Update on spasticity: part 1 - background and diagnosis.

Spasticity, characterised by a velocity-dependent increase in muscle tone, is a multifaceted condition resulting from central nervous system injury. Spasticity could be the initial symptom of disorders of the brain and spinal cord. Its clinical spectrum ranges from mild symptoms to severe hypertonia, resulting in pain, contractures and joint immobility. It needs to be differentiated from other causes of high tone, like rigidity. Early recognition of spasticity is essential to limit its impact on functional independence and quality of life. This review provides an overview of the causes, pathophysiology, clinical manifestations, differential diagnosis, impact and measurement of spasticity.