What is Sensory Integration (SI)?

Sensory integration: part of sensory processing

Sensory processing is the ability to take in sensory input from our bodies and the environment, interpret this input and organize sensations in order to behave appropriately. Sensory processing is an umbrella term; sensory integration, the ability to integrate these senses for daily activities, is a component of sensory processing.

There are two types of sensory processing disorders:

Sensory modulation dysfunction

The under/over responsivity to ordinary sensations from the body or environment. This happens because the central nervous system inefficiently organizes and regulates reactions to sensations. It causes a child to exhibit atypical behaviors. In other words, the degree, intensity, and quality of the child’s responses do not match the environmental demand.

  • Under responsivity – craves intense input to organize or alert oneself, may seem under-aroused or has poor attention, difficult to engage.
  • Over responsivity – fears touch, movement, bright lights, loud sounds and perceives these inputs as threatening or painful, can also be viewed as negative or defiant by others.

Poor sensory discrimination

The misinterpretation and poor organization of sensory information coming from a child’s body and from the external environment. This happens because the central nervous system inefficiently integrates sensory messages. It leads to a child’s difficulty in using sensory information to make adaptive, meaningful responses.

  • Child looks uncoordinated, clumsy, has poor motor planning, poor handwriting, or poor body-in-space awareness

Sensory systems

Although there are children who do have sensory integration dysfunction, all children can benefit from added sensory experiences in their daily life. All children need to move and experience all kinds of sensations. Sensory integration is something that occurs naturally everyday with all people.

As children, we are all taught about the 5 basic senses: vision, hearing, smell, taste, and touch. There are two other very important sensory systems that most people are not aware of: the vestibular system and the proprioceptive system. Sensory integration therapy is based upon using activities that provide vestibular, proprioceptive, and tactile input.

Vestibular System

The vestibular system has its receptors in the inner ear and senses movement of the head in all directions. The sensory input we get through the vestibular system tells us exactly where we are in relation to gravity, whether we are moving or still, how fast we are going, and in which direction. Through its influence on muscle tone, the vestibular system affects posture and movement. Movement input can also have an extremely important impact on the regulation of attention and arousal.

Children with vestibular processing or modulation problems might display some of the following behaviors

  • May tolerate an enormous amount of movement (merry-go-round, swinging, spinning)
  • Does not get dizzy or nauseous
  • Has poor integration of the two sides of the body
  • May be constantly “on the go”, craving movement
  • Is easily confused by directions or instructions
  • Has low muscle tone, appears loose and floppy, has poor body awareness
  • Has poor trunk control, slumps in chair/leans on table, trouble holding static body positions, may “w” sit
  • Fatigues easily during physical activities
  • Has poor balance and frequently falls, clumsy
  • Has trouble understanding of the two sides of the body and how to coordinate arms/legs
  • Decreased ability to control eye muscles
  • Displays anxiety or stress when feet leave the ground/on elevated surfaces, when moving, assuming a new position, or when someone else tries to control his movement or position; swings, merry-go-rounds, and other playthings that move the body in non-ordinary ways may feel terrifying
  • Becomes dizzy or nauseous with movement (riding in cars, buses, subway)
  • Has difficulty making postural shifts through trunk to maintain balance while moving; can tolerate movement betters when they are not required to use their own muscles for support
  • Has a great fear of falling
  • Dislikes head being inverted or tipped (like with rinsing hair or during diaper changes)
  • Appears uncoordinated since he/she avoids movement activities
  • Seems willful and uncooperative

Proprioceptive System

The proprioceptive system has its receptors in muscles, tendons, and joints. Sensory information from this system is created by the contraction and stretching of muscles and by the bending and straightening, pulling and compression of joints between bones. This information is constantly being sent to the brain to tell us about our body’s position and where our joints are in space. When we have adequate proprioceptive processing, our brain knows where all our body parts are and what they are doing without the eyes having to look at them.

Children with proprioceptive processing or modulation problems might display some of the following behaviors

  • Difficulty feeling the weight of objects
  • Poor left – right awareness, gets lost easily
  • Difficulty with body awareness and personal space boundaries
  • Stomps his or her feet
  • More clumsy movements, bumps or crashes into objects and people
  • Difficulty grading muscle force – muscle exertion is either too much or not enough when manipulating objects (firm or loose pencil pressure) or while performing gross or fine motor activities (getting on or off a riding toy, buttoning clothes, turning on a faucet, etc.); can also be rough with people or objects
  • Chews constantly on shirt collar, sleeve, non-food objects, toys, gum or grinds teeth

Tactile System

The tactile, or touch receptors, are located under the skin and differentiate light touch and pressure touch. Light touch sensation alerts the nervous system to be wary of possible danger. Pressure touch calms the nervous system, and because it enables us to discriminate shapes, textures and sizes by touch, it defines our body boundaries and is fundamental to how we learn about objects and people.

Children with tactile processing or modulation problems might display some of the following behaviors

  • Touches everything/everyone, enjoys messy textures, bumpy or rough surfaces, vibration and deep pressure, rubs hands along the wall
  • Mouths objects beyond an appropriate age, licks hands/arms
  • May be unaware of touch unless it is very intense (ie. food on face or a runny nose)
  • Has poor body awareness and body schema – unable to identify body parts or perform certain motor tasks without looking (buttoning, zipping, writing letters and numbers)
  • Appears clumsy and awkward
  • Leaves clothes twisted on body or shoes untied
  • Has trouble perceiving characteristics of objects such as shape, size, texture, and temperature, without visual cues
  • Has poor fine motor skills for tool use such as coloring, writing, cutting
  • Avoids the touch of other people, primarily in social/group activities
  • Over-reacts to unexpected touch, may perceive it as painful
  • Avoids messy play (paint, glue, chalk, sand) and getting dirty
  • Has difficulty tolerating grooming/self-care tasks (nail cutting, tooth brushing, nose wiping/blowing, lotion, hair brushing/washing, hand washing)
  • Is bothered by certain fabrics, elastic waist bands, sock seams, tags, fasteners rubbing against skin. Has difficulty making the transition between clothing with changes in season
  • Does not like to walk barefoot in grass, sand, outside and likes to keep socks on when indoor or must take them off
  • Can be a picky eater or have sound sensitivities