tone management
TRANSCRIPT
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.