Quantifying Spasticity With Limited Swinging Cycles Using Pendulum Test Based on Phase Amplitude Coupling

Area of Science:

• Rehabilitation Medicine
• Biomedical Engineering
• Neuroscience

Background:

• Traditional Pendulum test parameters are limited in assessing abnormal muscle activity in spasticity.
• Quantitative evaluation of muscle activation-movement interaction is crucial for understanding spasticity.
• Hemiplegic stroke patients often exhibit complex muscle-movement dysfunctions.

Purpose of the Study:

• To develop and validate a novel index for quantitative evaluation of muscle activation-movement interaction in stroke-induced spasticity.
• To explore the application of phase amplitude coupling (PAC) analysis for assessing spasticity.
• To compare the proposed method with traditional spasticity assessment techniques.

Main Methods:

• Utilized empirical mode decomposition (EMD) to process angular velocity data and extract intrinsic mode functions (IMFs).
• Calculated Shannon entropy based on the phase of angular velocity and the envelope of surface electromyography (SEMG) amplitude.
• Employed phase amplitude coupling (PAC) analysis to quantify the relationship between muscle activity and joint movement.

Main Results:

• The novel PAC-based index demonstrated effective discrimination between spastic and non-affected limbs in hemiplegic stroke patients.
• The method showed feasibility in evaluating spasticity within fewer than three swinging cycles.
• Results suggest superior characterization of muscle activation-movement coupling compared to traditional methods.

Conclusions:

• The proposed novel indices based on PAC offer a feasible and effective approach for evaluating spasticity in hemiplegic stroke patients.
• This method provides a quantitative measure of muscle activation-movement interaction, improving upon existing assessments.
• Further research can explore the clinical utility and broader applications of PAC analysis in neurological rehabilitation.