What is Sensory Integration?
It is a neurological process that organizes sensations from one's own body and from the environment and makes it possible to use the body effectively within the environment. Sensory information is processed in the body through an intricate system of sensory receptors, nerves and pathways to the brain. Incoming sensory information must be processed so that the upper layers of the brain, called the cortex, can act upon it.
Sensory processing disorder
Sensory Processing Disorder (SPD, formerly known as "sensory integration dysfunction") is a condition that exists when sensory information is not organized into appropriate responses. Pioneering occupational therapist and neuroscientist A. Jean Ayres, PhD, likened SPD to a neurological "traffic jam" that prevents certain parts of the brain from receiving the information needed to interpret sensory information correctly. A person with SPD finds it difficult to process and act upon information received through the senses, which creates challenges in performing countless everyday tasks. People with sensory processing disorder may show marked fluctuations and inconsistencies processing information. They may present with unpredictable behavior and have a difficult time changing their responses to fit the demands of a situation. Motor clumsiness, behavioral problems, anxiety, depression, school failure, and other impacts may result if the disorder is not treated effectively.
Human beings are sensory processing machines. We all have brains and central nervous systems and sensory systems. Therefore, we all have sensory needs and preferences. Intervention is recommended when difficulties processing sensory information begin to disrupt engagement in daily occupations and one's ability to participate and function.
The vestibular system, with receptors located in the inner ear, is stimulated by movement of the head and input from other senses. It effects balance, muscle tone, bilateral coordination, ocular motor skills and general organization for specific tasks. The vestibular system tells us where our body is in space, if movement is up, down fast slow or angular and is helps regulate attention and arousal level. The vestibular system is directly related to safety, arousal, attention, organization, and survival.
The proprioceptive system gives information to the brain about where our body parts are and what they are doing. It informs us abuot our body's position in space, the rate and timing of our movements, and the amount of force needed for tasks. Firm touch, or deep pressure, stretches the muscles, tendons and ligaments and provides proprioceptive input.
Interoception is our body's internal sense. It is our ability to feel and be connected to what is going on within our bodies. This includes feeling hunger and thirst, the need to eliminate or when we are not feeling well.
The tactile system has two primary functions: to protect when the body is threatened (fright, flight, fight response) and to perceive non-threatening touch and discriminate what is touching us. Enormous amounts of information is gathered through our skin. Adequate tactile discrimination is critical for fine motor skills and manipulation. Dysfunction in tactile processing of the mouth affects oral motor skills and speech.
Auditory and Visual systems provide information about our more distant external environment. They are important for learning, especially once the child enters the educational system. These environments are constantly changing, therefore putting demands on the central nervous system.
Auditory processing is a complex process that involves both hearing and processing sound. A child with SPD may have difficulty putting all of that together. Children with auditory difficulties may have trouble understanding what is being said, go off topic during conversation or written composition, demonstrate problems with reading and spelling or finding the right words to use. They also may have difficulty filtering out sound, unable to consistently focus on the most salient sounds in the environment.
The visual system involves more than the eyes' ability to pick up images accurately. Vision depends on proper function of the eye muscles. Some children crave visual stimulation and others are visually avoidant. Vision skills are closely allied with motor skills. Out eyes guide our hands and feet and help us to maintain our balance.
Gustatory (taste) & Olfactory (smell): Smell is a primitive sense that has served humans well. The senses of taste and smell are intimately connected. For those with SPD, taste and smells can be repulsive and make daily events stressful.