Excerpt from Chapter One: What is Sensory Processing Disorder?
Q. What is sensory processing?
A. Sensory processing or sensory integration refers to the nervous system's job of taking in all the information around us through our senses (movement, touch, smell, taste, visual, and hearing) and organizing that information so that we can attach meaning to it and act on it accordingly. Sensory integration is the basis for learning. It is what allows us to get an idea of what is going on in the world around us. We learn when we take in new information, cross reference the new information to previous similar experiences, and make an assessment as to how we should proceed given the current set of information.
For example, when you hear a dog barking, your ears take in the information and your brain attaches meaning to it, such as identifying it as an animal, not a cat but a dog, determining how close it is, and deciding whether it sounds like a big dog or a small dog. Then the brain matches that information with past experiences that have been stored as memory. If you have ever been bitten by a dog, you may run to get away when you hear the barking. On the other hand, if you grew up with dogs, the sound may make you homesick for your childhood home.
The development of sensory systems begins in the womb and continues throughout our lives. In the early childhood years, the nervous system is in hyper-development and sensory integration is being refined through typical childhood activities. This is why the first few years of childhood are considered the sensory-motor years, and are crucial for laying the foundation for our nervous system.
Q. What is Sensory Processing Disorder?
A. Sensory Processing Disorder (SPD) describes the difficulty that some people's nervous systems have in making use of and integrating sensory information. SPD can exist when there are no other underlying conditions or can be present in conjunction with other neurological or psychological diagnoses.
Q. What causes SPD?
A. Sensory Processing Disorder is a result of neurological disorganization that affects nervous system processing in a few different ways. The brain is not receiving messages, or the messages that are received are inconsistent, or the sensory information is consistent but does not integrate properly with other sensory information from the other related sensory systems.
Q. What are some of the general signs of Sensory Processing Disorder?
A. Here is a list of signs that may point to Sensory Processing Disorder:
- Overly sensitive to touch, movement, sights, or sounds
- Underreactive to touch, movement, sights, or sounds
- Easily distracted
- Social and/or emotional problems
- Activity level that is unusually high or unusually low
- Physical clumsiness or apparent carelessness
- Impulsive, lacking in self-control
- Difficulty making transitions from one situation to another
- Inability to unwind or calm self
- Poor physical self-concept
- Delays in speech, language, or motor skills
- Delays in academic achievement
Q. Who "discovered" SPD?
A. Sensory Processing Disorder (originally called Sensory Integration Dysfunction) was first "discovered" in the mid-1900s but was not given any attention until Dr. Jean Ayres, an occupational therapist, psychologist, and neuroscientist, wrote a book called Sensory Integration and Learning Disabilities in 1972. The book was based upon research that linked sensory processing to learning difficulties. Building upon Dr. Ayres's work, other researchers and therapists drew a link between sensory processing difficulties and behavior.
Q. What percentage of the population has Sensory Processing Disorder?
A. A recent study showed that at least 5 percent and up to 13 percent of the population has Sensory Processing Disorder.
Q. I've heard it called Sensory Integration Dysfunction and Sensory Processing Disorder. Which is it?
A. Beginning in the 1970s, the term Sensory Integration Dysfunction was commonly used. However, as the field matures and we learn more about how sensory processing difficulties can manifest themselves differently in children, there has been a need for a more expansive term that has evolved into the term Sensory Processing Disorder. You will still hear the term Sensory Integration Dysfunction occasionally.
The term sensory integration is mostly reserved for explaining how the nervous system processes sensory information, whereas Sensory Processing Disorder describes the condition that reflects difficulties with how we register and process that information. Sensory Processing Disorder is an umbrella term covering three categories, which will be discussed extensively in the next question.
