A Tendon Indentation Method to Quantify Velocity-Dependent Reflex Responses after Hemispheric Stroke.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Rehabilitation Science

Background:

• Spasticity assessment in stroke survivors often relies on stretch reflex responses.
• Current clinical methods, like ballistic tapping, may lack detailed resolution.
• Tendon indentation offers a potential alternative for eliciting and quantifying reflex responses.

Purpose of the Study:

• To introduce and evaluate a novel ramp-and-hold tendon indentation protocol for assessing spasticity.
• To compare the efficacy of this new method with traditional tendon-tapping techniques.
• To investigate the relationship between indentation velocity and reflex response elicitation.

Main Methods:

• A linear motor controlled by a position-controlled feedback loop was used to indent the biceps brachii distal tendon.
• A ramp-and-hold protocol was applied at various velocities to three chronic stroke survivors.
• A combined tendon indentation and tapping method was employed to quantify reflex thresholds.

Main Results:

• Reflex responses were elicited at indentation velocities of 50 mm/s or higher in 2 out of 3 subjects.
• One subject did not exhibit a detectable reflex response during the ramp-and-hold protocol.
• All subjects demonstrated a distinct reflex threshold using the indentation/tapping method, correlating with ramp-and-hold responses.

Conclusions:

• The ramp-and-hold tendon indentation method shows promise for providing higher resolution in quantifying spasticity.
• This technique may offer a more nuanced assessment of reflex responses than current clinical methods.
• Further research is warranted to validate its clinical utility and compare it directly with established spasticity measures.