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Each child has a unique set of emotions, abilities and behaviors that are regulated by an equally unique nervous system, reflecting a child's personal developmental history. Sensory information is constantly coming into our bodies through our five senses, as well as internally, through our muscles, joints and movement receptors (in the inner ear).
Occupational therapists are especially interested in determining a child's strengths and needs in the area of sensory processing. The sensory systems serve as the foundation for all self-awareness, motor skill, relational abilities, communication and learning - one's human occupation throughout the lifespan. Brief descriptions of the sensory systems will assist us in better understanding a child's self-regulating behaviors. Click on the puzzle pieces below to explore each sensory system as well as key concepts in sensory processing theory.
The Tactile System The Tactile System has the largest sensory organ - our skin. Thousands of receptors detect the quality of touch and temperature and details of the shape and pressure of an object. The mouth and fingers have the greatest density of receptors. When this system functions optimally, we bond and attach, wear clothing, get haircuts, play with messy stuff, stand calmly in line and sit quietly next to a buddy. Children who are over sensitive to tactile input may fuss if their sock is twisted or refuse to wear clothing with tags. They interpret touch as a threat, and avoid messy play. These children become easily overwhelmed as they emotionally over-react to being bumped or touched unexpectedly. For children with under-reactive tactile systems, they don't react to falls, changes in temperatures, and generally accept a variety of textures that are in the environment. Precision hand skills are generally lacking in these children, since the tactile system has great influence over our motor planning abilities. If you lack a keen sense of the quality of objects in the hand, it is difficult for the hand to develop skill. The Vestibular System Our Vestibular System, our inner gyroscope detects movement and gravity. Not just our movement through space, but creates the sensation that something is moving around us. Remember closing your eyes in an elevator? After it stopped, your inner ear and muscle and joint receptors (proprioceptors) let you know that the ride was over. Our vestibular system affects our arousal state, muscle tone, and stabilizes eye muscle during movement. When this system functions optimally, we are upright with good balance, we coordinate both sides of our body, and we don't get carsick! Some children do not register or orient to the sensation of movement, so they are constantly moving. Often called "sensory seekers", these children are revving up their nervous system, just to get ready for action. This under-responsiveness takes a great deal of energy, appears unsafe and does not develop into refined motor skill. For children who over-react to vestibular input, a simple movement through space or attempting a single step present as overwhelming obstacles. Swinging and running are avoided, especially any movements that require the head "upside down" or feet off the ground. This special system contributes to our "body in space awareness" combining body movement, balance and visual spatial skills. The Proprioceptive System The Proprioceptive System is part of the vestibular system, where special receptors in muscles and joints travel quickly from the cerebellum to enhance tone and joint stability. Performed by a person during push-pull activities, proprioception is a calming, safe input to use with a child who appears disorganized. This input doesn't reverberate in the nervous system for hours like other sensory input, so it is the essential component of a child's "sensory diet". It is important to reintroduce the input often, throughout the day. Heavy-work input releases serotonin which sets the firing levels of all neurotransmitters. Many children experience body awareness for the first time when they start to wear weighted backpacks, vests or blankets. This is an important strategy used often in therapy. The Visual System The Visual System is complex and divided into 3 areas:
The Auditory System The Auditory System myelinates by 4 months and the auditory bundle travels with the vestibular nerve to deliver cochlear information to association centers. This old, powerful system is highly discriminative. An exciting relationship exists with input from the vestibulocochlear nerve. Movement has an excitatory effect to stimulate sound production, just as intensity of sound has an effect on our rhythm of body movement. The Olfactory System The Olfactory System is the only sensory tract that bypasses the brainstem. Incoming information travels from the nose to the olfactory bulbs to the hippocampus (old part of brain). This system may give a highly disorganized person their strongest link to the environment. Children who revert to smelling things may be telling us how unreliable the other sensory systems are to them. Our taste or Gustatory System has close links to the olfactory and association areas of the limbic system - evoking memories. The taste buds transmit information regarding 4 sensations of sweet, sour, salty and bitter, along 2 cranial nerves to association centers. Even with impairments in memory, this special sense offers strong connections to past events. Key Concepts in Sensory Processing Theory
How To Optimize A Child's Sensory Processing Start with keen observations of how sensory information contributes to a child's arousal level. if a child's nervous system is poorly equipped to modulate responses to ordinary events, you may see reactions that seem like inappropriate over-reactions. How can we help him register the information? Respect signs of overload. Each child's nervous system is unique. What does he enjoy? How can we expand on that activity? Self-stimulating or self-regulating behaviors are reactions to the stress induced by an uncertain and unpredictable world. Work closely with an occupational therapist to develop individual programs. Repetitive actions tell us a child is stuck and can not conceptualize (the first stage of motor planning) what to do with his body or with toys. First, we want to heighten body awareness, then simplify and guide play activities. Movements that are slow, rhythmic and linear are calming in nature. Deep pressure to the palms or trunk is calming. Quieter music with 1 beat per second, of simple nature sounds or a single instrumental is calming. Sustained heavy work at the mouth is calming, achieved by rhythmic sucking or chewing. Soft indirect lighting is calming. Quiet spaces offer breaks from auditory and visual overload. Swaddling in a blanket brings warmth and quiet. Irregular, rotary movements are alerting. Complex classical music is exciting (Mozart). Light and messy touch activities are alerting. Sour liquids and candies capture our attention. Chewy foods are alerting. Novel activities bring attention. Erratic bouncing is exciting. Irregular blowing is alerting. The most important part of a child's sensory diet are the strategies that are organizing. Daily routines bring comfort. Weighted backpacks, clothing, blankets, wrist or ankle weights give a child an anchor to the ground. It tells them where they are in space. Sipping through a long straw promotes binocular vision, jaw stability and rhythmic breathing. Any "heavy work" activity offers proprioceptive input (pulling a rope, pushing resistively, hanging from a trapeze), to enhance the release of serotonin. This important neurotransmitter enhances the function of all others. In closing, "Mere activity in itself, does not necessarily further better sensory integration. If it did, the hyperactive child would be the better organized child. The action must represent direction and effort that is more mature than that previously possible. Desire and will to accomplish the difficult must be present. Without these elements, the movement may be just an expression of a nervous system that says, move - never mind how." ~ Dr. Jean Ayres, 1972 Marget Wincent, OTR/L Director OT Outcomes Bibliography Ayres, A.J. (1979). Sensory Integration and the Child. Los Angeles, CA: Western Psychological Services. Greenspan, S. and Wieder, S. (1998). The Child with Special Needs. Reading, Mass.: Addison-Wesley. Kranowitz, Carol (1998). The Out-of-Sync Child. New York: Perigree Books. Oetter, P., Richter, E. and Frick, S. (1993). MORE: Integrating the Mouth with Sensory and Postural Functions. Hugo, MN: PDP Press, Inc. Wilbarger, P. (1991). Sensory Defensiveness in Children: an Intervention Guide for Parents and other Caretakers. Santa Barbara, CA: Avanti Educational Programs. Williams, M. and Shellenberger, S. (1994). How Does Your Engine Run: The Alert Program for Self-Regulation. Albuquerque: Therapy Works, Inc. |
