Tone ManagementEmily Peters, OTS

August 2014

What is Muscle Tone?

• “Continuous state of mild contraction, or a state or preparedness in the muscle” (Pendleton, 2012, p. 468)

• “Muscle tone does not produce active movements, but it keeps the muscles firm, healthy, and ready to respond to stimulation” (Marieb & Hoehn, 2010, p. 296)

Physiology of Muscle Tone

• Signals received at neuromuscular junction result in continuous muscle contraction

Muscles and muscle tissue, 2013

Characteristics of Normal Tone

• High enough to resist gravity, yet low enough to allow movement

• Slight, involuntary, resistance to passive movement

• Ability to maintain position of limb if placed passively, and then released

• Ease of ability to shift between stability ↔ mobility

• Ability to use muscles in groups or selectively with normal timing and coordination

Why is Muscle Tone Important?

• Across the lifespan, normal muscle tone allows us to engage in meaningful occupations by:• Keeping muscles ready for

action

• Maintaining posture

• Maintaining balance

• Laying framework for quick, reflexive movements

Causes of Abnormal Tone

• Children

• Down Syndrome

• Cerebral Palsy

• Muscular dystrophy

• Adults

• CVA

• TBI

• Brain tumor

• SCI

• MS

• Myasthenia gravis

• The onset and course of abnormal tone is dependent upon the cause

Hypotonia

• Abnormally low tone

• Likely to occur in the acute stages of CVA, contralateral to brain lesion

• Diminished deep tendon reflexes

• Flaccidity: complete absence of deep tendon reflexes

Hypertonia

• Abnormally high tone

• Likely to occur following the acute stages of CVA

• May occur in synergistic movement patterns: Co-contraction of flexors and extensors • Flexor synergy often seen in UEs

• Extensor synergy often seen in LEs

• Rigidity: simultaneous high tone of agonist and antagonist • Lead pipe

• Cogwheel

• Decorticate

• Decerebrate

Decorticate vs. Decerebrate Posture

• Decorticate - Flexor synergy upper extremities & extensor synergy lower extremities

• Decerebrate - Extensor posturing

Spasticity

• Spasticity is a subset of hypertonia• Overactive reflexes

• Involuntary movements

• Feel a “catch” with passive movement

• May lead to contractures if unmanaged

• Clonus: Repetitive contractions in antagonist muscles in response to rapid stretch

• Can be associated with moderate-severe spasticity

• Finger flexors and ankle plantar flexors

• Medical management • Botox injections

• Baclofen pump

Managing Tone: General

• Aims of early positioning and mobility• Provide support

• Inhibit abnormal tone

• Promote symmetry

• Provide normal sensory input

• Relieve pain and provide comfort

• Develop and reinforce basic elements of movement

• Principles to remember• Normal movement cannot be superimposed on abnormal tone

• Proximal stability facilitates distal mobility

Managing Hypotonia

• Check for subluxation at glenohumeral joint before ROM

• Position patient in supported sit

• Facilitate tone • Quick stretches in attempt to elicit clonus

• Cold temperatures

Managing Hypertonia

• Deep, slow stretches

• Deep pressure on muscle belly

• Warm temperatures

• Splinting and serial casting to encourage functional position of extremities

Assessing High Tone: Modified Ashworth Scale

Grade Description

0 No increase in muscle tone

1 Slight increase in muscle tone, catch when limb is moved

1+ Slight increase in muscle tone

2 More marked increase in muscle tone through >50% of the ROM, but affected easily moved through passive range

3 Considerable increase in muscle tone, passive movement difficult

4 Affected limb rigid in flexion or extension

References

Bohman, I. M. (2003). Handling skills using in the management of adult hemiplegia (2nd ed.). Albuquerque: Clinician’s View.

Marieb, E. N., & Hoehn, K. (2010). Muscles and muscle tissue. Human anatomy and physiology (8th ed) (pp. 275-319). San Francisco: Pearson Education, Inc.

Muscles and Muscle tissue (2013). Overview of Muscle Tissue. Retrieved from http://classes.midlandstech.edu/carterp/Courses/bio210/chap09/lecture1.html.

Pendleton, H. M. H., & Schultz-Krohn, W. (2012). Evaluation of motor control. Pedretti's occupational therapy: Practice skills for physical dysfunction (7th ed.) (pp. 468-473). St. Louis: Mosby/Elsevier.