Donald W. Warren

University of North Carolina at Chapel Hill, North Carolina, United States

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Publications (74)72.28 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 = 14) that received inconsistent ratings from each listener or variable ratings among listeners (i.e., unreliable ratings) and (2) the samples (n = 14) that received consistent ratings from each listener and similar ratings among listeners (i.e., reliable ratings). These results suggest that the severity of hypernasality was easy to rate in some speech samples and not in others. Voice quality deviation and a particular type of spectral change that related to the severity of hypernasality could be factors that influence perceived hypernasality.
    Folia Phoniatrica et Logopaedica 07/2001; 53(4):198-212. DOI:10.1159/000052675 · 0.55 Impact Factor
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    ABSTRACT: 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 the average 1/3-octave spectra from the hypernasal group and the normal resonance group were compared, spectral characteristics of hypernasality were identified as increased amplitudes between F1 and F2 and decreased amplitudes in the region of F2. Based on the findings of the children's speech, 36 speech samples with manipulated spectral characteristics were used to minimize the influences of voice source characteristics on perceived hypernasality. Multiple regression analysis revealed a high correlation (R = 0.84) between the amplitudes of 1/3-octave bands (1 k, 1.6 k, and 2.5 kHz) and the perceptual ratings. Increased amplitudes of bands between F1 and F2 (1 k, 1.6 kHz) and decreased amplitude of the band of F2 (2.5 kHz) was associated with an increasing perceived hypernasality. These results suggest that the amplitudes of the three 1/3-octave bands are appropriate acoustic parameters to quantify hypernasality in the isolated vowel [i].
    The Journal of the Acoustical Society of America 06/2001; 109(5 Pt 1):2181-9. DOI:10.1121/1.1360717 · 1.56 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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 = 14) that received inconsistent ratings from each listener or variable ratings among listeners (i.e., unreliable ratings) and (2) the samples (n = 14) that received consistent ratings from each listener and similar ratings among listeners (i.e., reliable ratings). These results suggest that the severity of hypernasality was easy to rate in some speech samples and not in others. Voice quality deviation and a particular type of spectral change that related to the severity of hypernasality could be factors that influence perceived hypernasality.
    Folia Phoniatrica et Logopaedica 01/2001; 53(4):198-212. · 0.55 Impact Factor
  • D J Zajac, D W Warren
    Journal of Speech Language and Hearing Research 01/2001; 43(6):1532-4. DOI:10.1044/jslhr.4306.1532 · 1.93 Impact Factor
  • Andrew P. Lane, Amelia F. Drake, Donald W. Warren
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    ABSTRACT: The purpose of this study is to determine the effect of histamine-induced nasal congestion on nasal airflow and the perception of externally applied resistance to nasal breathing. Nasal cross-sectional area and nasal airflow during free breathing were measured in 15 adult subjects before and after histamine challenge. The threshold for perception of resistance to nasal breathing was determined using a dynamic perturbator device, with both free breathing and controlled nasal air-flow. The average threshold for perception of nasal resistance was 0.383 Pa/cm3/s at baseline. After histamine application, there was a significant decrease in nasal cross-sectional area (p = 0.0001), associated with a decrease in nasal airflow (r = 0.6). The average threshold of perception increased to 1.373 Pa/cm3/s (p < 0.0001). When nasal airflow was controlled at the baseline rate, the threshold of perception improved to 0.638 Pa/cm3/s (p = 0.024). These findings indicate that nasal congestion causes a reduction in both nasal airflow and the perception of resistance to nasal breathing. The ability to detect nasal airway impairment is improved with increased nasal airflow. An improved understanding of the physiology of the subjective perception of nasal patency may lead to innovative methods for the treatment of nasal obstruction.
    American Journal of Rhinology 01/2000; 14(1):1-5. DOI:10.2500/105065800781602876 · 1.36 Impact Factor
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    ABSTRACT: Twenty healthy adults, age range 20-55 years, participated in a study to assess the responses of the upper airway to sudden, unanticipated pressure venting during speech production. A computer was used to open or close a valve in a random fashion during one of two productions of the word 'hamper'. The SAR System (Microtronics Corp., Chapel Hill, N.C., USA) was used to collect and monitor respiratory variables associated with speech production. Results indicated no significant changes in duration between vented and unvented conditions. Although intraoral pressure was reduced under vented conditions, the magnitude was sufficient for sound generation. Respiratory effort increased when the airway was suddenly vented, suggesting a compensatory response to experimental perturbation. However, the response contrasted somewhat from what has been observed in patients with velopharyngeal inadequacy, indicating that the strategy used may be different.
