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spd1Sensory Integration (SI) is a term that has become quite well-known since its discovery in the 1960’s by developmental psychologist and occupational therapist, A. Jean Ayres, PhD, OTR.  During her work, she observed that many children appeared to have difficulty tolerating or interpreting the sensory information from their environments.  She described this as a sensory integration dysfunction (now called Sensory Processing Disorder or SPD).  She developed tests to examine these skills, which led to increased insight into how the sensory systems are related and how functional skills are impacted when they are not functioning correctly.  She spent the next few decades of her life researching her theory, which, thanks to her and her followers, has now become one of the most researched areas of occupational therapy.

Overview, Causes, and Prevalence
The sensory systems involved in sensory processing are:

  • Tactile – touch
  • Vestibular – movement
  • Olfactory – smell
  • Gustatory – taste
  • Auditory – hearing
  • Visual
  • Proprioception – the sense of our joints and muscles For example, if the lights are turned off, it’s the sense that tells you where your body is without looking.  Difficulties with this sense can present as extreme clumsiness or difficulty with tasks such as jumping, catching, and throwing.
  • Interoception – the sense of our internal body including organs and body systems For example, being able to tell if you are hungry or when you need to go to the bathroom.

Aspects of Sensory Processing

  1. Sensory Modulation. Sensory modulation is the ability to appropriately adjust the intensity of a response to incoming sensory information.  Children with modulation difficulties may have an extreme emotional response to sensory information (over-response) or may appear not to notice sensory information at all (under-response).  For example, some children are aversive to textures on their bodies and may cry when at the beach because of the coarse texture of the sand, or they may be oversensitive to movement and may throw a tantrum when put on a swing.

Children can also have the opposite reaction of being undersensitive to sensory stimulation. A child with this type of sensory processing may not notice or pick up on the sensory information from his environment.  He may not notice when his hands are dirty or he might have a very high pain threshold and not realize when he is injured or sick because he requires more tactile input than most people to be able to register this type of sensory information.

Sensory modulation difficulties can be present in a variety ways – a child who is oversensitive to a particular sense may also seek additional stimulation from that sense.  An example would be the tactile system – often children that avoid certain types of touch (such as not tolerating wearing certain types of clothing) may seek out others (such as having a favorite blanket or stuffed animal).  In addition, a child who is unaware of certain types of sensory information (such as being unaware of the proprioceptive system) may be hypersensitive to others (such as being oversensitive to vestibular stimulation).

  1. Sensory Regulation. Sensory regulation refers to the arousal state of the nervous system. Some children may be hyper-aroused and may present as hyperactive, destructive, or poorly behaved.  Others may be under-aroused and seem to have no motivation to complete daily activities.  They may be slow learners and may require additional cues to complete daily tasks independently. Children with regulatory problems almost always have difficulty attending in school.
  1. Sensory Integration and Praxis. Through research conducted using the sensory processing tests that she created (formerly known as the Southern California Sensory Integration Tests (SCSIT), now known as the Sensory Integration and Praxis Test (SIPT)), A. Jean Ayres discovered a direct relationship between sensory processing and praxis. Praxis is the scientific term for motor planning which is figuring out how to perform new motor tasks (such as tying shoelaces).  Whereas children with properly functioning sensory systems can learn a new motor task with relative ease and few repetitions, children with motor planning issues will need to practice a new motor task repeatedly to learn how to do it and even then may struggle with performing the task in a smooth, coordinated manner.

Another common difficulty for people with motor planning issues is organization.  People with SPD often appear to have difficulty with organization of materials, sequencing steps of a game or motor activity, and organizing their thoughts on how to initiate and complete tasks.

Causes and Prevalence
Although the causes of SPD are not known at this time, it is a disorder than can be present on its own or can be associated with developmental disabilities such as autism, prematurity, or bipolar disorder.  It generally appears to be present from birth, but may not be noticed right away.  Research indicates that 1 in 6 children have sensory symptoms severe enough to impact how they are able to function in daily life.

Dysfunction vs. Impairment
It is important to note that everyone has different levels of sensory functioning and different sensory preferences.  Sensory dysfunction does not necessarily indicate impairment–a person’s ability to interpret sensory information and level of neurological arousal can vary from day-to-day.  When you are sick or tired, you may have a harder time tolerating loud music or certain smells.  This is similar to what people with SPD go through on a regular basis. Their sensitivities may be more or less severe, but the difference is that it impacts their abilities to function in daily life.

Warning Signs
It is important to see an occupational therapist for an assessment if you observe certain behaviors with your child.  has provided a downloadable Referral Checklist, along with the Short Sensory Profile to allow you to look at some issues that may indicate SPD.

If SPD is suspected, a referral to an occupational therapist (OT) should be made.  A parent can either contact a local OT directly or go through his or her pediatrician to get a referral for an OT.  The OT should have had special training in SI techniques to be able to most effectively treat this disorder.

True sensory integration treatment is child-directed and playful.  It involves providing the child with organized sensory experiences and the child using his body to move through space to explore various sensory challenges.  Sensory integration treatment is different for every child based on his specific needs. The goal of SI treatment is to achieve what is called an “adaptive response.”  An adaptive response occurs when a child has an appropriate response to an environmental challenge.  For example, a child may have difficulty timing and sequencing his movements so that he is able to jump from a moving surface.  He achieves an adaptive response when he is able to coordinate his movements so that he is able to jump off the surface at the correct time and land safely.

If not treated, SPD usually does not resolve on its own.  In addition to the behavior issues and other difficulties the child will continue to have, the child will most likely struggle with attention, socialization, self-esteem, and academics as he gets older.  As an adult, the person may have difficulties with anxiety, organization, and maintaining successful relationships.  The earlier SI dysfunction is treated, the happier the child and everyone who interacts with him will be.