Spastic hypertonia: mechanisms and measurement

摘要: Spastic hypertonia has been defined as a motor disorder characterized by velocity-dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks, resulting from hyperexcitability of the reflex, one component upper neuron syndrome. Heightened muscle tone may be result changes intrinsic to or altered reflex properties. Increased motoneuronal excitability and/or enhanced stretch-evoked synaptic excitation motoneurons are mechanisms that might enhance reflexes. Two distinct parameters pathologic reflex--the "set point," angular threshold and "gain," amount force required extend limb proportion increasing joint angle. Earlier studies fail dissociate contributions gain. Recent investigations suggest spastic decrease without significant gain, was previously believed. Various clinical scales, biomechanical paradigms, pendulum models, electrophysiologic have used quantify hypertonia. Biomechanical methods seem correlate most closely state. is but syndrome, whose features also include loss dexterity, weakness, fatigability, various release phenomena. These other syndrome well more disabling patient than tone.