Type of Document	Dissertation
Author	Harmon, Jr., Archie Bernard.
URN	etd-07242010-151641
Title	Effects of Transcutaneous Electrical Stimulation on Acoustic and Perceptual Measures of Vocal Function across Body Types
Degree	Doctor of Philosophy
Department	Communication, School of; Communication Science and Disorders, School of; and the Library and Inform
Advisory Committee	Advisor Name Title Richard Morris Committee Chair Juliann Woods Committee Member Julie Stierwalt Committee Member Marc Freeman University Representative
Keywords	Voice Voice Therapy Electrical Stimulation Swallow Therapy Dysphagia
Date of Defense	2010-07-01
Availability	unrestricted
Abstract There is great interest in determining the effects of Transcutaneous Electrical Stimulation (TES) on voice. A possible factor that influences electrical stimulation transfer to the extrinsic and intrinsic laryngeal muscles is subcutaneous fat, which relates to neck fat. Recent reports have shown a correlation between the thickness of the subcutaneous fat layer and the loss of electrical signal within the skin. The objectives of this study were to 1) determine if participants grouped by somatotype displayed different acoustic voice outcomes following a one-hour TES session, and to 2) examine whether subjective reports of vocal–warm-up, vocal fatigue, and delayed onset muscle soreness (DOMS) differed among the somatotype groups. Thirty-three subjects grouped by somatotype completed an hour of TES to the anterior neck. Pre and post voice recordings of sustained vowel and oral reading were used to calculate speaking fundamental frequency (SFF), speaking fundamental frequency standard deviation (SFFSD), and sound pressure level (SPL) and harmonic amplitude differences. In addition, participants provided comments regarding the neck sensation five minutes and 48 hours after TES. These responses related to three categories: vocal warm up, vocal fatigue, and DOMS. Repeated measure ANOVAs were used to test the differences from pre-stimulation to post-stimulation for each of the dependent variables. Post-hoc comparisons were completed using the Bonferroni test. No statically significant differences occurred for the F0 and SPL among the somatotype groups. However, somatotype group differences occurred between the amplitudes of the first and second harmonics (H1*, H2*), whereas the amplitude differences between the first harmonic and the first and third formant frequencies (H1*-A1, H1*-A3*) were not statically significant. With regard to perceptual measures, Over half (51.5 %) of all participants reported sensations of vocal warming up five minutes after the end of stimulation. Two out of four endomorphs, fifteen out of 25 mesomorphs, and no ectomprophs reported symptoms of vocal warm-up. Almost half of the participants 48.5% reported sensations of vocal fatigue immediately after stimulation ended. Fourteen out of the thirty-three participants (42.4%) reported symptoms of DOMS 24- 48 hours following the stimulation. All four of the endomorphic population reported symptoms of DOMS, 25% of the mesomorphic participants reported symptoms of DOMS, and no ectomorphic participants reported symptoms of DOMS. Results suggest no systematic effects of TES to the anterior neck on the selected acoustic measures. However, these results indicate that clinicians should use caution when applying TES to patient populations with high endomorphic characteristics.
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