Zur Elektromyographie des Larynx mit Hautoberflächenelektroden

Phonation into a Tube as a Voice Training Method: Acoustic and Physiologic Observations

“…The average values for EMG and VLP signals were calculated from two periods of time in each phonation sample: the interval from 350 ms backwards to 250 ms forwards from the beginning of the phonation and from 250 ms backwards to 350 ms forwards from its end. These periods were chosen as they have been reported to give information on the average level of EMG activity in phonation [7], Average values were obtained from 20 samples of/u;p/ before and after the tube exercise and from 20 samples of tube phonation. All the average values were printed as diagrams, from which the comparisons between the different phonato ry tasks in the four parameters were made visually.…”

“…All the average values were printed as diagrams, from which the comparisons between the different phonato ry tasks in the four parameters were made visually. In the comparison of the EMG values special attention was paid to the time interval from 350 ms before the start of phonation to the moment when the phonation started, as this time period gives information on the prephonatory muscular activation, which in turn has been found to correlate with phonatory effort [7]. Changes in the EMG signal close to the end of phona tion of the lm.pl syllables reflect changes in the muscu lar activity related to the /p/ articulation and arc thus not directly related to phonatory quality.…”

“…The methods were chosen because due to their noninvasiveness they are very comforta ble and nonrisky for the subjects. Although the risk of artefacts cannot be denied, electro myography with surface electrodes has been reported to act successfully at intrapersonal level in giving information on the mean activ ity changes of the muscles in the laryngeal region, mainly cricothyroid and thyroaryte noid muscles [7], Dual-channel electroglottography has been developed for studying the vertical movements of the larynx from the amplitude difference between the signals ob tained with two pairs of electrodes placed on both sides of the thyroid cartilage at the level of the vocal folds with a certain vertical dis tance from each other [8], Inverse filtering is nowadays a widely used method for studying voice quality. The iterative adaptive inverse filtering method used here performs inverse filtering on the acoustic signal [9], This meth od has been found to be very successful also in problematic cases, e.g.…”