Effects of computer system and vowel loading on measures of nasalance

Differences in velopharyngeal pressures during speech sound production in patients with unilateral cleft lip and palate (UCLP) and healthy individuals

Background

During articulation the velopharynx needs to be opened and closed rapidly and a tight closure is needed. Based on the hypothesis that patients with cleft lip and palate (CLP) produce lower pressures in the velopharynx than healthy individuals, this study compared pressure profiles of the velopharyngeal closure during articulation of different sounds between healthy participants and patients with surgically closed unilateral CLP (UCLP) using high resolution manometry (HRM).

Materials and methods

Ten healthy adult volunteers (group 1: 20-25.5 years) and ten patients with a non-syndromic surgically reconstructed UCLP (group 2: 19.1-26.9 years) were included in this study. Pressure profiles during the articulation of four sounds (/i:/, /s/, /ʃ/ and /n/) were measured by HRM. Maximum, minimum and average pressures, time intervals as well as detection of a previously described 3-phase-model were compared.

Results

Both groups presented with similar pressure curves for each phoneme with regards to the phases described and pressure peaks, but differed in total pressures. An exception was noted for the sound /i:/, where a 3-phase-model could not be seen for most patients with UCLP. Differences in velopharynx pressures of 50% and more were found between the two groups. Maximum and average pressures in the production of the alveolar fricative reached statistical significance.

Conclusions

It can be concluded that velopharyngeal pressures of patients with UCLP are not sufficient to eliminate nasal resonance or turbulence during articulation, especially for more complex sounds. These results support a general understanding of hypernasality during speech implying a (relative) velopharyngeal insufficiency.

Normative nasalance scores in Chilean adults

PURPOSE

The present study is aimed towards determining and comparing normative nasalance scores in Chilean Spanish-speaking adult men and women.

METHODS

40 women (age range 18 to 35, X = 25.79, SD = 5.83) and 36 men (age range 18 to 35, X = 26.45, SD = 4.08) were invited to participate, all of them without any previous speech therapy, neurological pathologies, intellectual deficits, hearing loss, syndromes, or other diagnosed pathologies that could impact speech production.A study of proper velopharyngeal function was performed, using a perceptual resonance evaluation. Nasalance was determined using a model 6450 Nasometer, during the reading of three standardized speech samples in Spanish: a nasal passage (NP), an oronasal passage (ONP), and an oral passage (OP). Also, the nasalance distance was calculated. Genders were compared using Wilcoxon tests for independent samples.

RESULTS

The NP presented the highest percentage of nasalance, with 52.13% (± 4.73), followed by the ONP with 25.38% (± 3.7), and finally the OP, which presented the lowest value of 14.15% (± 5.03). Meanwhile, nasalance distance was 37.98% (± 5.32). Finally, no significant differences were observed when comparing the nasalance between genders (p >0.05).

CONCLUSION

The nasalance values obtained were similar to those observed for other Spanish speakers. Also, male and women showed similar scores. The results of this study are a contribution to the indirect assessment of velopharyngeal function in Chilean adults.

Tratamiento de la nasalidad transpalatal en un caso complejo con trastorno fonológico

Se presenta el proceso de evaluación e intervención logopédica en una niña de 9 años con hipernasalidad y dificultades fonológicas perceptivas y expresivas. Se evalúo el nivel fonético y fonológico del lenguaje, el timbre nasal mediante nasometría, la integridad funcional de las estructuras velopalatofaríngeas y la audición. La paciente pronunciaba los sonidos [d], [l] y [t] muy distorsionados y con características de [n], al tiempo que no era capaz de distinguirlos de la consonante nasal. La configuración de su cavidad oral y su base articulatoria idiosincrática favorecía el fenómeno de nasalidad transpalatal: presencia excesiva de resonancia nasal durante la emisión de sonidos no nasales en ausencia de disfunción velofaríngea. Para el abordaje de la hipernasalidad se aplicó un tratamiento intensivo con la herramienta de biofeedback visual Nasometer II, como recomienda la literatura existente para los casos de nasalidad de origen funcional. El tratamiento fue eficaz para el control voluntario de la reducción de la hiperrinolalia, pero no fue efectivo debido a que la paciente no fue capaz de reducir el timbre nasal en el uso espontáneo del habla.

