Rhythmic Movement Disorder
Encyclopedia
Rhythmic Movement Disorder (or RMD) is a neurological disorder characterized by involuntary, repetitive movements of large muscles groups immediately before and during sleep often involving the head and neck. It was independently described first in 1905 by Zappert as jactatio capitis nocturna and by Cruchet as rhythmie du sommeil. The majority of RMD episodes occur during NREM
sleep, although REM movements have been reported. RMD is often associated with other psychiatric conditions or mental retardation. The disorder often leads to bodily injury from unwanted movements. Because of these incessant muscle contractions, patients’ sleep patterns are often disrupted. It differs from Restless Legs Syndrome in that RMD involves involuntary muscle contractions before and during sleep while Restless Legs Syndrome is the urge to move before sleep. RMD occurs in both males and females, often during early childhood with symptoms diminishing with age. Many sufferers also have other sleep related disorders, like sleep apnea
. The disorder can be differentially diagnosed into small subcategories, including sleep related bruxism, thumb sucking, hypnagonic foot tremor, and rhythmic sucking, to name a few. In order to be considered pathological, the ICSD-II requires that in the sleep-related rhythmic movements should “markedly interfere with normal sleep, cause significant impairment in daytime function, or result in self-inflicted bodily injury that requires medical treatment (or would result in injury if preventive measures were not used)”
.
. In unique cases, RMD sufferers hum or moan while asleep during an episode. Some patients describe the repetitive movements as relaxing and are only occasionally awakened by an RMD episode. Often, it is the sufferer’s partner or parent who first notes the symptoms. Additionally, it is often the partner or parent who led patients to seek medical attention.
Other less common muscle movements include:
The majority of sufferers have symptoms that involve the head, and the most common symptom is head banging. Usually, the head strikes a pillow or mattress near the frontal-parietal region. There is little cause for alarm at the movements as injury or brain damage as a result of the movements is rare. Some infants with diagnosed Costello Syndrome
have been observed to have unique RMD episodes affecting the tongue and other facial muscles, which is an uncommonly affected area. Episodes usually last less than fifteen minutes and produce movements that vary from 0.5 to 2 Hz. Muscle movements during REM sleep are often twitches and occur simultaneously with normal sleep. The position of the body during sleep may determine which motor symptom is displayed. For example, Anderson et al. reported that one individual showed entire body rolling movements while sleeping on his side while displaying head rolling movements when sleeping supine.
. Many find that their sleep is not refreshing and are tired or stressed the following day, despite getting a full nights rest. However, other patients report that their sleep patterns are infrequently interrupted due to RMD episodes and do not report being excessively sleepy during the next day as scored on the Epworth Sleepiness Scale
. Thus, as can be seen, the effects and severity of RMD vary from person to person.
, which includes video recording, EEG
during sleep, EMG
, and ECG. These aforementioned brain monitoring devices eliminate the possibility of epilepsy as a cause. Other sleep related disorders like sleep apnea are ruled out by examining the patients’ respiratory effort, air flow, and oxygen saturation. RMD patients often show no abnormal activity that is directly the result of the disorder in an MRI scan
. RMD episodes are strongly associated with stage 2 NREM sleep and, specifically, K Complexes
. Additionally, there is a close association with Alpha wave
s that contain a mixture of K complexes and arousals, regardless of the NREM stage in which the RMD occurred. The occurrence of these two sequences of brain waves suggests that the disorder is linked to an “unstable vigilance level” throughout NREM sleep
. It has been interestingly noted that there is a complete absence of any EEG signs during or immediately after an intense rhythmic movement
. After the episode, normal EEG patterns return. Functional MRI scans have shown that the mesencephalon
and pons
may be involved in the loss of motor control seen during an RMD episode, which is similar to other movement disorders
.
. However, use of a polysomnogram can help distinguish one disorder from the other as RMD involves movements in both REM and NREM sleep, which is unusual for seizures
. Additionally, patients can usually stop the movements upon request, unlike the movements observed in epilepsy. Other movement disorders like Parkinson’s Disease, Huntington’s Disease, ataxia
, and dystonia
differ from RMD in that they occur primarily during wakefulness and reduced sleep, whereas RMD episodes occur in or around sleep
.
. An alternative theory suggests that the rhythmic movements help develop the vestibular system in young children, which can partially explain the high prevalence of RMD in infants. It has been seen that children who have underdeveloped vestibular systems benefit from performing RMD-like movements which stimulate the vestibular system
.
or other psychiatric disorders like Autism
. More recent studies have shown there is a strong link between prolonged RMD and ADHD
.
