Glossary of Movement Disorder Terms
Akinesia / bradykinesia / hypokinesia
Akinesia means absence of movement. Bradykinesia means slowness of movement. Hypokinesia means decreased amplitude or range of movement. These three terms are commonly grouped together and referred to as bradykinesia. Bradykinesia is a prominent feature of parkinsonism and is mild in early disease stages but becomes more severe in advanced stages of parkinsonism.
The term akathisia comes from the Greek word meaning “unable to sit still”. Akathisia refers to a feeling of inner restlessness that is reduced or relieved by movement. When sitting, a person may caress their scalp, cross and uncross their legs, rock or squirm in their chair, get out of the chair often and pace back and forth and even make noises such as moaning. When standing, a person with akathisia may involuntarily march in place. Akathitic movements are complex and occur repetitively, often making one feel very uncomfortable.
Ataxia / dysmetria / asynergia
Ataxia is an unsteady and swaying walk, often with feet planted widely apart. People have difficulty walking a straight line with their heel touching the toe of the shoe in front (the drunk test). Ataxia can occur in a number of neurologic conditions.
Dysmetria is misjudging the distance to a target. A person with dysmetria will have problems reaching out and accurately touching a targeted object.
Asynergia is a breakdown of movement, so that movements of the arms and legs become irregular and clumsy.
For more information, visit the National Ataxia Foundation website at www.ataxia.org.
Athetosis means slow, writhing, continuous, involuntary movements. Athetosis sometimes resembles slow dance-like movements, changing randomly in a flowing pattern. It is a term often used to describe the movements of someone with cerebral palsy (CP).
Blepharospasm is a focal dystonia of the muscles surrounding the eyes which can result in rapid blinking or even sustained or forceful eye lid closure.
For more information visit the Benign Essential Blepharospasm Research Foundation at www.blepharospasm.org.
Bradyphrenia means slowed thinking. Many people with parkinsonism will have slowed thinking or a delay in answering questions or “tip of the tongue” phenomenon. “Tip of the tongue” phenomenon is described as the inability to come up with the correct word immediately even though the person knows what to say. People with bradyphrenia often rely on others to speak for them. It is important to differentiate slowed thinking from being passive or depressed which are also common in parkinsonism as depression can be treated.
Chorea refers to involuntary, irregular, purposeless, non-rhythmic, abrupt, rapid or unsustained movements that seem to flow from one body part to another. A characteristic feature of chorea is that the movements are unpredictable in timing, direction and body parts affected. Chorea may be suppressed when mild and infrequent and often can be incorporated into movements that appear purposeful. When infrequent, the movements appear as isolated, small, brief, somewhat slow dance-like movements. Chorea is usually accompanied by an inability to maintain a sustained grip or posture.
Cortical-basal ganglionic degeneration (CBGD)
CBGD is an uncommon form of parkinsonism that affects one side of the body more than the other. A person with CBGD may have rigidity, dystonia, tremor at rest and on action and difficulty demonstrating a particular task (playing charades), such as combing hair with an imaginary comb, brushing teeth with an imaginary toothbrush, or cutting a loaf of bread with an imaginary knife and fork. Some people will report their arm or leg acts on its own without the person realizing there is movement.
For more information visit Cure PSP at www.psp.org/education/cbd.html
Diffuse Lewy-body disease (DLBD)
A condition in which the pathologic changes seen in Parkinson disease have spread beyond the brainstem to involve the cerebral cortex. The symptoms include a decline in cognition and episodes of hallucinations. It is debated whether diffuse Lewy-body disease is a continuum of Parkinson disease or a distinct disease entity.
Dyskinesia is a general term for any abnormal involuntary movement. “Tardive dyskinesia” is a term used for abnormal involuntary movements that begin after taking certain medications used to treat nausea or emotional problems. Tardive dyskinesia sometimes resembles chorea, dystonia, myoclonus, tics or tremor. Therefore, it is important that dyskinesias are very precisely described by the examiner in terms of rhythm, speed, duration and pattern. It is very important for the individual to tell the examiner what brings on or helps control the dyskinesia and when during the day the dyskinesia is easier or more difficult to control.
