Muscle Performance: Assessment of Muscle Tone and Abnormal Synergistic Patterns

which are the pathological reflexes that indicate UMN lesions?

• hoffman’s (UE)

• babinski (LE)

• clonus

• hyperreflexivity

when is clonus considered pathological?

when see multiple/repeated beats in response to a sustained stretch

what is muscle tone?

resistance of resting muscle to passive stretch, represents steady-state of slight residual contraction of resting muscle- is generated by resistance from titin and weak actin-myosin bonds

hypotonia

decreased tone below normal resting levels, decreased motoneuron input to muscles, associated with LMN lesions affection anterior horn cells or peripheral nerve

hypertonia

increased muscle tone above normal levels, increased motoneuron input ot muscles, loss of normal inhibition from CNS (UMN lesion characteristic)

rigidity

stiffness and resistance to stretch is independent of velocity of movement associated with lesions of the basal ganglia (PD), excessive supraspinal drive acting on alpha motor neurons, spinal stretch reflex typically normal

spasticity

velocity dependent increase in muscle tone with increased resistance to passive stretch, associated with UMN lesions, lesions descending motor pathways producing disinhibition of spinal stretch reflexes, hyperexcitability of alpha motor neuron pool

dystonia

impaired or disordered tonicity, involuntary muscle contractions and movements, trouble relaxing, associated with CNS lesions commonly in the basal ganglia, may be a side effect of parkinsons disease medication

compare and contrast hypertonicity and rigidity

hypertonicity involves either agonist or antagonist muscles, rigidity involves both agonist and antagonist and movement is difficulty in all directions

lead pipe rigidity

uniform resistance throughout the ROM

cogwheel rigidity

resistance that feels like “little jerks” or “catches”, describes as ratchet like

what are some factors influencing muscle tone?

• stress

• effort

• environment

• intrinsic visco-elastic properties of muscle (stiffness of muscle and connective tissue)

• tonic stretch reflex (ie spinal stretch reflex)

how do we assess tone and spasticity?

palpate/observe, look at passive ROM

what is normal tone?

no resistance to passive movement

what is mild tone?

slight resistance to passive movement

what is moderate tone?

considerable resistance to passive movement, but able to move through full ROM

what is severe tone?

marked resistance, unable to move through full ROM

describe the pattern of spasticity after UMN lesion of the scapula?

retraction, downward rotation

describe the pattern of spasticity after UMN lesion of the shoulder

adduction, internal rotation, depression

describe the pattern of spasticity after UMN lesion of the elbow

flexion

describe the pattern of spasticity after UMN lesion of the forearm

pronation

describe the pattern of spasticity after UMN lesion of the wrist

flexion, adduction

describe the pattern of spasticity after UMN lesion of the hand

finger flexion, clenched fist, thumb adducted into palm

describe the pattern of spasticity after UMN lesion of the trunk

lateral flexion, posterior rotation

describe the pattern of spasticity after UMN lesion of the pelvis

retraction (hip hiking)

describe the pattern of spasticity after UMN lesion of the hip

adduction (scissoring), internal rotation, extension

describe the pattern of spasticity after UMN lesion of the knee

extension

describe the pattern of spasticity after UMN lesion of the ankle?

plantarflexion, inversion

describe the pattern of spasticity after UMN lesion of the foot?

toes claw, toes curl

what are standardized tests that help us quantify level of muscle tone?

• modified ashworth scale

• tardieu spasticity scale

what is the modified ashworth scale?

tool for measuring spasticity that takes into account resistance to passive ROM at fast speeds, must move limb fast to feel for catch. scale is from 0-4 (0, 1, +1, 2, 3, 4)

what does 0 on the ashworth scale represent?

no increase in tone

what does 1 on the ashworth scale represent?

slight increase in tone, manifested by catch or by release or by end of the range of motion when the affected part is moved in flexion/extension (or abduction/adduction, etc)

what does 1+ on the ashworth scale represent?

