In this study, a double-blind placebo-controlled approach was used to assess the relation between hydration level and phonatory effort. Twelve adult, untrained voice users with normal voices participated as subjects. Each subject received a 4-hour hydration treatment, a 4-hour dehydration treatment, and a 4-hour placebo (control) treatment. Following each treatment, phonatory effort was measured with a physiological measure, phonation threshold pressure (PTP), and with a psychological measure, direct magnitude estimation of perceived phonatory effort (DMEPPE). Summarizing the results across these measures, the findings indicated an inverse relation between phonatory effort and hydration level, but primarily for high-pitched phonation tasks. The findings for PTPs replicated those from an earlier study conducted without double-blind experimental manipulations (Verdolini-Marston, Titze, & Druker, 1990). Theoretical discussion focuses on the possible role of vocal fold tissue viscosity for hydration and dehydration effects, although direct measures of tissue viscosity are lacking.

The hypothesis that acoustic measures of relative speech timing remain constant across large changes in speaking rate was tested for fluent utterances produced by normal and neurogenically disordered speakers. For all speakers, relative timing tended to be statistically invariable across conversational and fast speaking rates. This finding was considered especially interesting in the case of speakers with dysarthria and apraxia of speech, because absolute measures of speech timing associated with these disorders are typically aberrant. A post hoc analysis of relative variability across speakers showed the ratio measures to be consistently less variable than measures of absolute interval duration. The greater similarity across speakers of ratio measures, as compared to interval measures, was taken to mean that characterizing the temporal structure of articulatory sequences in terms of relative timing is an appropriate way to capture an important aspect of the biological constraints associated with speech production.

The variance of speech timing measures has been used by a variety of investigators as in index of speech motor control. Children tend to have larger variances than adults for segment durations as do some adult dysarthrics compared to neurologically intact adults. The implication is that the larger variances reflect functional immaturity and deficits in the speech mechanisms of children and neurogenically involved adults, respectively. The present report deals with variance characteristics of segment and ratio measures of timing in normal and dysarthric speakers. Two interesting results are (1) fast speaking rate increases the variability of temporal ratios in all normal subjects, and in some dysarthric subjects, and (2) increased utterance length is associated with increased timing variability in spastic dysarthrics. These results are discussed relative to organizational and biomechanical differences between conversational and fast speaking rates, and as they may apply to models of dysarthria. [Work supported by NIH.]

In a previous paper [G. Weismer, J. Acoust. Soc. Am. Suppl. 1 73, S65-S66 (1983)] we presented evidence that conversational and very fast speaking rates have virtually identical relative timing characteristics, thus supporting the notion of relative timing as a nonessential variable in speech production. In the present paper we replicate these findings and extend the analysis to the case of very slow speaking rates. In addition, measures of fundamental frequency contour and formant transition rate are studied to determine how their form may be altered by changes in speaking rate. Because slow speaking rates are often used as a strategy in rehabilitation of various speech disorders, it is important to know if the form of various vocal tract outputs is disrupted by unusually slow rates. Recent biomechanical studies indicate that slow rates may require unique control strategies, thus implying that a critical value of the nonessential variable speaking rate may be demonstrated experimentally by requiring normal speakers to produce speech at very slow rates. [Work supported by NIH.]

For a number of years, faculty and students from the University of Iowa have been providing services to orphans in China. To improve sustainability, the effort was increased to also include training to hospital and orphanage staff as well. It became clear that the scope of our tasks and the amount of preparation for the students involved was exceeding what we could fit into the spare time of the typical graduate student and the mentor-of the-year. With the onset of a second humanitarian project—demanding similar training preparation and planning—a course was developed to better prepare the students for both the upcoming trips, as well as a lifetime of international collaboration and reciprocity. Funded entirely by student/faculty fundraising efforts (and personal resources), our commitment to global teaching and service is a strong one.