Dystonia refers to twisting movements and postures that tend to be sustained at the peak of the movement, often patterned and repetitive. Opposing muscles contract simultaneously to produce the sustained quality of dystonic movements. When dystonia first appears, the movements typically occur only with a voluntary movement of the affected body part (action dystonia). As dystonia worsens, dystonic movements can appear in the affected body part at rest even when other parts of the body are moving voluntarily (overflow dystonia). When a single body part is affected, the condition is referred to as focal dystonia. Common forms of focal dystonia affect the eyelids (blepharospasm), the voice (spasmodic dysphonia), the neck (spasmodic torticollis or cervical dystonia), and the hand (writer’s cramp). There are focal task-specific dystonic postures that affect the well-practiced muscles of professional musicians (musicians’ dystonia). Generalized dystonia indicates involvement of one or both legs, the trunk, and some another part of the body.
Essential tremor (ET)
Essential tremor is the most common movement disorder among adults as well as the most common cause of tremor. An estimated thirteen million people of all ages and ethnic groups are affected by essential tremor in the United States alone. In essential tremor, hand or head tremor occurring with voluntary movements (action tremor) is most common. Although the condition is frequently labeled “benign essential tremor,” this term is misleading as ET may worsen over the years and eventually interfere with basic daily activities such as dressing, eating, combing, brushing, bathing, writing, and using keys and tools which can become disabling.
Freezing refers to being stuck in one place, usually lasting seconds. It is one of the possible signs of parkinsonism. When someone freezes, the opposing muscle groups are simultaneously contracting and the ability to move is “blocked”. The person feels “stuck” or “glued to the ground”. After a few seconds, the freezing clears spontaneously, and the patient is able to move at a normal pace again, until the next freezing episode occurs. Freezing most often affects the legs while walking, however speech and arm movements can also be involved. Freezing often occurs in crowded spaces, before reaching a chair or obstacle or when pressured for time such as at the top of the escalator or just before the elevator door closes. Often tricks such as humming, stepping over lines in the floor or over the handle of an inverted cane can help overcome the “block”.
Hemifacial spasm refers to muscle contractions involving only one side of the face. Generally these are rapid, brief, repetitive spasms but can also be mixed periods of sustained or absent spasms. Often the movements are triggered by voluntary facial movements such as smiling. Hemifacial spasm usually affects both upper and lower parts of the face at the same time. In some cases, it may be due to pressure on the facial nerve by a nearby blood vessel.
Huntington’s Disease is an inherited progressively disabling disorder that causes problems with emotional control and thinking in addition to difficulty with coordination and stability. The classic sign of HD is a dance-like involuntary movement, called chorea. Other problems resemble dystonia, myoclonus, motor restlessness or tremor.
To learn more about Huntington’s Disease please visit www.hdsa.org.
Multiple System atrophy (MSA)
Multiple System Atrophy (MSA) is a sporadic, progressive disorder affecting multiple parts of the nervous system (hence the term). These systems include the basal ganglia (parkinsonism), cerebellum (balance problems), motor neurons (spasticity and weakness) and autonomic function problems (impotence, noisy breathing or snoring, low blood pressure when standing up, urinary problems, dizziness, cold pale hands).
MSA now includes three diagnoses previously called olivopontocerebellear atrophy (OPCA), striato-nigral degeneration (SND) and Shy-Drager syndrome.
For more information, please visit the Multiple System Atrophy Support Group at www.multiple-system-atrophy.com.
Myoclonic jerks are sudden, brief, shock like involuntary movements caused by muscle contractions (positive myoclonus) or sudden loss of muscle tone (negative myoclonus). Myoclonic jerks are usually irregular, but can be rhythmical and may occur in only one part of the body or in several different body parts. Myoclonus rarely if ever can be suppressed by the person. The jerks may be triggered by sudden stimuli such as sound, light, visual threat, or movement. Myoclonus can occur in isolation or along with other neurologic symptoms.
Myokymia and synkinesis
Myokymia is a fine persistent quivering or rippling of muscles. Myokymia occurs most commonly in facial muscles and can continue during sleep.
Synkinesis is the occurrence of involuntary movements in one part of the face when there is voluntary movement is another part of the face. For example, when a person smiles, the eyelids will close involuntarily.