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

what does 2 on the ashworth scale represent?

more marked increased in muscle tone through most of the range of motion, but affected parts(s) easily moved

what does 3 on the ashworth scale represent?

considerable increase in muscle tone, passive movement difficult

what does 4 on the ashworth scale represent?

affected part(s) rigid in flexion or extension (or abduction/adduction)

describe the validity and reliability of the ashworth’s

in term of validity- good scale to communicate general level or amount of resistance to passive stretch, but reliability there is no operational definition for how fast examiner is to move the limb with causes variations in reliability

how is intra-rater reliability of the ashworths?

moderate to good

how is the inter-rater reliability of the ashworths?

poor to moderate

what are the limitations to MAS?

inability to detect small changes in spasticity, inability to distinguish between neural changes and muscle viscoelastic changes, difficulty with lower MAS ratings (1, 1+, 2)

what is the modified tardieu scale?

tool for measuring spasticity, tests resistance to passive movement at fast and slow speeds. there are two components to scoring: quality of muscle reaction, angle of muscle reaction

what does a score of 0 mean on the modified tardieu?

no resistance throughout the course of the passive movement

what does a score of 1 mean on the modified tardieu?

slight resistance throughout the course of the passive movement, with no clear catch at precise angle

what does a score of 2 mean on the modified tardieu?

clear catch at a precise angle, interrupting the passive movement, followed by release

what does a score of 3 mean on the modified tardieu?

fatiguable clonus (less than 10 seconds when maintaining pressure) occurring at precise angle

what does a score of 4 mean on the modified tardieu?

infatiguable clonus (greater than 10 seconds when maintaining pressure) occurring at precise angle

what is the angle of muscle reaction/”spasticity angle”?

The angle of muscle reaction, or spasticity angle, is the specific joint angle at which a muscle exhibits a response during the modified Tardieu scale assessment. This angle represents the velocity dependent muscle tone. It is calculated by measuring the full range of motion at a slow velocity (R2) then subtracting the angle where you feel the catch occur (R1).

What does a larger spasticity angle indicate?

A larger spasticity angle indicates increased resistance to passive stretch, reflecting greater muscle hypertonicity and more pronounced spasticity in the muscle being assessed.

What are the Brunnstrom stages of recovery post-stroke?

• stage 1- flaccidity

• stage 2- synergy helps movement, emergency of spasticity

• stage 3- combined synergy, some movements able to break out of synergy; spasticity worsens

• stage 4- able to move out of synergy; spasticity lessening

• stage 5- able to perform isolated movement; fractionation of movement emerging

• stage 5- return to near normal movement

what are the predominant synergistic patterns after stroke?

• for UE: flexor synergy pattern

• for LE: extensor synergy pattern

describe the upper extremity flexor synergy components?

• scapular retraction and elevation (RE)

• shoulder abduction, ER (AER)

• elbow flexion (F)

• forearm supination (S)

• wrist and finger flexion (F)

describe the upper extremity extensor synergy components?

• scapular protraction

• shoulder adduction, IR

• Elbow extension

• forearm pronation

• wrist and finger flexion

describe the lower extremity flexor synergy components?

• hip flexion, abduction, ER

• knee flexion

• ankle DF, inversion

• toe DF

describe the lower extremity extensor synergy components?

• hip extension, adduction, IR

• knee extension

• ankle PF, inversion

• toe PF

what is the fugl-meyer assessment?

a quantitativ etest for post-stroke and motor and sensory recovery- motor function, balance, sensation, range of motion and pain scored on three point ordinal scale (0-2), tests the pt’s ability to move in and out of synergistic movement patterns

does the fugl-meyer have high reliability?

yes, both inter-rater (ICC = 0.96) and intra-rater (r= 0.98-0.99)

what are the 5 domains of the fugl-meyer test?

motor, sensory, balance, range of motion, joint pain

how is the sensory domain assessed in the fugl-meyer?

measured as absent, impaired, or normal for light touch (2 items), but this domain is not widely conducted in clinical practice bc it lacks a reliable and valid clinical measure to determine severity of light touch and proprioception

how is the motor domain assessed in the FMA (fugl-meyer assessment)?

The motor domain is assessed using a series of tasks that evaluate voluntary movement, including activities such as grasping, holding, and coordinated movements of the upper and lower limbs. lower UE and LE motor scores indicate greater motor severity and are correlated with lower functional abilities

describe the motor assessment of the FMA

• includes a UE subscale of 33 items and LE subscale of 17 items

• scored on a 3 point ordinal scale (0-2, 0 cannot be performed, 1 performed partly, and 2 performed faultlessly)

what is the MDC for the FMA motor assessment of the UE?

5.4 points