Nasalance Scores as a Function of Skeletal Malocclusion of English-Speaking Adults in the North Indian Population

OBJECTIVE

The objective of this study is quantitative assessment of nasalance for skeletal Class I (normative values), Class II, and III malocclusion in the English language for the North Indian population and to compare the normative values with the nasalance scores obtained from individuals with skeletal Class II and III malocclusion and to evaluate the normative values as a function of gender.

MATERIAL AND METHODS

The study was conducted on a total sample of 200 patients with 100, 50, and 50 in group 1 (control group, Skeletal Class I), group 2 (Skeletal Class II), and group 3 (Skeletal Class III), respectively. ANB angle (anteroposterior angle formed by point A, nasion, and point B) measured on lateral cephalogram was used to categorize the patients into 3 groups. The normative nasalance scores were compared for males and females in the control group. The nasalance scores of skeletal Class II and III subjects were compared to the combined normative scores of the control group. The NasalView was used for the objective assessment of nasalance. Oral syllables (/pa/and/pi/), nasal syllables (/ma/and/mi/), and 3 passages (Zoo passage, Rainbow passage, and Nasal sentences) were used to determine the nasalance scores.

RESULTS

The intragroup comparison of nasalance scores in group 1 showed statistically significant differences for different stimuli. The gender-related comparison showed no statistically significant differences in nasalance scores. The intergroup comparison of nasalance scores for skeletal malocclusion showed no statistically significant differences for different stimuli except statistically significant lower nasalance values for nasal sentences in group 3 compared to the control group.

CONCLUSION

The study concluded that the nasalance scores for nasal sentences in skeletal Class III malocclusion were significantly lower than in the control group and were not statistically significant between the 3 groups for all other stimuli.

Measurement of Nasalance Scores Without Touching the Philtrum for Better Comfort During Speech Assessment and Therapy: A Preliminary Study

OBJECTIVE

The Kay Pentax nasometer uses a separator plate that touches the philtrum of a patient to separate the nasal and oral sound energies for nasalance measurement. However, the separator plate can restrict the natural movement of the patient's upper lip and generate unpleasant pressure on the patient's philtrum. The present study was intended to measure nasalance scores without touching the philtrum for better comfort during speech assessment and therapy.

METHODS

Nasalance scores of 10 males and 10 females having no speech disorders were measured under 4 levels (0, 5, 10, and 15 mm) of the gap between the plate and the philtrum (denoted as plate-to-philtrum gap) using Nasometer II 6450 for nasal (Nasal Sentences) and oral (Zoo Passage) stimuli. Regression formulas were established to examine the relationships between nasalance score and plate-to-philtrum gap for the stimuli. To provide nasalance scores equivalent to those measured for the contact condition, compensation factors for the 5 mm plate-to-philtrum gap measurement condition were identified for the stimuli.

RESULTS

The nasalance scores were significantly different between the 4 different plate-to-philtrum gaps for the stimuli. Compensation factors for the Nasal Sentences and the Zoo Passage were identified as 1.17 and 0.71, respectively.

CONCLUSIONS

The 5 mm plate-to-philtrum gap condition after multiplying the compensation factors can provide equivalent nasalance scores to the conventional contact measurement condition which may provide better comfort in speech assessment and therapy.

Immediate effects of voice focus adjustments on hypernasal speakers' nasalance scores

OBJECTIVES

To explore the immediate effects of voice focus adjustments on the oral-nasal balance of hypernasal speakers, measured with nasalance scores.

METHODS

Five hypernasal speakers (2 M, 3 F) aged 5-12 (SD 2.7) learned to speak with extreme forward and backward voice focus. Speakers repeated oral, nasal, and phonetically balanced stimuli. Nasalance scores were collected with the Nasometer 6450.