With orthostasis, orthostatic hypotension or postural hypotension a person reports the sensation of lightheadedness when changing postures from lying to sitting or sitting to standing. This sensation occurs due to a drop in a person’s blood pressure with these changes in position. Orthostasis is commonly seen in parkinsonism but can also occur as a side effect of medications commonly used to treat parkinsonism.
Parkinson disease (PD)
Parkinson disease is the most common form of parkinsonism (a collection of motor signs). People with Parkinson disease have bradykinesia and at least two of the following signs: tremor at rest, rigidity, and loss of postural reflexes. They often also have a shuffling gait, a flexed posture, small handwriting, a soft voice and decreased facial expression. Later in the disease freezing and cognitive decline can occur. The “motor” symptoms of Parkinson disease (detailed above) usually begin above the age of 50, but it is being recognized that “non-motor” symptoms can precede the onset of “motor” symptoms by as much as ten years. These “non-motor” symptoms can include constipation, difficulty with urination, sexual dysfunction, loss of smell and/or taste, fatigue, depression, low blood pressure on standing (orthostasis), and REM sleep behavior disorder (RBD). Some of these “non-motor symptoms are however very common in the general population and other disorders as well making it difficult to diagnose Parkinson disease based on “non-motor” symptoms alone.
Parkinson disease is more common in men. In the United States there are about a million people with Parkinson disease (more than the combined numbers of multiple sclerosis, muscular dystrophy and ALS combined) and about 10 million worldwide. Approximately 60,000 Americans are newly diagnosed each year. The incidence of Parkinson disease increases with age.
Early Parkinson Disease is often very difficult to diagnose and is best managed by a movement disorder specialist in order to treat the symptoms that are most important to the person with PD. Many signs and symptoms remain mild and treatable for many years. No two people with PD are exactly alike.
To learn more about Parkinson disease please visit:
The Parkinson’s Disease Foundation at www.pdf.org.
American Parkinson Disease Association at www.apdaparkinson.org
The Michael J. Fox Foundation for Parkinson’s Research at www.michaeljfox.org
Parkinsonism is a neurological syndrome or collection of motor signs that has many causes. Parkinsonism may be any combination of six cardinal features: tremor at rest, bradykinesia, rigidity, flexed posture, freezing, and loss of postural reflexes. The specific diagnosis depends on details of the clinical history, the neurological examination, and laboratory tests. The specific diagnosis can be Parkinson disease (PD) or any of the disorders that mimic Parkinson disease such as Multiple System Atrophy (MSA), Progressive Supranuclear Palsy (PS), or Cortico-Basal Ganglionic Degeneration (CBGD).
Paroxysmal dyskinesias are movements that start suddenly and then disappear after being present for seconds, minutes, or hours. The person may remain free of attacks for many months or there can be many attacks in one day. Four disorders are briefly mentioned here:
- Paroxysmal Kinesigenic Dyskinesia (PKD) is triggered by a sudden movement. PKD is usually inherited in an autosomal dominant manor, but can also be sporadic.
- Paroxysmal Nonkinesigenic Dyskinesia (PNKD) is triggered by stress, fatigue, caffeine or alcohol, and can last minutes to hours. PNKD can be inherited or sporadic
- Paroxysmal Exertion-induced Dyskinesia (PED) is triggered by prolonged exercise and can last five to thirty minutes. PED can be inherited or sporadic.
- Paroxysmal Hypnogenic Dyskinesia (PHD) attacks occur during non-REM sleep and can last thirty to forty-five seconds.
For more information please visit the Dystonia Foundation at www.dystonia-foundation.org
Pediatric “neurotransmitter” disorders
These rare metabolic disorders are currently grouped together although the problems they cause are not necessarily the same. Children may have trouble controlling their eye muscles, loss of muscle tone (a form of weakness) in their neck, trunk, arms or legs, tremors, irritability or have developmental delays.
To learn more about this expanding list of rare metabolic disorders of childhood, check the website for the PND Association at www.pndassoc.org.
