Stereotypic movement disorder in typically developing children
Updated: May 3, 2019
Motor stereotypies are repetitive and rhythmic movements with a fixed pattern that can manifest in some typically developing children. The period of onset that is usually in early childhood (e.g. before 3 years of age) and the behaviors can persist into adulthood for most affected individuals. While motor stereotypies have long been associated with children with autism spectrum disorder (ASD) or intellectual disability (ID), these behaviors can in fact present in individuals who are otherwise typical in their development. Unfortunately there is a scarcity of research on stereotypies in children without developmental disabilities and no clear answers as to what causes the manifestation of these behaviors in some children.
Stereotypies can be primary, in that they appear to be purely physiological, or secondary, meaning that they are present in association with another neurological condition. This article will focus on the occurrence of primary stereotypies in otherwise typically developing children. Primary stereotypies can be classified as being either common or complex. Common stereotypies exist in approximately 20% of children and consist of behaviors such as pencil tapping, hair twisting, nail biting, etc. Complex stereotypies can include a variety and combination of motor mannerisms such as flapping, waving, wringing hands, contorting face, etc. These are estimated to affect 3-4% of children in the U.S. Stereotypies can occur when the child is engrossed in an activity, when bored, stressed, excited or tired. Unlike tics, there is no urge prior to engaging in the motor stereotypy to serve as a predictive mechanism. Children with complex motor stereotypies often present with other disorders such as attention-deficit/hyperactivity (ADHD), obsessive-compulsive disorder (OCD), or Tourett’s disorder.
Both biological and psychological factors are hypothesized to contribute to the etiology of these movements. Psychological factors may include the movements being executed as part of obsessive-compulsive or anxiety-related behaviors, or channeling of thoughts from excess capabilities into movements. However, there is much more evidence for a biological basis to the symptoms. Evidence for the biological abnormalities underlying this disorder come from studies showing neurochemical abnormalities that exist when motor stereotypies are present. The cortical-striatal-thalamo-cortical (CSTC) brain circuit is thought to be involved in the expression of motor stereotypies. Several brain regions are also believe to be involved as studies have found difference in the neural activation and structures of certain brain regions in individuals who present with stereotypies. There is evidence of a genetic component in the disorder in combination with environmental influences. Environments lacking sufficient sensory input or overstimulating environments may contribute to the presence or exacerbation of stereotypies.
There is no established pharmacological treatment for motor stereotypies as there have been no formal studies of the effect of medications for stereotypies in typically developing children. Behavioral therapy which specifically focuses on habit reversal and differential reinforcement of other or incompatible behaviors has some evidence for effectiveness in treating primary complex motor stereotypies. Therapy requires the active participation of the child who must have the cognitive capacity to understand and follow treatment guidelines. A parent-guided DVD intervention has recently been developed at Johns Hopkins University that focuses on suppressing complex motor stereotypies through behavioral therapy methods. Children are encouraged to exhibit the stereotypic movement intentionally to raise awareness of the behaviors and they are rewarded by parents during intervals when the stereotypic behaviors do not occur. This intervention was found to be beneficial and significantly reduced scores on all motor stereotypy screening scales.
Treatment is most likely to be successful when the child is cooperative and motivated, regardless of type of stereotypy present. The treatment package should incorporate habit reversal with differential reinforcement of competing responses, relaxation training, and self-monitoring. Habit reversal training consists of: 1) awareness training where the child learns to voluntarily exhibit the target behavior in order to become more aware of when it is occurring and 2) competing response training where the child learns to inhibit the target behavior by demonstrating another behavior that is incompatible with it.
Therapy consists of daily practice that begins with the child voluntarily exhibiting the stereotypic movements for 30 seconds followed by a 1-minute rest period. Parents provide feedback to the child to help him or her more closely approximate the target behavior in front of a full-length mirror. Parents also collect data on a daily basis regarding the occurrence of the stereotypic behavior and rank the severity level as mild, moderate, or severe. In the next phase of treatment parents and children are asked to select two 10-minute periods a day based on the initial data collected where the child will practice not exhibiting the behavior. Parents would praise and reinforce the child every few minutes when the child is successful in not exhibiting the stereotypy. Parents take data on instances of stereotypy occurring during these 10-minute periods. The initial habit reversal training phase of treatment continues to be practiced on a daily basis as well. Over time, parents are asked to increase the frequency of practice session to four per day, increase the length of each session from 10 to 20 minutes, and to include additional/tangible reinforcers for successful trials where no stereotypies were exhibited.
In summary, behavioral treatment can significantly reduce the symptoms of stereotyped movement disorders and this treatment modality can be implemented by parents under the direction of a therapist with knowledge and expertise regarding this disorders. Implementation of the treatment package is intensive in that it demands the availability of a caregiver to commit to daily basis of habit reversal training. Supporting children to incorporate regular relaxation exercises and mindfulness based practices can also help to reduce the overall arousal level of the nervous system and increase self-awareness. Readers who are interested in talking to their children about motor stereotypies should check out Motor Stereotypies and You as an informative resource on this subject.