Robert Mayo

Hypernasality and Velopharyngeal Impairment

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.

Nasalance and nasal area values: cross-racial study.

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 relationship between spectral characteristics and perceived hypernasality in children

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 childrens 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].

Effects of short-term endotracheal intubation on vocal function

Transient voice change associated with endotracheal intubation has generally been attributed to vocal fold trauma. To assess the role of altered vocal fold function in transient voice change, a study was designed to evaluate the audio‐acoustic, endoscopic, and laryngostroboscopic characteristics of the postintubation voice. Vocal function of 10 patients undergoing short‐term outpatient surgical procedures using general anesthesia and endotracheal intubation were studied preoperatively and postoperatively. A second group of 10 patients that did not have surgery or general anesthesia was used as an age‐matched control. Fundamental frequency, frequency perturbation, electroglottography, en‐doscopy (including laryngeal stroboscopy), and subjective speech analysis by experienced listeners were used to assess vocal function.

AERODYNAMICS OF NASALIZATION

Publisher Summary The pressure and airflow patterns associated with various sounds differ as a result of the characteristic postures assumed by vocal tract structures during their production. These postures also determine, to a great extent, how the sounds are perceived by the listener. For example, normal nasalization during the production of /m/, /n/, and /η/ occurs when the velopharyngeal orifice is open and the nasal airway is patent. Air flows through the nasal cavity, and the sounds that are produced are perceived by the listener as nasal. This chapter reviews the aerodynamics associated with normal nasal resonance, excessive nasal resonance, and reduced nasal resonance. The chapter describes the way the nose and velopharyngeal mechanism affect the aerodynamics of nasalization; however, the components of the speech system do not function in isolation. That is, speech structures interact in a coordinated fashion, and the changes in one structure ultimately affect other structures as well.

The Influence of Acoustic and Perceptual Factors on Perceived Hypernasality in the Vowel [i]: A Preliminary Study

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.

Dyspnea following Experimentally Induced Increased Nasal Airway Resistance

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 individuals 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.

Respiratory Responses to Sudden Pressure Venting during Stop Consonant Production

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.

Perceptual Assessment of Resonance Distortion in Unoperated Clefts of the Secondary Palate

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 relationship between spectral properties and perceptual evaluation of hypernasality in children with cleft palate—vowel /i/

The purpose of this study was to examine the relationship between spectral characteristics and the perceptual evaluation of hypernasality in speakers with cleft palate. Speech samples from 32 cleft palate patients (average age 9.3 years) and 5 normal subjects (average age 9.4 years) were used in this study. The isolated vowel /i/ produced by each subject was filtered using 16 one‐third octave bandpass filters from 200 Hz to 6.3 kHz to obtain a 1/3 octave spectrum. These spectra were normalized using the total power level of the 16 1/3 octave bands. Three sophisticated listeners rated the speech samples using a six‐point equal‐appearing interval scale. Average spectra obtained from the hypernasal and the normal groups were compared. Spectral characteristics of hypernasality in the vowel /i/ were identified as a rise in power level between the first formant (F1) and the second formant (F2) and a rise in power level of F1. Multiple regression analysis revealed a high correlation (r=0.81) between the averaged...