Rhythmic Movement Disorder (RMD) is a neurological condition characterized by repetitive, stereotyped movements, most commonly involving the head and neck, that occur just before or during sleep. While often seen in children, RMD can also affect adults, sometimes persisting from childhood or emerging later in life.
Understanding Rhythmic Movement Disorder in Adults
In adults, RMD typically manifests as involuntary, repetitive movements like head banging, body rocking, or head rolling. These movements usually occur during the transition into sleep or light sleep stages, though they can also be observed during quiet wakefulness. Episodes are generally short, lasting from seconds to minutes, but can occasionally extend for hours. While often considered a childhood phenomenon, the persistence or new onset of these movements in adulthood can disrupt sleep, lead to daytime fatigue, and may warrant further investigation.
Primary Rhythmic Movement Disorder
For some adults, RMD is classified as “primary” or idiopathic, meaning it occurs without an identifiable underlying medical, neurological, or psychiatric cause. It may represent a continuation of a childhood condition that did not resolve, or it can emerge in adulthood without a clear trigger. Although the precise cause remains unknown in these primary cases, these movements are often considered a benign sleep-related phenomenon, unless they cause significant sleep disruption, injury, or impair daytime functioning.
Secondary Rhythmic Movement Disorder
When RMD in adults is a symptom or consequence of another health issue, it is considered “secondary.” Various underlying conditions and external factors can contribute to its development.
Underlying Neurological Conditions
Neurological disorders can increase the incidence of RMD in adults. Conditions like intellectual disability and autism spectrum disorder frequently show a higher prevalence of RMD-like behaviors, which may persist into adulthood. These rhythmic movements might be a comorbidity or serve as a self-stimulating or self-soothing mechanism. RMD has also been reported following central nervous system injuries, including head trauma or conditions like herpes encephalitis, suggesting a potential link to neurological damage.
Medications and Substances
Medications and substance use can trigger or exacerbate rhythmic movements. Certain psychotropic drugs, including antidepressants, stimulants, and antipsychotics, are known to cause medication-induced movement disorders with rhythmic components. For example, stimulants, often used for conditions like ADHD, can sometimes lead to or worsen rhythmic behaviors. Alcohol and illicit drug use or withdrawal can also induce or intensify involuntary movements resembling RMD.
Other Sleep Disorders
RMD can co-occur with or be influenced by other sleep disturbances. Obstructive Sleep Apnea (OSA) is a contributing factor, with RMD-like symptoms sometimes following apneic events. Treating OSA with therapies like continuous positive airway pressure (CPAP) can improve or resolve RMD symptoms. Conditions like Restless Legs Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD) can also be found alongside RMD, though RMD involves involuntary contractions without the urge to move seen in RLS.
Psychiatric Conditions
Psychiatric conditions such as anxiety, depression, and stress can be associated with or worsen RMD in adults. While the direct causal link may be less clear than with neurological conditions, emotional distress and mental health challenges can influence sleep quality and contribute to the manifestation of sleep-related movement disorders.