    Folia Phoniatrica et Logopaedica 02/1999; 51(6):250-60. DOI:10.1159/000021521 · 0.55 Impact Factor
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    Robert Mayo, Donald W. Warren, David J. Zajac
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    ABSTRACT: The objective of this study was to determine the influence of velopharyngeal (VP) inadequacy on respiratory speech compensations. The pressure-flow technique was used to measure pressure, airflow, and timing variables associated with VP closure during the production of the initial plosive consonant /p/ in a series of the utterance "papa." The study was conducted in the speech and breathing laboratory of the UNC Craniofacial Center. Eighty-two subjects with cleft lip and/or palate were assessed. The subjects were divided into two groups, those with adequate VP closure (VP size <.010 cm2) and those with inadequate VP closure (VP size >0.10 cm2). The adequate group was comprised of 62 subjects, and 20 subjects were categorized as inadequate. Peak intraoral pressure decreased in the inadequate group, but the difference was not significant. Nasal airflow increased (p < .01), but duration of the pressure pulse was the same for both groups. The area under the pressure curve decreased for the inadequate group (p = .04). These data contrast with previously reported published data using /p/ in the utterance "hamper." This suggests that phonetic context influences the compensatory response to velopharyngeal inadequacy. Additionally, while the findings are somewhat similar to studies that involved noncleft subjects whose oral airway was suddenly vented during the production of /p/, there is enough difference to suggest that learning also affects the compensatory outcome.
    The Cleft Palate-Craniofacial Journal 07/1998; 35(4):299-303. DOI:10.1597/1545-1569(1998)035<0299:IPAVF>2.3.CO;2 · 1.24 Impact Factor
  • The Journal of the Acoustical Society of America 01/1998; 103(5). DOI:10.1121/1.421811 · 1.56 Impact Factor
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    ABSTRACT: 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 bite blocks and bleed valves are used to vent airway pressures. The purpose of the present study was to determine the sensitivity of the monitoring system psychophysically and to assess its physiological response to sudden, unanticipated perturbations. Twenty adults were asked to produce the utterance/pa/, and a calibrated perturbator valve permitted air to escape from the oral cavity on randomly selected productions. Respiratory responses were recorded using PERCI-SARS instrumentation. The results indicated that sudden openings of 0.14 cm2 (SD = 0.04) were detected by speakers. Compensatory respiratory responses to suprathreshold pressure-venting occurred rapidly (i.e., 27 ms [SD = 8]) after valve opening. Although peak pressure and area under the pressure pulse fell with valve opening, the magnitude of pressure was nevertheless sufficient for sound generation. Measurements of the slope of the rise in intraoral pressure after subthreshold pressure-venting in 10 participants were compared to measurements obtained from an-elastic model of the upper airway. The data demonstrated a significant difference between vented and unvented conditions for the model, but not the participants. This suggests that elastic recoil is actively and unconsciously controlled in humans to compensate for losses in airway pressure during speech.
    Journal of Speech Language and Hearing Research 09/1997; 40(4):848-57. DOI:10.1044/jslhr.4004.848 · 1.93 Impact Factor
  • Donald W. Warren, Robert Mayo, David J. Zajac, A H Rochet
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    ABSTRACT: Nasal resistance (NRZ) values for healthy adults range from 1.0 to 3.5 cm H2O/L/sec. Some oral breathing tends to occur at values above 3.5. The purpose of the present study was to determine at what level of NRZ individuals sense that nasal breathing is difficult. A diaphragm was used to add four different resistance loads in random to 15 adult subjects. These loads were 5,8, and 15 cm H2O/L/sec and a value 40% above the individual's normal NRZ. Loads were added under four conditions: normal breathing, fixed flow rate, fixed breathing rate, and fixed flow and breathing rate. The pressure-flow technique was used to measure NRZ under all conditions. The study revealed that the sensation of breathing difficulty occurred at a median resistance of 5 cm H2O/L/sec and, as subjects were constrained to maintain fixed flow and breathing rates, the magnitude of RZ, at which the sensation of dyspnea was noted, decreased. The values observed in this study support previous findings suggesting that individuals switch to some oral breathing to maintain an adequate level of upper airway resistance at values between 3.5 and 4.5 cm H2O/L/sec. The findings also show that individuals attempt to minimize increases in airway resistance by modifying breathing behaviors.
