It can be difficult to accurately distinguish between sensory craving and stereotypy. Both symptoms play a big role in autism and both are part of the ASD¹ diagnosis, so you might think they are distinct. But they're not. They can be easily mistaken for each other and even overlap. Does it matter that we identify exactly what is going on? Yes. How can we create successful interventions without pegging the problem correctly?
Look at the descriptions and examples below and see if you can pick out inherent problems. See if you notice the areas of overlap and blurry lines between them, and also with them and hyperactivity (ADHD²) and obsessive behaviors (OCD).
Stereotypy: Rapp and Lanovaz³ say, "Stereotypy is often characterized as repetitious, invariant behavior that generates its own reinforcing consequences (rewards)." Examples are vocalizations, flicking fingers, slapping things, nail biting, and similar habitual activities. The DSM describes it in terms of motor movement or use of objects and gives these examples: "simple motor stereotypes, lining up toys, flipping objects, echolalia, idiosyncratic phrases."
Sensory craving: I'll venture this definition: goal-driven behavior to satisfy a sensory need. The DSM more broadly talks about "unusual interest in sensory aspects of the environment ... such as ... excessive smelling or touching of objects, visual fascination with lights or movement."
Did you catch any problems? Stereotypy is defined in terms of motor, craving in terms of the senses—as if the two inhabit separate worlds or separate people. But they don’t. Let’s look at a few cases and see how the symptoms might occur in real life.
We’ll start with the example of the child who frequently vocalizes simple sounds or phrases. Is it echolalia--a motor repetition? Or is it sensory seeking: fascination with the sounds she produces, or the sensation in her throat? Or is she doing it for some other reason such as attention seeking? Without knowing what is driving the behavior, it's hard to classify it. In fact, the behavior may be driven by all of these factors. The stereotypy may co-exist with sensory seeking, and once the child learns that her behaviors draw attention, she may use them to do so.
How do school professionals view this behavior? It will likely be a mixed bag. First, behaviorists⁵ and sensory therapists will agree that the child is being rewarded by the sensation of certain sounds. She is craving sensory stimulation; but she is also engaging in stereotypy: behavior that generates its own reward. While there is definite overlap of stereotypy and sensory craving here, they will probably name it stereotypy and sensory therapists will look for any connection to craving. Teachers, who are with children for long periods and can see patterns in their behaviors, will be more attuned to the possibility of attention seeking.
Now let's explore this a little further. What about the child who has vocal tics. Does he fall into the categories of stereotypy or craving? No. Tics are involuntary speech and are usually the result of stress and anxiety.
How about a child who talks constantly? We see this in Asperger's Syndrome and it is often pegged as repetitive behaviors, but constant talking is also a symptom of ADHD hyperactivity. How do you distinguish between impulsive talking and self-rewarding ("He just likes to hear himself speak") stereotypy? For the unpracticed observer, the signs seem subtle, but the give-away to it being a repetitive behavior is constant talking about a single topic (such as types of aircraft). Finally, is the non-stop talking a sensory behavior? That's possible, but less likely.
Let's look briefly at a few more examples: children who touch everything or sniff things. Are these considered sensory cravings? Almost certainly, but it may be more than that. Some children learn about their world using alternate sensory paths: smell or touch instead of vision and hearing, and so the seeking behaviors may be a form of learning. But which came first: the craving or the learning pattern? It’s hard to know. And to further complicate things, the behavior can also be tagged as stereotypy, if she smells or touches the same things over and over in an “invariant pattern”.
Finally, let’s ask if a behavior that looks like stereotypy is actually obsessive compulsion (OCD). Hmm, it could be. The child who touches things in a certain prescribed way, may have OCD. The motivation for the behavior will be fear-based: "If I don't move in this exact sequence, something bad will happen", rather than the reward-based behavior of stereotypy. (The topic of differentiating OCD from stereotypy is explored in an article by Chok and Koesler in the September, 2014 issue of Behavior Modification journal, a special issue devoted to stereotypy, and I may blog on that at a later time.)
You can see that symptoms can be easily confused. In my years of teaching classes on the topic of self-regulation, I heard numerous accounts of doctors confusing craving or stereotypy with hyperactivity or OCD and giving children ADHD or OCD meds. It's truly important to distinguish the nuanced behavior so that the correct intervention is given.
In my next post, I'll look at the approaches taken by behavioral and sensory therapists to stop these behaviors. Sometimes the interventions are surprisingly alike.
Footnotes and References
- Autism Spectrum Disorder
- American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders. Arlington, VA: American Psychiatric Association.
- Attention-Deficit Hyperactivity Disorder
- Rapp, J. T., & Lanovaz, M. J. (2014). Introduction to the special issue: Assessment and treatment of stereotypy. Behavior Modification, 339-343.
- Rispoli, M., Camargo, S. H., Neely, L., Gerow, S., Lang, R., Goodwyn, F., & Ninci, J. (2014). Pre-session satiation as a treatment for stereotypy during group activities. Behavior Modification, 392-411.
- Chok, J. T., & Koesler, B. (2014). Distinguishing obsessive compulsive behavior from stereotypy: A preliminary investigation. Behavior Modification, 344-373.