Essential Tremor California
Essential tremor is the most common cause of tremor and the most common movement disorders. Tremors are involuntary rhythmic movements in different parts of the body. An essential tremor can occur at any age, though it most commonly occurs in individuals either in the second or third decade of life or when 60 years of age (and above).
Essential tremor typically starts in the hands and is usually affects both hands equally, although there may be some asymmetry. It may start off as a barely noticeable issue, but it can gradually develop into a more disruptive tremor. While essential tremor usually starts in the hands, it can involve any part of the body, including the head, neck and voice, which is more commonly seen in women. The disorder can make it difficult to perform simple daily tasks, like drinking water or writing. Essential tremor also commonly occurs in the head, face, mouth and tongue. People who suffer from essential tremor will notice that the severity of the issue decreases after periods of rest and increases with activity.
Treatment for essential tremor is only initiated once the symptoms of tremor become disruptive or interfere with activities of daily living. First line therapies include medications – specifically primidone and propranolol. Together, these can provide 50-70% tremor reduction and should always be tried first. While second line medical therapies are available, if the tremor is significant enough, one can generally consider surgical options if first line medical therapies are ineffective. There are several other factors that must be weighted when considering treatment options. These factors include:
- Patient age
- Cognitive function
- Severity of the issue
- Overall patient health
The most common surgical therapy used today is deep brain stimulation, which is a pacemaker for the brain. A lead is placed in the thalamus (deep part of the brain) and connected with a wire to a battery and generator in the chest. The advantage of deep brain stimulator is that it does not cause a permanent lesion in the brain and the stimulation can be adjusted over time if the tremor evolves or changes. More than 90% of patients see a 50-80% improvement in tremor with deep brain stimulation. For an appropriate candidate, side effects are reasonable, including a <1% risk of bleeding and ~4% risk of infection (under the skin, not in the brain). Deep brain stimulation also offers the chance to treat both sides of the brain, which are not currently options for the other surgical treatment options.
Stereotactic radiosurgery is also an option. Using very focused radiation and not requiring an incision, stereotactic radiosurgery also provides an average of 50% improvement in tremor in ~90% of patients, but cannot be controlled like deep brain stimulation can. Bilateral treatment is not an option.
MR-guided Focused Ultrasound is the newest treatment options and only available at a few centers across the country. Currently, Medicare does not pay for this treatment in most states. Like radiosurgery, focused ultrasound focuses energy (this time ultrasound) to create a lesion deep inside the brain. Unlike radiosurgery, though, the lesion can be tested, so it is thought that MR-guided Focused Ultrasound may be safer. There is limited experience with this technique although there is a lot of excitement about it.