The effect of gender on measures of electroglottographic contact quotient.

OBJECTIVES/HYPOTHESIS: The purpose of this study was to reevaluate the possible effect of gender on measures of electroglottographic contact quotient (CQ). In addition to criterion threshold methods frequently used for the computation of CQ's via electroglottography (EGG), derivative based methods of computing the EGG CQ that have not been previously evaluated in regard to their effectiveness in discriminating between male versus female EGG waveforms were also examined.

STUDY DESIGN: Causal, mixed design.

METHODS: EGG waveforms were recorded during sustained vowel production from normal voice men and women (total N = 50). Measures of EGG CQ were calculated using eight criterion thresholds (25-60% in 5% increments). In addition, CQs were computed using the EGG derivative (DEGG) as well as via two hybrid methods that combine thresholds with measures from the DEGG.

RESULTS: Only CQs calculated via the DEGG showed a statistically significant difference in the direction anticipated via previous research (ie, men > women). In addition, the DEGG was the only method to show statistically significant differences in CQ useful in discriminating between "knee"-shaped opening phases observed in 76% of the men versus no "knee" opening phases observed in 64% of the women.

CONCLUSIONS: The DEGG may provide advantages over other methods of EGG CQ analysis that are useful in revealing possible gender differences in vocal physiology. Further studies that examine the relationship between EGG, DEGG, and visualization of vocal fold dynamics via high-speed video may provide further insight into the possible differences between adult male versus female contacting and decontacting points during comfortable pitch and loudness phonation.