The Effects of the Menstrual Cycle on Voice Production Becca Walters & Cheryl L. Giddens, Ph. D. Oklahoma State University BACKGROUND

ABSTRACT

RESULTS

CONCLUSIONS

It has long been hypothesized that the two dominant ovarian hormones, estrogen and progesterone, known to influence fluid retention, may result in fluid retention (edema) at the vocal cords. Edema would increase the mass of the cords, altering the vibratory characteristics, and therefore potentially altering the fundamental frequency of vibration. In addition, there has been concern that edema would increase the subglottal pressure necessary to set the vocal cords into vibration. Repeated use of high subglottal pressures for professional singing performances or speaking engagements has been feared to be vocally damaging. If too great, the increased pressure could result in vocal cord hemorrhage during a particularly vigorous performance. Many studies have been conducted on the female voice over the menstrual cycle, but the results are equivalent. One explanation may be a lack of control for substances that can alter fluid retention. Caffeine, contraceptives, and many other substances demonstrate diuretic properties which could reverse the effects of estrogen and progesterone on the vocal cords and the voice. As such, the substances should be controlled in a well-designed study. Dr. Giddens is working to better understand the effects of the menstrual cycle on voice production under strict controls.

This single-subject design utilized Praat software to collect acoustic measures of fundamental frequency, jitter, shimmer, and voice breaks to document the effects of the menstrual cycle on the voice. Data was collected over a period of 24 days. Careful controls were implemented. Significant results were found for all four measurements, but further investigation is necessary to make any definitive conclusions.

Preliminary analysis of variance revealed a significant difference at level α=0.05 for the standard deviation of Fo, voice breaks, jitter, and shimmer.

We found a significant difference in standard deviation of the fundamental frequency (Fo), voice breaks, jitter, and shimmer values over the different phases of the menstrual cycle.

METHODS Participants Participants. We collected voice samples from a female college student, age 19. She was required to keep a journal of specific substances consumed that could affect fluid retention (coffee, tea, grapefruit, grapefruit juice, aspirin, ibuprofen, Excedrin, Midol, Pamprin, antihistamines, calcium, and magnesium). She was also asked to record when she experienced the menses portion of her menstrual cycle. Sampling Sampling. The sampling period was 24 days, with one voice sample in the evening each day. The sample consisted of a recording where the subject was required to repeat the syllable /pa/ into a microphone at a constant pitch. Praat software was employed for voice recording and analysis. Measures Measures. The measures recorded for this study were as follows: (a)Fundamental frequency (Fo) in hertz (Hz) – perceived as pitch

HYPOTHESIS Fundamental frequency, jitter , and shimmer will vary significantly over the phases of the menstrual cycle.

(b)Jitter (%) – the cycle-to-cycle variation in Fo of the voice; perceived as vocal roughness Shimmer (dB) – the cycle-to-cycle variations in the vocal intensity; perceived as roughness Voice breaks

Limitations/Future Directions: Due to the single subject design, the results of this study are interesting but not generalizable to a wider population. Future research should include a larger sample size and data collected over a longer period of time.

day 1 M status 1 no 2 no 3 no 4 no 5 yes 6 yes 7 yes 8 yes 9 yes 10 yes 11 no 12 no 13 no 14 no 15 no 16 no 17 no 18 no 19 no 20 no 21 no 22 no 23 no 24 no

Fo dev Fo V breaks jitter shimmer 196.274 2.042 0 0.601 0.463 182.519 1.647 0 0.755 0.551 183.813 0.919 0 0.406 0.313 186.04 0.934 0 0.54 0.3 197.099 1.352 0 0.479 0.287 192.108 7.847 0 0.301 0.208 187.653 17.416 1 0.298 0.212 192.757 1.378 0 0.364 0.205 181.779 1.304 0 0.32 0.249 185.533 1.704 1 0.448 0.234 183.921 0.947 0 0.298 0.208 181.781 1.008 0 0.298 0.179 189.437 1.05 0 0.439 0.207 197.487 2.891 0 0.477 0.291 199.063 2.184 0 0.409 0.259 194.971 21.852 1 0.584 0.389 190.296 1.479 0 0.402 0.369 186.566 3.385 0 0.381 0.192 195.474 1.249 1 0.859 0.625 187.242 10.259 1 0.643 0.535 183.471 22.617 1 0.657 0.889 184.987 1.19 16 0.914 1.697 202.663 66.283 8 0.968 1.403 197.513 1.858 12 0.794 1.377

AOV Sig Levels

≤0.004

≤0.032 ≤0.031

≤0.037

X HNR 0.019717 0.037505 0.015847 0.020475 0.020399 0.013709 0.017406 0.019764 0.015806 0.017178 0.015899 0.012511 0.014817 0.025716 0.023149 0.036442 0.017743 0.01142 0.051846 0.027292 0.157661 0.248728 0.223854 0.300903