Essential tremor is a type of movement disorder. This is a category of neurological conditions that involve abnormalities in the quality and quantity of spontaneous movement. Essential tremor causes involuntary shaking, particularly in the hands. The tremor tends to appear more pronounced the harder the muscles are working, such as during movement or by extending an arm. When the muscles are at rest, the tremor is typically not noticeable. The tremor may not be consistent initially, but it will frequently worsen as time goes on. In some cases, both sides of the body are not equally affected. Essential tremor is more common as people age and usually develops in people older than 40.
Although it is sometimes confused with Parkinson's disease, essential tremor differs from Parkinson's disease in several ways. While essential tremor occurs most frequently during muscle use, Parkinson's tremors tend to flare up while the hands are at rest. Essential tremor generally does not result in additional symptoms, whereas Parkinson's disease will often cause a slowing of movement, poor posture and walking issues.
Symptoms of Essential Tremor
Besides the hands, the tremor may sometimes be present in other parts of the body, including the muscles of the arms, head, face and neck. It is rare for the tremor to occur in the legs. When the head is affected, the tremor will usually be a side-to-side or up-and-down motion that takes place when the patient is in an upright position. Essential tremor may also involve the voice, which causes a quiver. The symptoms can increase when the patient is experiencing stress or fatigue or has consumed caffeine or nicotine. Essential tremor is not a life-threatening disorder, but for those with severe symptoms, it can impinge on the ability to perform everyday activities. The fine motor skills of the hands may deteriorate, making certain tasks such as writing, drinking from a cup, and eating with utensils much more difficult.
Causes of Essential Tremor
The exact cause of essential tremor is unknown, but essential tremors tend to occur when there are nerve-related problems that influence the muscles with which they are connected. Research has also indicated that the part of the brain that controls the movement of muscles may not function properly in patients with essential tremor. In some cases, several family members may have essential tremor, known as familiar tremor and it is believed to be caused by a genetic mutation.
Diagnosis of Essential Tremor
To determine whether symptoms are caused by essential tremor or another condition, a physician will review the patient's medical history and perform a physical examination. A neurological examination may also be performed to assess reflexes, muscle strength, sensation in the affected area, coordination and gait. Additionally, the doctor may request that the patient perform specific tasks to determine the progression of the tremors. Additional diagnostic tests may include:
- Blood tests
- Urine tests
- CT scan
- MRI scan
Diagnosis of essential tremor includes ruling out other potential causes of tremors, including thyroid conditions, certain medications, excessive caffeine intake, tobacco use and alcohol withdrawal.
Treatment of Essential Tremor
Treatment may not be necessary for essential tremor unless the disorder is hindering normal activities. Relaxation techniques may be effective in patients whose tremors are aggravated by stress. Medication may be used to treat symptoms and may include:
- Beta blockers
- Anti-seizure medications
- Calcium-channel blockers
- Mild tranquilizers
Botox injections in the affected area can help to temporarily weaken the muscles and decrease tremors. In extreme cases, cranial surgery, or surgery of the head, may be performed to treat essential tremor. Surgical options include:
- Stereotactic radiosurgery
- Deep brain stimulation
Numerous types of assistive devices are also available to make dressing, eating, writing and other daily activities easier and more comfortable for patients with essential tremor.