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 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.

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. Thus, as can be seen, the effects and severity of RMD vary from person to person.

Patients with PLMD will complain of excessive daytime sleepiness (EDS), falling asleep during the day, trouble falling asleep at night, and difficulty staying asleep throughout the night. Patients also display involuntary limb movements that occur at periodic intervals anywhere from 20–40 seconds apart. They often only last the first half of the night during non-REM sleep stages. Movements do not occur during REM because of muscle atonia.

People with PLMD often do not know the cause of their excessive daytime sleepiness and their limb movements are reported by a spouse or sleep partner.

PLMD is diagnosed with the aid of a polysomnogram or PSG. PLMD is diagnosed by first finding PLMS (periodic limb movements of sleep) on a PSG, then integrating that information with a detailed history from the patient and/or bed partner. PLMS can range from a small amount of movement in the ankles and toes, to wild flailing of all four limbs. These movements, which are more common in the legs than arms, occur for between 0.5 and 5 seconds, recurring at intervals of 5 to 90 seconds. A formal diagnosis of PLMS requires three periods during the night, lasting from a few minutes to an hour or more, each containing at least 30 movements followed by partial arousal or awakening.

Rapid eye movement behavior disorder (RBD) occurs when there is a loss of normal voluntary muscle atonia during REM sleep resulting in motor behavior in response to dream content. It can be caused by adverse reactions to certain drugs or during drug withdrawal; however, it is most often associated with the elderly and in those with neurodegenerative disorders such as Parkinson disease and other neurodegenerative diseases, for example multiple system atrophy and Lewy body dementia.

RBD is categorized as either idiopathic or symptomatic.

Rapid eye movement sleep behavior disorder (RBD) is a sleep disorder (more specifically a parasomnia) that involves abnormal behavior during the sleep phase with rapid eye movement (REM) sleep. It was first described in 1986.

The major and arguably only abnormal feature of RBD is loss of muscle atonia (i.e., the loss of paralysis) during otherwise intact REM sleep (during which paralysis is not only normal but necessary). REM sleep is the stage of sleep in which most vivid dreaming occurs. The loss of motor inhibition leads to a wide spectrum of behavioral release during sleep. This extends from simple limb twitches to more complex integrated movement, in which people appear to be unconsciously acting out their dreams. These behaviors can be violent in nature and in some cases will result in injury to either the patient or their bed partner.

Both of these conditions (RLS and PLM) are classified as dyssomnias according to the DSM-IV.

REM sleep behavior disorder or RBD is the most common REM sleep parasomnia in which muscle atonia is absent. This allows the individual to act out their dreams and may result in repeated injury—bruises, lacerations, and fractures—to themselves or others. Patients may take self-protection measures by tethering themselves to bed, using pillow barricades, or sleeping in an empty room on a mattress.

Demographically, 90% of RBD patients are males, and most are older than 50 years of age.

Typical clinical features of REM sleep behavior disorder are:

- Male gender predilection

- Mean age of onset 50–65 years (range 20–80 years)

- Vocalisation, screaming, swearing that may be associated with dreams

- Motor activity, simple or complex, that may result in injury to patient or bed-partner

- Occurrence usually in latter half of sleep period (REM sleep)

- May be associated with neurodegenerative disease

Acute RBD, occurs mostly as a result of a side-effect in prescribed medication—usually antidepressants. But if not then 55% of the time the cause is unknown the other 45% the cause is associated with alcohol.

Chronic RBD is idiopathic, meaning of unknown origin, or associated with neurological disorders. There is a growing association of chronic RBD with neurodegenerative disorders—Parkinson's disease, multiple system atrophy (MSA), or dementia—as an early indicator of these conditions by as much as 10 years.

Patients with narcolepsy also are more likely to develop RBD.

Motor disorders are malfunctions of the nervous system that cause involuntary or uncontrollable movements or actions of the body (Stone). These disorders can cause lack of intended movement or an excess of involuntary movement (Mandal). Symptoms of motor disorders include tremors, jerks, twitches, spasms, contractions, or gait problems.

Tremor is the uncontrollable shaking of an arm or a leg. Twitches or jerks of body parts may occur due to a startling sound or unexpected, sudden pain. Spasms and contractions are temporary abnormal resting positions of hands or feet. Spasms are temporary while contractions could be permanent. Gait problems are problems with the way one walks or runs. This can mean an unsteady pace or dragging of the feet along with other possible irregularities (Stone).

