Other Dyskinesias

The term tardive dyskinesia, commonly associated with the use of neuroleptic drugs used to treat mental illness as well as certain digestive disorders, simply refers to "dyskinetic" symptoms that appear after a period of time (the word "tardive" is etymologically related to the term "tardy").

However, the word dyskinesia actually refers to a wide range of movement disorders from minor tics associated with mild forms of Tourette's Syndrome to full-blown epileptic seizures.

Dyskinesia Defined

Like most medical terminology, dyskinesia is derived from Greek: the word kinesi refers to "motion," "movement" or "action" (it shares its root with the word "kinetic"), while the prefix dys- is simply a negation. Dyskinesia refers to any medical disorder in which voluntary muscle control is diminished. This can mean loss of muscle function, as is the case of Parkinson's Disease, or it can be loss of control over voluntary muscle movement as is the case of akathisia, an extreme form of dyskinesia in which a patient is literally unable to sit still.

Major Dyskinesias

Some of the more common forms of dyskinesia are:

Parkinson's Disease: once known as "shaking palsy," this manifests itself as muscular rigidity, weakness and tremors.
Tourette's Syndrome: although most commonly associated with sudden outbursts of profanity, most cases are relatively mild and consist primarily of facial tics or spasms.
Chorea: literally, "dance-like" (as in choreography). This appears as short, seemingly purposeful and irregular muscular contractions that start in one muscle group and work their way up (for example, from the toes, through the foot and up the leg).
Akathisia: patients suffering from this condition are unable to sit still; driven by intense anxiety, they are compelled to tap their feet, move their legs up and down or even pace back and forth.
Akinesia: this is the opposite of akathisia; the patient may appear to be paralyzed or asleep and unresponsive.
Athetosis: this condition consists of slow, almost graceful - but purposeless movements, primarily of the limbs and extremities.
Asterixis: sometimes called "flapping tremor," this is when a patient flaps their wrists involuntarily, similar to a bird flapping its wings.
Dystonia: there are many different types and causes of this movement disorder; it consists of sustained muscular contractions that may affect the entire body, causing the patient to twist into abnormal and even painful postures. Other varieties of dystonia are localized and may include:
- Torticollis (neck and spine)
- Blepharospasm (eyelids)
- Oculogynic Crisis (eyeballs)
- Oromandibular Dystonia (jaw, mouth and tongue)
- Laryngeal Dystonia (throat and larynx)
- Focal Hand Dystonia (similar to writer's cramp, but neurological in nature);
Such dystonias may effect only one side of the body, or both.
Myoclonus: this is characterized by brief, jerky spasms, primarily of the face and/or head and neck, torso, limbs and extremities. "Hiccups" are a common form of myoclonus that affects virtually everyone at some point in their lives.

Causes of Dystonia

The causes of various dystonias vary; in many cases, these are not diseases in and of themselves but symptoms of something else, which may be due to a pathogen (bacteria or virus), genetic defect, side effects of medication or even environmental (some kind of chemical toxin). In general however, these disorders involve the dysfunction of the dopamine receptors of the nervous system. Dopamine is the neurochemical that carries signals form brain to various muscle groups; when this mechanism fails to function properly, dystonia can be the result.

Source

http://www.nami.org/Content/ContentGroups/Helpline1/Tardive_Dyskinesia.htm
http://www.ninds.nih.gov/disorders/tardive/tardive.htm
Dorland's Illustrated Medical Dictionary, 31st Edition (2009).