    The Cleft Palate-Craniofacial Journal 06/1996; 33(3):231-5. DOI:10.1597/1545-1569(1996)033<0231:DFEIIN>2.3.CO;2 · 1.24 Impact Factor
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    ABSTRACT: Nasometry and nasal cross-sectional area data were obtained from 80 normal male and female speakers (40 African-Americans and 40 white Americans) all of whom were over the age of 18 and spoke the Mid-Atlantic dialect of American English. The nasalance scores for readings of the Zoo Passage did not differ significantly between the groups. However, nasalance scores for readings of the Nasal Sentences were found to be significantly higher among the white speakers. The pressure-flow method was used to obtain nasal cross-sectional area values. There were no racial differences in nasal cross-sectional area. The Nasal Sentences scores were not highly correlated with nasal cross-sectional area. The clinical significance of these findings is discussed.
    The Cleft Palate-Craniofacial Journal 04/1996; 33(2):143-9. DOI:10.1597/1545-1569(1996)033<0143:NANAVC>2.3.CO;2 · 1.24 Impact Factor
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    ABSTRACT: The hypothesis that upper airway breathing behaviors generally follow the rules of a physiologic regulating system implies the existence of sensors that monitor the airway environment. The purpose of this study was to assess the sensitivity of the monitoring system to sudden changes in airway patency in healthy, adult subjects. An instrument capable of changing airway dimensions in about 10 ms was used to assess psychophysical recognition and physiologic responses to sudden changes in airway size. Our results indicate that psychophysical recognition of change in patency occurred at a mean constriction area of 0.31 cm2. These findings suggest that recognition of change in airway size occurs well before the airway becomes flow-limiting or severely obstructed.
    The Cleft Palate-Craniofacial Journal 10/1995; 32(5):390-3. DOI:10.1597/1545-1569(1995)032<0390:MNAOAP>2.3.CO;2 · 1.24 Impact Factor
  • Maija T. Laine, Donald W. Warren
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    ABSTRACT: The purpose of the present study was to assess breathing behavior under various nasal resistance load conditions and, in particular, to determine whether respiratory responses to added nasal resistance loads occur before the threshold perception of an added load. The participants were 40 older adults who ranged in age from 59 to 82 years. Nasal airflow and resistance were measured with the pressure-flow technique, which was modified to create calibrated resistance loads. Statistical analyses revealed a significant decrease in airflow rate and volume during load conditions both before perceptual detection and at detection of increased resistance in comparison to a "no load" condition. No differences in respiratory behaviors were found between the load condition just before perceptual detection of an increased resistance load and the load condition at detection. The present findings suggest that physiologic responses to changes in the airway environment apparently occur even before there is perceptual recognition that the environment has changed.
    The Laryngoscope 05/1995; 105(4 Pt 1):425-8. DOI:10.1288/00005537-199504000-00016 · 2.03 Impact Factor
  • Donald W. Warren
    Journal of Oral and Maxillofacial Surgery 09/1994; 52(9):930. DOI:10.1016/S0278-2391(10)80071-0 · 1.28 Impact Factor
  • Donald W. Warren, Rodger M. Dalston, Robert Mayo
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    ABSTRACT: Although the primary cause of hypernasality is impaired velopharyngeal (VP) function, a variety of other factors influence the outcome perceived by the listener. The purpose of the current study was to assess the relationship between oral-nasal resonance balance and (1) velopharyngeal orifice area; (2) nasal airflow rate; and (3) duration of nasal airflow. The pressure-flow technique was used to estimate VP area and measure nasal airflow rate and duration. Ratings of oral-nasal balance were made on a 6-point equal-appearing interval scale. Results indicated a moderate correlation between hypernasality rating and VP area (0.66), nasal airflow (0.61), and nasal airflow duration (0.53). Adults tended to be perceived as more hypernasal than children for a given degree of VP impairment. Finally, when the degree of VP opening was small, perceived oral-nasal resonance balance appeared to be related to duration of the opening-closing movements.
