Tuesday, October 29, 2013

Reasons to pause when discussing a "sensory processing disorder" construct.


The Sensory Profile is an assessment tool that purports to measure sensory processing abilities (Pearson Education Inc., 2008); there are versions for infant/toddlers, school aged children, and adolescent/adult populations.  The tool has been used to document the incidence of a "sensory processing disorder" construct (Ahn, et. al., 2004; Ben-Sasson, et. al., 2009).  To date, although many scientists recognize that children can have difficulties with processing sensory information, this diagnostic construct has been rejected and is not considered as a distinct clinical entity (AAP, 2012).   For more in depth reading, please reference previous blog posts here.

I was interested to see an article in a recent OT Practice magazine regarding sensory processing abilities of children involved in the justice system (Shea and Wu, 2013).  The article presents an interesting test case for use of the Sensory Profile to help understand the nature of some difficulties that these adolescents may have.

Face validity is a construct that relates to whether or not an assessment measures what it is supposed to measure.  The question we can ask about this study is: Does the Sensory Profile measure what it is supposed to measure?  A statement in the article that caught my attention was
The occupational therapists were particularly surprised by the low score in sensation seeking, because they had hypothesized that these youths would have higher sensation-seeking tendencies, and their need to seek sensory stimulation may have led them to delinquent behaviors...The combination of high-sensation-avoiding and low-sensation-seeking profiles implies that the youth participants would be less likely to seek sensory stimuli and more likely to avoid stimuli than we had expected.

I had a similar experience with the Adolescent Adult Sensory Profile as documented here.  In my doctoral study, I hypothesized that people with Complex Regional Pain Syndrome would have heightened scores on Sensory Sensitivity scales.  Just as the authors in the present study, I was surprised that Sensory Profile Scores were quite different from what I expected.

Still, in both instances, the scores were atypical - they were just atypical in directions other than what was hypothesized.  This leads to a concern that I have with face validity of the tool.  It is certainly measuring something, but is it measuring sensory processing?  Is it measuring it the way that we think it is measuring things?  When a tool ends up giving us information that is diametrically opposed to what we believe we are going to get out of it then I think we need to start asking some serious questions about what it is exactly that we are measuring, and whether or not our theoretical construct and understanding  is correct.

Other questions seem rather pertinent:

1. Do the high numbers of atypical scores really indicate that 40-45% of this juvenile justice population has a 'disorder.'  That level of identification, if sensory processing difficulties as measured really are a disorder, would be rather stunning.

2. Do people who have atypical scores on the Sensory Profile truly represent a subset of the population that could also be more prone to violence or asocial behavior?  The Sensory Processing Disorder Foundation was quick to jump on the Sandy Hook massacre and describe Adam Lanza's behavior as a sensory 'diagnosis,' much to the outrage of families who made their opinions on the matter quite clear on the SPD website.

3. A fact not mentioned in the article is that in the past a small study was done on sensory profiles of people who have mental illness, and the distribution of scores as described for people who have schizophrenia was identical to the pattern of scores reported in this study - low sensory seeking and high sensory avoiding (Brown, et.al., 2002).  Other scientists have more recently supported the notion that the population of people who have schizophrenia also have sensory processing difficulties (Javitt, 2009).  It has been widely quoted that the incidence of mental health diagnoses in the justice system is 16% (Ditton, 1999). Since so many people in the current study scored atypically, is the Sensory Profile just measuring a "sensory processing disorder" construct, or is it measuring something else?

This analysis should help us to more deeply understand that our current assessment tools, which are apparently measuring something, may not just be measuring a sensory processing construct.  In my opinion, the assessment tool also includes many questions that are broad and general and could represent a number of behavioral phenomenon, primarily dependent on the interpretation or labeling of the examiner.

I believe that we should consider pausing when we use tools like the Sensory Profile to report an incidence of "sensory processing disorder."   It is apparent that atypical scores on this assessment may indicate co-morbid issues that are interwoven with a number of other behavioral and social and psychiatric diagnostic constructs.




References:


Ahn, R. R., Miller, L. J., Milberger, S., and McIntosh, D. N. (2004). Prevalence of parents’ perceptions of sensory processing disorders among kindergarten children. American Journal of Occupational Therapy, 58, 287–293

American Academy of Pediatrics (2012). Policy Statement: Sensory Integration Therapies for Children With Developmental and Behavioral Disorders. Pediatrics, 129(6), 1186-1189.

Ben-Sasson, A., Carter, A.S., and Briggs Gowan, M.J. (2009). Sensory over-responsivity in elementary school: prevalence and social-emotional correlates. Journal of Abnormal Child Psychology, 37, 705-716.

Brown, C., Cromwell, R., Filion, D., Dunn, W., and Tollefson, N. (2002). Sensory processing in schizophrenia: missing and avoiding information. Schizophrenia Research, 55(1-2):187-95.

Ditton, P.M. (1999). Mental Health Treatment of Inmates and Probationers, Washington, DC: US Department of Justice, Office of Justice Programs, Bureau of Justice Statistics.

Javitt, D.C. (2009). Sensory processing in schizophrenia: Neither simple nor intact. Schizophrenia Bulletin, 35(6), 1059-1064.

Pearson Education, Inc. (2008).  The Sensory Profile Technical Report.  Retrieved 10/29/13 from http://www.pearsonassessments.com/NR/rdonlyres/6AB47882-1271-4D6A-BB3D-1AF8692D67B9/0/SP_TR_Web.pdf

Shea, C. and Wu, R. (2013). Finding the Key: Sensory Profiles of Youths Involved in the Justice System. OT Practice 18(18),  9–13.

