Essential Tremor

About Essential Tremor

Essential tremor is the most common type of tremor and is characterized by involuntary rhythmic movements in various locations of the body
The condition is familial and can affect multiple members of one family.

Essential tremor mainly involves involuntary movements at the far end of a limb but may also involve the wrist and beginnings of the fingers, creating the appearance of hand flapping.
Involuntary movement usually occurs on both sides and may involve the head, face, mouth and tongue.
During adulthood or middle age, symptoms may become progressive and disabling.
Symptoms vanish with rest and worsen with activity. Symptoms often improve with alcohol.

β-blockers, primidone, and benzodiazepines may all help control involuntary movement and can ease symptoms. Not all medications are appropriate for all patients. Patients with asthma should not be given β-blockers. In addition, patients with diabetes, depression, thyroid disease and myasthenia gravis must be watched closely while on β-blockers.

Deep Brain Stimulation (DBS) Selection Criteria

Medication refractory tremor
- To be considered for DBS, patients should have failed medical therapy with maximum tolerated doses of medications described above and the tremor must be interfering with quality of life.
Intact cognitive function
- Because DBS surgery is brain surgery, it can exacerbate cognitive dysfunction. Moreover, in patients with cognitive decline, the greatest source of disability often is not the tremor but cognitive dysfunction. Significant cognitive decline is therefore a contraindication.
Age-appropriate brain MRI
- MRI of the brain should not have evidence of significant cerebrovascular disease or disproportionate atrophy. Although not as effective, DBS therapy can still be considered for those with MS.
Patient age
- Increasing age is associated with greater risk of surgery and decreased benefit of therapy. DBS therapy can still benefit those over 75 years of age, but expectations should be modest and patients should be in excellent general health and have intact cognition.
Medically suitable for surgery
- Major medical comorbidities, especially hypertension, increase the risk of DBS surgery. Patients should be medically suitable for surgery and have controlled blood pressure to be considered for surgery. Moreover, patients must be able to tolerate a 3-6 hours of awake surgery.
Realistic expectations and interest
- Patients must realize that DBS therapy is not a "cure" but symptomatic therapy.

Outcome

If essential tremor is the sole problem, stereotactic surgery or implant of a deep brain stimulator is helpful in 72 percent to 85 percent of cases.