Sensory integration is a term that is unique to occupational therapists. This term refers to the brains ability to take in information from the outside world as well as from the inside world of the child’s body and use this information to create purposeful activity. Without adequate sensory integration it is difficult for the child to respond to the demands that the world places on him/her as well as to plan movements to allow successful interaction within the world.
Problems with sensory integration can result in difficulties with gross and fine motor skills, balance, co-ordination and in-hand manipulation. Furthermore these problems can present as distractibility, tactile defensiveness and language and visual spatial difficulties. The functional outputs that parents and teachers will evaluate as being problematic include poor handwriting, reading, maths and organisational difficulties.
Two very important sensory systems are involved in the process of sensory integration, in addition to the 5 commonly known senses of touch, sight, vision, hearing, smell and taste. These 2 systems are:
- Proprioception (Body Sense)
Information is received from the muscles, tendons and joints, and provides us with an awareness of our body position in relation to our environment, gravity and space.
- Vestibular (Movement Sense)
Information is received from the inner ear, and relates to movement, gravity and balance.
Sensory Modulation is the first component of sensory integration. Sensory modulation acts like the brains filter to all incoming sensory inputs. If the sensory input is too intense the brain filters it out and if it is not intense enough the brain focuses in on it (if it is deemed to be important). In addition some sensory inputs that are consistently present throughout the day are habituated to and therefore no longer recognised (for example the clothes that you are wearing you are not always conscious of the sensation on your skin).
Problems with sensory modulation occur when the child has either too high or too low sensory thresholds. If the threshold is too high the sensory input is seldom sufficient to be registered by the brain and therefore these children either seek out sensory input and can display hyperactive type behaviours in an attempt to reach their thresholds or they simply live in a little bubble and seldom respond to the world around them, including appearing to ignore you when you speak to them.
The opposite is true for those children with low sensory thresholds. These children respond to all sensory inputs, even those of a very low intensity that will not typically be registered by the brain, and as a result are often in sensory overload. They often find it difficult to habituate to and screen out irrelevant sensory input. These children respond in one of 2 ways. Either they react negatively to sensory input in the form of tears or acting out alternatively they avoid sensory input. Typically children that are sensory sensitive initially react negatively but through a learnt response begin to avoid situations in which unexpected or threatening inputs may be experienced. As a result the child may become anxious, fearful, excessively attached to his/her parents, manipulative of the situation and behaviours can be quite ritualistic in an attempt to control their sensory environment.