    The Cleft Palate-Craniofacial Journal 08/1994; 31(4):257-62. DOI:10.1597/1545-1569(1994)031<0257:HAVI>2.3.CO;2 · 1.24 Impact Factor
  • D W Warren, J C Walker, A F Drake, R W Lutz
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    ABSTRACT: A technique that combines psychophysical measurements with continuous recording of nasal patency and respiratory behavior was used to study the psychophysical and respiratory responses of 10 subjects to well-controlled stimulation with three compounds differing in relative stimulatory effectiveness for nasal olfactory and trigeminal chemoreceptors. All four concentrations of acetic acid, amyl acetate, and phenethyl alcohol were well above the odor detection threshold. The magnitudes of both the increase in odor strength and nasal irritation and the decreases in tidal volume were greatest for acetic acid and least for phenethyl alcohol. Among the odorants, differences in nasal irritation were greater than those in odor strength, and tidal volume appeared to have a reasonably close and inverse relationship to nasal irritation.
    The Laryngoscope 06/1994; 104(5 Pt 1):623-6. · 2.03 Impact Factor
  • David L. Witsell, Amelia F. Drake, Donald W. Warren
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    ABSTRACT: Seven patients who received pharyngeal flaps for velopharyngeal incompetence (VPI) were studied to assess the effect of the procedure on nasal airway size. The findings suggest that the pharyngeal flap does not significantly decrease the upper airway in all patients. The effect of the flap did not correlate with the type of cleft, and was most pronounced in the inspiratory phase of the breathing cycle. Reasons for this variable effect, assumed to be related to an already impaired nasal airway in most cleft patients, are discussed.
    The Laryngoscope 02/1994; 104(1 Pt 1):12-5. DOI:10.1288/00005537-199401000-00004 · 2.03 Impact Factor
  • D W Warren, A F Drake
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    ABSTRACT: Clefts of the lip and palate frequently produce nasal deformities that tend to reduce the size of the nasal airway. Surgical correction of nasal, palatal, and pharyngeal structures may compromise breathing further. A significant number of individuals with cleft noses mouthbreathe to some extent because of the high prevalence of airway compromise.
    Clinics in Plastic Surgery 11/1993; 20(4):769-79. · 1.35 Impact Factor
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    Robert Mayo, Rodger M. Dalston, Donald W. Warren
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    ABSTRACT: The purpose of this study was to examine the frequency with which five speech-language pathologists made judgments of hypernasality during the clinical assessment of young children with unoperated and repaired clefts of the secondary palate. Among the 293 nonsyndromic patients with secondary palate clefts included in this study, 219 were between 1 and 2 years of age. Of those, 83 had undergone primary palatoplasty whereas 136 had not. The remaining 74 children were between the ages of 4 and 5 years and presented with repaired secondary palatal clefts. The results showed that the clinicians were unable or unwilling to assess hypernasality in 31% of the 1 to 2 year old children with unoperated clefts. The same clinicians failed to evaluate oral-nasal resonance balance in only 12% of the children in the 1- to 2-year age group who had undergone palate repair. Only 1 of the 74 older children (1.4%) was not evaluated for hypernasality. Possible explanations for these findings are presented and discussed.
    The Cleft Palate-Craniofacial Journal 08/1993; 30(4):397-400. DOI:10.1597/1545-1569(1993)030<0307:PAORDI>2.3.CO;2 · 1.24 Impact Factor
  • Donald W. Warren
    Journal of Oral and Maxillofacial Surgery 08/1993; 51(8):856. DOI:10.1016/S0278-2391(10)80102-8 · 1.28 Impact Factor

Publication Stats

969 Citations
72.28 Total Impact Points

Institutions

  • 1981–2001
    • University of North Carolina at Chapel Hill
      • • Department of Dental Ecology
      • • Department of Otolaryngology/Head and Neck Surgery
      • • Department of Surgery
      • • School of Dentistry
      North Carolina, United States