How common is it? Incidence and Prevalence

Dystonia is the third most common movement disorder.


1. many people have it and don’t know it . They may not seek medical help

  • some may have symptoms so mild they don’t seek help
  • some may not be need medical help
  • One UK study estimated that 22.4% – 29.9% of the local dystonia population             remains undetected

2. many people who have it and seek help may have been misdiagnosed

  • it was historically often thought just due to stress. Some patients were treated for mental health only.
  • For some time patients were treated with medication that made the condition worse or created side effects that muddied diagnosis

3. many doctors have not heard of it. It is hard to diagnose unless a person is aware of it as a possible explanation of symptoms

  • 10.7% were diagnosed within a year of onset of symptoms
  • 19.1% were diagnosed within the second year
  • 17.4% were diagnosed within the 3rd year
  • 9.8% were diagnosed within the 4th year
  • 37% took 4-19 years to get diagnosed
  • 6% took over 20 years to get a correct diagnosis

4. doctors who diagnose it as dystonia may over time adjust the name of it

  • the condition may sometimes itself change
  • researchers more specifically learn of causes, genetic links and then adjust the name for it

5. there is a reluctance by some patients to admit that they have the condition, given its stigma and especially in some careers eg. for athletes, musicians, radio announcers who often have to make career adjustments

6. there are privacy issues for medical records

  • doctors cannot divulge to the public or media who has a condition
  • official medical tallies in aggregate do not invade privacy but the data may not be being collected for dystonia. There is compulsory reporting of some infectious diseases but not of all medical conditions.
  • Governments vary widely in openness to reveal totals or may not know them

7. as doctors recognize it, it may seem to be more getting more common, but may not be. 

8. sometimes people have dystonia symptoms along with another condition

  • some people with Parkinson’s disease also have dystonia symptoms
  • some people with cerebral palsy also have dystonia symptoms so researchers have to decide if they count those patients in the tally


1. ask the public if they have it and count replies

  • problem knowing if diagnosis is accurate
  • problem deciding how to send out the request
  • problem in whether those with dystonia wish to respond

2. ask patients in a clinic to come forward to do a study

  • requires voluntary cooperation that may depend on their mobility, knowledge of that language for the study, distance and convenience to participate
  • some may not come forward due to stigma or fear

3. ask patients at a pharmacy through a questionnnaire to come forward

  • eg. Shoppers Voice database in 2007 sent an email to 60,062 customers

4. ask people in a profession that may have it to come forward

  • eg. a musicians survey in Japan in 2017 – of 1300 asked at 41 conservatories, 66 responded

5. ask people with a specific type of dystonia to come forward. 

  • ask at eye clinics, speech clinics, clinics that treat movement disorders and get a tally for one type of dystonia

5. take whatever number you get of respondents in that area and extrapolate that percent for the rest of the world

  • you can count the number in a given geographical area and then assume the same ratio for any larger population
  • you can count the number who come to a specialty clinic and compare that to numbers of all patients at a clinic
  • there may be a problem if one assumes the condition occurs at the same rate     everywhere. Maybe it is more common in some climates or among some ethnic   groups or in some environments

6. compare your estimate with those others make. This has resulted in vastly different tallies.

  • eg. 2013 – estimate of 20 per million
  • 28 per million
  • 183 per million
  • 4100 per million


Researchers have several options:

  • how many people in a certain area have dystonia
  • how many people in the world have dystonia
  • how many people have a specific type of dystonia in the world or in your area
    • eg. early onset, or affecting the eyes only
  • how many people of all who have movement disorders, have dystonia
    • eg. the most common movement disorder is Parkinson’s Disease
    • The second most common is essential tremor
    • The third most common is dystonia
  • how many people of all who have dystonia, have a given type of dystonia
    • eg. dystonia of the neck is more common than dystonia that affects the eyes or vocal cords
  • how many women of all the population have dystonia, or how many seniors, etc
  • how many of those who have dystonia are women, or how many are under 30 or what proportion of those with dystonia have early onset dystonia etc.
  • how to report the number
    • eg. total number of people with it
    • eg. proportion of people- eg 3 of every 100,000 people 


there are three main terms used:

  1. prevalence- number of population who have the condition at any given time
  2. incidence  -number of new cases in a given interval of time
    • (eg. a virus may have 300 cases in one city but 56 new ones today)
  3. penetrance – the fraction of individuals with a genotype who have signs or symptoms of the disease.

