has pointed out the importance of the fact that most of the righting functions are located in the brain stem, and are therefore outside voluntary control. The optic righting reflexes in the higher animals give the animal greater freedom in movement, corresponding to the greater variety of activity. With the optical centres taking over, the cortex is given control over the lower centres, and the reference posture encountered before becomes less definite.

Reflex development is a Phylontogenetic process in which reflexes are build on each other, starting with brain stem and developing towards cerebellum. If one reflex remains strong, the foundation is laid for weaker development of consequent reflexes. (Goddard Blythe)

4. The timeline of development
Growth in humans occurs chiefly during the first three seven-year periods of life (Verhulst):
The first seven-year period is characterized by rapid growth of the nervous system. Around age seven, the nervous system is 90 percent complete, and the brain (according to some scientists) has already achieved its final size
The second seven-year period is characterized by the greatest development of the lymphatic system. Its organs achieve extraordinary size around age ten, when they are much larger than they are in adults.
The third seven-year period is characterized by the explosive development of the reproductive organs. It remains a mystery why the growth of the larynx also accelerates during puberty, especially in boys, whose vocal cords can double in length within a year, causing their voices to “break.” The growth of the bridge of the nose is also pronounced during this period.

4.1. Development of the senses as pre condition for motor development

Before motor development, the senses have to develop first. When our eyes develop, the ability to grasp can develop, the same goes for hearing and turning of the head towards the sound, etc.

4.2. The timing of development as it coincides with organ and senses development

Mr. Gautier was an endocrinologist who had a slow Thyroid and a slow motor development. He was always convinced that these two were related. He spent his professional life trying to prove the relationship between the two and founded the system Equillos.
He shows that each developmental stage is preceded by a hormonal change.

5. Conclusion.
The implications for us Osteopaths is to better understand developmental problems. To not just look at the development of the nervous system as a separate system, but to see it in the context of intra-uterine life and developmental milestones in other organ systems. In this way the treatment strategy will also be different because it will include the assessment and treatment of other systems.

References:

van den Heede P., The Brain, 2009, course given at Panta Rhei, Zeeland NL
Blechschmidt E., The Ontogenetic basis of Human anatomy, 2004, North Atlantic Books, Berkely, California
Verhulst J., Developmental Dynamics, 2003, Adonis Science Books, Ghent, NY
Korpiun O., Cranio Sacral SELF waves. 2011, North Atlantic Books, Berkely, California
Smotherman W., The development of behaviour before birth, Developmental Psychology, 1996, Vol 32, No 3, 425-434
Prechtl H, The emergence of fetal behaviour, Early Human Development 7, 1982, 301-322
Davies P., Hemiplegie, 1989, Bohn Scheltema Holkema, Antwerpen
Feldenkrais M., Body and Mature Behaviour, 1949, Frog Books, Berkely, California USA
Goddard-Blythe S., What babies and children really need, 2008, Hawthorne press, Gloucestershire UK
Gautier J., www.endocrino-psychologie.org