RESULTS

From the average baseline of 34.27% for the oral stimulus, nasalance increased to 46.07% in forward and decreased to 30.2% in backward focus. From the average baseline of 64.53% for the nasal stimulus, nasalance decreased to 64.13% in forward and decreased to 51.73% in backward focus. From the average baseline of 51.33% for the phonetically balanced stimulus, nasalance increased to 58.87% in forward and decreased to 46.2% in backward focus.

CONCLUSIONS

Forward voice focus resulted in higher and backward voice focus resulted in lower nasalance scores during speech for a group of hypernasal speakers. However, there was an exception: One male speaker showed decreased nasalance in forward voice focus. Future research should investigate the longer-term effectiveness of the intervention.

Differences in nasalance and nasality perception between Texas South and Midland dialects

While previous research has primarily concerned the dialectal influence on speakers' production of oral-nasal balance, quantitatively represented by nasalance, information on cross-dialectal variation in nasality perception is limited. This study investigated the effects of speakers'/listeners' dialectal background on oral-nasal balance characteristics estimated by nasalance, as well as nasality perception measured by direct magnitude estimation with modulus. Represented by two geographically distinct regions, Texas South and Midland dialects were of special interest given that the two dialects lie at opposite ends of normal nasalance variation [Awan, Bressmann, Poburka, Roy, Sharp, and Watts. (2015). J. Speech Lang. Hear. Res. 58, 69-77]. Mean nasalance of various speech stimuli and direct magnitude estimation ratings on synthesized vowel stimuli with varying degrees of simulated nasalization were obtained from 62 participants (31 Texas South, 31 Midland). The results revealed that the two dialectal groups significantly differed in nasalance scores and nasality ratings, with Texas South exhibiting higher nasalance for standardized passage readings and assigning higher nasality ratings on the synthetic auditory stimuli than Midland. These findings indicate that, in addition to production variations of oral-nasal balance characteristics, perceptual variations of nasality exist at a dialectal level.

Influence of Altered Auditory Feedback on Oral-Nasal Balance in Speakers of Brazilian Portuguese

Purpose This study explored the role of auditory feedback in the regulation of oral-nasal balance in speakers of Brazilian Portuguese. Method Twenty typical speakers of Brazilian Portuguese (10 male, 10 female) wore a Nasometer headset and headphones while continuously repeating stimuli with oral and nasal sounds. Oral-nasal balance was quantified with nasalance scores. The signals from 2 additional oral and nasal microphones were played back to the participants through the headphones. The relative loudness of the nasal channel in the mix was gradually changed, so that the speakers heard themselves as more or less nasal. Results A repeated-measures analysis of variance of the mean nasalance scores of the stimuli at baseline, minimum, and maximum nasal feedback conditions demonstrated significant effects of nasal feedback condition (p < .0001) and stimuli (p < .0001). Post hoc analyses demonstrated that the mean nasalance scores were lowest for the maximum nasal feedback condition. The scores of the minimum nasal feedback condition were significantly higher than 2 of 3 baseline feedback conditions. The speaking amplitude of the participants did not change between the nasal feedback conditions. Conclusions Increased nasal signal level feedback led to a compensatory adjustment in the opposite direction, confirming that oral-nasal balance is regulated by auditory feedback. However, reduced nasal signal level feedback resulted in a compensatory response that was lower in magnitude. This suggests that, even in Brazilian Portuguese, a language with phonetic and phonological vowel nasalization, decreased nasality was not perceived as critically as increased nasality by the speakers.

Effect of vowel context on test-retest nasalance score variability in children with and without cleft palate

OBJECTIVE

The purpose of this study was to determine whether test-retest nasalance score variability differs between Korean children with and without cleft palate (CP) and vowel context influences variability in nasalance score.

PARTICIPANTS

Thirty-four 3-to-5-year-old children with and without CP participated in the study.

METHODS

Three 8-syllable speech stimuli devoid of nasal consonants were used for data collection. Each stimulus was loaded with high, low, or mixed vowels, respectively. All participants were asked to repeat the speech stimuli twice after the examiner, and an immediate test-retest nasalance score was assessed with no headgear change.

