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Summary Purpose The aim of the study was to compare the different parameters, regarding the peak and mean, at different phonatory tasks for standardization of electromyography signal of electrical activity (EA) of the laryngeal extrinsic muscles on voice evaluation. Methods The electrical potentials of the suprahyoid (SH) and infrahyoid (IH) muscles of 35 voluntary nondysphonic subjects were evaluated using three evaluations of rest, two maneuvers to determine maximum voluntary sustained activity (MVSA), and usual and strong intensity of vowel /ɛ/ and 20–30 count emissions. The EA signal was converted using root mean square in microvolts and normalized by mean and peak of each task. The selected normalization task was that with minor coefficient of variation for all muscles. Results The tasks that provided minor coefficient of variation of EA in both muscle groups were the peak of vowel /ɛ/ (mean potentials equal to 43.31 ± 2.97 for right IH, 36.27 ± 2.76 for left IH, and 42.11 ± 2.57 for SH) and the 20–30 count emissions (mean potentials equal to 31.30 ± 308 for right IH, 30.56 ± 2.76 for left IH, and 30.43 ± 4.22 for SH), both in usual intensity and MVSA, as second option. Conclusions The peak of vowel /ɛ/ and 20–30 count emissions is usual intensity, and the MVSA as second option should be considered for signal normalization in SH and IH muscles, and may provide conditions for using the surface electromyography in voice clinic. [ABSTRACT FROM AUTHOR]

Summary: Purpose: To investigate which muscular maneuvers provide larger electric activity (EA) of the suprahyoid (SH) and infrahyoid (IH) muscles to be used as surface electromyography (SEMG) signal normalization reference. Methods: The electrical potentials of the SH and IH muscles of 12 subjects were evaluated using six muscular maneuvers, involving the position of the tongue and effort. It was selected as maximum voluntary sustained activity maneuver, the one having the minor coefficient of variation and the smallest value for each muscle group. The EA signal was converted using the root mean square in microvolts. It was considered then the maximum signal of each maneuver as the difference between the mean of three measures and the resting potential. Results: The maneuvers that provided higher mean potentials with minor coefficient of variation and smallest P value were incomplete swallowing (IS) with effort (mean potential equal to 56.73±8.68 with coefficient of variation of 15.30%) in SH group, and tongue retracted with mouth open (TROM, mean potential equal to 46.57±7.83 with coefficient of variation of 16.81%) in IH group. Conclusion: The IS with effort and TROM maneuvers should be considered for signal normalization in these muscles, respectively, and may provide conditions for using the SEMG in voice clinic. Significance: The use of normalization standards in researches of SH and IH muscles in the voice area will allow comparisons among future works. [Copyright &y& Elsevier]