Loading Changes in Time-Based Parameters of Glottal Flow Waveforms in Different Ergonomic Conditions

Abstract

The effects of prolonged (5 × 45 min) reading in different environmental and ergonomic conditions on time-based glottal waveform parameters of normal female and male subjects (n = 80) were studied. The exposure groups (n = 5 females and males per cell) consisted of eight combinations of the following factors: (1) normal ( < 65 dB) or high ( > 65 dB) speech output level; (2) sitting or standing posture; (3) low (25 ± 5%) or high (65 ± 5%) relative humidity of ambient air. Two rest (morning and noon) and three loading (two in the morning and one in the afternoon) samples were recorded and analyzed. The glottal waveforms were obtained by inverse filtering of the acoustical signal using an automatic method. The following time-based parameters were analyzed from the estimated glottal now waveform: (1) length of fundamental period; (2) open quotient; (3) speed quotient, and (4) closing quotient. The analysis was based on inverse filtering of the first stressed syllable of ‘paappa’ words repeated 3x5 times with normal, maximally soft and maximally loud phonation. Humidity was a significant factor in serveral instances. The interactions between gender and the loading factors were striking.

Connections between Voice Ergonomic Risk Factors in Classrooms and Teachers’ Voice Production

“…The interpretation is speculative because the voice variables were measured on only 1 day, but gets support from Hunter and Titze [23], who reported that teachers still experienced voice symptoms 1 day after the fatiguing activity. Poor working postures especially accumulate loading effects and may cause more obvious impairment later [25]. …”

Comparison of Vocal Vibration-Dose Measures for Potential-Damage Risk Criteria

“…Cycle dose (measured in number of accumulated cycles) was originally introduced under the name vocal loading index (Vilkman, Lauri, Alku, Sala, & Sihvo, 1997); it quantifies the total number of oscillatory periods completed by the vocal folds over the exposure time and is obtained as follows:…”

Comparison of Two Inverse Filtering Methods in Parameterization of the Glottal Closing Phase Characteristics in Different Phonation Types

“…Different phenomena of voice production have been studied by concentrating on issues like phonation type, 17 intensity, 8 voice quality, 18 emotions, 19 pitch, 7,12 disturbed voice functions, 10,[20][21][22][23][24][25] singing styles, 16,[26][27][28] and vocal loading. 9,29,30 In addition, some studies have discussed IF from a methodological point of view. 6,31 Given the prevalence of IF in the field of voice science, it is surprising that the differences between IF methods have not yet been studied extensively.…”