Dystonia Arising from Occupations: The Clinical Phenomenology and Therapy

Dystonia is generally referred to belong to the generic terms, muscle spasm and muscle stiffness. Muscle spasms would be any involuntary abnormal muscle contraction, regardless of whether it is painful or not, that cannot be usually terminated by voluntary relaxation. Muscle stiffness is an involuntary muscle shortening that usually lasts for seconds to minutes, but may be sustained. Sustained muscle contraction may lead to posturing and even pain as seen in tetany, dystonia, spasticity, and contracture. Whereas tetany is brisk, short-lived, and associated with paresthesiae, dystonia is a slow, more sustained co-contraction of the agonist and antagonist muscles, that may characteristically be task-specific and abolished by “sensory tricks.”(1)