. Prescription medications such as ropinirole
or pramipexole
given to restless legs syndrome
patients do not show any clinical improvement in many patients with RMD.
) device has shown dramatic improvement in apnea and nearly complete resolution of RMD symptoms. Behavioral interventions may alleviate some RMD symptoms and movements. In such a therapy, sufferers are asked to perform RMD-like motions during the day in a slow and methodic manner. In such, patients come short of full rhythmic movements that they experience in sleep. Such behavioral training has been shown to carry over into sleep, and the forcefulness of the RMD movements is reduced or eliminated. Hypnosis and sleep restriction have been used in some cases to good effect.
NREM
Non-rapid eye movement, or NREM is, collectively, sleep stages 1 – 3, previously known as stages 1 – 4. Rapid eye movement sleep is not included. There are distinct electroencephalographic and other characteristics seen in each stage. Unlike REM sleep, there is usually little or no eye movement...
sleep, although REM movements have been reported. RMD is often associated with other psychiatric conditions or mental retardation. The disorder often leads to bodily injury from unwanted movements. Because of these incessant muscle contractions, patients’ sleep patterns are often disrupted. It differs from Restless Legs Syndrome in that RMD involves involuntary muscle contractions before and during sleep while Restless Legs Syndrome is the urge to move before sleep. RMD occurs in both males and females, often during early childhood with symptoms diminishing with age. Many sufferers also have other sleep related disorders, like sleep apnea
Sleep apnea
Sleep apnea is a sleep disorder characterized by abnormal pauses in breathing or instances of abnormally low breathing, during sleep. Each pause in breathing, called an apnea, can last from a few seconds to minutes, and may occur 5 to 30 times or more an hour. Similarly, each abnormally low...
. The disorder can be differentially diagnosed into small subcategories, including sleep related bruxism, thumb sucking, hypnagonic foot tremor, and rhythmic sucking, to name a few. In order to be considered pathological, the ICSD-II requires that in the sleep-related rhythmic movements should “markedly interfere with normal sleep, cause significant impairment in daytime function, or result in self-inflicted bodily injury that requires medical treatment (or would result in injury if preventive measures were not used)”
.
Signs and Symptoms
Most RMD symptoms are relatively passive and do not cause any pain. Many patients are often unaware that an episode is occurring or has occurred. The rhythmic movements may produce some bodily injury via falls or muscle strains, but this is not reported in all patients. In unique cases, RMD sufferers hum or moan while asleep during an episode. Some patients describe the repetitive movements as relaxing and are only occasionally awakened by an RMD episode. Often, it is the sufferer’s partner or parent who first notes the symptoms. Additionally, it is often the partner or parent who led patients to seek medical attention.
Motor symptoms
Symptoms of Rhythmic Movement Disorder vary, but most sufferers share common large muscle movement patterns. Many sufferers show consistent symptoms including:- body rocking, where the whole body is moved while on the hands and knees.
- head banging, where the head is forcibly moved in a back and forth direction.
- head rolling, where the head is moved laterally while in a supine position.
Other less common muscle movements include:
- body rolling, where the whole body is moved laterally while in a supine position.
- leg rolling, where one or both legs are moved laterally.
- leg banging, where one or both legs are moved in a back and forth direction.
- a combination of the aforementioned symptoms
The majority of sufferers have symptoms that involve the head, and the most common symptom is head banging. Usually, the head strikes a pillow or mattress near the frontal-parietal region. There is little cause for alarm at the movements as injury or brain damage as a result of the movements is rare. Some infants with diagnosed Costello Syndrome
Costello syndrome
Costello syndrome, also called faciocutaneoskeletal syndrome or FCS syndrome, is a rare genetic disorder that affects many parts of the body. It is characterized by delayed development and mental retardation, distinctive facial features, unusually flexible joints, and loose folds of extra skin,...
have been observed to have unique RMD episodes affecting the tongue and other facial muscles, which is an uncommonly affected area. Episodes usually last less than fifteen minutes and produce movements that vary from 0.5 to 2 Hz. Muscle movements during REM sleep are often twitches and occur simultaneously with normal sleep. The position of the body during sleep may determine which motor symptom is displayed. For example, Anderson et al. reported that one individual showed entire body rolling movements while sleeping on his side while displaying head rolling movements when sleeping supine.
