Sensory Processing Disorder: Sensitivity to Smell

Today I will be focusing on heightened sensitivity to smell and its possible impact on everyday life for autistic people. We have already looked at three senses affected by sensory processing disorder: sight, hearing and taste. A person with SPD perceives stimuli in a different way to others. This can result in either seeking or avoiding behaviours.

Every day, we are bombarded with a variety of different scents. Many are pleasant; others not so much. For an autistic person, this can cause a great deal of discomfort. An unpleasant or strong smell may trigger meltdown behaviour.

Sense of Smell: Overview

The sense of smell is closely linked to the sense of taste. We have special cells, located high in our noses that detect scents. These cells link to the brain. When an olfactory sensory neuron detects a smell, it sends a message to the brain. The brain interprets the data at receives and recognises it as a particular smell. Scents can also affect our emotions and stimulate memories.

Our sense of smell has two very different purposes. One is related to enjoyment; the scent of flowers, perfume, or delicious food cooking. Our sense of smell also functions as a powerful warning system. For example, we might detect a fire from the smell of burning. Likewise we would not eat a food if it smelled bad, as this would indicate spoilage.

Sensory Avoiding Behaviours: Olfactory

For some autistic children, certain scents are unbearable. My son hates strong food smells like vinegar and cheese. He was bullied by children at school who would deliberately put these foods near him to get an extreme reaction. Children who dislike strong odours may be picky eaters and refuse many foods because of their sensitivity to smell.

Smells in the environment can also be a big problem. My son will loudly protest if we visit a house or building that he considers “smelly.” This can be embarrassing when visiting someone’s home! It can be good to put ourselves in the child’s position. It is unpleasant for us if we are in a room that smells bad. Imagine how much worse it must be for a child with autism. They may often respond by trying to get away from the source of the smell. They may get very agitated and upset.

Olfactory Sensory Seeking Behaviours

On the other end of the spectrum, there are children who love strong smells and seek them out. They may even be attracted to particularly unpleasant odours like feces. This could result in dangerous behaviours, as such children may seek out substances like gasoline, which are harmful to inhale.

On a positive note, parents may be able to use fragrances in a useful way. If a child is agitated, a pleasant or familiar scent may be very calming and relaxing to them.

Helping Children with Sensitivity to Smell

Whether the child has seeking or avoidant behaviours, there are ways to help. It’s good to be aware of how a child may react in a different environment and make plans accordingly.

Some parents have had success introducing new scents to their child in small increments. This could help desensitise them to a certain smell.

Others have used scents as therapy. There are scented putties available which can be used as stress relief toys. Pleasant scents can distract a child from a bad smell. For example, if a family are visiting a zoo, they may anticipate some bad smells! Therefore, they could take along a small cotton wool ball or tissue with a few drops of essential oil. The child can use the pleasant fragrance as a distraction to cover any unpleasant smells. Certain oils like lavender are very relaxing.

It can also be good to make an “escape plan” and think of ways that you can physically remove a child from a situation if they are becoming emotional.

As individuals we should be considerate of those around us. It is not kind of us to wear very strong fragrances. This could actually be overwhelming to others and cause discomfort.

As with other sensory processing issues, it is best to consult a professional for advice about the best methods for helping your child. An occupational therapist may advise on a “sensory diet,” which is a series of exercises to help children with SPD.

Sensory Processing Disorder: Taste

The sense of taste is going to be the third part of my series on Sensory Processing Disorder. As we have seen in the previous two posts about visual and auditory processing problems, children with autism can have significant issues in everyday scenarios. This is due to the way that the brain deals with the information that it receives.

As the sense of taste relates to food, it is reasonable to conclude that a disturbance in processing taste can cause problems. Getting a balanced and healthy diet can be hard, and social situations difficult. Sensory processing issues related to taste can require creative solutions to overcome successfully.

Sense of Taste: A General Overview

The sense of taste is also known as gustation or gustatory perception. It is closely related to the sense of smell. The five main categories of taste have been identified as: sweet, sour, bitter, salty and umami. As well as these main tastes, the way we perceive our food can also be affected by the texture of the food. It can also matter how hot or cold it is.

A person with sensory processing taste issues may struggle to distinguish flavours from one another. As with other SPD types, we see both sensory avoiding and sensory seeking behaviours regarding food.

Food: Sensory Avoiding Behaviours

For some with sensory taste processing issues, certain flavours may be overwhelming. This may cause them to gag or to even vomit when eating a food that they don’t like. They may be extremely picky eaters, preferring very bland foods or limited foods from a certain category. It can be difficult for a child with SPD to get a balanced diet containing all of the necessary nutrients from the main food groups. In very extreme scenarios, a child may only wish to eat one particular type of food.

Another problem that may occur with SPD is that a child may not like certain foods on a plate to touch or mix together. A parent or caregiver may need to divide elements of a meal into separate plates to avoid them touching or contaminating one another.

