•Tremor is the most common movement disorder.
•Tremor represents an oscillation around a point of equilibrium
•Tremor is described by its frequency (from very slow 2Hz to very fast 16Hz), with a physiological tremor (tremor of the hands on emotion) around 8 to 10 Hz.
•Tremor can be regular or irregular, rythmic or arythmic, occuring at rest (hands tremor when watching TV), or when performing a task (writing), disappearing or not after drinking alcohol and running or not in the family.
•Hands tremor is the most frequent tremor
•Head tremor can occur in young adults and be very socially disabling; it’s not a sign of Parkinsob’s disease.
•Legs tremor is rare, and can be seen in hyperthyroidism (after physical exercise such as climbing stairs), when standing up only (orthostatic tremor) with the feeling of going to fall, or being the sign of a genetic form of parkinson’s disease. It can be also part of a generalised hereditary essential tremor.
•Facial tremor such as tongue tremor, lips tremor,  chin tremor are less common