Sleep
Because of the abnormal writhing movements, often patients’ sleep patterns are disrupted. This may be due to RMD’s comorbidity with sleep apnea, which has been observed in some patients. Many find that their sleep is not refreshing and are tired or stressed the following day, despite getting a full nights rest. However, other patients report that their sleep patterns are infrequently interrupted due to RMD episodes and do not report being excessively sleepy during the next day as scored on the Epworth Sleepiness Scale
Epworth Sleepiness Scale
The Epworth Sleepiness Scale is a scale intended to measure daytime sleepiness that is measured by use of a very short questionnaire. This can be helpful in diagnosing sleep disorders...
. Thus, as can be seen, the effects and severity of RMD vary from person to person.
Brain Activity
Rhythmic Movement Disorder is observed using the standard procedure for polysomnographyPolysomnography
Polysomnography , also known as a sleep study, is a multi-parametric test used in the study of sleep and as a diagnostic tool in sleep medicine. The test result is called a polysomnogram, also abbreviated PSG...
, which includes video recording, EEG
EEG
EEG commonly refers to electroencephalography, a measurement of the electrical activity of the brain.EEG may also refer to:* Emperor Entertainment Group, a Hong Kong-based entertainment company...
during sleep, EMG
Electromyography
Electromyography is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph, to produce a record called an electromyogram. An electromyograph detects the electrical potential generated by muscle...
, and ECG. These aforementioned brain monitoring devices eliminate the possibility of epilepsy as a cause. Other sleep related disorders like sleep apnea are ruled out by examining the patients’ respiratory effort, air flow, and oxygen saturation. RMD patients often show no abnormal activity that is directly the result of the disorder in an MRI scan
. RMD episodes are strongly associated with stage 2 NREM sleep and, specifically, K Complexes
. Additionally, there is a close association with Alpha wave
Alpha wave
Alpha waves are neural oscillations in the frequency range of 8–12 Hz arising from synchronous and coherent electrical activity of thalamic pacemaker cells in humans...
s that contain a mixture of K complexes and arousals, regardless of the NREM stage in which the RMD occurred. The occurrence of these two sequences of brain waves suggests that the disorder is linked to an “unstable vigilance level” throughout NREM sleep
. It has been interestingly noted that there is a complete absence of any EEG signs during or immediately after an intense rhythmic movement
. After the episode, normal EEG patterns return. Functional MRI scans have shown that the mesencephalon
Mesencephalon
The midbrain or mesencephalon is a portion of the central nervous system associated with vision, hearing, motor control, sleep/wake, arousal , and temperature regulation....
and pons
Pons
The pons is a structure located on the brain stem, named after the Latin word for "bridge" or the 16th-century Italian anatomist and surgeon Costanzo Varolio . It is superior to the medulla oblongata, inferior to the midbrain, and ventral to the cerebellum. In humans and other bipeds this means it...
may be involved in the loss of motor control seen during an RMD episode, which is similar to other movement disorders
.
Episodes
Episodes of RMD are short, lasting between 3 and 130 seconds. Rare cases of constant RMD can last for hours. The majority of RMD episodes usually occur just before or during sleep. Some cases have been reported on rhythmic movements during wakeful activities like driving. When occurring in sleep, RMD episodes are more likely to onset during non-REM, stage 2 sleep. Roughly 46% of sleep-RMD episodes occur only in non-REM sleep; 30% in non-REM and REM; and only 24% strictly in REM sleep. Most patients are unresponsive during an episode and are unlikely to remember the movements occurring upon awakening. In some patients who also experience sleep apnea, episodes of apnea can be followed immediately by RMD-like symptoms, suggesting that the apnea episodes may trigger an RMD episode. Similarly, current studies suggest that external stimuli are not the cause of RMD episodes.Diagnosis
Diagnosis of Rhythmic Movement Disorder is done on an exclusionary basis in which other closely related movement disorders are systematically ruled out. Because of this, a thorough clinical evaluation is necessary. Often, impairments are not severe enough to warrant this process and so RMD is not often diagnosed unless there are extremely interfering or disabling symptoms. Many patients do not seek treatment for RMD directly and most seek professional help to alleviate sleep-affecting symptoms. To compound the issue, many sufferers are often misdiagnosed as having Restless Legs Syndrome or sleep apnea or some combination of the two. Rhythmic Movement Disorder differs from Restless Legs Syndrome in that RMD involves involuntary contractions of muscles with no urge or uncomfortable sensation to provoke such movement. Additionally, 80-90% of Restless Legs Syndrome sufferers show periodic limb movements as observed on a polysomnogram, which are not common in RMD patients. Rhythmic Movement Disorder can also have symptoms that overlap with epilepsyEpilepsy
Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...