RESULTS

Children with CP exhibited significantly greater absolute difference in nasalance scores than children without CP. Variability in nasalance scores was significantly different for the vowel context, and the high vowel sentence showed a significantly larger difference in nasalance scores than the low vowel sentence. The cumulative frequencies indicated that, for children with CP in the high vowel sentence, only 8 of 17 (47%) repeated nasalance scores were within 5 points.

CONCLUSIONS

Test-retest nasalance score variability was greater for children with CP than children without CP, and there was greater variability for the high vowel sentence(s) for both groups.

Nasalization Amplitude-Timing Characteristics of Speakers With and Without Cleft Palate

OBJECTIVES

To examine the amplitude-temporal relationships of acoustic nasalization in speakers with a range of nasality and to determine the extent to which each domain independently predicts the speaker's perceived oral-nasal balance.

DESIGN

Rate-controlled speech samples, consisting of /izinizi/, /azanaza/, and /uzunuzu/, were recorded from 18 participants (14 with repaired cleft palate and 4 without cleft palate) using the Nasometer. The mean nasalance of the entire mid-vowel-nasal consonant-vowel (mid-VNV) sequence (amplitude-domain) and the duration of the nasalized segment of the mid-VNV sequence (temporal-domain) were obtained based on nasalance contours.

RESULTS

Strong linear and vowel-dependent relationships were observed between the 2 domains of nasalization (adjusted R² = 71.5%). Both the amplitude- and temporal-domain measures were found to reliably predict the speaker's perceived oral-nasal balance, with better overall model fit and higher classification accuracy rates observed in /izinizi/ and /uzunuzu/ than in /azanaza/. Despite poor specificity, the temporal-domain measure of /azanaza/ was found to have a strong correlation with the participants' Zoo passage nasalance scores (r_s = .897, p < .01), suggesting its potential utility as a severity indicator of perceived nasality.

CONCLUSIONS

With the use of relatively simple speech tasks and measurements representing the amplitude and temporal domains of nasalization, the present study provided practical guidelines for using the Nasometer in assessing patients with oral-nasal resonance imbalance. Findings suggest that both domain measures of nasalization should be examined across different vowel contexts, given that each domain may provide clinically relevant, yet different, information.

Validity of test stimuli for nasalance measurement in speakers of Jordanian Arabic

OBJECTIVE

The objective of the study was to establish the validity of passages for measuring nasalance of Jordanian speakers of Arabic.

DESIGN

Two Arabic text passages were constructed; the Spring Passage is devoid of nasal consonants and the Home Passage contains both oral and nasal consonants. Nasalance was measured for participants while reciting each passage three times. Perceptual ratings of hypernasality were also obtained for each participant on each passage using a 5-point equal-appearing rating scale.

PARTICIPANTS

Forty-seven children and adults ranging in age between 9 and 26 years participated in the study. Twenty-three participants had no history of communication disorders, and 24 had repaired cleft palate.

RESULTS

Correlation coefficient between ratings of hypernasality and the nasalance scores was significant for the Spring Passage (r = 0.88, p > 0.001) and for the Home Passage (r = 0.78, p > .001). Using cutoff scores of 17% and 36% of nasalance for the Spring and the Home Passages, respectively, and a threshold score of 1.5 for hypernasality, sensitivity for the Spring Passage was 88% and the Home Passage was 78%.

CONCLUSIONS

Results showed the validity of the Spring Passage and the Home Passage in measuring nasalance scores as proved by their high sensitivity and strong correlation with perceptual rating of hypernasality.

Delayed primary palatal closure in resource-poor countries: Speech results in Ugandan older children and young adults with cleft (lip and) palate

AIMS

Unrepaired clefts still regularly occur in resource-poor countries as a result of limited health-care access. The purpose of the present study was to report resonance, airflow and articulation characteristics following delayed (≥8years) primary palatal closure.

METHODS

Fifteen Ugandan participants with cleft (lip and) palate (CP±L) were included as well as 15 age- and gender-matched Ugandan subjects without clefts. Palatal closure was performed at a mean age of 15;10 years using the Sommerlad technique. Speech evaluations were carried out on a single occasion postoperatively (mean age: 18;10 years). Resonance and nasal airflow were perceptually evaluated and detailed phonetic and phonological assessments were carried out. Additionally, nasalance values were determined.

