What is dystonia?
Dystonia is a neurological movement disorder that causes uncontrollable muscle contractions. People with dystonia experience abnormal postures and repeated or sustained twisting movements that may be painful and interfere with daily activities.
Dystonia affects around 250,000 people in the United States. It is the third most common movement disorder. Parkinson’s disease and essential tremor are more common.
Dystonia affects people of all ages, ethnicities, and races. Women are three times more likely than men to experience dystonia.
How dystonia affects the body
Symptoms of dystonia differ from person to person. Involuntary muscle contractions can affect different body parts, causing specific movement problems.
- Cervical dystonia or spasmodic torticollis affects the neck muscles, causing the head to tilt or turn to one side, forward, or backward.
- Cranial dystonia affects the muscles of the head and face, causing problems with facial expressions and involuntary jaw and mouth movements. Cranial dystonia includes blepharospasm and oromandibular dystonia.
- Blepharospasm affects the muscles in the eyelids, causing problems with vision due to sustained eyelid closure.
- Oromandibular dystonia affects the muscles of the jaw, mouth, or tongue, causing problems with speech, swallowing, and chewing.
- Laryngeal dystonia or spasmodic dysphonia affects the vocal cords, causing strained or breathy speech or low speaking volume.
- Dystonia affecting the muscles of hands or forearms causes problems with handwriting or other activities using the hands.
- Dystonia affecting the muscles of the legs or feet causes difficulties when walking or running.
- Task-specific dystonia occurs only during performance of a specific activity. It doesn’t occur during other activities that use the same muscles. For example, a musician may experience problems with the right hand while playing the piano, but not while writing with that hand.
Symptoms may worsen over time, and in some cases spread to adjacent body parts. Certain triggers, including anxiety, fatigue, and stress can worsen muscle contractions. Specific repetitive activities, such as writing (writer’s dystonia) or playing a musical instrument (musician’s dystonia) may also worsen symptoms of dystonia.
Possible causes of dystonia
The exact cause of dystonia is unknown. Researchers think abnormalities in or damage to specific brain regions change the way nerves communicate, affecting control of movement.
Some types of dystonia are passed down in families. Others are symptoms of another underlying condition or disease, including:
- Parkinson's disease, Huntington's disease, or Wilson's disease
- Brain injuries due to childbirth or trauma
- Stroke or any other condition causing lack of oxygen to the brain
- Brain tumors
- Infections such as encephalitis or tuberculosis
- Heavy metal or carbon monoxide poisoning
- Reactions to certain medications
How dystonia is classified
Dystonia can be described in different ways. Specialists classify dystonia based on when it begins, which body parts are affected, how symptoms change over time, and what causes it.
Usually, the age when symptoms first appear helps predict if they'll spread. When dystonia starts at a younger age, it’s more likely to affect multiple areas of the body. If it begins later in adulthood, the symptoms often stay in one place and remain more manageable.
How dystonia is distributed across the body helps determine the type:
- Focal dystonia: Symptoms are in one body part or one muscle group, like the neck or hand
- Segmental dystonia: The condition involves two or more body regions next to each other
- Multifocal dystonia: Symptoms affect two or more unconnected body regions
- Hemidystonia: The condition affects the arm and leg on the same side of the body
- Generalized dystonia: Most or all of the body is affected, including the torso
Understanding how symptoms evolve over time can help providers diagnose the type of dystonia. Symptoms might:
- Stay the same (static)
- Get worse over time (progressive)
- Happen only during certain tasks, like writing or playing an instrument
- Occur only at specific times of day
Caused-based categories describe why dystonia occurs:
- Nervous system issues: Sometimes, brain scans show injuries or structural changes that cause movements
- Medication-related: Certain medications for psychiatric conditions can trigger symptoms
- Genetics: You might have inherited a gene change from a parent, or a change may have happened on its own during your life
- Unknown causes: When a specific trigger can't be found, it's called idiopathic dystonia
Evaluating and treating dystonia
Diagnosing dystonia involves a comprehensive physical examination. In many cases, that is all that is required for diagnosis. In some cases, doctors may order imaging or genetic testing in order to confirm a dystonia diagnosis.
Our movement disorder specialists customize treatment plans to meet the needs for every individual with dystonia. Penn's Movement Disorders Center offers all of the available treatments for dystonia, including medications, botulinum toxin injections, and surgical options.
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