Electroglottographic contact quotient in different phonation types using different amplitude threshold levels

Area of Science:

• Speech science
• Bioacoustics
• Laryngology

Background:

• Contact quotient (CQ) quantifies vocal fold contact duration during phonation.
• Electroglottography (EGG) is a non-invasive method to measure vocal fold contact.
• Understanding phonation types is crucial for voice production analysis.

Purpose of the Study:

• To investigate the relationship between CQ(EGG) and perceptual evaluation of phonation firmness.
• To determine the optimal amplitude threshold for CQ(EGG) measurement.
• To assess the influence of fundamental frequency (F0) and sound pressure level (SPL) on CQ(EGG).

Main Methods:

• Sustained vowel phonation was recorded in three phonation types: breathy, normal, and pressed.
• CQ(EGG) was calculated at amplitude threshold levels of 25%, 35%, and 50%.
• CQ(EGG) values were compared with expert perceptual judgments of phonation firmness.

Main Results:

• Significant differences in CQ(EGG) were observed across phonation types at all threshold levels (P < 0.01).
• Perceptual evaluation showed the best correlation with CQ(EGG) at 25% and 35% thresholds.
• Linear regression indicated that at the 25% threshold, F0 and SPL did not significantly affect CQ(EGG).

Conclusions:

• CQ(EGG) is a reliable measure for assessing vocal fold contact and perceived phonation firmness.
• Amplitude thresholds of 25% and 35% are recommended for optimal CQ(EGG) analysis.
• The 25% threshold minimizes the confounding effects of F0 and SPL on CQ(EGG) measurements.