Sensory/Motor Processing

Development And Difficulties

Sensations may be thought of as “food for the brain”, and when they flow in an integrated manner, the brain can use those sensations to form perceptions, behaviours and learning. Without integration, the sensations cannot be ‘digested’ and used. Perception involves collating, interpreting and assigning meaning to sensations by taking into account our expectations, our experiences and our culture. The primary perceptual functions assessed in young children include visual, auditory, and tactile discrimination. Some higher order perceptual skills include visual or auditory figure ground perception, visual-spatial relations, auditory memory, and the ability to perceive the form of an object by using the sense of touch. Sensation is influenced by the task demands and the child’s prior sensory experiences and level of arousal. For example, a light touch perceived as pleasant by one child might be considered threatening or even painful by another.

The human body was designed to move, and it is our early experiences that lay the foundation of what follows. Every movement is a sensory motor event, and movement reinforces our learning capacity – to truly store something mentally, some type of movement activity is required – either speaking out loud, writing or other physical action such as gesticulation. The brain develops from the moment of conception and continues to develop – normally in an ordered set of sequences well after birth.

Constant sensory input and processing are required throughout life as well as in the early stages to maintain active development of neural networks within the brain. Every new motor activity performed generates a burst of neural formation creating new connections within the brain. If these new connections are not reinforced, they are literally reabsorbed by the cell body. The brain will not expend more than it has to, and only puts energy into what it actively uses.

When children are born, they emerge from the womb with primitive reflexes – physical responses that are initiated without conscious thought or intention. These reflexes allow the child to cope with the influx of new sensory information in the new environment after birth. These initial reflex patterns should within the first few years be overtaken and inhibited by voluntary actions – these are referred to as postural reflexes or postural control. Sensory integration may be attributed to uninhibited primitive reflexes.

The retention of primitive reflexes does not always present clearly. One example is the palmar reflex, where the fingers automatically close when the palm is stimulated. A child who has retained the palmar reflex will not demonstrate this precise characteristic at the age of 6, but instead may have poor pencil grip and trouble with fine motor coordination or manual dexterity. Each primitive reflex has its own set of consequences if it hasn’t been fully inhibited by its postural equivalent.

In another example, babies who are not taught to sit up, generally do so when developmentally ready after the ‘creeping and crawling’ stages of normal development. Those who are left on their backs for long periods of time may not learn to crawl and instead, will often become ‘bottom shufflers’, or will pull themselves up to stand and walk, thus missing the important sensory-motor experiences of creeping and crawling. It is during creeping and crawling that lateralisation or the ‘choice’ of the dominant side – left or right, will take place. Excessive use of playpens, bouncers and walkers deny the childfree explorative movement on the floor, and any surface which hinders movement (such as slippery tiled surfaces etc.) can be a hindrance to normal development. Early walking under 10 months and not preceded by crawling and creeping can herald future problems, especially if the child is already hyperactive.

This hindrance is in the form of retained ‘primitive’ reflexes, which should have been inhibited at certain important stages of growth and development. (Often referred to as Developmental Movement Therapy). Therapies that address these issues in a sense, allow the child to relive the experience of sensory development so that the primitive reflexes are revisited and overtaken as they ideally would have been during the child’s infancy.

Finally, the integration of the cerebral cortex, eyes, hearing, the vestibular system and feedback from the core muscles of the body is central to the process of learning as all are important in our ability to maintain attention to the world around us. These activities have intimate connections to critical parts of the brain, particularly the Reticular Activating System, an important mechanism in maintaining our levels of arousal, our ability to maintain attention, to take in and consider information received. If there is disruption along the process lines at any point we may well find that we are not as alert, active, “in sync” or ready for learning as we should be.