Intra- and intersubject variability in acoustic measures of normal voice

Twenty-four normal adult women read part of the Rainbow Passage and sustained vowels three trials each. Utterances were assessed for selected parameters measured by Visi-Pitch (average and SD of fundamental frequency (F₀), average and SD of dBA, perturbation, and percent voiced/unvoiced/pause). Assessment of each parameter included measures of central tendency, dispersion, and distribution characteristics (skewness and kurtosis) of the data and of the ranges of values that would include 95% of the scores (95% fiduciary limits). Generally, differences for the group between the three trials were not significant. Intersubject variability for only a few parameters was less than 20% of the parameter's mean. For vowels, variability of jitter was 30–48% of the mean. Eight subjects provided performances 2 months later to obtain an estimate of intrasubject variability over time. There were desirable intrasubject correlations between performances for mean F₀, jitter in reading and on vowels /i/ and /a/, and percent of voicing. Inter- and intrasubject variability seems restricted and the data appear to resemble a normally distributed function for mean F₀ on reading, jitter on /i/, and percent of voicing. Thus, these parameters may have statistical merit for use in vocal testing.     

Normals in a Minkowski Plane

In this paper we will establish bounds on the average number of normals through a point in a convex body in a Minkowski plane for certain classes of convex bodies. Also, a related Euler relation is discussed.     

The Prevalence of Hypopharynx Findings Associated with Gastroesophageal Reflux in Normal Volunteers

Routine laryngeal examination of patients with otolaryngologic complaints often reveals findings thought to result from gastroesophageal reflux. The direct association between these mucosal findings and uncontrolled reflux is not well established. To begin exploring the specificity of tissue signs, 105 normal, healthy, adult volunteers were examined by routine video fiber-optic endoscopy for the presence of findings attributed to reflux disease. Medical conditions, lifestyle factors, and ENT complaints were surveyed to reveal potential airway irritants, while the study design attempted to eliminate silent reflux. The majority of subjects (86%) had findings associated with reflux and certain signs reached a prevalence of 70%. Prevalence was not affected by ENT complaint, smoking, alcohol, or asthma. Intraexaminer and interexaminer agreement information is provided. The traditional attribution of hypopharynx irritation signs to reflux is challenged; the need for improved diagnostic specificity is highlighted.