Initial symptoms of spasmodic torticollis are usually mild. Some feel an invisible tremor of their head for a few months at onset. Then the head may turn, pull or tilt in jerky movements, or sustain a prolonged position involuntarily. Over time, the involuntary spasm of the neck muscles will increase in frequency and strength until it reaches a plateau. Symptoms can also worsen while the patient is walking or during periods of increased stress. Other symptoms include muscle hypertrophy, neck pain, dysarthria and tremor. Studies have shown that over 75% of patients report neck pain, and 33% to 40% experience tremor of the head.

There are various terms which refer to specific movement mechanisms that contribute to the differential diagnoses of hyperkinetic disorders.

As defined by Hogan and Sternad, “posture” is a nonzero time period during which bodily movement is minimal. When a movement is called “discrete,” it means that a new posture is assumed without any other postures interrupting the process. “Rhythmic” movements are those that occur in cycles of similar movements. “Repetitive,” “recurrent,” and “reciprocal” movements feature a certain bodily or joint position that occur more than once in a period, but not necessarily in a cyclic manner.

Overflow refers to unwanted movements that occur during a desired movement. It may occur in situations where the individual’s motor intention spreads to either nearby or distant muscles, taking away from the original goal of the movement. Overflow is often associated with dystonic movements and may be due to a poor focusing of muscle activity and inability to suppress unwanted muscle movement. Co-contraction refers to a voluntary movement performed to suppress the involuntary movement, such as forcing one’s wrist toward the body to stop it from involuntarily moving away from the body.

In evaluating these signs and symptoms, one must consider the frequency of repetition, whether or not the movements can be suppressed voluntarily (either by cognitive decisions, restraint, or sensory tricks), the awareness of the affected individual during the movement events, any urges to make the movements, and if the affected individual feels rewarded after having completed the movement. The context of the movement should also be noted; this means that a movement could be triggered in a certain posture, while at rest, during action, or during a specific task. The movement’s quality can also be described in observing whether or not the movement can be categorized as a normal movement by an unaffected individual, or one that is not normally made on a daily basis by unaffected individuals.

"Ballism" was defined by Meyers in 1968 as "Repetitive, but constantly varying, large amplitude involuntary movements of the proximal parts of the limbs. This activity is almost ceaseless and movements are often complex and combined". Hemiballismus is usually characterized by involuntary flinging motions of the extremities. The movements are often violent and have wide amplitudes of motion. They are continuous and random and can involve proximal or distal muscles on one side of the body. Some cases even include the facial muscles. It is common for arms and legs to move together. The more a patient is active, the more the movements increase. With relaxation comes a decrease in movements. Physicians can measure the severity of the disorder by having the patient perform a series of basic, predetermined tasks and counting the hemiballistic movements during a set time session. The physicians then rate the patient on a severity scale. This scale gives scientists and clinicians a way to compare patients and determine the range of the disorder.

The name "hemiballismus" literally means "half ballistic", referring to the violent, flailing movements observed on one side of the body.

Myoclonus dystonia includes the rapid contractions of myoclonus alongside the abnormal postures classified under dystonia, as well as neurological and psychiatric issues. This disease typically begins during childhood with symptoms of myoclonus and slight dystonia, most commonly cervical dystonia or writer’s cramp. Dystonia symptoms tend to not get exaggerated over the course of the disease and is rarely the only associated symptom, while the myoclonus symptoms can become more severe. Psychiatric issues are clinically diagnosed with the aforementioned symptoms and include depression, anxiety, personality disorders and addiction. Obsessive-compulsive disorder is associated with myoclonus dystonia as both have been found to have a commonality on chromosome 7 in various studies.

Neurological symptoms are relatively common in those with myoclonus dystonia. Any neurological abnormalities won’t normally be present in those affected at a young age. Neurological testing has been performed to determine the origins of these symptoms and multiple parts of the brain have been pinpointed including the brainstem, neocortex, pallidum, and thalamus. These cause various effects in those diagnosed with myoclonus dystonia including changes in posture and tremors, and very rarely dementia and ataxia.

Dystonia is a response to simultaneous contraction of agonist and antagonist muscles seen as twisting and contorting that affect posture and stance. Other symptoms can include tremors and muscle spasms due to various interactions of muscle, contractions and movement. Dystonia can be either primary or secondary with the latter being more common. Primary dystonia or “pure” dystonia is only physiological in origin. Secondary dystonia has multiple origins that are physiological, pathological or neurological.

