Tests
Focal dystonias
In general there are no specific tests for dystonia. Tests may be used to rule out other conditions as an underlying cause for focal dystonia. The diagnosis is usually made based on history of symptoms and observation. Family history may reveal that other members of the family also have dystonia. Blood and urine tests will usually be normal. Genetic testing may be undertaken for specific forms of dystonia. Dystonia is usually managed in a hospital setting by a Consultant Neurologist who may specialise in ‘movement disorders’ although this is rare for focal dystonia. Medical evidence from the neurologist will be the best source of evidence of a diagnosis of dystonia. Other conditions that are not disabling and are not dystonia include facial tics and essential tremor.
Parkinson’s disease can be disabling and may be associated with dystonia type symptoms. In Parkinsonism syndromes such as supra-nuclear palsy dystonia of the facial and neck muscles may occur. In these cases the disabling effects of dystonia symptoms will be present in addition to any disabling effects of Parkinson’s disease itself. In addition, some individuals with Parkinson’s disease can have dystonic muscle spasms as part of the condition or because of drug treatment.
The focal dystonias described in this section are most often a primary disorder of unknown cause and not usually associated with other conditions.
Blepharospasm
There are no specific diagnostic tests for blepharospasm. The diagnosis is usually made based on history of symptoms and observation. Occasionally EMG (electromyography) maybe used to identify the muscles around the eye causing the symptoms to target treatment. Individuals with this form of dystonia may be seen by neurologists or ophthalmologists.
Oromandibular dystonia (cranial dystonia)
There are no specific diagnostic tests. The diagnosis is usually made based on history of symptoms and observation. EMG (electromyography) maybe used to identify the muscles causing the symptoms to target treatment.
Spasmodic dysphonia or laryngeal dystonia
There are no specific diagnostic tests. This type of dystonia is likely to be managed by an Ear, Nose and Throat (ENT) specialist rather than a neurologist. EMG may be used to identify muscles to target treatment.
Spasmodic torticollis or cervical dystonia
There are no specific diagnostic tests. The diagnosis is usually made based on history of symptoms and observation. Tests such as x-rays or MRI may be performed to rule out other causes of torticollis. Swallowing studies may be performed to assess and plan treatment for swallowing problems. Electromyography may be used to identify muscles affected to plan treatment. Torticollis may occur acutely and last for up to 2 weeks in adults without dystonia. This guidance refers to spasmodic torticollis/cervical dystonia that endures and does not usually resolve.
Hemifacial spasm
There are no specific diagnostic tests. The diagnosis is usually made based on history of symptoms and observation. Tests such as MRI may be performed to rule out other causes of spasm and assess suitability for surgical treatment.
Writer’s cramp or hand dystonia.
There are no specific diagnostic tests. The diagnosis is usually made based on history of symptoms and observation. EMG (electromyography) maybe used to identify the muscles causing the symptoms to target treatment.
Generalised dystonias
People who have developed dystonia in childhood may have had multiple investigations to rule out secondary causes such as metabolic conditions, tumours, drugs etc. They may also have had genetic testing to identify whether they have one of the known gene abnormalities associated with dystonia. They are also likely to have had a trial of levodopa treatment to see if they have ‘dopa responsive’ dystonia.
Rare dystonias
Myoclonus dystonia
There are no specific diagnostic tests. The diagnosis is usually made based on history of symptoms and observation. There may be a family history of myoclonus or dystonia and diagnosis can be confirmed in some cases by genetic or biochemical testing.
Tardive dystonia
There are no specific diagnostic tests. The diagnosis is usually made based on history of symptoms, exposure to causative drugs and observation of movements.
Tardive dyskinesia
There are no specific diagnostic tests. The diagnosis is usually made based on history of symptoms, exposure to causative drugs and observation of movements.
Amended May 2009
