Sensory processing difficulties: signs, causes and support in the UK

We take in information through the familiar senses of sight, sound, smell, taste and touch, and also through balance and movement (the vestibular sense), body position (proprioception) and awareness of internal states such as hunger, thirst, temperature and the need for the toilet (interoception). The National Autistic Society (NAS) explains that sensory processing is how the brain makes sense of the information arriving from these senses.

In sensory processing differences, this happens in a way that differs from most people. The NAS gives the example of a person with perfectly normal eyesight who finds bright lights overwhelming or struggles to process dense written information. The problem lies in how the information is handled, not in the eyes themselves.

You will also see the term sensory processing disorder (SPD). The NAS points out that SPD is not a formal diagnosis in the medical literature, and some people have it mentioned as part of another diagnosis. That does not make the experience any less real or any less worth supporting.

The NAS describes three broad patterns. Many people have a mixture of them, and sensitivity can change with tiredness, stress, illness or environment.

The NHS lists sensory differences among the signs of autism in children. Autistic children may react very strongly, or not at all, to lights, sounds, smells, tastes or textures, dislike brightly lit or noisy rooms, dislike wearing certain clothes or materials, eat only certain foods or in a certain way, dislike foods with certain textures, and find it difficult to describe feelings such as hunger or pain. The NHS also notes that some children actively look for sensations that feel calming or enjoyable, such as movement, pressure, sounds and textures.

The NAS lists common triggers of hyper-sensitivity: bright or fluorescent lighting and cluttered environments; loud speech, unexpected noises and background noise; crowded places, unexpected touch and some fabric or food textures; perfumes and cooking smells; and feeling too hot or cold. It says environments with a lot of input outside your control, such as shopping centres and schools, can be particularly challenging.

This guide draws on autism sources because they are the best UK material available. The NAS notes that some people have sensory processing disorder mentioned as part of another diagnosis, and that sensory differences can be identified and support provided whatever the label.

Sensory overload is when a person becomes overwhelmed by sensory input and cannot process any more. The NAS says it is not a clinical term but is used by autistic people to describe how sensory hyper-sensitivity combined with triggers can lead to overwhelm and distress. Being overwhelmed in just one sense can be enough.

• Not speaking or communicating, or appearing disengaged or closed off.

• Difficulty focusing, pacing, rocking or stimming.

• Higher than usual sensitivity to sensory input.

• Strong physical and emotional responses such as crying, shouting, running away, hiding or resisting touch.

There is no blood test or scan for sensory processing differences. The NAS says that in an autism assessment, how a person reacts to sensory input is considered as one of four examples of restricted and repetitive behaviours and interests, and that two of these four must be present for an autism diagnosis. Sensory differences are not required for a diagnosis but may count towards one.

If sensory differences are constant and having a negative impact on everyday life, the NAS suggests seeking support from an occupational therapist (OT), whose clinical assessment identifies sensory differences and allows individual adjustments to be put in place. It acknowledges that it can be difficult to access an OT assessment because of waiting times and private costs. The NHS advises speaking to a GP if you think a child might be autistic, and mentions the school or nursery SENCo as another route.

The NAS suggests starting with understanding the person’s sensory profile. A sensory diary can help identify triggers, sensitivities, times of day and what helps during and after overload. Practical items that autistic people have found helpful include ear defenders or noise-cancelling headphones (although using these a lot may increase sensitivity over time), sunglasses or tinted glasses, fidget toys, weighted blankets or vests and wobble cushions. The NAS notes that the Royal College of Occupational Therapists recommends an occupational therapist assess the use of weighted items.

For other people supporting someone, the NAS advises identifying triggers and the early signs of overload, reducing or removing triggers, providing a safe space, telling the person what to expect before going to busy places, and not judging or questioning their experience. If someone is already overloaded, it suggests removing triggers, moving them to a quieter place, reassuring them, keeping speech to a minimum and giving them time and space to recover.

Occupational therapists may use approaches such as sensory integration therapy, sensory diets and sensory circuits. The NAS says it is not clear how effective current sensory therapies are, that research shows mixed results, and that any therapy should put the autistic person at the centre of decisions, be delivered by professionals with good autism knowledge and be carefully monitored.

Consider speaking to a GP, a school SENCo or an occupational therapist when sensory difficulties affect eating, sleeping, learning, work, relationships or physical and mental health. The NAS lists these as areas that sensory differences can affect, including migraines, nausea, pain, anxiety and burnout. Sudden changes in sensory perception in someone who has not had them before, especially with headache, weakness or confusion, should be discussed with a GP or NHS 111 promptly.