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Form factor analysis of the surface electromyographic interference pattern
Author(s) -
Nandedkar Sanjeev D.,
Barkhaus Paul E.,
Stålberg Erik V.
Publication year - 2020
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.26922
Subject(s) - amyotrophic lateral sclerosis , electromyography , medicine , root mean square , physical medicine and rehabilitation , cardiology , disease , electrical engineering , engineering
In contrast to needle electromyography (EMG), surface EMG recordings are painless. It is of interest to develop methods to analyze surface EMG for diagnostic purposes. Methods Surface EMG interference pattern (SIP) recordings from the abductor pollicis brevis muscle of healthy subjects and subjects with amyotrophic lateral sclerosis (ALS) were analyzed by measuring root‐mean‐square (RMS) voltage, mean rectified voltage, form factor (FF), and the clustering index (CI). The FF vs SIP area plot was used for analysis. Results The SIP FF was increased and abnormal in ALS subjects, especially when SIP area was less than 200 mVms. Power regression showed a faster FF decline with SIP area in ALS patients than in healthy subjects. The CI and FF showed a strong correlation. Discussion FF is easy to calculate and demonstrates abnormalities in ALS patients.