David W. Warren

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The effect of increased vertical bite dimension on fricative sound productions was studied in five adults who wore dentures. Oral port size and sound intelligibility were evaluated at different degrees of artificially induced open bite. The data demonstrate that rapid compensatory adjustments occurred and oral port size changed minimally at all degrees of(More)
The articulation errors associated with velopharyngeal incompetence are of particular interest to clinicians and researchers because the problems they pose usually remain after surgical repair and the reasons they appear may have important implications for speech-motor control. The intriguing question of why individuals develop and maintain such detrimental(More)
Individuals with congenital velopharyngeal impairment generally maintain adequate levels of intraoral pressures during consonant production by increasing respiratory effort. The purpose of the present study was to determine if normal individuals respond to a decrease in velopharyngeal resistance in a similar way. The velar mechanism was perturbed by having(More)
The speech respiratory system is configured in ways that tend to maximize its ability to respond to changes in the airway environment. Intraoral pressures remain at levels sufficient to generate reliably recognized consonant sounds even in the presence of structural deficits such as velopharyngeal inadequacy. Similar respiratory compensations occur when(More)
The purpose of this study was to quantify perceived hypernasality in children. One-third octave spectra of the isolated vowel [i] were obtained from 32 children with cleft palate and 5 children without cleft palate. Four experienced listeners rated the severity of hypernasality of the 37 speech samples using a 6-point equal-appearing interval scale. When(More)
The purpose of this study was to examine the influence of acoustic and perceptual factors of speech on listeners' perceived hypernasality in the vowel [i]. The isolated syllable [pi] produced by 22 children with hypernasal speech and 6 noncleft children was rated by 10 listeners. These speech samples were then divided into two groups: (1) the samples (n =(More)
The ontogeny of function and mRNA expression of the inhibitory guanine nucleotide-binding regulatory protein (Gi) was studied in the rat testis. Dispersed testis cells of animals aged 8, 15, 20 and 30 days were cultured with or without 100 micrograms/l pertussis toxin (PT) for 24 h. The cells were then cultured for another 24 h with medium only, cholera(More)
Intraoral pressure measurements were made during multiple productions of the word "hamper" by each of 267 patients who manifested differing degrees of velopharyngeal inadequacy. The results indicate that intraoral pressure diminishes as the extent of velopharyngeal impairment increases. However, pressure remained above 3 cm H2O in the majority of subjects,(More)
This study examines the relationship between facial morphology and nasal respiration. Nasal resistance to expiratory airflow, average volume flow rate, and temporal characteristics of the respiratory cycle were measured for twenty-eight adults. Subjects were categorized as having (1) normal facial proportions with competent lips (n = 10), (2) normal facial(More)