Hyperkinesia, also known as hyperkinesis, refers to an increase in muscular activity that can result in excessive abnormal movements, excessive normal movements, or a combination of both. The word hyperkinesis comes from the Greek "hyper", meaning "increased," and "kinein", meaning "to move." Hyperkinesia is a state of excessive restlessness which is featured in a large variety of disorders that affect the ability to control motor movement, such as Huntington's disease. It is the opposite of hypokinesia, which refers to decreased bodily movement, as commonly manifested in Parkinson's disease. Many hyperkinetic movements are the result of improper regulation of the basal ganglia-thalamocortical circuitry. Overactivity of a direct pathway combined with decreased activity of an indirect pathway results in activation of thalamic neurons and excitation of cortical neurons, resulting in increased motor output. Often, hyperkinesia is paired with hypotonia, a decrease in muscle tone. Many hyperkinetic disorders are psychological in nature and are typically prominent in childhood. Depending on the specific type of hyperkinetic movement, there are different treatment options available to minimize the symptoms, including different medical and surgical therapies.

Symptoms vary according to the kind of dystonia involved. In most cases, dystonia tends to lead to abnormal posturing, in particular on movement. Many sufferers have continuous pain, cramping, and relentless muscle spasms due to involuntary muscle movements. Other motor symptoms are possible including lip smacking.

Early symptoms may include loss of precision muscle coordination (sometimes first manifested in declining penmanship, frequent small injuries to the hands, and dropped items), cramping pain with sustained use, and trembling. Significant muscle pain and cramping may result from very minor exertions like holding a book and turning pages. It may become difficult to find a comfortable position for arms and legs with even the minor exertions associated with holding arms crossed causing significant pain similar to restless leg syndrome. Affected persons may notice trembling in the diaphragm while breathing, or the need to place hands in pockets, under legs while sitting or under pillows while sleeping to keep them still and to reduce pain. Trembling in the jaw may be felt and heard while lying down, and the constant movement to avoid pain may result in the grinding and wearing down of teeth, or symptoms similar to temporomandibular joint disorder. The voice may crack frequently or become harsh, triggering frequent throat clearing. Swallowing can become difficult and accompanied by painful cramping.

Electrical sensors (EMG) inserted into affected muscle groups, while painful, can provide a definitive diagnosis by showing pulsating nerve signals being transmitted to the muscles even when they are at rest. The brain appears to signal portions of fibers within the affected muscle groups at a firing speed of about 10 Hz causing them to pulsate, tremble and contort. When called upon to perform an intentional activity, the muscles fatigue very quickly and some portions of the muscle groups do not respond (causing weakness) while other portions over-respond or become rigid (causing micro-tears under load). The symptoms worsen significantly with use, especially in the case of focal dystonia, and a "mirror effect" is often observed in other body parts: Use of the right hand may cause pain and cramping in that hand as well as in the other hand and legs that were not being used. Stress, anxiety, lack of sleep, sustained use and cold temperatures can worsen symptoms.

Direct symptoms may be accompanied by secondary effects of the continuous muscle and brain activity, including disturbed sleep patterns, exhaustion, mood swings, mental stress, difficulty concentrating, blurred vision, digestive problems, and short temper. People with dystonia may also become depressed and find great difficulty adapting their activities and livelihood to a progressing disability. Side-effects from treatment and medications can also present challenges in normal activities.

In some cases, symptoms may progress and then plateau for years, or stop progressing entirely. The progression may be delayed by treatment or adaptive lifestyle changes, while forced continued use may make symptoms progress more rapidly. In others, the symptoms may progress to total disability, making some of the more risky forms of treatment worth considering. In some cases with patients who already have dystonia, a subsequent tramatic injury or the effects of general anethesia during an unrelated surgery can cause the symptoms to progress rapidly.

An accurate diagnosis may be difficult because of the way the disorder manifests itself. Sufferers may be diagnosed as having similar and perhaps related disorders including Parkinson's disease, essential tremor, carpal tunnel syndrome, TMD, Tourette's syndrome, conversion disorder or other neuromuscular movement disorders. It has been found that the prevalence of dystonia is high in individuals with Huntington's disease, where the most common clinical presentations are internal shoulder rotation, sustained fist clenching, knee flexion, and foot inversion. Risk factors for increased dystonia in patients with Huntington's disease include long disease duration and use of antidopaminergic medication.

