The idea of sensory integration originated with an occupational therapist called Jean Ayres. She defined it as ‘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’ (Ayres, 1972).
Children absorb and process sensations from their movements and the environment around them. When this is done effectively, children can plan and organise behaviour which helps them with everyday activities as well as learning.
Children receive information from the environment through their eyes, skin, ears and mouths. The brain differentiates and processes huge quantities of sensory information from multiple sensory inputs at rapid rates. Different senses complement each other, adding layers of information to verify facts and add nuance.
Unfortunately, we increasingly seem to be valuing intellectual development at the expense of building the sensorimotor base. Sensorimotor activities are the building block of more cognitive abilities and cannot be bypassed without consequences.
Sensory integration functions develop in order and typically developing children naturally follow the same basic sequences. Integration is developed by ordinary childhood experiences such as rolling, playing, crawling, walking. Movements combine with the child's growing experiences, emerging knowledge and memories to make sense of the stimuli.
Crucially, children's senses are stimulated in the context of attachment, which helps them to self-regulate, gain a robust sense of selves and see the world as safe. Babies move in response to interactions such as proto-conversations and human contact. These movements and interactions help build pathways in the brain and central nervous system that form the foundation for socio-emotional development and impulse control.
Sensory deprivation can be very disorientating and can lead to mental disturbances.
The five senses
A sense is the physiological capacity that provides us with data for perception.
- Sight is the capability of the eye to focus on and detect images of visible light using photoreceptors in the retina which generate electrical nerve impulses. Vision dominates our perception of the world due to its reliability. It enables the child to perceive depth, locate objects and detect movement, colour and light intensity. Children develop sight rapidly and 20/20 vision is usually achieved by the age of three years.
- Hearing is the perception of sound, it uses receptors in the inner ear which turn vibrations into electrical nerve pulses. Hearing is normally fully developed in newborns. They will startle in response to loud sounds and pay attention to their parents' voice. Hearing is linked to learning disorders, concentration and emotional well-being. Taste or gustation helps us taste certain minerals and detect poisons and off-food. Flavour detection comes from a combination of taste and smell perception.
- Smell or olfaction is a chemical sense using hundreds of olfactory receptors which are excited by odour molecules. Grouped with taste, smell is one of the earliest sensations in children.
- Touch is a perception resulting from the activation of neural receptors in the skin, tongue and throat which can detect pressure, itching and pain. Certain parts of the body (such as hands and lips) are better than others. Pain or pleasure sensations develop first, before discriminative senses which allow us to explore objects.
Small, fluid-filled canals in our inner ear establish our direction of movement against gravity. This information helps us to orient ourselves, particularly our head movements. This is useful when swinging, spinning round, going upside down and so on, and increases postural control and balance. Children with vestibular difficulties may be rigid or find it hard to stand with their eyes closed. They may have poor muscle tone, balance and coordination and can dread movement.
Children need gentle stimulation such as hearing their mother's voice, being rocked and having interesting things to see. Rolling over stimulates the vestibular system; later on, monkey bars, roly-polies and cartwheels.
Sensory feedback from muscle and joints through tiny receptors tell our brain where our body parts are. This helps to coordinate body movements such as bringing a cup to our mouth or a finger to our nose while our eyes are closed. Well-developed proprioception helps to keep our movements fluid and coordinated rather than jerky, floppy or fidgety. Babies develop this through actions like rocking backwards and forwards on all fours.
Having awareness of their body in space prevents children from bumping into objects while doing complicated activities, giving them a sense of security. Touch and proprioception link with vision to give us hand-to-eye coordination and accurate movement planning.
Interoception is a fairly new area. It tells our brain what is going on inside our body; knowing when we are hungry/full, detecting temperature, pain, tickles and sensual touch. It also gives rise to sensations like our heart skipping a beat.
Jean Ayres was interested in sensory interaction which helps us to use our body effectively to concentrate, develop self-esteem, confidence and cognitive skills.
Children can combine senses from around one year old but cannot do this accurately, possibly due to lack of experience and because they prioritise speed over accuracy. Different senses develop at different rates, so sensory integration does not appear until the different senses have reached maturity.
Sensory processing disorder
It is estimated that five to 10 per cent of all children have sensory integration deficiencies (Ayres, 2007). This is where the brain is unable to accurately process the information receives from the senses. This results in impulsivity and regulatory problems, relational impairments and cognitive deficits. This is compounded where good, attuned relationships have not been available (DiCorcia and Tronick, 2011). Sensory processing disorders can involve problems with processing information and executing movements, which are often experienced in autism spectrum disorders. However, children who have experienced trauma or neglect may have different sensory issues if there has been a lack of the repeated sensory experiences needed to execute complex movement tasks. Neglect may leave children feeling hypersensitive or unresponsive.
