Tone Abnormalities Chapter 4

Muscle Tone Definition (page 77) – underlying tension in the muscle that serve as a background for contraction. Muscle tone include involuntary resistance generated by neurally activated fibers and passive, natural biomechanical tension in connective tissue.

Normal mm tone and activation depends on normal functioning of muscle, the PNS, and the CNS.

Description of Muscle Tone Muscle tone can be described as “low tone” or “high tone”. Tone can be palpated as a qualitative difference in the resistance to finger pressure over a muscle.

Low Tone Upon palpation the finger will sink into the mm with little resistance.

High Tone Upon palpation the muscle feels hard and resists deformation

Tone Abnormalities

Hypotonicity Low tone Decreased resistance to stretch compared with normal muscles. FLACCIDITY is a type of low tone. It is a total lack of tone or the absence of tone.

HYPERTONICITY High tone or increased resistance to stretch compared with normal muscles. Can be either RIGID of SPASTIC

Rigidity Abnormal, hypertonic state in which muscles are stiff or immovable and resistant to stretch. This type of tone is common in Parkinson’s disease

Spasticity This is different than a muscle spasm Velocity-dependent resistance to stretch. See table 4-1, page 79

Role Physical Agents with Tone Abnormalities

Physical Agents and Hypotonicity Rehab interventions are directed to increasing tone to promote easier activation of muscles. Physical agents may be used to assist with muscle activation. Hydrotherapy Quick ice Electrical Stimulation

Physical Agents and Hypertonicity Rehab interventions directed to decreasing tone to decrease discomfort, increase ROM, allow normal positioning, and prevent contractures. Physical agents may be used to assist with decreasing tone. Heat Prolonged ice Hydrotherapy Biofeedback Electrical Stimulation