RESULTS

Nasal emission occurred postoperatively in only 27% (4/15) of the patients, whereas resonance disorders and articulation errors were prevalent in 87% (13/15) of the patient group. Compared with the control group, a significantly higher prevalence of hypernasality and significantly higher nasalance values for all oral and oronasal speech samples were obtained in the CP±L group. Moreover, significantly smaller consonant inventories and significantly more phonetic and phonological disorders were observed.

CONCLUSIONS

Delayed palatal repair (≥8years) seems to be insufficient to eliminate nasal airflow errors, resonance abnormalities, and articulation disorders. In order to prevent patients' late presentation at specialized centers, the availability of high quality surgical cleft palate treatment should increase as well as people's awareness of the possibility and importance of early surgical intervention. Moreover, speech therapy following delayed palatal closure would be beneficial. Furthermore, a standardized and validated protocol for speech assessment in future studies is advocated.

Effects of Biofeedback on Control and Generalization of Nasalization in Typical Speakers

PURPOSE

The purpose of this study was to determine the effects of biofeedback on control of nasalization in individuals with typical speech.

METHOD

Forty-eight individuals with typical speech attempted to increase and decrease vowel nasalization. During training, stimuli consisted of consonant-vowel-consonant (CVC) tokens with the center vowels /a/ or /i/ in either a nasal or nonnasal phonemic context (e.g., /mim/ vs. /bib/), depending on the participant's training group. Half of the participants had access to augmentative visual feedback during training, which was based on a less-invasive acoustic, accelerometric measure of vowel nasalization-the Horii oral-nasal coupling (HONC) score. During pre- and posttraining assessments, acoustically based nasalance was also measured from the center vowels /a/, /i/, /æ/, and /u/ of CVCs in both nasal and nonnasal contexts.

RESULTS

Linear regressions indicated that both phonemic contexts (nasal or nonnasal) and the presence of augmentative visual feedback during training were significant predictors for changes in nasalance scores from pre- to posttraining.

CONCLUSIONS

Participants were able to change the nasalization of their speech following a training period with HONC biofeedback. Future work is necessary to examine the effect of such training in individuals with velopharyngeal dysfunction.

Short-term and long-term test-retest reliability of the Nasality Severity Index 2.0

PURPOSE

The Nasality Severity Index 2.0 (NSI 2.0) forms a new, multiparametric approach in the assessment of hypernasality. To enable clinical implementation of this index, the short- and long-term test-retest reliability of this index was explored.

METHODS

In 40 normal-speaking adults (mean age 32y, SD 11, 18-56y) and 29 normal-speaking children (mean age 8y, SD 2, 4-12y), the acoustic parameters included in the NSI 2.0 (i.e. nasalance of the vowel /u/ and an oral text, and the voice low tone to high tone ratio (VLHR) of the vowel /i/) were obtained twice at the same test moment and during a second assessment two weeks later. After determination of the NSI 2.0, a comprehensive set of statistical measures was applied to determine its reliability.

RESULTS

Long-term variability of the NSI 2.0 and its parameters was slightly higher compared to the short-term variability, both in adults and in children. Overall, a difference of 2.82 for adults and 2.68 for children between the results of two consecutive measurements can be interpreted as a genuine change. With an ICC of 0.84 in adults and 0.77 in children, the NSI 2.0 additionally shows an excellent relative consistency. No statistically significant difference was withheld in the reliability of test-retest measurements between adults and children.

CONCLUSION

Reliable test-retest measurements of the NSI 2.0 can be performed. Consequently, the NSI 2.0 can be applied in clinical practice, in which successive NSI 2.0 scores can be reliably compared and interpreted.

LEARNING OUTCOMES

The reader will be able to describe and discuss both the short-term and long-term test-retest reliability of the Nasality Severity Index 2.0, a new multiparametric approach to hypernasality, and its parameters. Based on this information, the NSI 2.0 can be applied in clinical practice, in which successive NSI 2.0 scores, e.g. before and after surgery or speech therapy, can be compared and interpreted.

