Evaluation of Fatigability of the Levator Veli Palatini Muscle during Continuous Blowing Using Power Spectra Analysis

2004 ◽  
Vol 41 (3) ◽  
pp. 320-326 ◽  
Author(s):  
Takashi Tachimura ◽  
Kanji Nohara ◽  
Koichi Satoh ◽  
Takeshi Wada

Objective The purpose of this study was to compare the fatigability of the levator veli palatini (LVP) muscle during blowing in speakers who exhibit velopharyngeal incompetence with that from normal speakers by means of power spectra analysis. Design All subjects were instructed to blow into a tube for more than 10 seconds at maximum possible effort. The LVP muscle activity (electromyography) was sampled at 2 kHz for 10 seconds from the time when the oral air pressure during blowing was stabilized. These samples were subjected to Fast Fourier Transfer analysis with analytic windows of 0.5-second width. The electromyography mean power frequency slope with respect to time for each subject was estimated. Participants Three speakers with repaired cleft palate and three normal speakers were selected as subjects. Results The slopes of the regression lines for all three subjects with repaired cleft palate were negatively signed with statistical significance (t test, p < .01). The slopes for all of the normal speakers were negatively signed, but these were not statistically significant. Conclusion These results suggest that the LVP muscle of speakers with repaired cleft palate who exhibit varying degrees of velopharyngeal dysfunction may deteriorate more easily in comparison with the LVP muscle of normal speakers.

2006 ◽  
Vol 43 (1) ◽  
pp. 103-107 ◽  
Author(s):  
Kanji Nohara ◽  
Takashi Tachimura ◽  
Takeshi Wada

Objective This study examined whether the levator veli palatini muscle in speakers with borderline velopharyngeal incompetence (BVP) with surgically treated cleft palate might be more fatigable during speech than that in speakers without clefts. Design Each subject was asked to pronounce the syllable /pu/ more than 50 times at a rate of one time per second. Mean power frequency (MPF) of one syllable was obtained from electromyogram data of the levator muscle by power spectral analysis. Participants Five patients with postsurgical cleft palates, who were identified as having BVP by nasopharyngeal fiberscopy, served as subjects, and five participants without clefts served as the control group. Results In all participants without clefts, the slopes of the regression line relating MPF to the course of syllable repetition were negative but not significant. However, in all participants with BVP, the slopes of the regression line were significantly negative. Conclusions These findings demonstrated that the levator muscle of speakers with BVP was more fatigable than that of speakers without clefts during repetition of syllables. This study suggests that the fatigability of levator muscle contributed to mild hypernasality in patients with BVP.


1991 ◽  
Vol 142 (4) ◽  
pp. 457-465 ◽  
Author(s):  
B. GERDLE ◽  
K. HENRIKSSON-LARSÉN ◽  
R. LORENTZON ◽  
M.-L. WRETLING

1993 ◽  
Vol 74 (6) ◽  
pp. 2704-2710 ◽  
Author(s):  
D. Gamet ◽  
J. Duchene ◽  
C. Garapon-Bar ◽  
F. Goubel

Spectral electromyographic (EMG) changes in human quadriceps muscles were studied to reinvestigate discrepant results concerning mean power frequency (MPF) changes during dynamic exercise. An incremental test consisting of a quasi-linear increase in mechanical power on a bicycle ergometer (for 20–100% of maximal aerobic power) was performed by forty subjects. During this test, surface EMGs from the quadriceps muscles showed that EMG total power (PEMG) increased with a curvilinear pattern for every subject, whereas MPF kinetics varied from one subject to another. PEMG changes had the same shape, which would lead to disappointing results in terms of discrimination between subjects. The ability of normalized MPF kinetics to define significant clusters of subjects was tested using a principal component analysis. This analysis led to the projection of all experiments onto a plane and revealed a relevant grouping of MPF profiles. Differences in MPF kinetics between clusters are interpreted in terms of various possibilities of balance between physiological events leading to an increase or a decrease in MPF.


2010 ◽  
Vol 37 (9) ◽  
pp. 692-697 ◽  
Author(s):  
E. SUZUKI ◽  
S. ISHIGAKI ◽  
H. YATANI ◽  
E. MORISHIGE ◽  
M. UCHIDA

Motor Control ◽  
2021 ◽  
Vol 25 (1) ◽  
pp. 59-74
Author(s):  
Taylor K. Dinyer ◽  
Pasquale J. Succi ◽  
M. Travis Byrd ◽  
Caleb C. Voskuil ◽  
Evangeline P. Soucie ◽  
...  

This study determined the load- and limb-dependent neuromuscular responses to fatiguing, bilateral, leg extension exercise performed at a moderate (50% one-repetition maximum [1RM]) and high load (80% 1RM). Twelve subjects completed 1RM testing for the bilateral leg extension, followed by repetitions to failure at 50% and 80% 1RM, on separate days. During all visits, the electromyographic (EMG) and mechanomyographic (MMG), amplitude (AMP) and mean power frequency (MPF) signals were recorded from the vastus lateralis of both limbs. There were no limb-dependent responses for any of the neuromuscular signals and no load-dependent responses for EMG AMP, MMG AMP, or MMG MPF (p = .301–.757), but there were main effects for time that indicated increases in EMG and MMG AMP and decreases in MMG MPF. There was a load-dependent decrease in EMG MPF over time (p = .032) that suggested variability in the mechanism responsible for metabolite accumulation at moderate versus high loads. These findings suggested that common drive from the central nervous system was used to modulate force during bilateral leg extension performed at moderate and high loads.


2002 ◽  
Vol 39 (5) ◽  
pp. 503-508 ◽  
Author(s):  
Takashi Tachimura ◽  
Kanji Nohara ◽  
Yoshinori Fujita ◽  
Takeshi Wada

Objective: The purpose of this study was to examine whether a speech-aid prosthesis normalizes the activity of the levator veli palatini muscle for patients with cleft palate who exhibit velopharyngeal incompetence. Design: Each subject was instructed to produce repetitions of /mu/, /u/, /pu/, /su/, and /tsu/ and to blow with maximum possible effort. Electromyographic (EMG) activity of the levator veli palatini muscle was recorded with and without a hybrid speech-aid prosthesis in place. Participants: The participants were five patients with repaired cleft palate who were routinely wearing a hybrid speech-aid prosthesis. Results: With the prosthesis in place, the mean value of levator activity changed positively in relation to oral air-pressure change during blowing. Differences in levator activity in relation to speech samples were similar to those in normal speakers. With the prosthesis in place, levator activity for speech tasks was less than 50% of the maximum levator activity for all subjects. The findings were similar to those reported previously for normal speakers. Conclusion: Placement of the prosthesis changed EMG activity levels of the levator veli palatini muscle to levels that are similar to normal speakers. It is possible that, with the increase in the differential levator activity between speech and a maximum force task, the velopharyngeal mechanism has a greater reserve capacity to maintain velopharyngeal closure compared with the noprosthesis condition.


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