What is Sensory Integration?

Sensory integration is an unconscious neurological process that registers and organizes input received from the senses. We are familiar with the senses of taste, smell, sight, touch, and sound. There are additional hidden senses that sense movement, body position and force of gravity. Sensory integration makes it possible to use the body effectively within the environment.
Sensory integration dysfunction is a complex disorder of the nervous system and is a broad term. There are four main areas that make up sensory integration: Sensory Defensiveness, Arousal Level, Modulation and Integration of Multiple Senses.

Sensory Defensiveness
The person affected by sensory defensiveness experiences stimuli that are typically “neutral” for most persons, as though it were painful, irritating or threatening. Two of the key symptoms of sensory defensiveness are unpredictable explosions of emotion/behavior which often seem to have no easily identified trigger, and withdrawal or avoidance behaviors. Persons affected sometimes experience frequent headaches or stomach aches. Persons affected by sensory defensiveness often develop withdrawal, aggressive or avoidance behaviors and may become easily overwhelmed. Sensory defensiveness can affect one, two or multiple sensory systems. It can range in severity from mild to severe.

Types of Sensory Defensiveness
Tactile defensiveness is an over-reaction to touch or tactile experiences. This may result in avoiding touch from others, dislike of crowds, irritation when having hair cut or washed, avoidance of certain types of clothing, and many other similar reactions.

Oral defensiveness is sensitivity to food textures and items in the mouth. Persons may be bothered by foods with mixed textures, certain types of meat, slimy/mushy textures, may have sensitive gag reflex, and/or they may have difficulty swallowing pills. They may dislike certain flavors of toothpaste or the feel of a tooth brush in their mouth.

Auditory defensiveness is an over sensitivity to certain sounds. Persons may be easily startled by sounds, may cover ears with loud or high pitched noises, becomes overwhelmed or have behavioral problems in noisy situations and are usually easily distracted by background noises.

Visual defensiveness appears as an over sensitivity to light or certain visual stimuli. This may include visual distractibility or avoiding eye contact. They may dislike lights from on-coming traffic at night, sunlight coming in a window or have difficulty finding objects in a cluttered area.

Olfactory Defensiveness is an alarm or defensive reaction to non-noxious environmental odors. Persons may dislike the smell of food, perfume, deodorant, cologne or scented lotions.

Vestibular Defensiveness is difficulty tolerating movement. Persons may get car sick or motion sickness easily and usually dislike rides at a fair or going on watercraft.

Proprioceptive defensiveness is a resistance to input into the joints either by compression or traction. Some children avoid putting weight into their joints such as when standing, pushing or jumping. Some complain about lifting heavy things.

Arousal Level
Arousal level is the intensity of input the nervous system receives from the senses. Sensory information is misperceived by the central nervous system. People may over register or under register sensory input. Typically, we see children who under respond to input which is the opposite of sensory defensiveness. In contrast to a child who has sensory defensiveness, an under-responsive child may seek out intense sensory experiences.

Types of Under Arousal
Tactile Under Arousal is an under response to touch. Persons affected may not feel touch, touch objects with a great amount of force, not feel when clothing is not on properly, touch objects in their environments frequently and be unaware of boundaries and invade other’s personal space.

Oral Under Arousal is an under response in the oral cavity. People affected may eat an excessive amount of food and not get full, pocket food, choke on food or drool excessively. A child may also seek oral stimulation by chewing on their shirt, collar, pencils, or fingernails.

Auditory Under Arousal may present as a person making constant or excessive noise, talking loudly or asking to turn the music or television up. They may also appear to tune you out or not respond when their name is called.

Visual Under Arousal may be present if a person is attracted to bright lights, patterns or an area with lots of visual input. A child may like a cluttered area and prefer to play with all of their toys out.

Olfactory Under Arousal occurs when someone smells objects frequently (candles, lotions, perfumes) and/or wears excessive amounts of perfume or cologne.

Vestibular Under Arousal is present when someone seeks lots of movement. They may fidget frequently, rock back and forth, pace, hang upside down, spin in circles or like to go on rides and won’t get sick.

Proprioceptive Under Arousal occurs when the muscles, tendons, ligaments and joints don’t pick up the amount of input they should. A person may appear clumsy, have difficulty with sports, bump into objects frequently and/or sit funny in chairs.

This is the ability to maintain a calm, alert state. Persons may be over aroused, under aroused, or fluctuate between the two. This is the temperature gauge in our body, which allows us to turn ourselves up and turn ourselves down when we need to. Persons who have difficulty modulating their nervous systems, usually have difficulty with sleep, transitions, a high or low activity level, low frustration tolerance, poor recovery time and may complete self injurious behaviors.

Integration of Multiple Senses
The tactile, vestibular and proprioceptive systems begin to function very early in life, even before birth. These basic senses are closely connected to each other and form interconnection with other systems of the brain as development proceeds. The interplay among the various senses is complex, and is necessary in order for a person to interpret a situation accurately and make an appropriate response. It is this organization of the senses for use that is termed sensory integration.

When a person has sensory defensiveness, under arousal or modulation difficulties, it is extremely difficult for our nervous system to simultaneously process all information coming in. If information can’t come into our nervous system correctly, it can’t go out correctly. Often times a person will have delayed gross and fine motor skills, difficulty using both sides of their body together for tasks, difficulty knowing how to move their bodies for tasks, and poor trunk strength and stability.