This page contains information about focal hand dystonia (also known as writer's cramp, musician's cramp and musician's dystonia) for medical professionals. For information on hand dystonia for patients and carers please click here.
Focal hand dystonia causes involuntary movement, cramps or tremor in the hand or arm muscles usually when making highly practiced hand movements such as writing or playing a musical instrument. Focal hand dystonia is often called writer’s cramp or musician’s cramp.
When focal hand dystonia affects writing, this is called writer’s cramp. Writing can become painful and written work less legible. There are two types: simple and dystonic.
Simple writer’s cramp is usually caused by over-use of the hand, poor writing posture or poor penhold. The resulting muscle strain can cause the writer to press down too hard on the paper and can lead to spasms and pain.
Symptoms of simple writer’s cramp only appear during writing and include some or all of the following:
These can make writing very difficult. Sometimes tremor is also a symptom although this is unusual. In many cases, symptoms are exacerbated by tension.
In some cases, difficulties in writing are caused by dystonic writer’s cramp which may occur together with a more generalised dystonia that can affect other parts of the body as well. In this case, the involuntary movements and muscle cramps can also be apparent when undertaking other non-writing tasks such as using a knife and fork or applying makeup etc.
Focal hand dystonia can affect any profession which requires repeated hand movement but is more common among musicians than any other professional group. Hand dystonia in musicians is often called musician’s cramp or musician's dystonia.
Symptoms can include reduced precision when playing and loss of control of the hand including fingers curling or sticking. Sometimes the effects are quite subtle - but they often prevent playing to a professional standard.
The cause of musician’s cramp is not fully understood but it appears that the motor control systems in the brain essential for performing music fail to work properly. Occasionally, the cramp may be related to another dystonia that can affect other parts of the body as well.
Focal hand dystonia is classified as a focal dystonia which means it affects only one region of the body. In the majority of cases the dystonia does not spread to other areas. However, in a minority of cases, other regions of the body also become affected and the dystonia is classified as a multifocal or segmental dystonia.
Focal hand dystonia is usually a primary pure dystonia. This means that torsion dystonia is the only clinical sign (apart from tremor) and there is no identifiable exogenous cause or other inherited or degenerative disease.
Focal hand dystonia usually appears in mid-life but sometimes affect younger or older people. It is therefore classified as a late-onset dystonia.
Where the hand dystonia only appears when performing a task such writing or playing music, this is called a task-specific dystonia.
Focal hand dystonia is often misdiagnosed by GPs. Conditions that focal hand dystonia is commonly mistaken for include orthopaedic problems, tendonitis or a psychological problem.
Indicators for a GP that the diagnosis may be focal hand dystonia rather one of these other conditions include:
There is no cure for hand dystonia. However, there are a number of ways of managing the problem.
Many individuals with writer's cramp benefit from techniques to help them ‘retrain’ their muscles and ‘unwind’ the problems with hand posture and pressure, one by one. Often there is a need to relax not only hands but attitudes to handwriting too. Click here to read about exercises that some people with Simple Writer's Cramp have found helpful. Some people with writer’s cramp can also gain benefit from treatment with drugs either on their own or together with regular injections. There are a variety of tablets that can be helpful, although none are universally successful and side effects can occur.
There are techniques that enable musicians to use different motor control systems when playing. This could be by changing the position of keys on a wind instrument or using the opposite hand for bowing on the violin. Some musicians also find techniques such as sensory retuning and sensory motor reeducation helpful. Medication can also be helpful. Regular injections are sometimes used to help musicians- generally to facilitate new techniques rather than as a solution in themselves.
Last reviewed March 2012
The Dystonia Society provides the information on this page as general information only. It is not intended to provide instruction and you should not rely on this information to determine diagnosis, prognosis or a course of treatment. It should not be used in place of a professional consultation with a doctor.
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