Everyone engages in self-stimulatory behavior! Self-stimulatory behaviors are repetitive movements of the body or objects or repetitive vocalizations. Some common examples of this, found in "typical" people, are nail biting, finger drumming or tapping, knee bouncing and hair twirling. Stereotopies can involve any or all of the body's sensory system — visual, auditory, tactile, taste and smell channels. Let me give you some examples that individuals with ASD might engage in for of each of these. Visual — staring at dust in the light, hand flapping; Auditory — TV talk, humming; Tactile — rubbing hand over a surface several times, scratching; Taste — licking objects, chewing objects; Smell — sniffing people and sniffing objects. As you can see from these examples children with ASD engage in self-stimulatory behaviors that look very different from the behaviors that you or I may engage in. These behaviors look different, however, they serve the same purpose or function.
Engaging in self-stimulatory behavior serves a purpose for everyone. The two main purposes it serves are calming or alerting. What do you do if you are waiting to hear distressing news about a good friend or a loved one? Do you bite your nails, drum you fingers, bounce your knee, or twirl your hair? You are likely engaging in one or many of these behaviors to keep yourself calm or relaxed. What do you do if you are sitting in a warm classroom listening to a not so interesting lecture? Do you bite your nails, drum you fingers, bounce your knee, or twirl your hair? You are likely engaging in one or many of these behaviors to keep yourself awake and alert. As you can see, one behavior can serve different functions.
Often times self-stimulatory behavior is viewed as a negative behavior or something to get rid of. Self stimulatory behavior should never simply be extinguished. Instead it should be shaped, if necessary, and it should be given a time and a place. Because the self-stimulatory behavior serves a purpose, if the behavior is extinguished the child will find another behavior to try to replace it. Tell a child to stop biting his shirt or his pencil and he may begin to bite himself or others instead. So how could you shape this behavior? The biting behavior is likely fulfilling an oral need for the child. So think about socially appropriate replacements such as chewing on a plastic pen or tubing, or chewing gum. When the child begins to engage in the shirt chewing behavior, gently stop the child and offer the child the replacement. Reward the child for chewing the "more appropriate" choice. Change will not happen overnight and you may have to search out and try multiple appropriate replacements. For some behaviors, replacement may not be an option! You may have to carve out a time and a location and put it into the child's schedule! An example I love to use is of a young man with Asperger Syndrome who works at a university. As a child he engaged in rocking — but never while sitting in a rocking chair! His rocking behavior was eventually shaped to a rocking chair. Today this young man works several hours a day but has a rocking chair in his office for his self-stimulatory breaks!
If you are thinking about setting up a sensory room in your home or classroom, spend some time observing the child. If your child loves to jump or skip, consider a mini tramp. If he likes to spin, consider a swing or a 'sit and spin'. It may also be necessary to have an occupational therapist with expertise in sensory processing perform an evaluation to determine the best items to meet their sensory needs.
Remember, the child's sensory needs will change over time and therefore, strategies will need to change as well.