.......Tomatis Topics

W hat is Sensory Integration? Sensory integration is the ability to receive information from the senses, combine it with prior information, memories, and knowledge, and use that interpreted information to respond appropriately. In the lingo of Occupational Therapy we refer to responding appropriately as an 'adaptive response'. Through the process of normal interactions with the environment the individual's brain constantly receive sensory input from the body; the ears constantly hear external and internal sounds, the skin receives constant sensory messages from the air and clothes, gravity a constant force that the individual must always orient to, and the eyes (while open) continually adapt to what is in their line of vision. These sensory messages are, in essence, 'food for the brain:' the brain needs sensory input in order to function and thrive.

First Level: Sensory Registration and Regulation:

The first level of sensory integration is the ability to take in the sensory information and adjust to it. We refer to this as sensory registration and self-regulation. Initially a baby reacts to sensory stimulation in a total and often defensive manner. For example, a baby's whole body will startle to a loud sound or withdraw from an unexpected touch. This is the early 'fight or flight' response that needs to be modified in order to respond 'adaptively'. The baby learns to discriminate whether the stimuli imposes a danger, or rather is something to be attended to and enjoyed. As the baby's brain matures and he is more accurately able to register and regulate his responses he enters a state of calm alertness, from which he can learn from his environment.

Sensory Registration: Reactivity (Thresholds):

A child's ability to register and regulate his response to sensory input can be either over-reactive (what we refer to as having low thresholds for sensory input, as described in the last paragraph), or under-reactive, (the child with high thresholds, who poorly registers sensory input). This might be the child who you have to call five times before getting his attention. More often we see a mixed profile; the child, for example, who seems oblivious to pain yet is bothered by every little noise. It can sometimes be confusing, for example a child that has such over-reactivity (low thresholds) to either touch or sound that they become overwhelmed, shutting down and consequently presenting as a child who is not reacting or registering the sensory input. This is important for the therapist to distinguish, because when therapy starts to 'open up' the sensory systems of such children, they can appear as if they have swung to the other extreme. An example of this is a child with such extreme auditory sensitivities that he shuts down and therefore his auditory system is not available to discriminate and learn language. During treatment it is observed that, though the child is now starting to discriminate sounds and develop language, he also at the same time is demonstrating sound sensitivity. The truth is he was always sensitive to sound; he had just closed off this system in order to protect himself. The treatment didn't cause the sound sensitivities, but rather uncovered them as we 'opened up' the auditory sufficiently for this child to attend to speech sounds. We can now treat the sound sensitivity that caused him to shut down in the first place. There are many variations of how the different sensory thresholds interact, and it takes careful study to determine the patterns that exist in each child.

Testing

S ensory Regulation: Registration and regulation operate on a scale with low thresholds and high thresholds on either end, and with self-regulation the homeostatic midpoint. It is in the balance between over-reactivity (low thresholds) and under-reactivity (high thresholds) that we are well regulated. In order for a baby, child, or for that matter anyone to be optimally available for learning, they should be in this 'quiet alert' state of regulation. If one is over reactive to touch for example and is focused on the tightness of his belt or the seams in his socks, his sensory system is not available to discriminate what the teacher is saying. Or a child may be unavailable for learning because he is so under-reactive to sound that he drifts off unless the conversation is highly animated. This lack of balance between low and high thresholds can be observed in a number of conditions from Autism, PDD, ADD, and auditory processing disorders. By contrast, just think of the well-rested baby who awakes for his nap ready to take in the world. This is the starting point of all leaning and it requires the registration and regulation of sensory input.

Sensory Integration

After children are able to register and regulate their responses to sensory stimuli they must put these separate pieces of information into a meaningful whole. This is what is referred to, as 'Sensory Integration.' The period from birth to eighteen months is a period of massive sensory integration where babies learn about the physical reality of the world through their senses. From their sensorimotor experiences they develop perceptual constructs of the world. The reality that they form based in large part upon the accuracy of their sensory integration, becomes the platform from which they interact and communicate with their environment. For example, when we eat an orange, we have a total sensory experience. We sense the orange through our eyes, (we see it), ears (the sound of the skin peeling), mouth (the taste), and skin (on our hands and fingers and in our mouth). We also receive information from less conscious sensory systems that tell us the exact position of our hand, how wide we open our mouth, how hard to bite down, how much to move our head to our hand, etc. Sensory integration allows us to put together all the needed sensory information to experience eating an orange. If we have misinformation (poor sensory integration) then we have a faulty picture of the world.

