Wednesday, December 30, 2009

Overlap in Sensory, ADHD and Autism

I am doing tons of reading right now to prepare for a class on self-regulation I'm giving in April.

Current literature is looking at ways to separate out ADHD from Autism and to identify sensory characteristics of each. This is a technical post, but if you read lightly, you can find some interesting tidbits.

There is a technical term: nosology that refers to the hieracrchy of diagnoses. The new nosology for sensory processing disorder (SPD) has several layers. There are 3 types of SPD: Sensory Modulation, Sensory Motor Issues (motor planning and posture) and Sensory Discrimination. Here is a quick look at it. See the Miller article referenced below for details.

Sensory Processing Disorder (SPD):
1. Sensory Modulation
------Over response
------Under Response
------Seeking/ Craving
2. Sensory Motor Issues
-----Dispraxia (Motor Planning)
-----Posture Disorder
3. Sensory Discrimination
-----Auditory. touch, vestibular, proprioception, etc.

The reason I taxed you with the nosology is to highlight the modulation piece. Modulation from sensory causes appears similar to ADHD, but ADHD is not caused by sensory issues. An assessment such as the Sensory Profile can tease out which is which.

ADHD as you probably know has characteristics of impulsivity, poor attention, hyperactivity, etc. that can also be found in SPD. Typically, ADHD is treated with therapies, patience, etc, etc or meds. SPD is treated with sensory therapy. Completely different.

Now we get into autism. What they are finding is that 42-88% of children with autism have sensory processing disorder. Some also have a sensory modulation disorder. 50%-80% of children with autism have ADHD. However (back to nosology) ADHD in the DSM-IV (Psychiatric Manual) is a level 2 disorder. Autism is a level 1 disorder and takes precedence. So technically, if a child has autism, they cannot be also diagnosed with ADHD (a disservice in my opinion).

Children with ADHD have communication and social issues, but they are not the same sort of issues as those found in autism. Hartley & Darryn (2009) pose the question "Is high functioning autism distinguishable from ADHD and from anxiety in older children?" The short answer is yes, but they share a number of seemingly similar characteristics in the areas of communication skills, social skills, and repetitive behaviors. Lots of overlap to sort through with children who are neurotypically different than their peers.

1. Miller, L., Anzalone, M., Lane, S., Cermak, S., & Osten, E. (2007). Concept evolution in sensory integration: A proposed nosology for diagnosis. American Journal of Occupational Therapy , 61, 135-140.
2. Hartley, S., & Darryn, M. S. (2009). Which DSM-IV-TR criteria best differentiate high-functioning autism spectrum disorder from ADHD and anxiety disorders in older children? Autism , 13, 485-509.