background, Developmental Delay, learning disability

Postural Reflexes

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What are the Postural Reflexes?

(Adapted from http://www.suehyland.co.uk/ond_postural.html)

Postural Reflexes are automatic movements that control the equilibration we require once upright and moving and having to combat the effects of gravity. They maintain posture, balance and fluidity of movement, replacing the Primitive Reflexes in a sequential manner, as those Primitive Reflexes inhibit. The first to emerge is the head righting reflex on a vertical plane. At birth the baby has no head control, they then develop conscious control to lift their head; lowering the head at that stage is more difficult. Eventually this movement is automated so that the head remains centrally aligned on top of the body with the crown uppermost. Tip a new born upside down and their head will just hang, tip a 12 week old baby and the head will extend backwards so that the crown is uppermost. Over time this ability to maintain head position develops on all planes. Another Postural Reflex is automatic flexion of the knee whenever the hip is rotated; this has obvious importance in walking and balance.

These reflexes are controlled by interplay between the sensory vestibular system; in the inner ear, the cerebellum and motor nerves controlling the muscles, as are the Primitive Reflexes but the area of control is higher up the brain stem within the mid brain. The development of the fibres creating stronger connections upwards is the result of normal neuro-development. Development between the lower and higher regions of the brain stem is never all or nothing; so that the majority of adults have deficits in this area and the reason that most of us, regardless of years of training, would not become top athletes. Children with Neuro-Developmental Delay (NDD) have less development in this area than is normal; the amount varying with the extent of delay and hence difficulty. There is inevitably a relationship between the number and strength of the retained Primitive Reflexes and that of the Postural Reflexes. This is the reason why so many children with learning difficulties have co-ordination and balance problems. Many parents will tell me that their child, though having reading difficulties, is exceptionally well co-ordinated. These are often children with less profound learning difficulty; children who have done a lot of sport and have well developed specific Postural Reflexes; or children who have developed all Postural Reflexes, but the connections are not as strong as they should be. These are the children that when put under pressure cannot maintain physical, emotional or academic competence. They fall to pieces in exams, cannot support physical prowess under slow or extreme circumstances.

The degree of learning difficulty is usually in direct relationship with the ability to automatically control the eyes. Eyes position is maintained by 6 paired muscles, attached to the outside of each eye. To clearly perceive an image the two eyes must be in alignment with the image and with each other. This is achieved by developing a dominant eye, with the other, as slave, lining up in response to its master. If this is not achieved then the image fails to be correctly fused and the individual will see double; for brief periods it is possible to consciously compensate, so that the image will fuse, fragment, fuse and fragment.Readingand copying are very difficult given this situation. The difficulty will be directly related to the degree of alignment error. The eye position in the orbit also needs to change according to whether the eye is looking at something far away, or near to; accommodation of the eye for distance is not entirely within the realms of the internal lens of the eye. Individuals with retained Primitive Reflexes frequently cannot manage this adjustment; with neither eye accommodating, or with only one. The degree of difficulty will depend on the degree and type of error; from poor definition to double image. For effective eye function we must have inhibited the Primitive Reflexes and developed effective Postural Reflex control from strong neural links between the vestibular system and the external muscles of the eye.

The relationship between the Primitive and Postural Reflexes can best be illustrated by the relationship between the foundations and upper structure of a house. If the foundations are weak then the house will begin to slip, the degree of slippage dependent upon the weakness in the foundations and the pressure from above on the structure of the house. This explains why the degree of difficulty experienced becomes greater the greater the pressure. The greater the importance of competence, and the more that competence is being measured, the greater the stress. All sensory input, other than taste and smell, is directed to the higher regions of the brain through the brain stem. The underdeveloped nerve pathways within the brain stem can cope more effectively the less the number of impulses transmitted. This is also why multi-sensory teaching, though very beneficial for the child with learning difficulties, must not be simultaneous; otherwise the child experiences the very real likelihood of sensory overload with the brain closing down because it cannot process or respond to any.