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Neuro E&I
Change in Muscle Tone after CNS Injury
Question | Answer |
---|---|
Stiffness of a resting muscle. Resistance to active or passive elongation. | Tone. note: assessment if a passive measure of stiffness |
Increased resistance to passive stretch | Hypertonicity => Includes spasticity and rigidity |
Decreased resistance to passive stretch | Hypotonicity |
Excessive resistance to either active or passive muscle stretch. | Muscle Hyperstiffness. (myoplasticity and overactive neural input) |
Muscle Hyperstiffness occurs as a result of what two factors? | Myoplasticity and Overactive Neural Input (more theoretical) |
Adaptive changes in ms in response to a change in activity and prolonged positioning. | Myoplasticity |
Which UMN damage is a typically used term for pts. with stroke? | Hyperstiffness |
Unlike spasticity, what key factor is missing in hyperstiffness | Hyperreflexia |
What is the key difference between rigidity and spasticity? | Rigidity is NOT velocity dependent. Spasticity is velocity dependent |
Which subcategory of hypertonicity does one exhibit either a "lead-pipe" or "cog-wheel" resistance in the flexor muscles of the trunk and limb? | Rigidity |
What causes hyperreflexia and which branch of hypertonicity is it related to? | Velocity dependent resistance to passive stretch that is cause by an increase in alpha motor neuron excitability. Related to SPASTICITY. |
Slide: What causes increased ms stiffness post-stroke? | Weakness, Myoplastic changes, UMN overactivity (theoretical) |
Clinician definition of SPASTICITY refers to.... | all UMN motor changes post-injury/disease. This list includes: Parasis Myoplastic Hyperstiffness Co-contraction Hyperreflexia |
Velocity dependent resistance to passive stretch associated with exaggerated tendon reflexes | Spasticity |
Which is the most commonly used assessment tool for spasticity? How many grades are associated with it? What is the alternate method and what population is it gaining popularity with? | Modified Ashworth Scale (MAS) =>0, 1, 1+, 2, 3, 4 Tardieu Scale =>gaining popularity in ped/research |
How does the Tardieu Scale quanity muscle tone? | Test involves varying the velocity of limb movement. -Measures the difference in the ANGLE OF RESISTANCE between slow and fast movement |
What is the spasticity angle? | Measures the difference in the ANGLE OF RESISTANCE between slow and fast movement R1 (fast speed)/R2 (slow speed) DYNAMIC WINDOW |
True or False Reduced spasticity does not independently correlate with increased function. | True. STRENGTH has a stronger relationship with function |
Why is it an indication to reduce the use of anti-spasticity drugs? | 2ยบ side-effect can include muscle weakness. STRENGTH has a stronger relationship with function, rather than reduced spasticity. |
Assessment of Tone: Passive or Active measure of stiffness? | Passive measure of stiffness |
What is normal muscle tone characterized by? | Minimal bonding of actin and myosin that exists on a continuum of tone from flaccidity to hypertonicity. Optimal Tone is TASK & ENVIRONMENT specific |
What does resting muscle tone results from? | Relaxed muscles are electrically silent. RMT results from intrinsic stiffness of muscles and tendons. |
CHOOSE: Myoplasticity involves the selective atrophy/hypertophy of slow/fast twich fibers. | Myoplasticity involves the selective atrophy of fast twich fibers. |
List adaptive changes seen in myoplasticity | 1. Contracture 2. Increase in number of Actin-Myosin bonds 3. Selective atrophy of fast twitch ms fibers |
Discuss the relationship of the UMN and LMN in the Overactive Neural Input theory for hyperstiffness | UMN stimulation of LMN producing sustained ms activity as a result of UMN injury |
Rigidity is primarily seen with what types of injuries? Spasticity is primarily seen with what type of injuries? | Rigidity: Results from Brain Stem or Basal Ganglia injuries. Ex. Parkinson's Disease Spasticity: As a result of UMN Lesion (SCI, MS, TBI, CP) |