In functional dystonia, there is abnormal, unintended movement or positioning of the body due to the nervous system not working properly. Functional dystonia can cause movement symptoms in the face, neck, shoulder, torso, and/or limbs. The onset of symptoms is often preceded by an injury, illness, or emotionally stressful event. In some cases, functional dystonia may occur in individuals exposed to psychological stressors or affected by psychiatric disorders.
Functional dystonia belongs to a category of disorders called functional movement disorders. Many people with functional movement disorders experience a mix of motor symptoms including dystonia, tremor, myoclonus, gait disorders, and tics. They may also experience pain, weakness, sensory symptoms, non-epileptic seizures, and other functional neurological symptoms.
Functional movement disorders are common, representing up to 25% of patients treated in movement disorder clinics. Functional movement disorders affect men and women as well as children.
Functional Movement Disorders
- Are real and disabling disorders.
- Are not deliberate. Patients are not making up symptoms.
- Are due to dysfunction of the nervous system, not neurological damage or disease.
- Are treatable.
Functional dystonia can affect different areas of the body. Functional dystonia may share some characteristics with dystonia due to other causes, but also has distinguishing features. Common expressions of functional dystonia include:
Dystonia of the Face: This may include intermittent facial spasms, fixed postures, or downward pulling of one side of the mouth. Symptoms may come and go, with normal functioning of the facial muscles in between episodes.
Blepharospasm: Individuals may experience sudden onset of blinking and/or sustained closure of the eyes. Eye symptoms may affect both eyes or occur with spasms on one side of the face.
Fixed Dystonia: Functional dystonia often manifests as a fixed posture, typically in a limb, hand, or neck/shoulder. It should be noted that dystonia acquired from other secondary causes, such as an injury, may also be fixed. Functional dystonia with pain and dysautonomic symptoms (difference in skin temperature, skin color, sweating, or swelling) may suggest complex regional pain syndrome.
Episodic Dystonia: Functional dystonia commonly occurs in episodes or attacks, which is also a hallmark of movement disorders called paroxysmal dyskinesias. Episodes of functional dystonia can produce movements in the torso and limbs, and may last varying lengths of time in the same patient, from seconds to days. The predominant movement symptoms may change from one episode to the next. Episodes of functional dystonia may be preceded by triggers that are not consistent with triggers associated with paroxysmal dyskinesias.
Diagnosing functional dystonia can be difficult and should be left to movement disorder neurologists and psychiatrists with training and experience in diverse neurological diseases. A person may have a specific neurological movement disorder in addition to functional symptoms.
The diagnosis of functional dystonia is made on the positive observation of the clinical signs in the neurological examination, not solely by ruling out other disorders or the presence of psychological or psychiatric factors. Although psychological and psychiatric factors often contribute to functional dystonia, these signs are not always present.
Psychiatrists may recognize functional dystonia in the context of functional neurological symptom disorder (a revised classification and understanding of conversion disorder), in which psychological distress is expressed in physical symptoms.
It is common for individuals with functional dystonia to have a history of misdiagnoses. Many healthcare providers are not trained to recognize or treat functional movement disorders. Patients often report difficulty in having their symptoms and disability taken seriously, especially by healthcare providers. Many develop a general distrust of medical professionals. If a diagnosis of functional dystonia is suspected, it is essential that patients be promptly referred to a movement disorder neurologist.
Possible indicators of functional dystonia include:
- Sudden symptom onset
- Minor injury preceding symptom onset
- Symptoms are varying and unpredictable across time
- Symptoms contradict hallmark features of other neurological disorders
- Symptoms are lessened with distraction
- Spontaneous remissions and relapse
- Abnormal movements and pain are inconsistent with extent of injury
- Psychiatric symptoms
- Exposure to psychological stressors
- Many additional medically unexplained symptoms
Many researchers believe functional movement disorders occur due to an underlying vulnerability in the brain combined with an external trigger, though the mechanism is not yet fully understood. Research suggests that the process in the brain that helps a person sense whether a movement is voluntary or involuntary becomes disordered, resulting in unintentional movements or postures. These disorders are caused by changes in how the brain functions, not damage to the structures of the nervous system.
Functional dystonia is sometimes called psychogenic dystonia, which refers to the observation that many cases have psychological or psychiatric factors that contribute to the physical symptoms. Treating underlying emotional and mental disorders can reduce the movement symptoms, though researchers do not yet fully understand why this is the case.
The human brain is a spectacularly complicated and interconnected system. Areas of the brain associated with movement are also involved in cognition, emotion, memory, and other mental functions. Researchers are actively studying functional dystonia and functional movement disorders to better understand the underlying neurology and improve treatment.
Many individuals with functional dystonia have complex healthcare needs, so a team of medical experts may be appropriate. The team may include a movement disorder neurologist, psychiatrist, psychotherapist, physical therapist, and additional healthcare providers. Therapy for functional movement disorders must be tailored to the unique needs of the individual. The goal of treatment is to lessen symptoms and improve function by helping the brain override the mechanism that is causing the unintentional movements or postures.
Treatment may require physical and/or occupational therapy, cognitive behavior therapy, and/or oral medications such as antidepressants. There have been reports of improvement in some individuals with non-invasive brain or nerve stimulation techniques, acupuncture, hypnosis, and placebo therapies. Patients with functional movement disorders who educate themselves about the diagnosis and actively participate with their healthcare professionals to develop a treatment strategy tend to benefit most from treatment.
Many individuals with functional dystonia may have complex healthcare needs, so a team of medical experts may be appropriate. The team may include a movement disorder neurologist, psychiatrist, psychotherapist, physical therapist, and additional healthcare providers.
Living well with a functional movement disorder is possible. In some cases, treatment can dramatically reduce or eliminate symptoms.
Individuals affected by functional dystonia are strongly encouraged to:
• Seek evaluation from a neurologist with special training in movement disorders.
• Seek expert mental health professionals to diagnose and treat possible underlying emotional or mental disorders.
• Learn about functional movement disorders and treatment options.
• Develop a support system of support groups, online resources, friends, and family.
• Explore complementary therapies for overall wellness.
• Get active within the patient advocacy community.