Essential tremor. Essential tremor (ET, also referred to as benign tremor or familiar tremor) is the most common movement disorder; its cause is unknown.
It typically involves a tremor of the arms, hands or fingers but sometimes involving the head or other body parts during voluntary movements such as eating and writing.[1] It is distinct from Parkinson's disease—and often misdiagnosed as such—although some individuals have both conditions.[1] Essential tremor is commonly described as an action tremor (it intensifies when one tries to use the affected muscles) rather than a resting tremor; rigidity, such as is seen in Parkinson’s, is usually not included among its symptoms.[2] Classification[edit] This type of tremor is often referred to as "kinetic tremor".
Gilbert syndrome. Gilberts syndrome.