Sensory Processing Disorder
This is the first in a three part series on Sensory Processing Disorder. This first post explains about what the disorder is and how it works. Future posts will detail how music therapy can help individuals who have this disorder, as well as resources online and in the community.
This is a topic that is rather personal for me, because I personally have sensory processing disorder, as well as some auditory processing issues. Unfortunately, these issues are not very well understood or researched, but I wanted to take some time to discuss what we do know.
What is Sensory Processing?
For every sense we have, there are two components-- the organ receiving the sensation (ie, your eyes, your ears, etc), and your brain processing that information.
Let's take sight as an example. When you look at something, light is bouncing off that object and into your eye. From there (and, yes, I am simplifying this quite a lot), the image is passed along the optic nerve to the part of the brain that processes visual information (the occipital lobe). There, your brain analyzes what you are seeing (say, a kitten), and then you are able to decide what to do about it.
Sensory processing is what happens once the information (the image of the cat) gets to your nervous system-- you analyze the information you are receiving and decide what action to take.
Having a sensory processing disorder is very different from having a "sensory disorder". For example, if someone is blind, that means that they aren't receiving the visual information at all (ie they can't see the cat). If someone has issues with visual processing, they can see the cat-- but they might not understand what they are seeing (they can see the cat but don't know it's a cat, or they think the cat is closer or further away than it is, or that the cat is more threatening than it is).
Sight is an easy sense to talk about this way, but there are many more than just 5 senses, and sensory processing disorders can affect any or all of them. These can include the kinesthetic sense (the awareness you have of what position your body is in), the vestibular sense (knowing which way is up and which way is down), or others, in addition to touch, scent, sound, and taste.
Sensory Seeking vs Sensory Defensive
Sensory processing issues can affect each individual differently. In addition to struggling to understand the information one is receiving from their senses, it is also possible to have different sensory needs than other people.
Some individuals can be sensory seeking-- they seem to have a hard time getting enough of a particular sense.
For an example, if someone with auditory processing issues is sensory seeking, they might struggle with silence, preferring to always be listening to something-- especially something loud. Or someone who struggles with their proprioceptive sense (awareness of pressure, knowing how hard to push) might always be bumping and crashing into things, trying to get the sensation they need to be aware of their senses.
Someone who is sensory defensive, on the other hand, would be hypersensitive to the stimuli they are receiving. They tend to avoid certain senses because they can be uncomfortable, overwhelming, even painful.
A person who is auditory defensive might find loud music painful, and prefer to wear noise cancelling headphones in order to avoid certain sounds. Someone who is tactile defensive might be uncomfortable with being touched, or with wearing clothes made out of certain materials.
Plenty of individuals have a mix of sensory-seeking and sensory-defensive issues. Really, everyone has this to a certain degree-- most people will avoid loud noises when they have a headache, or will seek out certain sensations for comfort (physical touch, the taste of a familiar food, etc) when feeling unhappy. The reason that we are talking about this in terms of being a disorder is because for some individuals, the degree to which they seek or avoid certain sensations becomes a problem in their day to day life. Any child might dislike wearing a shirt with an itchy tag-- but a child with sensory processing disorder might have a meltdown and be unable to function because of how uncomfortable the tag makes them.
Spiders Analogy for Tactile Defensiveness
Tactile defensiveness (hypersensitivity to touch) is an issue for me, which makes it a good example for me to explain the experience of sensory processing disorder to someone who doesn't have it.
I apologize in advance to any readers with arachnophobia.
Touching each other's backs is a fairly normal part of our culture here in America, something that most people take for granted. If someone did a good job, you pat them on the back. Many people will touch someone they know on the back as they pass by, just as a friendly acknowledgement of the person's presence. People pay good money to have their backs massaged. Couples scratch each others' backs while sitting together in public places. This is all very normal and few people mind it-- most seem to enjoy it.
But things that are normal for most people can be very uncomfortable for individuals with sensory processing disorder-- and for me, having someone touch my back is beyond uncomfortable.
The best way to explain the sensation is to say that when someone touches my back, my body responds the same way as I would if someone unexpectedly put a tarantula on my back.
If you're a spider lover, I'm sure you can come up with something else that gives you the creepy crawlies for this analogy-- rats, perhaps, or earwigs, or moldy chunks of pineapple. I don't dislike spiders, myself, but being surprised by one still does give me the heebie jeebies.
Now, imagine you are living in a society where, oddly enough, it is normal to show friendship and affection by putting spiders on each other's backs.
If someone wants to tell you that you did a good job, they'll put a tarantula right on your shoulder blade. When a friend walks by you at a party, you'll suddenly realize that they left you a couple of black widows climbing up your spine. People regularly go to spas to get "spider massages". And romantically involved couples, while sitting next to each other, will constantly pour buckets of spiders down each others' shirts.
You, being the sane "normal" person in this situation, might be tempted to scream or yell or start hitting people, because there's a spider on your back. But everyone is only trying to be nice, and screaming and yelling is not socially acceptable (nor is doing anything to get rid of the spiders) so you need to do your best to just grit your teeth and wait for your skin to stop crawling.
