The impact of menopause on voice: past, present, and future.

B ecause half of the people on this planet will experience menopause, the question about its impact on voice is certainly a germane one. Although the literature on this subject is scant, the consensus of objective data available thus far, including the analysis by D’haeseleer et al in this issue of Menopause, is that the fundamental frequency, an acoustic correlate of vocal cord vibration rate and pitch, becomes lower after menopause. This follows logically from the knowledge that the estrogen-progesterone to androgen ratio decreases after menopause as well as from other reports that show a decrease in fundamental frequency after exogenous androgen administration. The study of D’haeseleer et al, as well as others, analyzed the voices of premenopausal versus postmenopausal women using a combination of objective aerodynamic/acoustic measures and subjective assessments (both participant-reported and Bexpert[derived). In her group’s analysis, only a few of the objective voice measures (including fundamental frequency and vital capacity) exhibited statistically significant differences after menopause. Assuming all other things equal (which, in fact, they were potentially not, particularly with respect to vocal aging; see below), this may reflect a lack of sensitivity in standard clinical measures of voice, which are designed to differentiate normal and overtly pathological vocal function; they are not necessarily capable of detecting the types of subtler differences that may be associated with menopause. There is also a movement away from the voice qualityYrelated acoustic measures that were used in this study (eg, jitter and shimmer) to newer cepstral-based methods, which seem to have several advantages including better correlation with auditory perception of disordered voice quality. Even so, as a laryngologist, I have yet to encounter a woman who complains of her Bphonation quotient[ being not quite right, or her Bjitter[ or Bshimmer[ being slightly elevated, and so perhaps much more important than today’s current objective measures of voice are subjective assessments. Although there are speech pathologists, physicians, and other clinicians with highly trained ears who can consistently perceive subtle vocal differences between women, I submit that it is a woman’s perception of her own vocal difficulties that is paramount. There are several validated, patient-rating scales that attempt to measure this (Voice Handicap Index, Voice-Related Quality of Life, etc). Granted, even these have limitations that are inherent to all scales that are based on self-assessment, but to the authors’ credit, they did use one of the best validated and accepted instruments, the Voice Handicap Index. Nevertheless, in the analysis by D’haeseleer et al, there was no statistically significant difference in participant-scored subjective voice measurements before and after menopause. This is an understated point and raises the possibility that no clinically appreciable vocal difference exists between average voice users before and after menopause. The key, however, lies in the concept of type of voice users. For centuries, European female opera singers did not perform around the time of their menses, and a recent study that longitudinally analyzed voices in a cohort of classically trained female conservatory students found that the singers themselves (but not their vocal pedagogues) detected subjective voice changes across their menstrual cycle. These data suggest that the impact of sex hormone variations on voice is especially noticeable in women with high vocal demands. Although literature describing the effect of menopause in vocal professionals is lacking, one can extrapolate that this cohort may be similarly particularly susceptible to postmenopausal vocal difficulties. Clearly, additional research in this subgroup of postmenopausal women, who may depend on the maximal performance capabilities of their voices for their livelihood, is warranted. Despite the biological effects of sex hormones on laryngeal structure as well as the objective and subjective vocal changes that may accompany menopause, the proverbial elephant in the room is that of vocal aging and associated phonotrauma. In most cases, with menopause comes physiological aging, and this is a tremendous confounder in assessing the vocal changes elicited by menopause. Moreover, although chronological age roughly correlates with lifetime voice use, this is not always the case. For instance, one would not expect the vocal cords of an 80-year-old hermit to exhibit the same structural changes seen in those of a 40-year-old heavy-metal singer. Thus, even more important than age in years is the cumulative amount of phonotrauma that any given woman has sustained. Proceeding from superficial to deep, the vocal cords have a delicately layered microstructure consisting of an epithelial surface, followed by a tri-layered lamina propria, a vocal ligament, and the thyroarytenoid muscle. The superficial layer of lamina propria (SLP) is critical for allowing gliding of the mucosal surface over the static body of the ligament and muscle during phonation. This phenomenon of normal voicing is (indirectly) visible on the stroboscopic office examination of the larynx as a Bmucosal wave[ and can be roughly