Just as in my foray into the world of autism, most of what I say about Sensory Processing Disorder (SPD) will come from Wikipedia and the book I've read on the subject. Again, I do not profess to know everything, or much of anything, about SPD and I encourage you to read about and research it on your own if you want to learn more.
[Side Note: I will be going back to ASD subjects, but I wanted to forge ahead and get a few things defined and introduced before getting more in depth anywhere.]
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Sensory Processing Disorder is also known as Sensory Integration Disorder or Sensory Processing Dysfunction. It is a neurological disorder that causes difficulty with taking in, processing and responding to sensory information from the environment around us.
For those with SPD, sensory information may be sensed and perceived in a way that is different from most other people. Unlike blindness or deafness, sensory information can be received by people with SPD, the difference is that information is often registered, interpreted and processed differently by the brain. The result can be unusual ways of responding or behaving, finding things harder to do. Difficulties may typically present as difficulties planning and organising, problems with doing the activities of everyday life (self care, work and leisure activities including work and play), and for some with extreme sensitivity to sensory input, sensory input may result in extreme avoidance of activities, agitation, distress, fear or confusion.
SPD is a widely acknowledged theory, but there is much controversy over whether or not it sould be considered a distinct diagnosis or as a feature of separate diagnosis. It is not recognized in any standard medical manual such as the DSM-IV, but it is an accepted diagnosis in Stanley Greenspan’s Diagnostic Manual for Infancy and Early Childhood and as Regulation Disorders of Sensory Processing part of the The Zero to Three’s Diagnostic Classification. SPD is often associated with a range of neurological, psychiatric, behavioral and language disorders. There is no known cure; however, there are many treatments available.
When you consider all the things your body must do to interspret a sensory message correctly, you realize just how amazing it is! As listed in the SPD book I read (see side bar to left; it's called Sensory Integration Disorder in the book), successful sensory integration involves the following:
* Receiving the sensory information successfully (all the things you see, hear, smell taste, and feel start out as waves of light or sound, chemicals in your nose or on your tongue, or pressure against nerve endings in your skin. Those sensations are translated into electrical impulses that zip along neurons in your brain)
*Interpreting all this sensory information correctly
*Combining information from different senses to create a complete picture
*Deciding on a response based on information from all sources
*Executing that response by sending electrical impulses back out to the muscles and limbs
And we all do this each and every day, constantly, without having to give it a thought...it's automatic and we don't even notice that it's happening! For someone with sensory processing problems, it's awfully hard to ignore. They might have trouble:
* Receiving sensory information successfully if his/her brain needs a larger than normal amount of information before it reacts, or reacts too strongly to a small amount of info
*Interpreting sensory information correctly if not enough info gets through, or so much information gets through that it is overwhelming and cannot be interpreted
*Combining information from different senses if info from some of the senses isn't successfully received or correctly interpreted , or info from different senses can't be put together
*Deciding on a response if s/he doesn't have a complete picture to base it on, or if her/his brain hasn't developed and/or stored a plan for action
*Executing that response if his/her brain doesn't know what his/her muscles are up to already
Our world and the world of someone with sensory processing problems are different, built by unique brains out of the blueprints provided by the senses. For someone with SPD, the world might seem bigger, louder, scarier than the way we interpret them, and other things we notice might not register at all!
Let's look briefly at the Seven Senses that send our brains the information about our surroundings and our bodies placement to our brain for processing. And yes, I said seven. (These are taken from the same Sensory Integration Book at left and discuss some of the possible hyper- and hypo- symptoms of someone with SPD. Hyper- being when they receive too much info, and Hypo- being when they receive too little info):
1) Gustatory Sense (Taste). Craves very strong, sharp or sour flavors; refuses all but the blandest of foods; can't tell the difference between foods; eats or sucks on non-food items
2) Olfactory Sense (Smell). Has trouble telling the difference between smells; Can't readily identify odors; has extreme reactions to certain smells; has no reaction to strong smells
3) Auditory Sense (Hearing). Has extreme reactions to sirens, alarms, vaccuum cleaners; can't calm down in noisy rooms; doesn't hear or respond to your calls if there are too many other sounds in the room
4) Visual Sense (Sight). Can't stand bright lights; feels agitated around bright colors or busy rooms; can't pick items out of a detailed picture or background; can't see how a puzzle goes together
5) Tactile Sense (Touch). Has extreme reations to clothing, combing, hair cutting, dental work; doesn't react enough to pain, cold, discomfort; avoids hugs, tickles, cuddles
6) Vestibular Sense (Balance). Either fears or craves swinging; becomes upset when tipped backwards; fears heights and having feet off the ground; loves to spin around repeatedly and/or rock back and forth
7) Proprioceptive Sense (Body Position). Regularly bumps into things accidentally or on purpose; has trouble planning simple sequences of movements; jumps or rocks; likes hard hugs
Since sensory integration involves receiving and interpreting information from the senses and combining the info to form an accurate picture, problems with one sense can cause problems with all sensory input and output. If the feel of clothing is a distraction, it's going to affect the ability to listen and see detail and to stay still. If someone feels off-balance, it's going to effect the way things are seen, how movements are coordinated, and whether or not they are able to hear things and to what extent. Because of this, it's important to look for patterns of behvior across senses, especially strong over- or under-reactions.
Let's go back to my friend Wikipedia to look at the Classifications fro SPD. There are three primary diagnostic groups:
Type I - Sensory Modulation Disorder (SMD). Over, or under responding to sensory stimuli or seeking sensory stimulation. This group may include a fearful and/or anxious pattern, negative and/or stubborn behaviors, self-absorbed behaviors that are difficult to engage or creative or actively seeking sensation.
Type II - Sensory Based Motor Disorder (SBMD). Shows motor output that is disorganized as a result of incorrect processing of sensory information affecting postural control challenges and/or motor planning
dyspraxia.
Type III - Sensory Discrimination Disorder (SDD). Sensory discrimination or incorrect processing of sensory information. Incorrect processing of visual or auditory input, for example, may be seen in inattentiveness, disorganization, and poor school performance.
Furthermore, sensory modulation problems include
- Sensory registration problems - This refers to the process by which the central nervous system attends to stimuli. This usually involves an orienting response. Sensory registration problems are characterized by failure to notice stimuli that ordinarily are salient to most people.
- Sensory defensiveness - A condition characterized by over-responsivity in one or more systems.
- Gravitational insecurity - A sensory modulation condition in which there is a tendency to react negatively and fearfully to movement experiences, particularly those involving a change in head position and movement backward or upward through space.
Sensory Processing Disorder is a common symptom of autism spectrum disorders, and might be more common in autistic children than in adults with autism. The trend is more toward undersensitivity than oversensitivity or sensory seeking in ASD, but seeking and oversensitivity do, of course, occur as well.
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I hope this gives you a brief overview of what SPD is and how it can effect those who have it. We can talk about different therapies later on, and I might go into a few details here and there with it. But, for now, this should be more than enough to you started!
Take care!
