Childhood Disorders: Stereotypic Movement Disorder

Stereotypic movement disorder (SMD) is a neurodevelopmental condition characterized by repetitive and involuntary movements. Often, these movements—called stereotypies—serve no apparent purpose, making them bothersome for the individual. They can include head banging, hand waving, finger wiggling, and other random actions.

If you suspect that your child may have stereotypic movement disorder, it is important to familiarize yourself with the condition, including common symptoms, causes, and the various treatment options. ^[1]

What is Stereotypic Movement Disorder?

Stereotypic movement disorder is a neurodevelopmental condition characterized by repetitive, purposeless, and involuntary movements. Symptoms typically appear within the first three years of life, yet they can (albeit less commonly) affect adult patients. ^[6]

Patterned Movements

The movements occur in specific parts of the body—usually the head, fingers, or limbs. Although the location can vary between individuals, the movements always occur in the same manner for each person. For example, if a child experiences stereotypies in his fingers, his fingers will always be the affected body part.

Duration and Triggers

Generally, episodes can last anywhere from a few seconds to a few minutes. More so, they can occur multiple times per day, making the condition incredibly bothersome for the individual.

SMD is usually triggered by emotion. If the person is overly excited, stressed, tired, or even bored, they are likely to experience an episode. As they age, these movements can begin to interfere with daily life and activities. In extreme cases, they can even lead to unintentional self-harm.

How Long Does SMD Last?

Luckily for most children, the symptoms associated with SMD begin to decrease or disappear as they get older. However, in certain cases, the condition can persist into adulthood. This usually occurs when the individual also suffers from other developmental conditions or disorders. ^[1]

Signs and Symptoms of Stereotypic Movement Disorder

The movements associated with SMD are repetitive, rhythmic, and involuntary. If you suspect that your child may have the condition, it’s important to identify their movements and consider any other common warning signs and symptoms.

These characteristics can be used to identify whether or not a particular movement is a result of SMD:

• Repetitive movements – The most common movements are hand flapping, body rocking, head banging, nail biting, finger wiggling, and thumb-sucking. Some of these actions are common in children under the age of 3 (such as thumb-sucking), meaning that this isn’t always a reliable identifier.
• Predictable patterns – As we’ve mentioned, the movements always occur in the same area of the body. This can make them somewhat predictable.
• Lack of purpose – The movements don’t have any purpose or goal.
• Movements occur in specific situations – The movements always occur under certain conditions and in particular situations, such as when the child is nervous, excited, or bored.

Types of Movements

These movements are split into two different categories: common motor stereotypies, which include more simple movements, and complex motor stereotypies, which include intricate movements. ^[2]

Causes of Stereotypic Movement Disorder

Like a lot of childhood disorders, the exact cause behind SMD is not fully understood. With that being said, experts believe several factors contribute to the disorder. These include:

• Neurological factors – Research shows that many children who develop SMD have certain abnormalities in their brain structure. These can occur as a result of a significant head injury, or the individual may simply have been born with the defect.
• Developmental disorders – SMD is usually associated with other developmental disorders. Autism, intellectual disabilities, and sensory impairments (such as blindness or deafness) are common conditions that lead to the development of SMD.
• Environmental factors – Certain environmental factors, such as loud noises, bright lights, or high levels of anxiety caused by social situations, can lead to the development of the condition. To be more specific, sensory deprivation or overstimulation can trigger these movements. Long periods of inactivity, childhood trauma, and neglect are also environmental factors that can play a significant role.
• Psychiatric conditions – Anxiety disorders have been linked to SMD. This includes obsessive-compulsive disorder (OCD), which is fairly common among autistic individuals.
• Genetic predisposition – Research shows that there is a genetic predisposition to SMD. In other words, the condition seems to run in families. Children who have had family members with SMD are much more likely to develop the condition themselves. ^[3]

Diagnosing Stereotypic Movement Disorder

When diagnosing the condition, there are several important steps to ensure an accurate assessment. First, if you suspect that your child may have SMD, be sure to seek the help of a professional. They will be able to properly assess the situation and perform the necessary tests.

Medical History and Physical Examination

The doctor will ask for a detailed medical history record, including any developmental delays, neurological conditions, or genetic predispositions your child may have. It is important to find out whether anybody in your family has had the condition before, as this will significantly increase your child’s chances of having it themselves.

The doctor will also perform a thorough physical examination in order to rule out any other medical conditions that may cause repetitive movement.

Behavioral Assessment

Once other conditions have been ruled out, the doctor will monitor your child’s behavior. They will observe their specific movements and compare them with the characteristics of SMD movements.

During this period, the doctor may also conduct interviews with caregivers, siblings, teachers, or the individual themselves (if possible) to gather more information on the extent to which the movements impact the individual’s life and the frequency and duration of the movement episodes.

Diagnostic Criteria

In order to diagnose the condition, the following criteria need to be met:

• Repetitive and purposeless movements. As we’ve already discussed, stereotypies are patterned movements that have no function. More so, they always occur in the same location of the body.
• Early onset. The symptoms appear before the individual reaches the age of three.
• Interference with functioning. The stereotypies will interfere with daily activities. In other words, they are bothersome for the individual. On top of this, there is a risk that the stereotypies can lead to self-injury. ^[3]

How Does Stereotypic Movement Disorder Impact Daily Life?

SMD can severely impact an individual’s quality of life, especially when it interferes with everyday activities. Obviously, this depends on the overall severity of the symptoms and each person’s movement pattern.

The Physical Impact

Stereotypies have a physical impact on the individual. Any repetitive movement can lead to self-injury, including nail biting and head banging. Constant movements, especially when aggressive, can cause fatigue, dizziness, and muscle soreness.

The Social Impact

Unfortunately, some people (especially children) can be cruel or insensitive towards things they don’t fully understand. As stereotypies are not common everyday movements, children with SMD can be bullied or belittled for them.

Over time, this often causes the child to withdraw from social situations and develop a fear of social interaction. This can also cause the symptoms to intensify, creating a vicious cycle.

Dependency

Stereotypies can lead to a disruption in routine. They can also make basic tasks, such as bathing, cooking, or driving, incredibly difficult. As a result, severe cases of SMD require around-the-clock assistance from caretakers, which is incredibly expensive. This also strips the individual of any sort of independence. ^[4]

Treatment for Stereotypic Movement Disorder

Behavioral Interventions

There are a number of behavioral interventions that could reduce the symptoms associated with SMD. This includes differential reinforcement of other behaviors (DRO).

This form of therapy teaches the child to adopt socially appropriate mannerisms through a system of reward. In other words, it encourages the child through positive reinforcement. Over time, this method has been shown to significantly reduce stereotypies.

Relaxation techniques are also fairly common. Deep breathing and mindfulness teach the child to relax and avoid triggers that prompt stereotypies.

Medication

It is important to note that medication is usually not the first line of defense against SMD. However, in severe cases, it can be a last resort. The most common types of medications used are antipsychotic medications, selective serotonin reuptake inhibitors, stimulant medications, and mood stabilizers. ^[3]

Supporting Someone with Stereotypic Movement Disorder

If someone in your family has SMD, it is important that you adhere to the following supportive measures:

• Environmental modifications – This involves creating a safe and supportive environment to reduce any triggers for stereotypies.
• Raising awareness – Raising awareness of the condition, especially amongst those with whom the individual will frequently come into contact, will reduce any sort of stigma.
• Regular monitoring – By closely monitoring the individual and adopting protective measures, you can ensure that the stereotypies don’t accidentally lead to self-injury. ^[3]