Post #9 Sensory differences

Many autistic children, young people and adults process sensory information differently and as a result we may see unusual responses to sensory information in their behaviours. 

Sensory processing consists of the following: 1) messages are received from our senses 2) our brains interpret and organise the sensory information received 3) processing of sensory information leads to our response. Sensory processing is going on all the time:

Sensory processing in individuals with autism is thought to be different. These differences manifest in different ways for different individuals. For many individuals, the messages the brain receives are perceived differently:

• Hypersensitivity/over-responsive - imagine sensory information entering the brain through a magnifying glass, resulting in too much sensory input
• Hyposensitivity/under-responsive - in this case sensory information may not be received by the brain, or is dulled, resulting in limited sensory input
• Sensory-seeking/unusual interests in sensory aspects of the environment - individuals may be fascinated by certain sensory input and seek out these sensory experiences, for example excessive smelling of objects, visual fascination for lights.

These sensory processing differences, and consequent responses/behaviours, can occur in any of the senses as illustrated below:

Senses	Examples of hypersensitivity	Examples of hyposensitivity
Visual - sight	May cover eyes in bright lights, notices tiny pieces of fluff or dust motes, looks down	Seeks out visual input, e.g., light, holds objects close to eyes and becomes absorbed, fascinated by reflections & bright coloured objects, shadows, may not ‘see’ what an object is
Olfactory - smell	Pushes people away if wearing particular scent, avoids/rejects food smells, runs away from certain smells, may gag or vomit	Seems unaware of smells, excessive smelling of people or objects
Gustatory - taste	Strong reactions to certain food, food refusal, may  gag or vomit	Seeks out objects and licks, chews, mixes strong flavours such as sweet & sours, eats things which are inedible
Auditory - sound	Afraid of sounds e.g., washing machine, hand dryers, thunder storms, afraid of haircuts, very light sleepers, may make repetitive noises to block out sounds they dislike, may hear sounds we can’t hear	Seeks out certain sounds, leans head against electrical equipment, create sounds to stimulate their hearing e.g., makes repetitive sounds, bangs doors, tapping, humming
Tactile - touch	Gentle touch may be painful, holding a pencil might hurt their fingers, avoids certain fabrics and textures, fear of having nails cut, heightened sense of pain, reacts negatively to unexpected touch	May not be aware of pain and/or temperature, seems unaware of touch unless it is intense, seeks out firm touch/pressure, repetitive movements such as head banging, loves firm pressure
Vestibular – this sensory system helps us to keep our balance and gives information about speed and direction of movement, links with vision	Dislikes/avoids spinning, swinging, afraid of heights, intolerance of movement, may have difficulty walking or crawling on unstable surfaces	Thrill seeker (loves big fairground rides!), seeks out intense movement such as bouncing, always moving, may rock back and forth
Proprioceptive – body awareness, input from muscles	Hold body in odd positions, may have difficulty manipulating small objects	Unaware of where body is in space, unaware of body sensations, bumps into things, stumbles, stamps feet when walking,  chews objects, leans on hands, poor balance

Watch the film to learn how one boy explains his sensory differences: 

It is important to remember that each individual is unique and so sensory differences will vary enormously. Some individuals may have these experiences in one sense, while others will experience unusual sensory processing in more than one sensory system. To add to the complexity, it is possible to be hyper- and hypo- sensitive in the same sensory system! For example, a young person who I taught felt intense pain if required to use his finger-tips when writing, but in other parts of the body he felt no pain, hence hyper- and hypo sensitive to touch.

Sensory processing includes interpretation and organisation of sensory messages in the brain. For many individuals with autism, this process is also different and can result in unusual behaviours and responses. Some individuals will, at times, experience sensory overload, this can happen if the brain becomes over-stimulated with too much sensory information and/or is overloaded when trying to interpret and organise sensory information. Watch this animation to get a feel for what this may feel like:

Or this film made by the National Autistic Society which illustrates sensory overload in a shopping centre:

When this happens, your son or daughter may have a melt-down which means they might lose control. If this happens they might benefit from particular strategies to help them to relax or to become calm. (See sensory strategies post).

Sensory processing differences and consequent behaviours can affect any age and any level of ability. Some individuals may be able to explain their sensory experiences, as in the boy in the above film, whilst others will not. Individuals with autism and learning disabilities may show more extreme behaviours which may be attributable to differences in the way they are processing sensory information in the environment. They may engage in self-stimulatory behaviours, sometimes called 'stimming', to create sensory input or feedback or they may 'stim' to block out other sensations. 

Another important point is that these unusual sensory experiences can differ from day to day and sometimes even from moment to moment. Other factors may affect sensory experiences and behaviours too, for example fatigue or when an individual feels unwell. 

So how can you tell if your son or daughter experiences unusual sensory processing? Observe your son or daughter, look at what they do and listen to what they say where possible, paying close attention to the environment and the context. If your son or daughter has autism and learning difficulties you might find it helpful to complete a sensory profile like this: Sensory screening. Alternatively this checklist, designed for teachers in mainstream schools, may help you to identify areas of sensory difficulties at home: Sensory assessment checklist Screening tools like this might help you to pinpoint areas of difficulty which you might then be able to address. 

My next post will cover sensory strategies which you could try at home.