title: Investigation of fatigue, delayed-onset muscle soreness, and spectral-based cepstral measurements in healthy speakers after neuromuscular electrical stimulation.
abstract: OBJECTIVE
  We observed whether 30 minutes of neuromuscular electrical stimulation applied to the necks of healthy speakers would result in significant acoustic changes and perceptions of fatigue and/or delayed-onset muscle soreness (DOMS).
  
  
  METHODS
  Twelve participants were assigned to experimental (n=6; 3 male and 3 female) and control groups (n=6; 3 male and 3 female). Neuromuscular electrical stimulation was applied to the anterior neck in the experimental group only. All participants produced 3 trials of the vowel /a/ and the Rainbow Passage before and after completing a 30-minute phonation protocol. Recorded samples were analyzed for measures of the cepstral peak prominence, the ratio of low- to high-frequency spectral energy, and their respective standard deviations. Perceptions of fatigue and DOMS were rated on visual analog scales before, 5 minutes after, and 24 hours after completion of the phonation protocol.
  
  
  RESULTS
  Statistically significant acoustic findings reflecting reduced relative sound pressure level, increased high-frequency noise, and phonatory instability were observed in the experimental group. In addition, reports of fatigue and DOMS were also reported by some participants.
  
  
  CONCLUSIONS
  A 30-minute dosage may be too high for some people experiencing neuromuscular electrical stimulation for the first time.
authors.affiliation: Department of Educational Psychology and Special Education, Georgia State University, PO Box 3979, Atlanta, GA 30302, USA.
authors.forename: Linda P
authors.initials: LP
authors.lastname: Fowler
authors.forename: Shaheen N
authors.initials: SN
authors.lastname: Awan
authors.forename: Mary
authors.initials: M
authors.lastname: Gorham-Rowan
authors.forename: Richard
authors.initials: R
authors.lastname: Morris
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology*; D009132:Muscles / Q000502:physiology*; D009333:Neck; D009469:Neuromuscular Junction / Q000503:physiopathology*; D010147:Pain Measurement; D010699:Phonation / Q000502:physiology*