Essential Tremor (ET) is one of the most common tremor disorders and is characterized by a postural and/or kinetic tremor. ET can be a progressive disorder. Tremor will typically start on one side of the body but in time both sides will become affected making it a bilateral disease.1 Tremor onset can occur in either older age groups or early in life.2
ET most commonly affects the upper extremities (~90% of patients) followed by the head (~30%), voice (~20%), face or jaw (~10%). Head tremor will appear as a “yes-yes” or “no-no” motion.3 Symptoms begin gradually and worsen with movement.
The exact cause for ET is unknown; however, it is believed that certain parts of the cerebellum may be affected. ET is found to be mostly hereditary. Children of a parent with essential tremor have a 50% chance of inheriting the condition.3 Diagnosis for ET is made based upon reported symptoms and a complete neurologic exam.
There is not a cure for tremor but there are treatments available that may offer improvement to symptoms.
Propranolol and Primidone are commonly used for treatment of limb tremor. They have been proven to reduce tremor by approximately 50%. However, medication is not effective for 30-50% of people with ET.4
Botulinum toxin is used for the treatment of limb, head, and voice tremor. It has been proven to be moderately effective for limb tremor (20% improvement), and slightly more effective for head (67%) and voice tremor (22-30%). The main side effect from botulinum toxin is temporary weakness in the affected limb.4 According to American Academy of Neurology (AAN) it is recommended botulinum toxin only be considered in medically refractory cases.
Deep brain stimulation (DBS) has been proven to be safe and effective for the treatment of limb tremor. According to several clinical studies, DBS has demonstrated a mean improvement of 60-90% for ET based on clinical ratings.4
The DBS procedure includes a modest medical device which sends signals to the brain. The signals help control the motor functions that are affected by movement disorder symptoms such as tremor, slowness and rigidity. The physician will place one or two insulated wires called leads in the brain. The leads are then connected to the stimulator (similar to a pacemaker), which is typically placed under the skin in the chest. The device produces mild electrical impulses that stimulate a specific region of the brain. This may help regulate signaling in the brain, resulting in improvement of ET symptoms. Although DBS is not a cure, it may help improve day-to-day experiences and quality of life.