All the information our brains receive comes in through our senses, we do not get information any other way. Although most people are familiar with the traditional five senses of sight, sound, touch, taste and smell, there are in fact seven sensory systems, the others being vestibular (movement and gravity) and proprioception (muscles, joints and ligaments).
The process of taking in and linking up the masses of sensations which flow via the senses into the nervous system from the environment and from within the body is called ‘sensory integration’. In practice, much more information is available to us than we actually need for the task in hand and thus part of the integration process involves a screening facility which can ignore the extraneous and select data we need.
Much of this integration process is organised in the areas of the brain which look after processes at the automatic level, that is, there is no conscious effort involved and the higher levels of the brain are thus free to work most efficiently, concentrating on the aspect of what we are doing which does need to be consciously directed.
As the brain receives and efficiently integrates feedback from all the various senses it is able to direct increasingly proficient functions such as co-ordinated gross and fine movement, control over attention and activity levels, planning, organising and sequencing, and feeling ‘in sync’ with the environment and the regulation of emotional state.
A disruption in sensory processing or sensory integration is termed ‘Sensory Processing Disorder’. The following describes some of the signs which might alert you to possible disturbances in processing related to specific sensory systems:
Tactile: the sense of touch. Input from the skin receptors about touch, pressure, temperature, pain and movement of the hairs on skin.
Common Issues:
Sensitive to clothing textures, cuts out labels in clothes, reacts to dirty hands or feet, has itchy, tickly skin, looks fidgety or wriggly, dislikes hair being brushed/cut/washed, prefers being covered up with clothes or prefers wearing no clothes where possible, unusually sensitive to being too hot or too cold, over reacts to pain, reacts badly to being touched unexpectedly, hates to stand in line, reacts badly to being in a crowd or has a particularly wide personal space.
Fails to register if too hot or too cold, dresses inappropriately for the weather, seems to crave touch.
Vestibular: the sense of movement - input from the inner ear about equilibrium, gravitational changes, movement experiences and position in space.
Common Issues:
Avoids playground apparatus and moving equipment, fearful of heights, dislikes moving into space behind or moving backwards, dislikes being tipped upside down, often afraid of falling, dislikes walking on uneven surfaces and avoids rapid, sudden or rotating movements.
Craves any possible movement experience, especially fast or spinning, never seems to sit still, is a thrill seeker, often feels travel-sick, loves being tossed in the air, never seems to get dizzy, full of excessive energy and falls frequently.
Proprioception: the sense of position - feedback from the muscles and joints about body position, weight, pressure, stretch, movement and changes in position.
Common issues:
Constantly jumping, crashing, and stomping, loves to be squished and loves bear hugs, prefers tight clothing, loves rough-housing and may be aggressive with other children.
Difficulty understanding where their body is in relation to other objects, appears clumsy, bumps into things often or moves in a stiff and/or uncoordinated way.
Doesn’t know how hard to push on an object, misjudges the weight of an object, breaks objects often and tears paper when erasing pencil marks.
Auditory: the listening sense. Hearing is different to listening, which is a dynamic interaction with the world of sound, the ability to field sound, to screen out extraneous noise and zoom in on what is pertinent at the time in order to correctly perceive, discriminate and respond accurately.
Common Issues:
Over-reacts to sudden or loud noises, low tolerance of noise generally, fearful of noise, responds to noises not noticed by others, covers ears with hands, says that noise hurts ears or gives him/her a headache, resists going to loud public places or places where acoustics vary.
Seems not to register sound, under-responsive to noise, fails to respond to hearing his/her name called, finds it hard to respond to instructions given to the group (e.g. at school), talks quietly/too loudly or has a poor sense of self in time.
Oral: the ability to correctly perceive, discriminate, process and respond to taste, texture and input within the mouth.
Common Issues:
Picky eaters with determined food preferences and limited range, may gag on textured food, difficulty with sucking, chewing, and swallowing, extremely fearful of the dentist, dislikes toothpaste and brushing teeth.
May lick, taste or chew on inedible objects, loves intensely flavoured foods, may drool excessively, frequently chews on pens, pencils, or shirt.
Olfactory: the sense of smell - ability to correctly perceive, discriminate, process and respond to different smells and odours.
Common Issues:
Disturbed by cooking, bathroom or perfume smells, refusal to go places because of the way it smells, choosing foods based on smell, notices smells not normally noticed by others.
May not notice unpleasant or noxious odours, smells everything when first introduced to it, may not be able to distinguish smells/fragrance.
Visual: the sense of sight and handling of input relating to sight - one’s ability to correctly perceive, discriminate, process and respond to what one sees.
Common Issues:
Blinks excessively, rubs eyes, screws up eyes, chooses to wear a hat or sunglasses outdoors, notices little environmental details others would not, fussy about order in the surroundings, falls over things he or she has not noticed, bumps into people and things, seems overwhelmed in a visually ‘busy’ environment, keeps to the edge of groups and crowds, visually highly vigilant, uncomfortable in open spaces.
Difficulty controlling eye movements and tracking objects, mixes up similar letters, focuses on little details in a picture and misses the whole, loses his/her place frequently when reading or copying from the blackboard.
Other more general behaviours and traits can be associated with sensory processing issues for instance:
- Becoming ‘high’, over-excited, giggly or aggressive when moving about actively
- Generally resists or, conversely, craves physical activity
- Has nervous tics or habits
- Frequently fights with other children/siblings
- May require a large amount of attention
- Is easily frustrated
- Has separation anxiety
- Has unusual fears, easily gets anxious, stressed, tearful or agitated
- Emotional responses are extreme and may swing about or, conversely, a child may seem flat and lacking emotion
- ‘Switches off’ or seems to glaze over at times, may often seem sluggish, tired or bored
- Has trouble concentrating
- Has trouble mastering new skills
- Has sleep difficulties, particularly in winding down to drop off to sleep
- Lacks confidence or self-esteem
- Fatigues easily
- Seems out of sync with self, others and/or the environment