Tone Flashcards
What is muscle tone?
Resistance offered by muscles when passively lengthened
What is the range of muscle tone?
Flaccidity –> Hypotonia –> Normal –> Spasticity –> Rigidity
What is hypertonicity a diagnostic indicator of?
UMN problem
What is hypotonicity possibly an indicator of?
UMN or LMN problem
Examples from UMN syndrome
CVA, PD
Examples of UMN or LMN problems
Peripheral nerve damage, Down’s Syndrome, Cerebellar damage, UE after CVA
What is lost in hypotonia?
Loss of normal alpha and gamma motor neuron coactivation
What is spasticity dependent on?
Velocity-dependent of hypertonia and hyperreflexia
In neural cause of hypertonia, what motor neurons are most sensitive to input?
Alpha motor neuron, depolarized so it’s closer to firing threshold
Cause of non-neural hypertonia
Immobilization (e.g. contracture)
Change in muscle fiber structure (e.g. atrophy)
What does examination of tone look like?
Passive movement of limbs at varying speeds
Reflexes
- DTRs/Clonus (hyperreflexia)
- Babinski
What scale is used for passive stretch?
Modified Ashworth Scale
Tardieu (peds)
Is there a scale for hypotonia?
No
What should we consider when treating abnormal tone?
Neural mechanisms
Non-neural mechanisms
Influence of other systems
Functional relevance
What are other modes of treatment?
Pharmacological
Surgical