7 comments:

Tonya said...

It is measuring behavior, and I have found that some kids may exhibit that behavior due to sensory reasons, and others exhibit the same behavior due to lack of impulse control, and the inability to filter actions. I always make sure I qualify with parents that the test does not give a diagnosis, but only looks at behaviors, which we then observe to determine possible causes.

Christopher Alterio said...

Thanks for your comments Tonya. I think that many OTs consider the results the way that you describe. The problem is that there are also voices who loudly proclaim that the results indicate the presence of some unitary diagnosis.

I would like to see a second edition that makes an attempt to more clearly delineate sensory, regulatory, and behavioral issues. I don't know if that is possible, but it would be good to try.

Dee Berline said...

I agree with Tonya. When I use this particular tool I always look at the behavior issue.
Chris, I found the article in last month's OT Practice regarding mental health and sensory particularly interesting. What was glaringly absent was the work of Lorna Jean King back in the late 70's (I know-way before your time) but I used many of her treatments when I worked with non-paranoid schizophrenic patients and they had some changes in both behavior and sensory processing. Of course, I did not keep good enough notes to do any sort of good research but there were reports by family members and others who had no knowledge of the treatment regimen.
As always Chris, good points and good discussion.

Cheryl said...

I cannot tell you how much I appreciate your continued scrutiny of the poorly-defined construct of sensory processing disorder. For years I have marveled at the fact that the Sensory Profile is blindly accepted as a valid assessment, much less a diagnostic tool. How on earth can the behaviors listed on the questionnaire distinguish between sensory issues and ADHD or impulse control disorders? I cannot believe that psychologists are not up in arms over this assessment! Do you have any insight as to why nobody besides yourself has ever challenged the validity of this instrument? It just doesn't seem right that it is used to diagnose sensory processing disorder when it does not even begin to rule other disorders out.

Christopher Alterio said...

Thanks for your comments Cheryl. As with most science the more we learn the less we know. That leaves us in a position where it becomes increasingly important to update these kinds of assessments so we can further refine our efforts. We certainly don't do ourselves any favors by using this as a diagnostic standard. It was a good 'first generation' attempt at defining some of these issues but it is simply incorrect to use it for diagnostic purposes now. I find it difficult to guess why others might not be as vocal as I am - I suspect that people often interpret constructive criticism as a personal attack - which it absolutely is not. As Reilly paraphrased Merton: "Merton finds that criticism stings a profession into a new and more demanding formulation of purpose and maintains a policy position of divine discontent with the state of affairs as they are." Good words to live by.

Anonymous said...

My cousin's child was diagnosed with Sensory Processing Disorder without having been seen by either a psychiatrist or a neurologist. I always wondered what an MD would have diagnosed, and then I stumbled on Developmental Coordination Disorder. The description seemed to fit him very well, so I emailed my cousin about it, and she wrote back that he had been diagnosed with DCD for the purpose of getting the insurance company to pay for OT. But as far as she's concerned he has Sensory Processing Disorder.

Now I'm extremely puzzled about this. I would understand non-physicians creating a new disorder not recognized by the medical profession if there were patients whose symptoms were being dismissed or ignored. But there is so much overlap between SPD and DCD that I don't understand why a new disorder had to be invented. The main difference as I understand it is that while proponents of SPD attribute all the symptoms to the sensory processing problems, the medical profession says that the underlying cause of the whole cluster of symptoms is unknown. The treatment is the same in either case - OT and PT - and the prognosis seems to be the same.

So what's puzzling me is why so many people are so determined to have SPD recognized? Why are so many kids being diagnosed by non-physicians (and who is diagnosing all these cases of SPD?) If these kids can be diagnosed with medically-recognized disorder and receive the same treatment, why aren't they being?

As an OT, is there any difference in how you would work with these two diagnoses? Do you see them as being different disorders?

Christopher Alterio said...

Hi anonymous,


Since 'SPD' is not recognized as a diagnosis I am not sure how to answer some of your questions. I believe that what some people call 'SPD' is probably already represented in other known conditions e.g. developmental coordination disorder, anxiety disorders, ADHD, autism, etc.


I am puzzled as much as you are. I see no utility in chasing down an 'spd' label. In fact, as it is not a recognized condition, the only impact of the 'spd' label that I notice is near-immediate insurance denial.


You are correct - the treatment for children who have functional deficits related to accepted diagnoses as listed above is not impacted by any lack of an 'spd' designation. However, as there are those who have made 'spd' their career and as there is a rather significant cottage industry now created around the notion of 'spd' it is not likely that it will disappear soon.


I periodically get email from angry people who don't understand why I don't 'believe' in the 'spd' construct. That notion has always confused me. Of course children can have difficulties with sensory processing - that is a major component of some of these other diagnoses! I always figure that the difference in how I look at this is that I have made the functional treatment of children the focus of my career - not the promotion of a diagnostic concept.


I have no book to sell. I have no assessment to sell. I have no therapy equipment to sell. I have no conference hall to fill. I have no foundation to support. All I have is kids to see and families to help. That is easiest when I am working within accepted medical diagnostics. Doctors know what I am talking about when I talk about DCD or anxiety disorders or autism. Insurance companies do too. There is no reason for me to promote some poorly accepted and theoretical diagnostic concept that will only serve as a barrier to a child who needs services.