. However, use of a polysomnogram can help distinguish one disorder from the other as RMD involves movements in both REM and NREM sleep, which is unusual for seizures
. Additionally, patients can usually stop the movements upon request, unlike the movements observed in epilepsy. Other movement disorders like Parkinson’s Disease, Huntington’s Disease, ataxia
Ataxia
Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum...
, and dystonia
Dystonia
Dystonia is a neurological movement disorder, in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures. The disorder may be hereditary or caused by other factors such as birth-related or other physical trauma, infection, poisoning or reaction to...
differ from RMD in that they occur primarily during wakefulness and reduced sleep, whereas RMD episodes occur in or around sleep
.
Causes
The direct cause and pathophysiological basis of RMD is still unknown and can occur in children and adults of perfect or non-perfect health. Rare cases of adult RMD have developed due to head trauma, stress, and herpes encephalitis. Familial cases have been reported suggesting there may be some genetic aspect to the disorder; however, to date, this explanation has not been directly tested. As familial incidence rate is still relatively low, it is believed that behavioral aspects may play a larger role in RMD than family history and genetics. Many sufferers report no family history of the disorder. Another theory suggests that RMD is a learned, self-stimulating behavior to alleviate tension and induce relaxation, similar to tic movements. An alternative theory suggests that the rhythmic movements help develop the vestibular system in young children, which can partially explain the high prevalence of RMD in infants. It has been seen that children who have underdeveloped vestibular systems benefit from performing RMD-like movements which stimulate the vestibular system
.
Development
Sleep-related movements are commonly seen in children, especially infants. However, the majority of these movements stop as the child ages. Some 66% of infants of 9-months show RMD-like symptoms compared to only 8% of 4 year olds. The disorder is closely associated to mental retardationMental retardation
Mental retardation is a generalized disorder appearing before adulthood, characterized by significantly impaired cognitive functioning and deficits in two or more adaptive behaviors...
or other psychiatric disorders like Autism
Autism
Autism is a disorder of neural development characterized by impaired social interaction and communication, and by restricted and repetitive behavior. These signs all begin before a child is three years old. Autism affects information processing in the brain by altering how nerve cells and their...
. More recent studies have shown there is a strong link between prolonged RMD and ADHD
.
Medication
Pharmacological treatment is often not necessary in children as symptoms usually alleviate spontaneously as the child ages. However, because the disorder may affect wakeful behavior, many adults who continue to suffer from RMD may seek treatment. Benzodiazepines or tricyclic antidepressants have been considered as therapeutic options in managing the disorder. Infantile and adolescent RMD respond well to low doses of clonazepamClonazepam
Clonazepamis a benzodiazepine drug having anxiolytic, anticonvulsant, muscle relaxant, and hypnotic properties. It is marketed by Roche under the trade name Klonopin in the United States and Rivotril in Australia, Brazil, Canada and Europe...
. Prescription medications such as ropinirole
Ropinirole
Ropinirole is a non-ergoline dopamine agonist. It is manufactured by GlaxoSmithKline , Cipla and Sun Pharmaceutical. It is used in the treatment of Parkinson's disease...
or pramipexole
Pramipexole
Pramipexole is a non-ergoline dopamine agonist indicated for treating early-stage Parkinson's disease and restless legs syndrome...
given to restless legs syndrome
Restless legs syndrome
Restless legs syndrome or Willis-Ekbom disease is a neurological disorder characterized by an irresistible urge to move one's body to stop uncomfortable or odd sensations. It most commonly affects the legs, but can affect the arms, torso, and even phantom limbs...
patients do not show any clinical improvement in many patients with RMD.
Non-Pharmacological
Treatment of sleep apnea via a continuous positive airway pressure (CPAPCPAP
CPAP may stand for:* Continuous positive airway pressure, a particular type of ventilation therapy* The Center for Public Administration and Policy, an academic department at Virginia Tech...
) device has shown dramatic improvement in apnea and nearly complete resolution of RMD symptoms. Behavioral interventions may alleviate some RMD symptoms and movements. In such a therapy, sufferers are asked to perform RMD-like motions during the day in a slow and methodic manner. In such, patients come short of full rhythmic movements that they experience in sleep. Such behavioral training has been shown to carry over into sleep, and the forcefulness of the RMD movements is reduced or eliminated. Hypnosis and sleep restriction have been used in some cases to good effect.