<qa>  What is the most common form of idiopathic limb dystonia?Focal dystonia affects one body area and includes blepharospasm, oromandibular dystonia, spasmodic dysphonia, torticollis, and limb dystonia. Focal dystonia typically presents as task-specific muscle spasms or occupational cramps in which learned or repetitive motor tasks such as writing or playing a musical instrument trigger muscle spasms and interfere with performance while other actions remain normal. Writers cramp is the most common form of idiopathic limb dystonia 1-3 where involuntary muscle activity and abnormal postures affect the arms and hands, but virtually any part of the body may be affected, even the lips when playing a woodwind or brass instrument 4. Patients may develop two focal dystonias but rarely does focal dystonia progress to more generalized forms. 