FROM MY PT SCHOOL NOTES · MODALITIES · UNIT 1 · CHAPTER 04
How Do Muscle Tone, Spasticity and Rigidity Differ?
Describe the response to movement before assigning a label.
At a glance
SPASTICITY
Velocity-sensitive stretch response
RIGIDITY
More consistent passive resistance
CONTRACTURE
Structural restriction of motion
What matters most
- Spasticity is classically associated with velocity-dependent stretch-reflex hyperexcitability, while rigidity is not primarily defined by stretch velocity.
- Passive resistance can also reflect muscle and connective-tissue stiffness, contracture or pain; these can coexist with neurologic contributors.
- The Modified Ashworth Scale describes resistance during passive motion but cannot by itself isolate the neural component.
Safety and limits
Do not select treatment based on a scale score alone. Link observed tone to gait, transfers, hygiene, positioning and purposeful movement.
Think it through
Scenario: An arm resists passive movement during a rapid test. Does that automatically identify the cause of restricted reach?
Reveal the reasoning
No. Consider speed, active control, pain, range, contracture and task performance; test competing explanations.
From my original class materials: 5 Tone Abnormalities .pdf. Summarized and reframed for learning; not an official course or clinical protocol. Compare with current device instructions, scope, and evidence before application.
