Functional dystonia is a condition where some specific symptoms of dystonia appear but tests that normally establish the cause of these symptoms are negative.
Functional dystonia breaks down into two types: functional fixed dystonia and functional paroxysmal dystonia.
Symptoms are fixed abnormal posture of the affected limb often combined with a lot of pain. Often the limb that is postured cannot be moved and, when someone else tries to move it, the limb is fixed in position. Such symptoms are usually caused by degeneration of the brain or a stroke, but patients with functional fixed dystonia do not show evidence of this. Tests like “scanning the brain” or “checking the nerves and muscles” are normal.
Symptoms are similar to paroxysmal dystonia – intermittent attacks of abnormal postures. However, unlike paroxysmal dystonia, the attacks do not have very particular duration or triggers. Often epilepsy is considered as a possible diagnosis, but tests for epilepsy are negative.
In functional dystonias, there is a problem with the voluntary movement system. Symptoms tend to alleviate when distraction techniques are used which seems to indicate that conscious attention is very important in maintaining symptoms. Unfortunately, this means that many patients are told by doctors that the symptoms are "made up" or "imagined", but the reality is much more complex.
Many people with functional dystonia report that the problem is triggered by an event, often a physical illness or injury. In addition, many patients report a background of stress and psychological difficulty. It is possible that the combination of these two factors (or even one or other on its own) causes the brain to learn an abnormal pattern of movement or posture which becomes ingrained in the system and occurs without the person's control. Because it is part of the voluntary system of movement that has malfunctioned, distraction and other techniques can transiently improve the situation. Much work is still to be done to try to understand how these disorders develop.
There is unfortunately a lack of evidence about what treatment is best as these types of dystonia have been rather neglected (as they just don't fit). However, in general, tablets used for dystonia are not effective for these forms of functional dystonia, and can cause side effects.
Generally a multi-disciplinary rehabilitation approach aimed towards getting the limb moving again including and intensive physiotherapy, occupational therapy. It should also involve an open-minded discussion between the patient and the doctor as to whether psychological and stress factors might either have helped to trigger the condition or have developed along the way and be adding to symptoms. If these factors seem relevant, then they should be actively treated too, for example with cognitive behavioural therapy. If pain is a dominant symptom, then joint management with a pain clinic is an excellent idea. Usually it is best to avoid surgical treatments (for example tendon lengthening operations or joint fusions) as these can worsen the situation.
Generally, cognitive behavioural therapy by an experienced therapist who has treated similar patients before is most effective and the most useful thing to try first.
For more information, call our helpline on 0845 458 6322
Last reviewed October 2011
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.
The Dystonia Society is not responsible for the consequences of your decisions resulting from the use of this information, including, but not limited to, your choosing to seek or not to seek professional medical care, or from choosing or not choosing specific treatment based on the information. You should not disregard the advice of your physician or other qualified health care provider because of any information you receive from us. If you have any health care questions, please consult the relevant medical practitioner.