Physiologic tremor and Enhanced physiologic tremor
Everyone has some small degree of tremor that may not be physically apparent but can be recorded electrophysiologically. This tremor is known as physiologic tremor. In some people this tremor can worsen in the setting of stress, anxiety or with stimulants such as caffeine and is known as enhanced physiologic tremor. Enhanced physiologic tremor is not a progressive disorder and needs no treatment.
Loss of postural reflexes is a feature of parkinsonism that can contribute to falls or walking faster and faster with tiny steps. A simple test (the “pull test”) is the usual way to check a person’s ability to recover their balance in one step. The examiner stands behind the patient with hands on the patient’s shoulders. The patient stands with eyes open and feet comfortably apart. The examiner explains that he will suddenly without warning pull back on the patient’s shoulders. The patient is instructed to keep his balance and take one step back, if needed.
Progressive Supranuclear Palsy (PSP)
A person with PSP typically develops unsteady gait and frequent falls very early in the disease course. The person walks with feet wide apart, an erect posture and unbent knees. Some people with PSP move and think very slowly and may complain of trouble looking down, trouble keeping their eyelids open, blurry or double vision and general eye discomfort. They can have stuttering speech or speech “blocks” and “get stuck” when turning both of which are examples of freezing. This disorder seems to occur sporadically, although there are rare families with more than one relative affected. PSP was previously known as Steele-Richardson-Olszewski syndrome.
For more information, visit Cure PSP at www.psp.org.
REM sleep behavior disorder (RBD)
In vivid dreaming states most people’s bodies are still. However people with RBD lack muscle paralysis resulting in their “acting out” their dreams. This can include talking, screaming, shouting, hitting, punching or kicking, even propelling them out of bed. This can be scary and dangerous if they strike their partners or other bedside objects involuntarily. RBD is common in Parkinson disease and can begin long before the onset of declining motor function. Fortunately it is also a very treatable condition.
Tremor in the fingers, wrists or lips while when the body part is completely relaxed or “at rest” is a common sign of parkinsonism. The involuntary “pill rolling” tremor of the thumb and fingers is a common rest tremor often seen in people with Parkinson disease. Rest tremor stops when the body part is moved on purpose. Resting tremor can also occur in a person with action tremor.
Restless legs and Restless Legs Syndrome (RLS)
With restless legs, a person has unpleasant crawling, pulling or itchy feelings in the muscles or bones of the legs. These sensations occur particularly when lying down in bed, and can occur with sitting and relaxing in the evening later on in the disease. These sensations improve or disappear when walking.
Restless Legs Syndrome (RLS) consists of several problems. The unpleasant sensation of restless legs is the most common symptom, but some people may have involuntary movements during sleep, myoclonic jerks, inner restlessness, and dystonia. RLS may begin before age 20 as a mild disorder and most people seek medical advice in midlife when symptoms worsen.
For more information, visit the Restless Legs Syndrome Foundation at www.rls.org.
Rigidity or stiffness is increased muscle tone which is felt when the examiner tries to move the neck, arm or leg when completely relaxed. Rigidity may occur in the neck, chest wall, elbows, hips and knees and can result in a person bending over or to the side when seated, standing or lying down. With elbows and knees slightly bent, the person tends to shuffle the feet. Rigidity is another sign of parkinsonism.
Spasmodic dysphonia is a focal dystonia resulting in spasms of the vocal cords that lead to a tight, jerky, quivery, strained or strangled quality to the voice. Periods of no sound (aphonia) and normal near normal voice occur.
For more information visit the National Spasmodic Dsyphonia Association at www.dysphonia.org.
Stiff person syndrome
Stiff Person Syndrome is a progressive autoimmune disorder in which a person experiences involuntary painful spasms and muscle rigidity, resulting in an increased force required to move any body part. The spasms most commonly involve the lower back and legs and can be triggered by voluntary movement, anxiety, emotions or sudden environmental events (such as a loud noise).
For information please visit the Stiff Person Syndrome page of the National Organization for Rare Disorders at www.rarediseases.org.
Sydenham’s chorea (formerly known as St. Vitus dance) is an uncommon autoimmune disease with dance-like movements, called chorea. It tends to occur in children and is generally preceded by a group A streptococcal infection (the same infection can also cause rheumatic fever leading to rheumatic heart disease). In Sydenham’s the chorea is often accompanied by emotional and thinking problems.