Temperature can also play a big part in whether a child may accept a certain food. They may only like it served at room temperature and dislike hot food. Likewise, a child may try and avoid foods with certain textures, such as lumps.

Food: Sensory Seeking Behaviours

The opposite is true of a child with sensory seeking behaviour. They might love strongly-flavoured foods or hot and spicy dishes. They may also drool and dribble excessively. Such a child may also crave foods that are inedible and potentially dangerous, such as stones, dirt or feces. This is known as pica.

Some children also seek out general oral stimulation by chewing objects or clothing because they like the sensation.

Help for Children with Gustatory Processing Issues

Food should be made as appealing and as easy to manage as possible. This will depend on the preference of the child. Parents could try cutting food into small chunks or presenting it in a novel or creative way.

Friends and family should try and set a good example for by showing how enjoyable a varied diet can be. They should offer plenty of praise for trying out new foods. This can really encourage a child with sensory processing taste issues.

It can be a good idea to let a child help out in the preparation of a meal, so that they can associate food with enjoyment. They may be more willing to try something that they have made themselves.

For a child seeking oral stimulation, there are a variety of sensory toys available, including chewable jewellery. This will enable them to satisfy their need to chew without being destructive.

An occupation therapist or dietician may also be able to help with further suggestions on how to enable a child to eat a varied and balanced diet.

In my next blogpost in the series, I’m looking at the sense of smell and it’s associated sensory seeking and avoidant behaviours.

Sensory Processing Disorder: Hearing

In this second part of my series on SPD, I’m going to be looking at the different ways that autistic people may process sound. As previously mentioned, Sensory Processing Disorder occurs when the brain has difficulty with the information it receives via the senses.

When I discussed visual SPD in the last blogpost, I mentioned that sensory behaviours can be either “seeking” or “avoiding.” The same is true with hearing sounds and we are going to look at how this can impact on everyday life.

How May SPD Affect How Someone Processes Sound?

It is estimated that as many as 7% of children have a problem with processing sound. This can also be known as auditory hypersensitivity. Unlike deafness, the child has no problem actually hearing sounds. The problem occurs in the way that the brain processs the sounds. For example, in a typical classroom there may be a teacher talking to the class, but there is also a variety of background noise, like a ticking clock, squeaking chairs, whispering children or outside traffic. A child with SPD may struggle to filter the relevant noises from the background ones.

As a result of this, a child with auditory hypersensitivity may have trouble remembering information if it is given verbally. It may also affect their social development if their ability to interact with peers is affected. Many opportunities for socialising involve noisy venues, so this can create real problems when a child with SPD reaches the teenage years and cannot access these places without feeling uncomfortable.

Scientists at the University of California studied the brains of autistic children exposed to traffic sounds and scratchy noises. They found that the amygdala (part of the brain associated with social and emotional behaviour) was more active in autistic children than neurotypical children when hearing these sounds.

Sensory Seeking Behaviours

A child with SPD may seek out loud noises or crave them. They might enjoy listening to loud music on their headphones. They may like visiting noisy, crowded places or self-stimulate by banging objects loudly.

Some autistic people are sensitive to pitch and a group of British researchers studying autistic children found that 20% had “perfect pitch,” meaning that they have an exceptional ability to distinguish between musical notes. However, other children in the same study had problems distinguishing the loudness of a tone. These children were the ones least likely to cope with everyday noises.

Sensory Avoiding Behaviours

Some children with autism can actually feel physical pain when exposed to certain sounds, especially very loud and unexpected sounds like a fire engine or someone shouting in the street. This can lead to public meltdowns, which can be very distressing for both parent and child.

If asked to picture an autistic child, we may conjure an image of someone covering their ears, trying to blot out the noise. This is because auditory sensitivity is so common in autistic children. From a practical point of view, concentrating in class at school may be hard as competing sounds merge together as one. A child may even be able to hear people having a conversation in the distance. Sounds that we may view as “normal” may be unbearable to an autistic person.

Helping A Child With Auditory Processing Issues

There are many practical ways that parents and friends can help a child with SPD. For example, ear defenders, the type used by industrial workers, can be a great help, as they muffle out the noise and make it more bearable. This can be a useful strategy if you are visiting a crowded or noisy place; for example, a fireworks show.

Sensory seekers may benefit by having their needs met, for at least some part of the day, in a home or school setting. This could include having access to musical instruments or being able to listen to music on headphones.

It can be a good idea to prepare a child before going somewhere that may potentially cause issues. Think about the place that you are visiting and any problems that you could foresee occurring. The child may be best positioned away from loud sources of noise (unless they are a sensory seeker!) or away from windows and sources of conflicting sounds.

Children with SPD may enjoy listening to recordings of white noise as a way to relax. Earbuds or noise-cancelling headphones could also be useful devices that may help a child.

In my next blogpost, I will be looking at how the sense of taste is affected by SPD, and some of the implications associated with taste hypersensitivity.