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Abnormal involuntary movements

Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Dystonia article more useful, or one of our other health articles.

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What is dyskinesia?

Abnormal involuntary movements (AIMs) are known as 'dyskinesias'. There are several varieties of dyskinesia which have different clinical appearances, underlying causes and treatments. Tremor, chorea, dystonia and myoclonus are examples of types of dyskinesia which have different mechanisms and modalities of treatment.

Tics and stereotypies may also be considered to be related but some experts call these 'unvoluntary' because there is an element of voluntary control.

Cerebrovascular diseases are a common cause of secondary movement disorders. Post-stroke movement disorders include Parkinsonism and a wide range of hyperkinetic movement disorders, including chorea, ballism, athetosis, dystonia, tremor, myoclonus, stereotypies and akathisia.



Sinuous, slow, involuntary writhing movements affecting the fingers, hands, toes and feet. The arms, legs, neck and tongue may also be affected. Causes include asphyxia, neonatal jaundice, Huntington's chorea, cerebrovascular disease and trauma. Management can be difficult but treatment options include medications (eg, diazepam, haloperidol, tetrabenazine), surgery and retraining techniques.


Continuous jerky movements in which each movement is sudden and the resulting posture is held for a few seconds. This usually affects the head, face or limbs. The focus may move from one part of the body to another at random.

Chorea may be caused by adverse effects of drug treatments, especially medications for Parkinson's disease, epilepsy and schizophrenia. Other causes of chorea include the following:


  • Huntington's chorea - autosomal dominant inheritance, usually presents in middle age with chorea and dementia. Insidious onset with motor, cognitive and psychiatric abnormalities. There is no treatment.

  • Benign hereditary chorea.

  • Wilson's disease.


Chorea may occur with athetosis and is then called choreoathetosis.


A dystonia is a sustained muscle contraction, frequently causing repetitive twisting movements or abnormal postures2 . It is a dynamic condition that often changes in severity, depending on the posture assumed and on voluntary activity of the area of the body involved. The diagnosis is clinical and there are no specific tests available; therefore, expert opinion should be sought. Dystonias may be primary or secondary3 .

Treatments available for dystonia include oral medications, botulinum toxin and surgical procedures. Oral medications are generally used for generalised and segmental dystonia. Botulinum toxin is the mainstay of treatment for focal dystonia. Surgical procedures are available for medication-refractory dystonia, markedly affecting quality of life4 .

Primary pure dystonia is inherited in a mainly autosomal dominant pattern5 . Two genes have been identified: DYT1 and DYT6. It usually presents in children, with dystonic spasms of the legs on walking and occasionally of the arms, trunk or neck. It is normally progressive and spreading to the whole body, causing severe disability within about ten years. A levodopa trial should be offered to patients with early-onset dystonia without an alternative diagnosis6 . Blepharospasm and writer's cramp are both focal dystonias. Blepharospasm involves recurrent spasms of eye closure. Writer's cramp is the inability to write or use any manual instrument, due to abnormal posture of the hand and arm7 . Botulinum toxin injection is the first-line treatment for most types of focal dystonia8 . Hemidystonia involves half of the body and is usually secondary to a structural lesion in the contralateral basal ganglia.

Dystonias may be secondary to a neurological condition such as a focal brain lesion, exposure to drugs or chemicals, or as part of Parkinson's disease. Infantile cerebral palsy is the most frequent cause of acquired dystonias in children. Many children also have other symptoms and signs in addition to dystonia, particularly spasticity, cognitive impairment, or epilepsy, thus qualifying to be grouped into the category of complex dystonias9 . Intrathecal baclofen can be indicated in patients where secondary dystonia is combined with spasticity.

Deep brain stimulation (long-term electrical stimulation of the globus pallidus internus) is an effective treatment for primary generalised or segmental forms and for those patients who do not achieve sufficient relief with a more conservative approach10 11 . However, deep brain stimulation is less effective for secondary dystonias12 .