Even when dystonia is suspected to be inherited, researchers have found that not everyone with that type of dystonia has those gene markers and that not everyone with those gene markers develops dystonia. So a person can inherit the genes for it and still not get it.         

  • eg. there is a 30-40% chance of showing symptoms of active dystonia among those who have the genes linked to it


1980 approx. estimated 24 per million

1991- estimates are that dystonia is six times more prevalent than Huntington’s Disease, ALS or muscular dystrophy. However estimates of its actual incidence vary widely from 11 per million people to 248 per million.

1993 – a NE England survey of dystonia finds 143 cases. by 1996 finds 641, and by 2002 finds 1339. As the disease gets better identified a medical referral centre is set up, and the survey attempts to look at ‘everyone known to have dystonia’ in the area.

 1996 – in the greater Vancouver area, cervical dystonia rate is 14.2 per hundred thousand

2003 – one estimate says it affects over 300,000 people in North America

2004 – Northeast England town of Darlington studies dystonia in the entire region and estimates are that 1 in 1850 people have it

2004 – UK researchers say dystonia is the third most prevalent movement disorder in the UK, after Parkinson’s disease and benign essential tremor

2004 – one UK study says that among musicians’ dystonia prevalence may be one in 200, which would be 500 in 100,000


  • cervical dystonia in the US affects 60,000 to 90,000 people
  • spasmodic torticolllis 18.31 per 100,000
  • blepharospasm 8.14 per 100,000
  • spasmodic dystonia 4.26 per 100,000
  • writer’s cramp 2.69 per 100,000
  • generalized dystonia 3.92 per 100,000
  • segmental dystonia 3.99 per 100,000
  • hemidystonia 1.57 per 100,000
  • multifocal 1.15 per 100,000
  • all focal dystonias 38.08 per 100,000

2007 –  email sent out to 60,062 customers at Shoppers Voice database; 42% of those said they were not receiving treatment


  • estimated 220 per million
  • early onset 3 per million up to 50 per million
  • late onset 30  per million up to 7320 per million
  • one estimate is that adult onset focal dystonia happens in 30 of every 100,000             people

2012 – one study estimates that 16.43  per 100,000 have dystonia and that 1.07 per 100,000 have cervical dystonia

2020 – one estimate is that 100,000 in the UK have dystonia

2020 – webinar says:

  • cervical is 4-5 per 100,000          
  • cervical is 20-4100 cases per million, or 5 per 100,000
  • eye blepharospasm is 4-5 per 100,000

2020 – for types of dystonia

  • One estimate for eye dystonia is five per 100,000  (50 per million)
  • In Europe an estimate for eye dystonia was 36 per million   
  • In Italy an estimate for eye dystonia was 133 per million
  • Jaw dystonia is 68.9 per million
  • Cervical dystonia is 9-30 per 100,000 in the US (90- 300 per million)
  • Hand dystonia occurs in  7-69 per million
  • Focal task-specific dystonia (FTSD) is  295 per million

2020 – current estimates

  • in Europe – 500,000 in population of  741 million
  • in US – 250,000 in population of 328.5 million
  • in Australia – 70,000 in population of 25.49 million
  • in the UK – 70,000 in population of 66.6 million
  • in Canada – 50,000 in population of 37.5 million
  • that could extrapolate to from 6.3 million to 9.75 million in a world of 7.8 billion             people

(so yes, dystonia is somewhat rare, and yet not)