There are a great number of symptoms experienced by those with a functional neurological disorder. It is important to note that the symptoms experienced by those with an FND are very real , and should not be confused with malingering, factitious disorders, or Munchausen syndrome. At the same time, the origin of symptoms is complex since it can be associated with physical injury, severe psychological trauma (conversion disorder), and idiopathic neurological dysfunction. The core symptoms are those of motor or sensory function or episodes of altered awareness

- Limb weakness or paralysis

- Blackouts (also called dissociative or non-epileptic seizures/attacks) – these may look like epileptic seizures or faints

- Movement disorders including tremors, dystonia (spasms), myoclonus (jerky movements)

- Visual symptoms including loss of vision or double vision

- Speech symptoms including dysphonia (whispering speech), slurred or stuttering speech

- Sensory disturbance including hemisensory syndrome (altered sensation down one side of the body)

Typically, episodic ataxia presents as bouts of ataxia induced by startle, stress, or exertion. Some patients also have continuous tremors of various motor groups, known as myokymia. Other patients have nystagmus, vertigo, tinnitus, diplopia or seizures.

Spasmodic torticollis is an extremely painful chronic neurological movement disorder causing the neck to involuntarily turn to the left, right, upwards, and/or downwards. The condition is also referred to as "cervical dystonia". Both agonist and antagonist muscles contract simultaneously during dystonic movement.

Causes of the disorder are predominantly idiopathic. A small number of patients develop the disorder as a result of another disorder or disease. Most patients first experience symptoms midlife. The most common treatment for spasmodic torticollis is the use of botulinum toxin type A.

Dystonia is a neurological movement disorder syndrome in which sustained or repetitive muscle contractions result in twisting and repetitive movements or abnormal fixed postures. The movements may resemble a tremor. Dystonia is often intensified or exacerbated by physical activity, and symptoms may progress into adjacent muscles.

The disorder may be hereditary or caused by other factors such as birth-related or other physical trauma, infection, poisoning (e.g., lead poisoning) or reaction to pharmaceutical drugs, particularly neuroleptics. Treatment must be highly customized to the needs of the individual and may include oral medications, chemodenervation botulinum neurotoxin injections, physical therapy, or other supportive therapies, and surgical procedures such as deep brain stimulation.

Episodic ataxia type-3 (EA3) is similar to EA1 but often also presents with tinnitus and vertigo. Patients typically present with bouts of ataxia lasting less than 30 minutes and occurring once or twice daily. During attacks, they also have vertigo, nausea, vomiting, tinnitus and diplopia. These attacks are sometimes accompanied by headaches and precipitated by stress, fatigue, movement and arousal after sleep. Attacks generally begin in early childhood and last throughout the patients' lifetime. Acetazolamide administration has proved successful in some patients. As EA3 is extremely rare, there is currently no known causative gene. The locus for this disorder has been mapped to the long arm of chromosome 1 (1q42).

Functional neurological disorders are a common problem, and are the second most common reason for a neurological outpatient visit after headache/migraine. Dissociative (non-epileptic) seizures account for about 1 in 7 referrals to neurologists after an initial seizure, and functional weakness has a similar prevalence to multiple sclerosis.

Ballismus or ballism (called hemiballismus or hemiballism in its unilateral form) is a very rare movement disorder. It is a type of chorea caused in most cases by a decrease in activity of the subthalamic nucleus of the basal ganglia, resulting in the appearance of flailing, ballistic, undesired movements of the limbs. It can also appear rarely due to certain metabolic abnormalities. It is a rare movement disorder, being 500 times rarer than Parkinson's disease. Hemiballismus can cause significant disability. Symptoms can decrease during sleep.

Geniospasm is movement disorder of the mentalis muscle.

It is a benign genetic disorder linked to chromosome 9q13-q21 where there are episodic involuntary up and down movements of the chin and lower lip. The movements consist of rapid fluttering or trembling at about 8 Hz superimposed onto a once per three seconds movement of higher amplitude and occur symmetrically in the V shaped muscle. The tongue and buccal floor muscles may also be affected but to a much lesser degree.

The movements are always present but extreme episodes may be precipitated by stress, concentration or emotion and commence in early childhood.

The condition is extremely rare and in a study in 1999 only 23 families in the world were known to be affected, although it may be under-reported. Inheritance is aggressively autosomal dominant. In at least two studies the condition appeared spontaneously in the families.

The condition responds very well to regular botulinus toxin injections into the mentalis muscle which paralyse the muscle but cause no impairment of facial expression or speech.