Spasticity Management

Spasticity is a disorder of the sensorimotor system characterized by a velocity-dependent increase in muscle tone with exaggerated tendon jerks, resulting from hyper excitability of the stretch reflex.

It is one component of the upper motor neuron syndrome, along with released flexor reflexes, weakness, and loss of dexterity.

Spasticity is the hyper tonicity in the muscle group. It can be defined as an initial catch or resistance felt by the examiner when rapid passive movements are performed.

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In an upper motor neuron syndrome, the alpha motor neuron pool becomes hyper excitable at the segmental level.

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Spasticity occurs because the inhibition normally provided by the suppressor areas of the brain is not present.

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Brain lesions disrupt the linkages and upset the balance between suppressor and facility areas of the brain.

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The major consequence of the disruption of the balance is the excess facilitation of gamma motor neurons resulting in hypersensitive muscle spindles. This results in hyperactive phasic stretch reflexes ,hyperactive tonic reflexes, and clonus.

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Spasticity caused by spinal cord lesions is often marked by a slow increase in excitation and over activity of both flexors and extensors with reactions possibly occurring many segments away from the stimulus.

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Cerebral lesions often cause rapid build-up of excitation with a bias toward involvement of antigravity muscles.

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Chronic spasticity can lead to changes in the rheological properties of the involved and neighboring muscles.

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The abnormal joint positioning, postures, and unequal distribution of muscle activity imposed by spasticity can produce profound and lasting changes in joints and muscles.

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Stiffness, contracture, atrophy, and fibrosis may interact with pathological regulatory mechanisms to prevent normal control of limb position and movement.