Sensory Processing and Sensory Processing Disorder

What is Sensory Processing?

Sensory processing is a term which describes how we 'tune in', process, and respond to the environment around us. It is an important function of our central nervous system (brain and spinal cord). It is unique to each of us. For example, when one person finds a room 'too chilly', others won't have an issue with it. One person's 'gentle tap' is another person's 'slap'. The radio volume can be 'too soft' to hear or 'blaring out' unpleasantly - even when the volume dial isn't changed. And how about theme park rides and roller coasters? Love them or hate them? Thrilling or nauseating?

All of the above are examples of sensory processing and how we respond to 'incoming information' from our internal and external environment in everyday life situations. Once picked up, a signal moves onto the relevant part of the brain for processing and interpretation. How our brain processes this information can have a significant impact on how successful we are in a wide range of day-to-day activities.

The ways each of us reacts or responds to a particular sensory stimulus can vary greatly (imagine someone clicking a pen repeatedly in a meeting! Does it bother you? Some people won't even notice it as their brain has screened it out.)

When we think about child development, we can also appreciate that these systems mature, change, and develop over time (this 'brain learning' is sometimes called neuroplasticity). Sensory processing is a dynamic process.

What is a Sensory Processing Disorder?

'Sensory Processing Disorder' isn't a recognised medical diagnosis and so the term is used more in some countries than in others. Regardless of this, children (and adults!) with Autism, ADHD, and similar conditions have different 'brain wiring', and so it is understandable that sensory information is processed differently by the brain too. Research suggests that the majority of autistic children have sensory processing difficulties to a level which has an impact on their functioning.

Children with ASD et al can respond in different ways to each of the 8 forms of sensory input. They may experience:

Over-responsivity (hyper-reactivity) which means the child is more sensitive to that particular stimulus. For example, they may find some lights, sounds or textures uncomfortable or overwhelming. Their systems 'over-respond' and the signal is interpreted as 'too strong/ too much' eg. a gentle stroke of the arm or light touch on the shoulder can be felt as painful.
Under-responsivity (hypo-reactivity)- which means they have reduced sensitivity to a sensory input. For example, they may not respond sights or sounds that other people notice. The child's systems 'under-respond' and the input signal is 'not enough / too weak' to be picked up on or registered. Does your child ignore you when you call their name? Perhaps they haven't picked up on the signal so are not ignoring you after all!
Sensory Seeking - some OTs believe that sensory seeking is a reaction to under-responsivity (I share this view). Because the child's systems don't 'get' enough signals, they seek out more. For example, the child who constantly has to touch everything may have an under-responsive tactile system. The child with an under-responsive visual system sits far too close to the TV screen, and so on. Others still consider sensory seeking to be a distinct pattern of responding.

Each sensory system may also be 'typical', with no differences of difficulties noticed in the way incoming information is responded to.

Remember that a child can under-respond to to some inputs and over-respond to others. It is therefore important to build a picture of their particular profile of need.

By understanding your child's sensory responsivity you can help in the creation of strategies and supportive environments to improve their quality of life and daily functioning.