Dystonia may lead to permanent contractions, by causing tendons to shorten.


These are wild flinging/throwing movements of one arm or leg, usually occurring as a result of a cerebrovascular event. They can vary in intensity from mild to severe and may even cause injury. They usually subside over a period of 3-6 months but can be treated with a phenothiazine, haloperidol or tetrabenazine. They may require neurosurgery to be adequately controlled.


These are rapid muscle jerks that are frequently repetitive and cause significant disability. They appear as:

  • Benign essential myoclonus: affects much of body, repeated as many as 50 times per minute. Presents in childhood or adolescence with mild disability. Helped by alcohol and beta-blockers.

  • Progressive myoclonic encephalopathies: appear as part of a range of other neurological disorders.

  • Static myoclonic encephalopathies: Lance-Adams syndrome after cerebral anoxia.

  • Myoclonic epilepsies: eg, focal myoclonus - restricted to one part of the body (eg, hemifacial spasm, mainly affecting older women).

Myoclonus usually requires a combination of drugs (in large doses)14 . Antiepileptic drugs (eg, valproate, levetiracetam and piracetam) are effective in cortical myoclonus but less so in others. Clonazepam may be helpful with all types of myoclonus. Botulinum toxin may be useful for segmental myoclonus.

Spasmodic torticollis

Torticollis is a twisting of the head and neck caused by a shortened sternocleidomastoid muscle, tipping the head toward the shortened muscle, while rotating the chin in the opposite direction. Torticollis may occur in all ages, from newborns to adults15 . See also the separate Neck Pain (Cervicalgia) and Torticollis article.

Tardive dyskinesia

This is characterised by orofacial mouthing with lip-smacking and tongue protrusion, body rocking and distal chorea. In younger patients it may also cause axial and cranial dystonia. It usually occurs following at least six months of treatment with neuroleptics. The risk of new cases is around 5% per year of cumulative drug exposure, with age and early occurring extrapyramidal side-effects being two important risk factors16 .

  • Preventing tardive dyskinesia is the best option, and clinicians should follow best practice for prescribing antipsychotic medication, including limiting the prescription for specific indications, using the minimum effective dose, and minimising the duration of therapy17 .

  • The first-line management of tardive dyskinesia is the withdrawal of antipsychotic medication if clinically feasible. Yet, for many patients with serious mental illness, the discontinuation of antipsychotics is not possible due to disease relapse.

  • Switching from a first-generation to a second-generation antipsychotic, such as clozapine or quetiapine, may be effective in reducing tardive dyskinesia symptoms.

  • VMAT2 inhibitors (vesicular monoamine transporter 2) are integral membrane proteins that regulate monoamine uptake from the cytoplasm to the synaptic vesicle for storage and release. There are 3 VMAT2 inhibitors: tetrabenazine, valbenazine and deutetrabenazine. These medications have not been approved and may be unavailable for use outside the USA.


These are repetitive stereotyped movements. The patient can initiate them voluntarily and can also intentionally suppress them for a short time:

  • Simple tic - sudden rapid twitch always occurring at the same site. Occurs in a quarter of all children and resolves within a year. May persist into adulthood; rarely treated.

  • Complex multiple tics - more extensive and severe. When occurring with the patient speaking, particularly swearing, they may represent Tourette's syndrome. They may also appear as a symptom of encephalitis lethargica and of neuroacanthocytosis; they can also be drug-induced.


See also the separate Tremor article.

This is a rhythmic movement of part of the body. Essential tremor and Parkinsonian tremor are the most common forms of tremor19 . There are three types of pathological tremor:

  • Static - occurs in a relaxed limb when fully supported at rest. Causes include Parkinson's disease, Parkinsonism, other extrapyramidal diseases, multiple sclerosis.

