Neurológia pre prax 1/2015

Pathophysiology of spasticity

Spasticity is defined as impaired muscle tone (hypertonia) caused by an increase in tonic stretch reflexes that is dependent on the speed of passive muscle stretching, and this increase in tonic stretch reflexes is likely to directly result from abnormal processing and modulation of proprioceptive impulses conducted by class Ia and Ib proprioceptive fibres, in the eloquent cortex in the brain. In the clinical setting, spasticity is a part of upper motor neuron syndrome, being one of the so-called positive signs. It is accompanied by other phenomena that are a manifestation of abnormal excitatory as well as inhibitory supraspinal descending drive: flexor spasms, clasp-knife phenomenon, efferent drive, and associated reactions. Recently, major importance in the genesis of spasticity and its therapeutic management has been attributed to the plasticity of the cerebral cortex.

Keywords: spasticity, pathophysiology, plasticity of cerebral cortex.