Tremor
A tremor can be defined as a rhythmic, back and forth or oscillating involuntary movement about a joint axis. Tremors are symmetric about a midpoint within the movement, and both portions of the movement occur at the same speed. Unlike the other hyperkinetic movements, tremors lack both the jerking associated movements and posturing.
Essential tremor (ET), also known as benign essential tremor, or familial tremor, is the most common movement disorder. It is estimated that 5 percent of people worldwide suffer from this condition, affecting those of all ages but typically staying within families. ET typically affects the hands and arms but can also affect the head, voice, chin, trunk and legs. Both sides of the body tend to be equally affected. The tremor is called an action tremor, becoming noticeable in the arms when they are being used. Patients often report that alcohol helps lessen the symptoms. Primary medical treatments for ET are usually beta-blockers. For patients who fail to respond sufficiently to medication, deep brain stimulation and thalamotomy can be highly effective.
A “flapping tremor,” or asterixis, is characterized by irregular flapping-hand movement, which appears most often with outstretched arms and wrist extension. Individuals with this condition resemble birds flapping their wings.
Read more about this topic: Overactive, Classification