  • Postural - occurs if a limb is static (can also remain during movement). Types include physiological tremor, exaggerated physiological tremor - eg, in thyrotoxicosis, anxiety states, alcohol abuse, drugs (eg, sympathomimetics, antidepressants, valproate, lithium), heavy metal poisoning ('hatter's shakes' from mercury). Neurological disease - eg, severe cerebellar lesions, Wilson's disease, neurosyphilis, peripheral neuropathies, benign essential (familial) tremor, task-specific tremors (eg, primary writing tremor).

  • Kinetic or action tremor - occurs during voluntary active movement of an upper body part. Intention tremor is one that occurs when a tremor worsens as a goal-directed hand movement nears its intended target. Brainstem or cerebellar disease including multiple sclerosis, spinocerebellar degenerations, vascular disease, tumours.

There are also psychogenic tremors.

Tremors and dystonias that are not secondary to Parkinson's disease may be effectively treated with deep brain electrical stimulation20 . Benign essential tremor is treated with alcohol in moderation. Beta-blockers or primidone are also used.

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Levodopa-induced dyskinesia21

Approximately 50% of people with Parkinson's disease will experience levodopa-induced dyskinesia (LID) 4-5 years after initiation of levodopa treatment. However, the percentage of those patients experiencing troublesome LIDs requiring intervention is actually much lower than 50%. There are three main forms of LIDs:

  • 'Peak-dose' dyskinesias are choreic movements related to high levodopa plasma concentrations.

  • Diphasic on/off dyskinesias, which coincide with rising and decreasing plasma concentrations of levodopa and may include both chorea and dystonia.

  • 'Off' dystonia, which is an often painful dystonic posture, appears early in the morning or at night and occurs when plasma levels of levodopa are very low.

Assessment of dyskinesia

Many different rating scales have been developed to assess people with dystonia22 23 .

The Abnormal Involuntary Movement Scale is used to assess tardive dyskinesias and other AIMs24 25 .

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Dyskinesia treatment and management

The management of AIMs will depend on the underlying cause. Drug treatments include26 :

  • Tetrabenazine - mainly used to control movement disorders in Huntington's chorea and related disorders. Haloperidol, olanzapine, risperidone and quetiapine can also be used to suppress chorea in Huntington's disease but are all unlicensed.

  • Haloperidol - can improve motor tics and symptoms of Tourette's syndrome and related choreas. Other treatments for Tourette's syndrome include pimozide and sulpiride (both unlicensed).

  • Trihexyphenidyl in high dosage - can also improve some movement disorders.

  • Chlorpromazine and haloperidol - are used to relieve intractable hiccup.

  • Propranolol or another beta-adrenoceptor blocking drug - may be used to treat essential tremor or tremors associated with anxiety or thyrotoxicosis.

  • Primidone - may provide relief from benign essential tremor.

  • Piracetam - is used as an adjunctive treatment for myoclonus of cortical origin.

