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, proprioception, tactile sensation, 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.
Muscle tone can also influenced by the vestibular system and when the vestibular system in not integrating information adequately it can contribute to hypotonia. Muscle tone is necessary for good proximal stability, and a lack of sufficient postural support can contribute significantly to difficulties in fine/gross and oral motor coordination.
The vestibular system also supports the development of bilateral coordination which is the ability of the body to use both sides in a coordinated manner, the development of laterality, and the specialization of each side of the body.
The vestibular system is anatomically joined with the cochlear system, and it has many close neuronal associations with the pathways for auditory processing and language.
Decreased vestibular processing can impact on the area of speech and language development.
Tactile Perception:
Tactile perception refers to touch. We have two sensory system for touch perception,
the protective system and the
discriminative system.
The protective system: responds to light or unexpected touch. It alert us to any stimuli that might be harmful. This is a survival system. It's the system that pulls our hand away from a hot stove.
The second system is our discriminative system. It is the system that enables us to gain information about our environment through our skin. It helps us feel the difference between hard and soft, smooth and rough.
These system have to be in balance, working together. If we are in too much of a protective mode, then we are unable to discriminate properly.
In infancy the protective system is primary yet as the baby moves around giving simulation to his/her own skin the protective system starts to become inhibited allowing the discriminative system to emerge.
Information from of skin regarding touch, pressure, pain, and temperature is very important for the formation of body schema. The tactile system starts to mylinate early, right after the vestibular/cochlear system and it is the only system that is fully mylinated at birth. Good tactile perception is important in the development of accurate neuronal body models.
Tactile defensiveness can interrupt the contribution of accurate tactile perception that is necessary for good motor planning.
Tactile sensitivity or tactile defensiveness is seen commonly in children with sensory integration disorders. In tactile defensiveness it is believed that the tactile system is unable to shift from its protective role to its more discriminative role. It remains in a hyper vigilant state and is not able to adequately discriminate.
Correlation's between hyperactive behavior and tactile defensiveness has been found. It is believed that the tactile system is primal in activating the reticular activating system which provides the foundation for attention.
Children with tactile defensiveness often are also hypersensitive to sound, have difficulty foreground from background noise, and are also easily visually distracted.
Proprioceptors
Our proprioceptors give us information about the position of our body parts. These receptors are located in our muscles, tendon, ligaments and joints. Our vestibular system is actually a specialised proprioceptor. We don't have to look at our arms and legs to know where they are and exactly what position they are in.
Next level of organization and Integration of Sensory Input
Body Perception or Body Scheme: Body Percept is like an internal map or blue print of our body. It is at a higher level of sensory integration because the brain needs to integrate tactile, vestibular,visual, auditory, and propriocetive messages to form an internal perception that tells us exactly the position of each body part in relation to the other parts, as well as each body pars potential for movement.
Gravitational Security. This is our feeling of security when we are moving our body in space and in changing our relationship to gravity. It is essential to have good security in our body's relationship to gravity to release ourselves from being earth bound.
Awareness and coordination of the two sides of the Body We must be able to use the two side of our body in a smooth effective, efficient manner. The development of laterality is dependent upon this.
Motor Planning: Praxis.
Motor planning or praxis is the ability of the brain to conceive, organize, and carry out a sequence of unfamiliar actions.
In dyspraxic syndrome there is a reduced ability to carry out non-learned movements, even though there is adequate motor and conceptual capacity to do so.
Difficulty with imitative behavior is a key indicator of dyspraxia necessitating that children organize themselves cognitively, rather than perform tasks automatically. This often becomes a source of frustration for them.
Praxis is believed to be a single function involving three basic processes: ideation or generating an idea of how one might interact with the environment; motor planning or organizing a program of action; and execution or the actual performance of a motor act.
Motor planning difficulties can manifest on a larger scale in the child's difficulty in organizing their environment and themselves in that environment. Learning routine and how one fits into the routine may take longer. Children with difficulties may perform slowly, or not be able to perform at all, when asked to follow multi-stepped directions. They may require a longer exposure to a new activity in order to learn it. They may initially use trail and error approaches to a task until they can generate a motor plan about how to approach the activity. This can also carry on to higher levels of reasoning. They can have difficulty organizing their thoughts and language to express themselves.
Next Level of Organization: Formation of Perceptual and Perceptual Schema
copyright Valerie Dejean 1998. Spectrum Center, Bethesda, Maryland.
Tomatis system auditory training. Spectrum Center, Bethesda MD. Valerie Dejean. Sensory Integration.
Tomatis therapy has been used to treat autism, dyslexia, as well as for sports enhancement for balance and coordination, a function of the inner ear. Recent book, The Mozart Effect, by Don Campbell, documents this music therapy approach. Basicly, the ear has two functions: hearing and balance. By getting to the inner ear through listening, one can affect balance and coordination as well as giving a person his Voice and his Place in three dimensional space.