Sensory Integration (SI) is the brain’s ability to take in, process and organise sensory information that we receive through different sensory systems in our bodies. Through our senses, we develop an understanding of our world; at times, this occurs without us even being aware.
Our brains must be able to organise and process information that comes from our sensory systems in order to respond appropriately. To do so, we must be able to integrate information from all of our sensory systems.
Beginning in the 1960s, Dr A Jean Ayres, the pioneering force behind SI, systematically investigated the nature of the way the brain processes sensory information so that it can be used for learning, emotions and behaviour, creating SI theory as it is currently used in occupational therapy practice and applied in paediatrics and childhood education. This approach is known as Ayres Sensory Integration® (ASI®).
‘Sensory Integration is the neurological process that organises sensation from one’s own body and from the environment and makes it possible to use the body effectively within the environment.’ ~ Jean Ayres, 1989
THE TACTILE SYSTEM
The tactile system protects us from stimuli that are interpreted by the brain as being harmful. Individuals with an over/under-sensitive tactile system interpret touch differently. When tactile input is misinterpreted as being harmful, such as stimulation from certain types of clothing, food textures, or unexpected touch, it may elicit negative reactions such as pulling away, increased or agitated activity, or strong emotional responses. The heightened sensitivity to touch, resulting in routine misinterpretation or unusual reaction to touch, is referred to as tactile defensiveness.
The tactile system, along with the proprioceptive system (explained in this article), allows us to have body scheme or an awareness of our body parts and the physical relationship of our bodies to objects and other people.
THE VESTIBULAR SYSTEM
The vestibular system provides us with a sense of security when moving. It is the foundation for the development of balance reactions and is important in motor development because of its influence on muscle tone, posture, the ability to use both sides of the body at the same time (bilateral motor coordination), balance, orientation in space, and eye movements. Children who are frightened of moving or falling, who fall over often, and those who crave movement often have difficulty with vestibular processing.
THE PROPRIOCEPTIVE SYSTEM
Proprioception is our muscle and joint sense, which helps us understand where our body is in space without looking. This allows for automatic movement without having to rely on our vision to monitor those movements. It also provides information about how much force we need to use for tasks such as picking up a glass with different amounts of liquid and writing without thinking about the process of forming the letters.
Proprioceptive input, obtained through moving, maintains and regulates body functions, including healthy neuromuscular and cardiovascular systems. People who exercise regularly may feel calmer and more alert. Children need increasing amounts of physical proprioceptive activity (jumping on a trampoline, stress balls, pushing and pulling heavy objects and eating crunchy foods/snacks) so that they can stay calm and alert throughout their day.
THE VISUAL SYSTEM
The visual system comprises our sense of sight and the ability of both eyes to work together. It enables the co-ordination of both eyes together to focus on an object, allowing the individual to form a clear picture of the people and world around him/ her. Co-ordinating movements of head, eyes and hands directs many skills we use in our daily lives.
THE AUDITORY SYSTEM
The auditory system provides us with the ability to hear as well as our ability to correctly understand what it is that we are hearing.
SI provides the foundation for us to learn even the simplest things and to behave appropriately throughout our day. Sensations flow into our brain at every moment, and provide us with information that we can use to help us understand what is happening around us, to know what we need to do and to plan how to do those things. The brain detects and organises these sensations in order to form perceptions, adapt behaviour and to support learning. Children must be able to process sensory information through all of the senses in order to perform skills automatically. They must be aware and comfortable with where their bodies are in relation to space; they must know where and how they are being touched and must know, without being taught, what sensory information to pay attention to and what to ignore.
SENSORY INTEGRATION DYSFUNCTION
Many children however, have difficulty organising information and performing the many complex tasks that are required for learning and functioning in our world. Jean Ayres, an occupational therapist and educational psychologist who developed SI theory for use in therapy practice, once said, ‘When the flow of sensation is disorganised, life can be like a rush-hour traffic jam.’ She linked deficits in motor learning, academic abilities, attention and behaviour to SI dysfunction.
Children with SI dysfunction need help and understanding to guide them throughout their daily activities and to give them the support they need to attempt routine tasks that most children perform easily.
SENSORY INTEGRATION DIFFICULTIES
Difficulties observed in children with SI dysfunction may include:
- Clumsy behaviour.
- Poor postural control.
- Sensory defensiveness, i.e. fussy dressers, fussy feeders, uneasy on jungle gyms/avoid swings, unsettled in noisy environments etc.
- Sensory dormancy (often resulting in seeking behaviours), i.e. constantly moving, fidgeting, touching, making noises, crashing into things, not hearing when being called (despite normal hearing), incomplete work in class due to ‘daydreaming’ etc.
- Difficulties co-ordinating the two sides of the body and/or crossing the body midline.
- Difficulties planning, sequencing and executing novel (new) movement patterns.
- Speech and language development may be affected.
- Poor participation and independence in self-care activities like feeding, grooming, dressing etc.
- Difficulties developing and sustaining relationships and poor social skills.
- Difficulty with focus and attention.
HOW IS A DIAGNOSIS MADE?
An occupational therapist trained in ASI® accredited by The South African Institute for Sensory Integration (SAISI) would be able to make a diagnosis of a SI dysfunction.
To make a diagnosis of SI dysfunction, there needs to be evidence of a deficit in the processing of vestibular, proprioceptive and/or tactile sensory inputs. These deficits must not be a result of either peripheral or central nervous system dysfunction.
The use of various standardised and non-standardised assessments, checklists and clinical observations are used in collaboration with collateral information. As occupational therapists, the child’s occupational performance (all the activities a child engages in) is taken into account. Any functional difficulties that the child is experiencing at home and at school should be supported by the findings of the assessment.
WHAT DOES ASI® TREATMENT ENTAIL?
When a child responds to his environment in an adaptive and creative way, he is able to learn and have fun. This ‘fun’ and ability to learn, relies on intact SI. Occupational therapists use purposeful activities, specialised equipment and sound clinical reasoning to create opportunities for enhanced SI in therapy. Once the child is processing and organising sensory information more effectively, he will find it easier to interact positively with his peers, play creatively, and achieve success in all of his occupational performance areas at home and at school. Pleasurable activities, i.e. play, are key to harnessing intrinsic motivation and drive.
- Ayres AJ. Sensory Integration and the Child. California: Torrance. 1979.
- Case-Smith J, O-Brien JC. Occupational Therapy for Children and Adolescents. Missouri: Elsevier. 2014.
- Bundy AC, Lane S J, et al. Sensory Integration Theory and Practice. 2nd ed. S.l.:The Taber’s Publisher. 2002.
- SAISI, South African Institute for Sensory Integration: https://www.instsi.co.za/
- SIGN, Sensory Integration Global Network: https://www.siglobalnetwork.org/