Further reading and references

  1. Merical B, Sanchez-Manso JC; Chorea
  2. Albanese A, Bhatia K, Bressman SB, et al; Phenomenology and classification of dystonia: a consensus update. Mov Disord. 2013 Jun 15;28(7):863-73. doi: 10.1002/mds.25475. Epub 2013 May 6.
  3. Charleswortha G and Bhatiab KP; Primary and secondary dystonic syndromes: an update; Curr Opin Neurol. 2013 Aug;26(4):406-12. doi: 10.1097/WCO.0b013e3283633696.
  4. Thenganatt MA and Jankovic J; Treatment of dystonia; Neurotherapeutics. 2014 Jan;11(1):139-52. doi: 10.1007/s13311-013-0231-4.
  5. Dystonia 1, Torsion, Autosomal Dominant, DYT1; Online Mendelian Inheritance in Man (OMIM)
  6. Albanese A, Barnes MP, Bhatia KP, et al; A systematic review on the diagnosis and treatment of primary (idiopathic) dystonia and dystonia plus syndromes: report of an EFNS/MDS-ES Task Force. Eur J Neurol. 2006 May;13(5):433-44.
  7. Zeuner KE, Peller M, Knutzen A, et al; How to assess motor impairment in writer's cramp. Mov Disord. 2007 Jun 15;22(8):1102-9.
  8. Anandan C, Jankovic J; Botulinum Toxin in Movement Disorders: An Update. Toxins (Basel). 2021 Jan 8;13(1). pii: toxins13010042. doi: 10.3390/toxins13010042.
  9. Herzog R, Weissbach A, Baumer T, et al; Complex dystonias: an update on diagnosis and care. J Neural Transm (Vienna). 2021 Apr;128(4):431-445. doi: 10.1007/s00702-020-02275-y. Epub 2020 Nov 13.
  10. Lyons MK; Deep brain stimulation: current and future clinical applications; Mayo Clin Proc. 2011 Jul;86(7):662-72. doi: 10.4065/mcp.2011.0045. Epub 2011 Jun 6.
  11. Costa J, Espirito-Santo C, Borges A, et al; Botulinum toxin type B for cervical dystonia. Cochrane Database Syst Rev. 2005 Jan 25;(1):CD004315.
  12. Albanese A, et al; EFNS guidelines on diagnosis and treatment of primary dystonias; Eur J Neurol. 2011 Jan;18(1):5-18. doi: 10.1111/j.1468-1331.2010.03042.x.
  13. Caviness JN; Treatment of myoclonus; Neurotherapeutics. 2014 Jan;11(1):188-200. doi: 10.1007/s13311-013-0216-3.
  14. Pena AB, Caviness JN; Physiology-Based Treatment of Myoclonus. Neurotherapeutics. 2020 Oct;17(4):1665-1680. doi: 10.1007/s13311-020-00922-6.
  15. Tomczak KK, Rosman NP; Torticollis. J Child Neurol. 2013 Mar;28(3):365-78. doi: 10.1177/0883073812469294. Epub 2012 Dec 26.
  16. Kane JM, Correll CU; Pharmacologic treatment of schizophrenia. Dialogues Clin Neurosci. 2010;12(3):345-57.
  17. Kremens DE; Treatment Strategies for Tardive Dyskinesia. J Clin Psychiatry. 2019 Dec 24;81(1). doi: 10.4088/JCP.NU18041BR4C.
  18. Pringsheim T, Okun MS, Muller-Vahl K, et al; Practice guideline recommendations summary: Treatment of tics in people with Tourette syndrome and chronic tic disorders. Neurology. 2019 May 7;92(19):896-906. doi: 10.1212/WNL.0000000000007466.
  19. Schneider S and Deuschl G: The treatment of tremor; Neurotherapeutics. 2014 Jan;11(1):128-38. doi: 10.1007/s13311-013-0230-5.
  20. Deep brain stimulation for tremor and dystonia (excluding Parkinson's disease); NICE Interventional procedures guidance, August 2006
  21. Bargiotas P and Konitsiotis S; Levodopa-induced dyskinesias in Parkinson's disease: emerging treatments; Neuropsychiatr Dis Treat. 2013;9:1605-17. doi: 10.2147/NDT.S36693. Epub 2013 Oct 22.
  22. Susatia F, Malaty IA, Foote KD, et al; An evaluation of rating scales utilized for deep brain stimulation for dystonia. J Neurol. 2010 Jan;257(1):44-58. Epub 2009 Jul 29.
  23. Albanese A, et al; Dystonia rating scales: critique and recommendations; Mov Disord. 2013 Jun 15;28(7):874-83. doi: 10.1002/mds.25579.
  24. Ayehu M et al; Movement disorders in neuroleptic-naive patients with schizophrenia spectrum disorders; BMC Psychiatry. 2014 Oct 9;14:280. doi: 10.1186/s12888-014-0280-1.
  25. Abnormal Involuntary Movement Scale (AIMS); The Virtual En-psych-lopedia by Dr Bob
  26. British National Formulary (BNF); NICE Evidence Services (UK access only)

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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