title: Incomplete swallowing and retracted tongue maneuvers for electromyographic signal normalization of the extrinsic muscles of the larynx.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
  
  
  CONCLUSIONS
  The use of normalization standards in researches of SH and IH muscles in the voice area will allow comparisons among future works.
authors.affiliation: Post-Graduation in Neuropsychiatry and Behavioral Sciences Department, Universidade Federal de Pernambuco, Pernambuco, Brazil. pbalata@uol.com.br
authors.forename: Patricia Maria Mendes
authors.initials: PM
authors.lastname: Balata
authors.forename: Hilton J
authors.initials: HJ
authors.lastname: Silva
authors.forename: Gerlane Karla O
authors.initials: GK
authors.lastname: Nascimento
authors.forename: Klyvia Juliana R
authors.initials: KJ
authors.lastname: Moraes
authors.forename: Leandro A
authors.initials: LA
authors.lastname: Pernambuco
authors.forename: Maria Clara R
authors.initials: MC
authors.lastname: Freitas
authors.forename: Leilane M
authors.initials: LM
authors.lastname: Lima
authors.forename: Renata S
authors.initials: RS
authors.lastname: Braga
authors.forename: Síntia R
authors.initials: SR
authors.lastname: Souza
authors.forename: Silvia Regina A
authors.initials: SR
authors.lastname: Moraes
mesh_terms: D000200:Action Potentials; D000293:Adolescent; D000328:Adult; D003679:Deglutition; D004576:Electromyography / Q000592:standards; D005260:Female; D006801:Humans; D007537:Isometric Contraction; D007821:Laryngeal Muscles / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009068:Movement; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted; D014059:Tongue / Q000502:physiology*; D014836:Volition; D055815:Young Adult