An exploratory study of voice change associated with healthy speakers after transcutaneous electrical stimulation to laryngeal muscles.
OBJECTIVE
The purpose of this study was to determine if measurable changes in fundamental frequency (F(0)) and relative sound level (RSL) occurred in healthy speakers after transcutaneous electrical stimulation (TES) as applied via VitalStim (Chattanooga Group, Chattanooga, TN).


METHODS
A prospective, repeated-measures design.


METHODS
Ten healthy female and 10 healthy male speakers, 20-53 years of age, participated in the study. All participants were nonsmokers and reported negative history for voice disorders. Participants received 1 hour of TES while engaged in eating, drinking, and conversation to simulate a typical dysphagia therapy protocol. Voice recordings were obtained before and immediately after TES. The voice samples consisted of a sustained vowel task and reading of the Rainbow Passage. Measurements of F(0) and RSL were obtained using TF32 (Milenkovic, 2005, University of Wisconsin). The participants also reported any sensations 5 minutes and 24 hours after TES.


RESULTS
Measurable changes in F(0) and RSL were found for both tasks but were variable in direction and magnitude. These changes were not statistically significant. Subjective comments ranged from reports of a vocal warm-up feeling to delayed onset muscle soreness.


CONCLUSIONS
These findings demonstrate that application of TES produces measurable changes in F(0) and RSL. However, the direction and magnitude of these changes are highly variable. Further research is needed to determine factors that may affect the extent to which TES contributes to significant changes in voice.
Fowler
Linda P
LP
Department of Educational Psychology and Special Education, Georgia State University, Atlanta, Georgia 30302-3979, USA. lpfowler@gsu.edu
Gorham-Rowan
Mary
M
Hapner
Edie R
ER
D000328:Adult; D005260:Female; D006801:Humans; D007821:Laryngeal Muscles / Q000294:innervation*; D008297:Male; D008875:Middle Aged; D010699:Phonation; D011446:Prospective Studies; D011932:Reading; D012677:Sensation; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D013061:Speech Acoustics; D013068:Speech Production Measurement; D004561:Transcutaneous Electric Nerve Stimulation / Q000009:adverse effects; D014833:Voice Quality; D055815:Young Adult