Turn and phase counts of individual motor unit potentials: correlation and reliability

Area of Science:

• Neurology
• Biomedical Engineering
• Quantitative Electromyography

Background:

• Quantitative analysis of motor unit potentials (MUPs) relies on various algorithms.
• Comparing the retest reliability of these algorithms is crucial for accurate MUP analysis.

Purpose of the Study:

• To compare the retest reliability of different turn algorithms for MUP analysis.
• To evaluate the effectiveness of turn counts and phase counts in discriminating between normal, myopathic, and neuropathic MUPs.

Main Methods:

• Recorded 420 myopathic and neuropathic MUPs twice.
• Correlated turn counts from first and second recordings to assess retest reliability.
• Utilized discriminant analysis to evaluate MUP discrimination based on amplitude limits and parameter counts.

Main Results:

• The Willison algorithm demonstrated superior retest reliability compared to algorithms based on amplitude criteria.
• An amplitude limit of 25 microV was more effective than 50 microV for discriminating myopathic from normal MUPs using turn counts.
• Turn counts were superior to phase counts for discriminating myopathic from normal MUPs.
• Both turn and phase counts were necessary for discriminating normal from neuropathic MUPs, as they measure independent features.

Conclusions:

• The Willison algorithm is recommended for reliable MUP turn analysis.
• Specific amplitude limits and parameter combinations are optimal for different MUP discrimination tasks.
• Turn and phase counts provide complementary information for classifying MUPs in neurological disorders.