Problems can involve under-processing, over-processing or interference in processing. Children might have an acute awareness of background and loud noises, a fascination with lights, make repetitive movements, walk on tiptoe, little awareness of pain or temperature or difficulty with transitions, clothing or food. They may have poor posture, difficulties with mark making, bump into things, not know if they are hot or cold, hit people or react strongly to stimuli. They may not know which body part is being touched. They might find it hard to make friends, have difficulties with clothes and sleep, be fidgety and throw tantrums.
The neurosequential approach to child development examines whether a child's systems have been adequately primed. Each stage of development is built on the last one with the reptilian brain forming first, so in utero disruption might affect the brainstem (temperature, breathing, swallowing, etc.).
Babies develop from the head down so they can raise their head, then roll over, then sit and eat finger food before they can walk. Where there is neglect, adults can help by filling in the gaps with sensory and motor activities. These activities should be joyful, child-directed activities and gently challenging. Children can be hypersensitive or hyposensitive. Hypersensitive children over-react to stimuli such as clothing, noise and light whereas hyposensitive children show little reaction to pain, noise and other environmental stimuli. Practitioners can fine-tune children's responses by making dens, turning down lights and limiting sound for overstimulated children or stimulate under-responsive children with swinging, bouncing, or a gentle rough-and-tumble.
Experimenting with touch allows young children to have fun testing objects
Sensory functioning is linked to the limbic systems for emotions. It is like background music, setting the tone and context for how we interact and receive sensory data.
There is no diagnosis for ‘sensory processing disorder’ in the Diagnostic and Statistical Manual (DSM) and there is some controversy in this area. It is hard to diagnose as some of the difficulties are shared with children with autistic spectrum disorder, attention deficit disorders, anxiety or behavioural problems. Where problems are significant, occupational therapists might work with a child and their family in different contexts, enhancing their processing of sensory stimulation.
Due to young children's neuroplasticity, earlier interventions are generally more successful. Begin by learning about your own sensory profile and your responses to stimuli. To understand how impairment might feel, try to draw round something while looking in a mirror or complete an obstacle course while looking through back-to-front binoculars.
Observe how children hold things, walk and stand. Pay attention to children with challenging behaviour which might cause peer issues, risk to themselves or others or diminish their access to the curriculum. Look for antecedents to this behaviour and whether there might be sensory stimuli triggering certain reactions. Development Matters suggests we provide novelty in the environment to encourage the use of the senses both indoors and outdoors (Department for Education, 2012). Scaffolding children's skill building in sensory contexts is essential, ensuring they are working within, or at the edge, of their ‘window of tolerance’ (Siegel, 2011).
Supporting children with cognitive approaches can help by providing commentary on their activity and its outcomes. This should be done playfully by a safe person in a safe place so they can gain warm, supportive feedback on their activity. Mentally preparing children for an activity with talk or relevant stories is also useful.
Finding activities which involve the prone position (lying on their stomach) especially when involving reciprocity or to-and-fro helps build pathways between muscles and the brain/nervous system. Try ‘Superman’ (lie on your stomach with arms and legs extended up and out, or on a yoga ball if it is easier). Cloths, brushes and textured pillows help develop the tactile system. Swinging in hammocks or swings and rocking and rolling on gym balls help the vestibular senses.
Activities like squeezing, blowing, crunching, stacking, spraying, squishing and brushing are beneficial. Provide feely bags, bubble wrap, spinning, parachute and hopscotch games, digging equipment, frisbees and balloons, and make them crawl under things, dance, roll chalk over salt, stand on a tray of marbles (with/without water), or blow paint bubbles. Treasure baskets, massages, textured materials and gentle smells can also help children. When they are older, handstands, wheelbarrows and cartwheels are effective.
Sensory integration is important for a child to be able to integrate their experience and respond accordingly. Practitioners can observe children and plan for a rich sensory diet.
Why Does Izzy Cover Her Ears: Dealing with sensory overload by Jennifer Veenendall. Published by AAPC Publishing (ISBN: 9781934575468). Follows a child whose behaviour is misunderstood.
The Out of Sync Child by Carol Stock Kranowitz. Published by Perigee. (ISBN: 9780399531651)
- Sensory integration is the foundation of children's activities
- Impairment can come from disorders or from trauma and neglect
- Rich sensory experiences are important in the early years due to neuro-plasticity and neuro-sequential development.