Tardive dyskinesia / tardive dystonia
Tardive Dystonia and Tardive Dyskinesia are abnormal involuntary movements that occur in people who are taking medication that “block the dopamine receptors” in order to treat gastrointestinal problems or emotional disturbances.
Tics are abnormal movements (motor tics) or abnormal sounds (phonic tics). When both types of tics are present, the diagnosis of Gilles de la Tourette syndrome or Tourette syndrome is commonly given. Motor and phonic tics can be simple or complex. A single simple motor tic may be an abrupt, sudden, isolated movement such as a shoulder shrug, head jerk, blink, dart of the eyes, and twitch of the nose. Most simple tics are repetitive, such as a run of eye blinking. Even when tics are simple jerks, more complex forms of tics may also be present in the same individual. Complex motor tics are very distinct, consisting of coordinated patterns of sequential movements which can appear in different parts of the body and are not necessarily identical from one occurrence to another. Examples include touching oneself, head shaking with shoulder shrugging, kicking legs or obscene gesturing. Abnormal sounds (phonic tics) can range from simple throat clearing sounds, sniffing or grunts to more complex words, phrases or curses.
Tics are usually preceded by an uncomfortable feeling or urge that is relieved by carrying out the movement. When suppressed, inner tension builds up and is only relieved by an increased burst of more tics. Tics frequently vary in severity. Tics most commonly occur in childhood and can often fade away in early adulthood, but may recur later in adult life. They can occur abruptly for brief moments or occur continually.
Torticollis is a focal dystonia of the neck muscles in which there is a simultaneous contraction of opposing muscle groups causing the neck to twist, tilt, shift, and pull forwards or backwards. Torticollis can be accompanied by head tremor.
For more information visit the National Spasmodic Torticollis Foundation at www.torticollis.org.
A diagnosis of Gilles de la Tourette syndrome or Tourette syndrome is given to a person who has had both abnormal movements (motor tics) and abnormal sounds (phonic tics) occurring in childhood or adolescence before the age of 18, lasting for over a year.
For more information, visit the Tourette Syndrome Association at www.tsa-usa.org/.
Tremor is an oscillation that is usually rhythmical and regular that affects one or more body parts, such as the arms, legs, neck, tongue, chin or vocal cords. Tremor is produced by rhythmic alternating or simultaneous contractions of opposing muscles. Tremors can be classified as rest tremor, postural tremor, action tremor or intention tremor. It is helpful to determine whether the tremor is present at rest (with the person seated or lying down), with posture holding (with the arms or legs extended in front of the body), with action (such as writing or pouring water), or with intention maneuvers (such as holding a finger on a target). Some tremors may be present only during a specific task (such as writing) or with a specific posture, such as standing (orthostatic tremor). These are called task specific or position specific tremors. Other tremors seem to run in families and are often referred to as essential tremor. The diagnosis and treatment of tremors differ according to the type of tremor. Jerky, irregular “tremor” is usually a sign of another movement disordered called myoclonus.
Wilson’s disease is a curable condition caused by an abnormal metabolic condition which allows copper to build up in the brain, eyes, liver and other tissues of the body. The signs and symptoms are highly variable from person to person and can include clumsiness, depression, difficulty speaking, swallowing, and walking, drooling, easy bruising and fatigue, tremor, joint pain, nausea, loss of appetite, skin rash and yellowing of the skin (jaundice). As it is a treatable condition, anyone under the age of 50 with a movement disorder should undergo a complete evaluation for Wilson’s disease.
For more information visit the Wilson’s Disease Association at www.wilsonsdisease.org.
Writer’s cramp and musician’s dystonia
Writer’s Cramp is a focal dystonia of the finger, hand or forearm in which there is a simultaneous contraction of those muscles while writing or doing specific skilled tasks. Writer’s cramp may begin after repetitive use and is therefore often considered an occupational dystonia, more commonly experienced by typists, draftsmen, musicians and sportsmen.
When musicians are affected, it is called musician’s dystonia (or cramp). When the muscles involved are around the mouth (such as in horn players), it is called embouchure dystonia.
For more information visit the Dystonia Medical Research Foundation www.dystonia-foundation.org.