What is a Dystonic Tremor?
Tremor is an uncontrollable/involuntary oscillation or shaking or rapid movement of a part of a person’s body.1 For example, if a person has head tremor, then there will be involuntary shaking movement of the head. Similarly, if a person has hand tremor, then there is uncontrollable shaking of the hands. Tremor can affect any part of the body including eyes, vocal cords, arms, face, trunk and legs.
Dystonic tremor is a type of tremor which the patient develops along with or in association with dystonia.2 Dystonia is a neurological disorder where there is transmission of incorrect messages from the brain to the body resulting in unwanted movement or over-active or abnormal postures. Patient experiences Dystonic Tremor commonly in young adulthood or mid-life.
Symptoms of Dystonic Tremor
The symptoms of dystonic tremor can differ from patient to patient. Sometimes sensory tricks can temporarily cause tremor to disappear, such as, if the patient has head tremor, then placing the head against a headrest or a light touch to the chin can resolve the dystonic tremor of the head. Dystonic tremor can also affect the patient’s quality of life and cause tiredness in the patient and feels of isolation in social gatherings. Anxiety or stress worsens all types of dystonia also symptoms of dystonic tremor. In some patients, a small quantity of alcohol can temporarily relieve the symptoms of dystonic tremor; however, patient can experience a rebound worsening of the dystonic tremor the next day.
Differentiation between Dystonic Tremor & Essential Tremor
Essential tremor is the most common type of tremor3 and it is very important to differentiate it from dystonic tremor. Essential tremor commonly affects the hands, arms, or fingers. The primary differences between dystonic tremor and essential tremor are:
- The movement or tremor of dystonic tremor is often irregular; whereas, in essential tremor, patient has regular movements or oscillation of the affected part.
- Dystonic tremor appears with dystonia; whereas essential tremor does not appear in combination with dystonia.
- Sensory trick can temporarily relieve a dystonic tremor; whereas, essential tremor cannot be relieved with this.
- In majority of the patients with essential tremor, the arms, fingers or hands are affected symmetrically; whereas, other parts of the body, such as the head can be affected with dystonic tremor without the involvement of the arms or hands. However, in some cases, dystonic tremor can also affect the hands.
Types of Dystonic Tremor
- Dystonic tremor appears in the same area of the body which is affected by dystonia. So, a person suffering from neck dystonia will have twisting of the head along with shaking movements of the head.
- Dystonic tremor can also appear in a different part of the body to the dystonia. If a person has neck dystonia he/she can have dystonic tremor in the hand.
- Dystonic tremor may not be present with other dystonic symptoms; however, if a person has a family history of dystonia, then it can be suspected that he/she may also have dystonia.
Treatment of Dystonic Tremor
Oral Medications: Oral medications can be effective in relieving dystonic tremors in some patients. They work by interrupting the neurotransmitters, which are responsible for sending messages within the brain. Some medicines act by relaxing the muscles and thus reducing the dystonic tremors. These medicines need to be taken continuously and they also have side effects.
Botulinum Toxin Injections: This treatment can be given if the dystonic tremor is localized to one or two areas of the body. Botulinum toxin injections work by weakening the overactive muscles and they need to be taken every three months or so. If the patient is not having any improvement from the Botulinum Toxin Injections, then it may mean that the dose needs to be adjusted or the injections have not been accurately targeted. Ultrasound or electromyography (EMG) machine can be used to identify the affected muscles which need to be injected. Dystonic head tremors especially benefit from botulinum toxin injections and arm tremors do not benefit as much by them.
Surgery for Dystonic Tremor: Deep Brain Stimulation (DBS) is a surgical procedure which can be done if the patient has severe dystonic tremor and if they do not respond to other treatment methods. In Deep Brain Stimulation (DBS), electrodes are planted into the brain so they can help in rebalancing the movements of the patient and controlling the posture. A battery implanted in the chest provides power to the electrodes.
Occupational Therapy for Dystonic Tremor: If the patient has been having difficulty with daily activities of living, such as driving, cooking or eating, then special equipments can be used upon advice from the occupational therapist, which will assist the patient in managing his/her daily tasks.