Physical Agents - Ch. 5 Tone Abnormalities

muscle tone

the underlying tension in the muscle that serves as a background for contraction

what muscle tone revealed as

stiffness or slackness of muscles

what does muscle tone include

involuntary resistance generated by neurally activated muscle fiber and passive tension

when is tone considered abnormal

when it affects function or causes pain

example of high tone in quadriceps muscle

getting down in start position for a race

example of low tone in quadriceps muscle

relaxing after running a race

True or False: muscle tone is on a spectrum, not a point

true

Hypotonicity (low tone)

decreased resistance to stretch compared with normal muscles

Flaccidity

total lack of tone (within mid-range of muscle length)

What is the difference between flaccidity and paralysis

paralysis is a movement disorder while flaccidity is a descriptor of tone

paralysis

complete loss of voluntary muscle contraction

Hypertonicity (high tone)

increased resistance to stretch compared to normal muscles

rigidity

hypertonicity in which the muscles are stiff or immovable regardless of velocity of movement

akinesia

loss or impairment of the power of voluntary movement

how does akinesia differ from hypertonicity

akinesia is a movement disorder, not a descriptor of rigidity

spasticity

velocity-dependent resistance to stretch; resistance increases as velocity increases

clonus

multiple oscillations or beats of muscle contractions in response to quick stretch

clasp-knife phenomenon

initial resistance followed by a sudden release of resistance

posture

an observation assessment

dyskinesia

abnormal movement that is involuntary and has no purpose

chorea

dancelike, jerky movements

ballismus

ballistic, throwing-like movements

tremor

low amplitude, high frequency oscillations

athetoid

writhing or wormlike

dystonia

sustained muscle contractions usually resulting in abnormal postures or repetitive twisting movements

which part of the body does dystonia usually involve

dystonia

why are dyskinesia movement patterns exhausting for individuals

it is a constant expenditure of energy

when measuring tone, keep in mind:

• avoid generalizing the results of single or multiple tests to all conditions of the muscle

• include measures of movement or function to obtain a more complete picture of the subjects ability to use muscle tone appropriately

quantitative measure of muscle tone

• dynamometer/myometer

• isokinetic testing systems

• Near-Infrared spectroscopy (NIRS)

• Shear-Wave Ultrasound Elastography

• Electromyography (EMG)

• Pendulum test

How does NIRS work?

It measures the amount of blood flow to muscle to determine the amount of metabolism needed for muscle activity

How does a shear-wave ultrasound elastography quantify tone?

Measures viscoelastic properties of the muscle via tissue deformation after dynamic stress to a muscle is applied

What could be a problem with using Shear-Wave Ultrasound Elastography to quantify tone?

It cannot differentiate between biomechanical and neurological sources of stretch resistance

Advantages of using Electromyography to quantify tone

• measures low level muscle activity

• assesses timing

• biofeedback

How do you perform a pendulum test

Passively hold a limb and then release it for a quick stretch

0 on clinical tone scale

no tone

1 on clinical tone scale

hypotonicity

2 on clinical tone scale

normal tone

3 on clinical tone scale

moderate hypertonicity

4 on clinical tone scale

sever hypertonicity

0 on modified ashworth scale for grading spasticity

no increase in muscle tone

1 on Modified Ashworth Scale for grading spasticity

slight increase in muscle tone manifested by a catch and release or by minimal resistance at the end of the ROM when the affected part is moved in FLEX or EXT

1+ on modified ashworth scale for grading spasticity

slight increase in muscle tone manifested by a catch, followed by minimal resistance throughout the remainder (less than half) of the ROM

2 on modified ashworth scale for grading spasticity

more marked increase in muscle tone through most of the ROM, but affected part easily moved

3 on modified ashworth scale for grading spasticity

considerable increase in muscle tone, passive movement difficult

4 on modified ashworth scale for grading spasticity

affected part rigid in flexion or extension

what reflex is this?

Asymmetrical Tonic Reflex

what should you document when measuring muscle tone

Position of limb, body, neck, and head to one another and to gravity

what reflex is this?

Symmetrical tonic neck reflex

What type of touch increases tone

light touch

What type of touch decreases tone

firm touch

Which position is most accurate for the measuring of muscle tone?

midrange