These studies have frequently been constrained by one or more factors, including limitation to a few examination parameters, or to a single sex or age level. Although some vocal function profiles have compared performance in young adults and geriatrics, they have largely ignored speakers in their middle years. Moreover, previous voice studies have not always considered demographic characteristics, such as health status, relevant laryngoscopic examination, and prior professional voice use. This omission may seriously limit the applicability of normative data. For example, the singer's literature has provided adequate evidence that differences exist between vocal function measures in trained and untrained speakers, which must be accounted for in any normal data base (Schutte and Miller, 1983; Peppard, Bless, and Milenkovic, 1988).

Additionally, the reported findings have not all been in agreement regarding age-related changes for such features as habitual frequency and intensity levels. These discrepancies may be explained in part by differences in such factors as the physical condition of the population sampled (Ramig and Ringel, 1983; Young, Bless, McNeil, and Braun, 1983), equipment differences (Titze and Scherer, 1985) and test protocol (Turner, 1988). This disagreement in the literature may in di cate that existing data do not adequately reflect the underlying complexity of phonation, nor the variability in vocal function measures across normal subjects. Regardless of the source of the discrepancies, these limits make it difficult to apply the current Normative values to the clinical population or to a better understanding of voice production.

Thus, basic questions remain about the vocal performance of normal speakers on a series of phonatory function tasks, including: what constitutes normal voice? and, how does performance vary with advancing age? We sought to address those issues by conducting a cross-sectional study of normal voice in adults. We collected stroboscopic, acoustic, aerodynamic, perceptual, laryngoscopic, and demographic data on males and females between the ages immediately post-puberty through senescence. These preliminary data begin to establish an age-referenced data base of normal phonatory function measures. Results from a standard vocal function battery are reported for measures of airflow rate, frequency, intensity, perturbation, audio perceptual judgments, and vibratory movement patterns for 146 normal speaking adults on sustained vowel production and connected speech tasks.