Benign Essential Tremor Syndrome
Benign Essential Tremor Syndrome Definition
Benign essential tremor (ET) is a movement disorder affecting the neurological system. It is characterized by involuntary fine rhythmic tremor of a body part or different parts, mostly the hands and arms (upper limbs). In many individuals affected by this, upper limb tremor may occur as an isolated finding. In others, however, tremors may gradually involve other regions of the anatomy, such as the head, voice, tongue, or palate (roof of the mouth), leading to dysarthria, or difficulty articulating speech. Less common are tremors that affect muscles of the torso or legs. It is also known as Presenile Tremor Syndrome, familial essential tremor, or hereditary benign tremor.
Benign Essential Tremor Syndrome Prevalence
Assessments of prevalence and incidence vary greatly depending on the methodology and diagnostic criteria. The prevalence of ET is estimated at 0.3-5.6% of the general population in the United States. A 45-year study of ET from Rochester, Minnesota, reported an age- and sex-adjusted prevalence of 305.6 per 100,000 and an annual incidence of 23.7 per 100,000. An estimated 0.5-11.1% of affected individuals seek out medical attention.
Benign Essential Tremor Syndrome Symptoms and Signs
Essential tremor (ET) usually presents as a rhythmic tremor that is present only when the affected muscle is exerting effort. The tremors do not present at rest. Any kind of physical or mental stress tends to make the tremor worse, often creating the false impression that the tremor is psychosomatic of origin. It is typical for the tremor to become worse in "performance" situations, such as when writing out a check at a checkout counter. ET-related tremors do not occur during sleep, but patients may complain of an especially coarse tremor upon waking up that becomes noticeably less coarse within the first few minutes of being awake. The intensity of the tremor can otherwise worsen in response to fatigue, strong emotions, cold, lithium salts, low blood sugar, caffeine, some antidepressants or other factors. In disabling cases, ET can interfere with a person's ability to perform tasks of required of daily living, including dressing, feeding, and activities of personal hygiene.
Benign Essential Tremor Syndrome Treatment
Drug treatment of the tremors may include tranquilizers, beta-blockers, and antiepileptic drugs. Surgical treatments, generally reserved for the most severe cases, include botulism toxin injections into the affected muscles, pallidotomy, thalamotomy, and deep brain stimulation wherein a pacemaker is inserted into the brain. The medications that are prescribed the most for control of ET symptoms are the anticonvulsant Primidone (or Mysoline) and the beta-blocker propranolol (or Inderal). Less severe cases of ET can be treated with physical therapy and development of the muscles in the sections of the body that are affected and are severe in their shaking. Other potential sources of tremor, such as excessive caffeine consumption, medications, recreational drug use, and hyperthyroidism, should be excluded if possible.