Patients with focal dystonia have involuntary contractions of their muscles in specific areas of the body, such as the jaw, vocal cords or neck. Several different factors can cause focal dystonia.
For example, injury to the brain, such as trauma or stroke, can cause focal dystonia. If there is a lack of oxygen during birth, the baby may have focal dystonia.
Some people have may inherited abnormalities, which result in focal dystonia. Other causes of focal dystonia include a vitamin B12 deficiency, infections, carbon monoxide poisoning and heavy metal poisoning.
To diagnose focal dystonia, a doctor may run several different tests. For example, the patient may undergo blood tests, genetic tests, urine tests and a spinal tap. The doctor may test the electrical activity of the patient’s muscles with an electromyography.
A nerve conduction study may be used to measure the electrical activity of a nerve, while an electroencephalography may be used to measure electrical activity in the brain. The doctor may choose to do a brain scan, such as a MRI scan or CT scan.
Other examinations that may be done to diagnose focal dystonia include a transcranial ultrasound, neurological evaluation, eye exam and biopsies of the nerve, skin or muscle.
Several different treatments are available for focal dystonia. One option is medication, which affects the neurotransmitters. NYU Langone Medical Center listed bromocriptine, trihexyphenidyl, muscle relaxants, benztropine, procyclidine HCl, and levodopa and carbidopa. While these medications do not slow the progression of focal dystonia, they can help alleviate symptoms.
Side effects can occur with all of these medications. For example, anticholinergic agents, such as benztropine and trihexyphenidyl, can cause sedation and memory problems. The National Institute of Neurological Disorders and Stroke noted that these side effects occur more often in older patients or when the medication is given at a higher dosage.
Another focal dystonia treatment option is injections of the botulinum toxin.