A study of voice changes in various phases of menstrual cycle and in postmenopausal women.

Larynx is responsible for the generation of voice and subsequently impacts on communication, social interaction, personality, and artistic expression. The vocal instrument is comprised of the vibratory body, the respiratory power source, and the oropharyngeal resonating chamber. The lungs are the power supply, the larynx is the vibratory source, and the supraglottal vocal tract (supraglottal pharynx oral cavity, nasal cavity) is the resonator that shapes the sound into words and songs. During the phase of expiration as the diaphragm relaxes and the chest wall recoils, air is pushed through the nearly closed vocal folds. The aerodynamic forces of the air column and myoelastic properties of the vocal folds are responsible for the repeated opening and closing of the glottal tissue that pulses that air column as it flows out. These disruptions in the steady state of tracheal air pressure by glottal activity and vocal fold vibrations result in voice production. Voice is characterized by its frequency intensity and harmonics. The harmonics are hormonally dependent. This is illustrated by changes that occur during male and female puberty. The female voice evolves from childhood to menopause under the varied influences of estrogen, progesterone, and testosterone. These hormones are the dominant factor in determining voice changes throughout life. Female voice has a fundamental frequency one-third lower than that of a child. In males, androgen released at puberty is responsible for the male vocal frequency being an octave lower than that of a child. The females have a reproductive system, which undergoes a regular cyclic change known as the menstrual cycle. Laryngeal changes are evident and fluctuate systematically during the reproductive years with the menstrual cycle. The main objective of this experiment is to provide a solid ground with evidence of changes in voice because of sexual hormones, which will form the base of a multidisciplinary approach to a comprehensive and integrated understanding of premenstrual and menopausal female voice. (c) 2010 The Voice Foundation. Published by Mosby, Inc. All rights reserved.