- Chorea - Dystonia - Athetosis - Myoclonus - Tremor - Tics - Stereotypies

- weakness - Selective Motor Control - Ataxia - Dyspraxia - Bradykinesia - Balance

Measuring Muscle Tone in Children Flashcards by Rachel Goecke

Characteristics of hypotonia

 Lack of resistance to passive movement
 Decreased strength/Poor definition of muscles
 Decreased activity tolerance
 Decreased motor skill development
 Rounded shoulder posture with a tendency to lean onto supports
 Hypermobile joints
 Increased muscle f lexibility
 Poor attention and motivation

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How to examine hypotonia?

Subjective in nature/process of exclusion following muscle biopsies and imagine

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Examining hypotonia - Observation

Do they look floppy?
Do they have anti-gravity movements of the head and limbs (prone, vertical, supine)?
Do they have a frog-legged posture? (hips abducted and externally rotated)

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Examine hypotonia - Palpation

Soft, pliable musculature
Excessive ROM

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Hypertonic –>

spasticity, dystonia, rigidity

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Hyperkinetic –>

Chorea
Dystonia
Athetosis
Myoclonus
Tremor
Tics
Stereotypies

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Negative –>

weakness
Selective Motor Control
Ataxia
Dyspraxia
Bradykinesia
Balance

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What is hypertonia?

Abnormally increased resistance to externally imposed movement about a joint

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What are hyperkinetic movements?

Any unwanted excess movement

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Negative motor signs in CP

Insufficient muscle activity or insufficient control of muscle activity

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Movement Disorders in CP

Hypertonia
Hyperkinetic Movements
Negative Motor Signs

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Spasticity Definition

 Velocity-dependent resistance of a muscle to stretch presenting with one or both of the following clinical signs
 Resistance to externally imposed movement increases with increasing speed of stretch and varies with the direction of joint movement
 Resistance to externally imposed movement rises rapidly above threshold speed or joint angle

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Review physiology of spasticity on slides 16 and 17

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Reticulospinal Tract

Inhibits muscle tone

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Vestibulospinal tract

Excites muscle tone of antigravity/extensor muscles

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Damage to corticobulbar tracts in CP:

Loss of reticulospinal inhibition of muscle tone
Continued vestibulospinal excitation –> increased lower extremity extensor tone

Definition of Dystonia

 Involuntary sustained or intermittent muscle contractions resulting in twisting and repetitive
movements and/or abnormal postures

What is hypertonic dystonia?

 Resistance to externally imposed movements at low speeds (not dependent on velocity)
 Simultaneous co-contraction (observed in rapid reversal)
 Limb returns toward fixed involuntary posture
 Triggered/worsened by voluntary movements of other body parts
 Varies with level of arousal
 No other detected spinal cord or peripheral lesion

Rigidity

 Rarely reported in children
 “Joint cannot be moved”
 Resistance to passive movement is independent of posture and speed of movement
 “Lead-Pipe”
 Not specific to task or posture

4 Clinical Measures of Hypertonicity

Observation
Hypertonicity Assessment Tool
Modified Ashworth
Modified Tardieu

What is the Hypertonicity Assessment Tool?

 7 item tool incorporating tasks of the bilateral upper and lower extremities
 Developed for children 4-19 y/o
 Purpose: to differentiate the different forms of
hypertonicity

How is the hypertonicity Assessment Tool Scored?

The presence at least one HAT item per
hypertonia subgroup (spasticity, dystonia, rigidity) confirms the presence of the that subtype
 The presence of more than one subgroup confirms the presence of mixed tone

How is the Hypertonicity Assessment Tool Administered?

 Position the child in supine
 Child wears comfortable, unrestrictive, clothing
 Hands placed gently on upper abdomen
 Place roll under knees and pillow under head

What muscles should you consider when evaluating tone in the lower extremities?

Hamstrings
Gracilis
Rectus Femoris
Gastrocnemius

Modified Ashworth Scale

- Used most in pediatric research - Many variations (Bohannen, Other formates score for hypotonia) - Standard test positions for children

Modified Ashworth Grading

0: No increase in muscle tone 1: Slight increase in muscle tone (catch or minimal resistance) at end of ROM 1+: Slight increase in muscle tone (catch) followed by minimal resistance throughout the remainder (< half ) of the ROM 2: More marked increase in muscle tone through most of ROM, but affected part easily moved 3: Considerable increase in muscle tone, passive movement difficult 4: Affected part rigid in flexion or extension (immobile)

Validity of Modified Ashworth Scale

- Correlates with other measures of hypertonicity (Tardieu), function (GMFM), isokinetic - High scores of scale do correlates with isokinetic measurements of resistance to stretch

Is Modified Ashworth Scale a TRUE measure of spasticity

Nope! Does not discriminate dynamic versus passive components of spasticity/hypertonicity

Reliability of Modified Ashworth Scale

 Reliability not well demonstrated in children; children with CP  inter-rater in elbow flexors and hamstrings (ICC > .75)  Intra rater in hamstrings (ICC >.75)  Other studies have lower inter and intra rater reliability  Test-retest reliability varied greatly  Low to average reliability for elbow, wrist, hip add, hamstrings, plantar flexors of children with CP

Is Modified Ashworth Scale sensitive enough to measure smaller differences in Spasticity?

Nope

Modified Tardieu Procedure

 Measure end-point range of motion to slow velocity ROM after 3 reps=R2  Measure angle when feel “catch” on 3rd trial of high velocity ROM = R1

Modified Tardieu Scoring

R2-R1 = dynamic component of spasticity mTS = quantify quality of muscle reaction

Tarieu Quantification of Quality of Reaction

0 = No resistance throughout passive movement 1 = Slight resistance throughout passive measurement 2 = Clear catch at precise angle, interrupting passive movement and followed by release 3 = Fatigable clonus (<10 secs.) at precise angle 4 = Unfatigable clonus (>10 secs.) at precise angle

What does Modified Tardieu Scale do??

Assesses passive joint ROM at different speeds. to determine dynamic tone

Tardieu Scale Validity

- Implied in MAS studies - Responsive to change

Tardieu Scale Reliability

 Reliability = .70 or greater = acceptable measure in children with CP  Improves after training

Other frequently used measures of "spasticity/hypertonicity"

 Palpation –firm feel to mm belly  Quantification of DTR  Reflex testing Measures hyperactive stretch reflex  NOT velocity dependent  Quantification of Clonus  Measures neuro hyperexcitability of mm  NOT velocity dependent

Considerations for measuring "tone"

 Dynamic component (response to mm stretch)  Best done with Tardieu scale  Passive component –changes in tissue mechanics  Resting state of the muscle  Environment, time of day, behavioral state, level of excitement, amount of effort