Lecture 8: Spasticity - Assessment and Management Flashcards
Define spasticity
- what is the most common leg and upper limb posture
A neurological condition causing large increases in muscle tone when a muscle is stretched. spastic muscles resist stretch and remain abnoramally contracted for long periods
Equinovarus feet: most common pathologic leg posture; can prevent even limited ambulation
Upper limbs: adduction and internal rotation of the shoulder and flexion of the elbow, wrist and fingers
What disorders can lead to spasticity?
Disorders leading to spasticity include: stroke, spinal cord injuries, cerebral palsy, multiple sclerosis, TBI
What can trigger spasticity
Spasticity can be brought on by a rapid muscle stretch (e.g., clasp-knife reflex) or by other sensory stimulation (draft of cool air)
Describe morphological changes to spastic muscles?
Spastic muscles become stiffer, shorter.
Reduction in # of sarcomeres as well.
What causes spasticity?
There is decreased inhibition from the brainstem. This can affect spinal reflexes as antagonists will not be inhibited.
At the same time, there is increased muscle spindle input, caused by collateral sprouting of peripheral afferents. This increases the gain.
Motor neurons become hyperexcitable. As excitatory signals from the sensory nerves and inhibitory signals from the brain are unbalanced, normal muscular tone cannot be maintained.
Differentiate between dynamic and fixed contractures
Dynamic contracture
- increased stiffness upon stretching a muscle
- can usually be reduced with drug treatment
- if left untreated, can be replaced by fixed contracture
Fixed contracture
- a permanent shortening and hardening of muscles and tendons
- cellular changes (loss of sarcomeres, fibrous scar tissue formation, shortened tendon) leave spastic muscles rigid
- can lead to permanent joint deformity and rigidity
- often painful
- can only be treated with surgery
Why does clonus occur?
The inhibition of antagonists is impaired in patients with upper motorneuron syndrome. As such, antagonist muscles are allowed to contract and the joint will oscilliate between opposing movements (flexion/extension
What is clonus/tremour frequency?
8-13Hz
What are the effects of spasticity on the following:
- activities of daily living
- hygiene
- mobility
- comfort
- Activities of daily living: Inability to independently control muscles can affect activities of daily living such as dressing, eating, grooming.
- Hygiene: Stiff, contractured or spastic muscles can prevent access to areas such as the palm, armpit or groin, interfering with hygiene. Odor and skin breakdown may occur. Bowel/bladder care are more difficult.
- Mobility: Spasticity in leg muscles interferes with mobility, seating and transfers, such as from bed to wheelchair or from sitting to standing.
- Comfort: Spasticity may make it difficult to sit comfortably or to change positions to prevent joint pain and pressure sores.
How is spasticity assessed?
Assessment includes identifying which muscles are overactive and determining the effect of spasticity on all aspects of patient function including mobility, employment and activities of daily living.
Describe some of the upper limb postures that can be observed in a patient exhibiting spasticity
adducted/internally rotated shoulder
pronated forearm (pronator quadratus and/or pronator teres)
clenched fist (flexor digitorum sublimis)
flexed elbow
flexed wrist - can result in wrist subluxation and carpal tunnel syndrome
thumb in palm deformity
(flexor pollicis longus; adductor pollicis, thenar muscles)
Describe some of the lower limb postures that can be observed in a patient exhibiting spasticity
equinovarus
stiff knee: persistent knee extension
striatal toe: overactive extensor hallucis longus
flexed knee (taut hamstring tendons)
adducted thigh: spastic adductors produce a narrow base of support at feet (scissoring thighs)
How to determine which muscle is affected by spasticity
Dynamic EMG studies and temporary diagnostic motor point blocks may be used to determine involvement of specific muscles
Involuntary background activity = spasticity
If you stretch muscle and observe inappropriately large EMG response = spasticity
In the flexed elbow, _____ is spastic more often than ____ and ___
brachioradialis
biceps
brachialis
What can the flexed wrist position result in?
carpal tunnel symptoms may occur secondary to compression of the median nerve
Even after good proximal recovery in the upper limb, loss of ___________ often endures
finger and thumb dexterity
Definitions of spasms
- Spasm is a jumping or twitching of a muscle or limb without control;
- A spasm can be a “shooting” of the body part into a position without control;
- A rapid series of “spasms” without significant pausing is defined as one spasm.
list the spasticity examination rating scales
- spasm frequency scale
- modified ashworth scale
- adductor tone rating
- global pain scale