And that is more or less how I feel about people touching my back. Other people with sensory processing issues will have a different experience than I do, but I think that gives you a starting idea on the kind of effect this could have on your day to day life.
Now, imagine that you have someone who can't "just grit their teeth and wait out" whatever is making them uncomfortable. Say, a small child, or an individual who has autism and is unable to speak. It shouldn't come as a surprise when they do respond by screaming or crying or even hitting-- because if a pair of socks with an uncomfortable seam made you as uncomfortable as finding a tarantula on your foot, you might just do the same.
What causes sensory processing issues?
Now, this is a harder question to answer.
There are several disorders and disabilities which can cause some kind of problem with sensory processing. Autism is the big contender; sensory defensiveness and issues with sensory processing are actually some of the criteria that are used to diagnose autism spectrum disorders.
Some people develop sensory processing issues after some kind of trauma-- a head injury, for example, or domestic abuse.
ADHD is also related to sensory processing issues. Gifted individuals often display sensory defensiveness-- in that research literature it is often referred to as "sensual overexcitability".
Then there is Sensory Processing Disorder itself, sometimes abbreviated to SPD. (In older documents, you may find it referred to as Sensory Integration Disorder). SPD is actually a rather contentious disorder-- it's not an "official" diagnosis, and many professionals argue that it doesn't exist, that the symptoms are only manifestations of one of the above disorders that perhaps has not been diagnosed yet.
Arguing about whether or not a disorder exists is beyond the scope of this blog (or my own expertise-- As a music therapist, I'm not qualified to diagnose any disorders, only to treat whatever symptoms and behaviors are present), but some recent research on the brain activity of children with a diagnosis of SPD to imply that there are some key differences between them and children with other disorders.
One theory about what causes SPD lies in the sympathetic and parasympathetic nervous systems. You might have heard of something called the "flight or fight response". When you become aware of something dangerous, your sympathetic nervous system kicks in. You get a boost of adrenaline and cortisol, your heart rate goes up, your awareness of your surroundings increases, your body gets ready to attack or run away from whatever is threatening you. Once the crisis is over, your parasympathetic nervous system comes in--slowing your heart rate and breathing, getting your body to relax. But studies in kids with SPD show that their sympathetic nervous systems are overactive and they're parasympathetic nervous systems are underactive. In other words, their bodies are usually only a few steps away from crisis mode, and it's hard for them to relax.
Another theory has to do with brain structure. Most of the information we receive from our senses is processed in a part of the brain called the Thalamus. The thalamus collects information from the occipital (sight), parietal (touch), olfactory (smell), and temporal (sound/hearing) lobes of the
brain, and then sends that information where it needs to be. But some research on individuals with Sensory Processing Issues suggests that instead this process is being done in the Frontal Lobe. Typically, the Frontal Lobe has to do with attention, organization, and other executive functioning tasks. (People with ADHD tend to have less developed frontal lobes, which can be part of why they struggle with these kinds of tasks) So if the frontal lobe is busy processing all of that sensory information-- well, it makes sensory stimuli harder to ignore (your brain just won't let you forget about that darn spider on your back, or the fact that you are wearing shoes that rub your ankles every time you take a step), and it also means that too much sensory stimulation prevents the brain from handling executive functioning tasks. (ie, you are so focused on the spider that you can't really manage to pay full attention to the conversation you are having with the person who put the spider there).
So How Is It Treated?
Most of the research that exists in treating SPD is in Occupational Therapy. Treatment tends to involve helping clients receive a proper "sensory diet" or a set of sensory experiences meant to meet each person's unique needs-- whether that's helping someone who iss sensory seeking to find safe and appropriate ways to get that feedback, or helping someone who is sensory defensive build more of a tolerance for new stimuli. I have to admit that I don't know as much as I would like about this process, since I was diagnosed at an old enough age that I never really got access to these services myself. (Very few people treat SPD in adults; most treatment services are only available to children. Yes, I find this extremely frustrating.) In the future, I'd like to ask an Occupational Therapist to do a guest blog post on the subject of how they treat sensory processing issues. In the meantime, watch out for our third post in the series which will list several resources for finding sensory processing treatment (and what resources I have been able to find for adults).
One principle of treatment I do understand, which will be discussed more in the next section on music therapy and sensory issues, is giving clients control over their sensory environments. Research has found that being in control of a sensory experience makes it less threatening-- so someone who is tactile defensive has an easier time touching other people than being touched. Helping individuals with sensory defensiveness feel in control of threatening stimuli can give them more power, and make those experiences easier to tolerate. (One practical example: if your child with sensory issues hates the sound of the vacuum cleaner, give them the job of vacuuming the house. It might take them a long time to do the job, but having the ability to turn the vacuum on and off will make it easier for them to handle the noise)
That's it for now, but we'll be back soon for Part Two. Questions? Comments? Disagreements? Feel free to leave a comment below or to contact us, we'd love to hear from you! In the meantime, enjoy your summer, and see you soon!