How Does Sensory Integration Relate to My Child?

In a well-functioning brain, messages from the central nervous system reach their optimal destination in the brain and are responded to. However, in some individuals, sensory messages are misinterpreted, intensified, or omitted, which, in turn, does not allow the brain to respond appropriately. A. Jean Ayres, Occupational Therapist and creator of Sensory Integration Theory, asserts that the primary building blocks of the central nervous system are the senses, particularly the special senses - vestibular, tactile, and proprioceptive. All other skills are complex processes based on a strong foundation of sensory integration. In Ayres book, Sensory Integration and the Child, she likens sensory integration disorder to a large city in which traffic consists of neural impulses. 'Good sensory processing enables all the impulses to flow easily and reach their destination quickly. Sensory integration dysfunction is a sort of 'traffic jam' in the brain. Some bits of sensory information get 'tied up in traffic,' and certain parts of the brain do not get the sensory information they need to do their jobs.' (Ayres, Sensory Integration and the Child, page 51)

Participation

H ow the Senses Interact: Special Senses Part I

First Level of Sensory Integration The Special Sensory Receptors In sensory integration theory we consider senses that are normally below the level of our awareness. We think of classic senses yet there are many more which are just as essential to or possibly more essential to our survival. These include the vestibular sense, tactile sensation, proprioception, and kinesthetic sensation.

Vestibular System: Really the vestibular/cochlea system!

The vestibular system detects motion, gravity and provides us with our sense of balance. The system develops early in utero and through its many connections with the rest of the brain, it is believed to provide the foundation for many other functions. When the influences of vestibular stimuli fail to reach their natural destinations, they cannot adequately contribute to sensory integration. Hypersensitivity to movement and fear of movement are both indicators of a vestibular disorder. Children who excessively crave movement and appear never to get dizzy also may have disorders of the vestibular system.

Benefits

T he vestibular system enables individuals to develop an understanding of self. We need a 'self' and a 'non-self' in order to interact and understand the world around us. The ear, then, refers to the body schema and sense of self provided by the vestibular system in order to determine the meaning of the sounds it hears. Similarly, the eyes refer to vestibular information to make sense of what they see. For example, when a person walks down the street, the eyes do not know if the street is moving or the person is moving until they check in with the vestibular system.

Both Dr. Alfred A. Tomatis and Dr. A. Jean Ayres emphasized the importance of the vestibular system in the inter-relatedness of the senses. The vestibular system is part of the inner ear and its job is to detect motion and gravity, and provides us with our sense of balance. It tells us where we are in space. The vestibular system is a very old sensory system and was the first sensory system to develop on this planet. We needed to know whether we were up or down before we needed to see, hear, taste, touch or smell. The vestibular system is the first sensory system to develop in the womb, and starts to develop when the fetus is only two weeks old. It is fully formed and starting to function in the womb by 4 and 1/2 months gestation. Because of this early development the vestibular system has many connections with the rest of the brain, which develops around it; consequently it is believed to provide the foundation for many other functions. When the influences of vestibular stimuli fail to reach their natural destinations, they cannot adequately contribute to sensory integration.

One of the functions that is particularly influenced by the vestibular system is a person's muscle tone. Muscle tone is the normal level of muscular tension that exists when the body is at rest yet ready for action. The vestibular system particularly influences the muscle tone that helps us resist the influence of gravity. Gravity is always pulling us to the ground and if muscle tone is decreased, it is more difficult to initiate movement or to maintain muscle tension during movement. The person may appear 'floppy', not sit up straight, or their joints may appear hyper-flexible. All refined movements of the extremities and head are dependent on an adequate base of muscle tone to provide postural support. A lack of sufficient postural support can contribute significantly to difficulties in controlled movement of our limbs and tongue. This results in difficulties in gross, fine and oral motor coordination. Thus, muscle tone can also be influenced by the vestibular system and when the vestibular system in not integrating information adequately it can contribute to hypotonia.

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