I was happy to see the American Academy of Pediatrics publish their new policy statement about sensory integration. I know that a lot of people are up in arms about this policy but in my estimation the AAP presents a very fair and balanced assessment.
Defenders of 'sensory processing disoder' are quick to point out that some more recent research was not included in the AAP review. I was disappointed when I read Dr. Miller's letter to the editor where she talked about the 2007 RCT. This was a great study
and I think they did an impressive job of looking at limitations in
previous studies but it was only a pilot study and it lacked statistical
power, there were noted blinding problems, and it relied on GAS which
many people believe opens up issues of expectancy and confirmation
My point here is not to rip apart people's efforts because
actually it was a good step forward in our research. The problem is
that we can't point to studies like this and expect to sway other
people's opinions. Significant methodological problems are also present
for some of the other 'newer' research that she referenced.
Herein lies the problem with too many of my occupational therapy colleagues. The best analogy I can think of is that OTs are like the kittens who had their eyes sutured shut at a critical period in their development - and then permanent changes happened in the way that they went on to process visual information. Similarly, OTs are inculcated/programmed en masse about sensory integration in their educations - and even though we STILL can't point to what sensory integration disorder even IS it doesn't stop anyone from developing questionnaires, writing books, developing intervention protocols, and in general attributing all manner of atypical childhood behavior to this undefined sensory integration process.
These attributions are taking us into really dangerous territory and in fact they are probably even contributing to AAP feeling the need to address the issue and even more directly it probably contributes to the insurance companies uniformly denying reimbursement for this intervention. We have some really bizarre claims that the evidence-based medicine world just doesn't know what to do with.
The prevalence issue may sit on top of the heap of concerns. These studies (here and here) state that between 5% and 15% of the population has a sensory processing disorder. The problem is that they rely on sensory questionnaires that DO NOTHING to contribute to differential diagnosis. So we really have no way of knowing if these children have any co-morbid disorders. Actually we shouldn't even be using the word "co-morbid" because we don't even know if sensory integration difficulties constitute a disorder and if these traits are just part of other problems. In fairness, the Ben-Hasson, Carter, & Briggs-Gowan (2009) study did control for some diagnostic conditions but the results also showed that gestational age, birth weight, and socioeconomic status were more likely to be associated with sensory over-responding. I guess that means that children who have a history of prematurity may have atypical sensory responsivity - which is no surprise - but does that mean that they have a unique sensory disorder? Or is it more accurate to describe their difficulties in terms of nervous system immaturity when they were born and long term impact of things like mild PVL or IVH? Or does environmental enrichment (or lack thereof) also play a role which is also suggested in the data?
What these studies show is that children may have difficulties with sensory processing skills - or at least they have difficulties that we want to think are associated with sensory processing skills - but that we really can't stretch this and make statements that this 'proves' anything about actual prevalence of a distinct condition.
I am not sure why but over time and after a lot of repetition it seems that people just start repeating these prevalence statements as if they are undisputed facts. In my opinion just about any statement made about prevalence of 'sensory processing disorder' has been an overstatement of our research results.
This is a major reason why I really have no problem with the AAP policy statement. I also think that if there was this kind of prevalence of children with this disorder that I would be seeing it in my clinic - but I just don't. Sure, I see kids with sensory processing difficulties, but these difficulties are almost always associated with other disorders. Most commonly these sensory differences are associated with conditions like ADHD or autism. Less frequently these sensory differences are associated with esoteric clinical problems. There was this case study about the child who had congenital adrenal hyperplasia. Or there was this case study about the child who had a conditioned fear response that caused piloerection and tooth pain. Or I could just talk about the six year old child who I saw a couple weeks ago. The parent brought him in because the child can't stand his clothing and has frequent behavioral meltdowns. All other aspects of his development are normal, and as I scratched my own head trying to figure things out I watched him scratch at his own arms - and then I saw large raised welts appear across his skin. With the parents permission I tested the skin on his legs and back - and indeed the child has dermatographia so I sent him back to the pediatrician who prescribed antihistamines as needed and magically the "tactile defensiveness" to clothing has disappeared.
Why does this matter? Well, mostly because we already know what kinds of interventions are most effective for children who have ADHD. We also know what kinds of interventions are most effective for children who have autism. If we stopped trying to define some 'new' diagnostic entity maybe we would also stop trying to create some 'new' intervention protocol. Then we could fall back to family education, trial practice, skill training, behavior modification, and adaptive/compensatory approaches that we all know work.
The AAP and others in the broader medical community would probably be happy to see some more discretion when we talk about prevalence and whether or not these problems constitute distinct diagnostic entities. OTs need to be willing to 'de-program' themselves from their educational experiences that cause them to call too many things "sensory processing disorders."