Essential tremor differs from the tremor caused by Parkinson's disease in the following ways:

• Essential tremor may affect the head and voice. Head tremor is uncommon in early Parkinson's disease.
• Essential tremor is almost always worse when the affected part of the body is in motion than when it is at rest. Tremor associated with Parkinson's disease generally decreases or disappears when the person moves the affected part of the body.
• Essential tremor is faster than the tremor of Parkinson's disease.
• Small amounts of alcohol can noticeably reduce an essential tremor but usually have no effect on tremor caused by Parkinson's disease.
• Essential tremor does not improve in response to levodopa, but it may be relieved with other medicines (propranolol, primidone, phenobarbital, or benzodiazepines).
• Unlike tremor caused by Parkinson's disease, essential tremor will sometimes occur in family members.