Motor Control Exam 4 --> Management of Abnormal Muscle Tone (2/2)

what is muscle tone?

- tension in a relaxed muscle

- resistance during a passive stretch of a joint when the muscles are at rest

is tone a continuum?

yes

what is flacid?

- no resistance

- instability, exhaustion

what is hypotonia

- low resistance

what is spasticity?

- velocity dependent resistance to passive stretch

what is rigidity?

- velocity independent resistance to passive stretch

- contractures

- stiffness, immobility

what is the pathophysiology of hypertonia?

- spasticity / rigidity

- loss of supraspinal control mechanisms

- output system problem

what is dystonia?

- uncontrollable muscle movements

what is the pathophysiology of dystonia?

- dysfunction between basal ganglia and thalamo-cerebello-cortical connections

- system level processing problem

what is paratonia?

- dementia induced motor abnormality

is the medial reticulospinal tract ipsilateral or contralateral? excitatory or inhibitory?

- ipsilateral

- excitatory / facillatory

is the dorsal reticulospinal tract ipsilateral or contralateral? excitatory or inhibitory?

- contralateral

- inhibitory

is the corticospinal tract ipsilateral or contralateral?

contralateral

what can you infer about the pathophysiology of a TBI that has dystonia?

- more than just a cortex injury

- involvement of the midbrain

what is the pathophysiology of post stroke spasticity?

- damage to both corticospinal tract and corticoreticular spinal tract

> decrease in output signals from the muscles

- hyperexcitability or spontaneous firing in spinal motor neurons

explain post stroke spasticity using the different corticospinal tracts and corticoreticular spinal tracts (3)

- medial reticulospinal tract of the contralateral cerebral hemisphere exhibits increased excitability (+++++)

- lack of inhibition from the ipsilateral dorsal reticulospinal tract causes excitability since nothing is inhibiting (+++++)

- increased alpha and gamma motor neurons cause overexcitation of the stretch reflex

does a selective lesion of the pyramidal tract lead to spasticity? what tracts does this include?

- corticospinal

- corticobulbar

- does not lead to spasticity (will have motor and strength involvement, leading to weakness, but not spasticity)

what happens if you have damage to the motor cortex and corticospinal tracts?

- negative UMN signs

- hemiparesis (muscle weakness on the affected side)

what happens if you have loss of cortical inhibition?

- positive UMN signs

- spasticity

- synergistic coupling

if a patient has a CNS lesion, should you strengthen, treat spasticity, or both?

- both

what is axonal sprouting?

- formation of extra abnormal neural pathways in the reflex arc

- effect on stretch reflex overexcitation

- you try to improve the neural connection, but end up increasing tone

UMN vs LMN

- UMN originate in the cerebral cortex and travel down to the brainstem or spinal cord

- LMN begin in the spinal cord and go on to innervate muscles and glands in the body

what is hoffmann sign

- assesses UMN lesions

- flick middle finger nail

- (+) = thumb and index finger come together

what is babinski reflex

- assesses UMN lesions

> corticospinal tract

- stroke foot from base of heel up lateral sole towards big toe

- (+) = big toe extends and toes fan out

what is wartenberg sign

- assesses LMN lesion

- pt flexes fingers and you resist their flexion by pulling fingers apart

- (+) = thumb will flex

what are the 5 objective scales for reflexes?

- tardieu scale

- tendon reflex scale

- wartenberg pendulum test

- modified ashworth scale

- fugl-meyer assessment

0 on MAS

- no increase in muscle tone

1 on MAS

slight increase in muscle tone (a catch and release, or minimal resistance at the end of a flexion-extension ROM)

1+ on MAS

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

2 on MAS

- a marked increase in muscle tone throughout most of the range of motion, but affected parts are still easily moved

3 on MAS

- considerable increase in muscle tone, passive movement is difficult

4 on MAS

- affected parts are rigid in flexion or extension

T/F: MAS do not align with modern definitions of spasticity.

- true

- recommended to use modified tardieu

how to interpret tardieu (R1, R2)

- R1 = angle of catch, where sudden increase in muscle resistance is felt during fast passive stretch

- R2 = angle indicating the tested muscle length during slow PROM

- R2-R1 differentiates spasticity from contracture

how to identify spasticity vs contracture with tardieu

- R2-R1 is small = contracture

- R2-R1 is large = spasticity

what are the 3 speed definitions of tardieu

- V1 = as slow as possible

- V2 = speed of limb falling under gravity

- V3 = as fast as possible

how to interpret the grades of tardieu scale

- 0 = no resistance to PROM

- 1 = slight resistance followed by release

- 2 = clear catch at a precise angle, followed by release

- 3 = fatigable clonus occuring at precise angle (<10sec)

- 4 = infatigable clonus at precise angle (>10sec)

level of Achilles reflex

S1-2

level of patellar reflex

L3-4

upper limb flexor synergy

- scapular retraction

- shoulder elevation

- shoulder abduction

- shoulder ER

- elbow flexion

- forearm supination

- wrist and finger flexion

upper limb extensor synergy

- scapular protraction

- shoulder depression

- shoulder adduction

- shoulder IR

- elbow extension

- forearm pronation

- wrist extension

- finger flexion

lower limb flexor synergy

- pelvis anterior tilt

- hip flexion

- hip abduction

- hip ER

- knee flexion

- ankle DF

- toe extension

lower limb extensor synergy

- posterior pelvic tilt

- hip extension

- hip adduction

- hip IR

- knee extension

- ankle PF

- toe flexion

what type of drug is baclofen?

GABA agonist

how does botox work? how long is it effective?

- paralyzing spastic muscles

- reaches full efficacy 10-14 days

- lasts 3 months

how do phenol injections work? how long is it effective?

- prevent transmission of too many nerve impulses

- lasts 4-12 months

T/F: medical injections should be done along with physical therapy

true

when are intrathecal baclofen pumps indicated?

- when oral medications have too many side effects

- smaller adjustable doses

> less side effects

> regional effects

what are surgical options for spasticity?

- selective dorsal rhizotomy = separation of nerve roots to bring sensation back

- tendon lengthening = makes more functional tendon

conservative management for spasticity

- inhibition techniques

> prolonged stretching, deep pressure, traction

- vibration and WB activities

- thermotherapy

> warm

(only provide short term effects and should not be stand alone treatments)

benefits of a standing program

- increase bone mineral density

- increase ROM

- reduce spasticity

how to dose standing protocols

- 45-60 minutes daily for range of motion and spasticity

- 60-90 minutes daily for bone mineral density

indication for serial casting

- non-compliant with bracing

- limb is placed in stretched position and casted

- stay in the casted position for one week

- re-cast in new range

cons to serial casting (3)

- can cause wounds

- stretching pain

- decreased blood flow

what are dyasplints

- low tension

- prolonged period of bracing