Dialectical effects on nasalance: a multicenter, cross-continental study

PURPOSE

This study investigated nasalance in speakers from six different dialectal regions across North America using recent versions of the Nasometer. It was hypothesized that many of the sound changes observed in regional dialects of North American English would have a significant impact on measures of nasalance.

METHOD

Samples of the Zoo Passage, the Rainbow Passage, and the Nasal Sentences were collected from young adult male and female speakers (N=300) from six North American dialectical regions (Midland/Mid-Atlantic; Inland North Canada; Inland North; North Central; South; and Western dialects).

RESULTS

Across the three passage types, effect sizes for dialect were moderate in strength and accounted for approximately 7%-9% of the variation in nasalance. Increased differences in nasalance tended to occur between speakers from distinctly different geographical regions, with the highest nasalance across all passages observed for speakers from the Texas South dialect region.

CONCLUSION

Clinicians and researchers who use perceptual and instrumental measures of speech production should be aware that dialectical and socially acquired speech patterns may influence the acoustic characteristics of speech and may also influence the interpretation of normative expectations and typical versus disordered cutoff scores for instruments such as the Nasometer.

Effects of spectral content on Horii Oral-Nasal Coupling scores in children

A miniature accelerometer and microphone can be used to obtain Horii Oral-Nasal Coupling (HONC) scores to objectively measure nasalization of speech. While this instrumentation compares favorably in terms of size and cost relative to other objective measures of nasality, the metric has not been well characterized in children. Furthermore, the measure is known to be affected by vowel loading, as speech loaded with "high" vowels is consistently scored as more nasal than speech loaded with "low" vowels. Filtering the signals used in computation of the HONC score to better isolate the correlates of nasalization has been shown to reduce vowel-related effects on the metric, but the efficacy of filtering has thus far only been explored in adults. Here, HONC scores for running speech and the vowel portions of consonant-vowel-consonant tokens were calculated for the speech of 26 children, aged 4-9 yrs. Scores were computed using the broadband accelerometer and speech signals, as well as using filtered, low-frequency versions of these signals. HONC scores obtained using both broadband and filtered signals resulted in well-separated scores for nasal and non-nasal speech. HONC scores computed using filtered signals were found to exhibit less within-participant variability.

Comparison of nasal acceleration and nasalance across vowels

PURPOSE

The purpose of this study was to determine the performance of normalized nasal acceleration (NNA) relative to nasalance as estimates of nasalized versus nonnasalized vowel and sentence productions.

METHOD

Participants were 18 healthy speakers of American English. NNA was measured using a custom sensor, and nasalance was measured using the KayPentax Nasometer II. Speech stimuli consisted of CVC syllables with the vowels (//, /æ/, /i/, /u/) and sentences loaded with high front, high back, low front, and low back vowels in both nasal and nonnasal contexts.

RESULTS

NNA showed a small but significant effect of the vowel produced during syllable stimuli but no significant effect of vowel loading during sentence stimuli. Nasalance was significantly affected by the vowel being produced during both syllables and sentences with large effect sizes. Both NNA and nasalance were highly sensitive and specific to nasalization.

CONCLUSIONS

NNA was less affected by vowel than nasalance. Discrimination of nasal versus nonnasal stimuli using NNA and nasalance was comparable, suggesting potential for use of NNA for biofeedback applications. Future work to improve calibration of NNA is needed to lower intersubject variability.

Nasalance scores of children with repaired cleft palate who exhibit normal velopharyngeal closure during aerodynamic testing

PURPOSE

To determine if children with repaired cleft palate and normal velopharyngeal (VP) closure as determined by aerodynamic testing exhibit greater acoustic nasalance than control children without cleft palate.

METHOD

Pressure-flow procedures were used to identify 2 groups of children based on VP closure during the production of /p/ in the word hamper: (a) children with repaired cleft palate and normal VP closure ( n = 23) and (b) controls without cleft palate and with normal VP closure ( n = 16). Acoustic nasalance scores were obtained for all children during the production of syllables with high-pressure consonants and sentences with low-pressure consonants (i.e., low-pressure sentences).

RESULTS

Nasalance scores were generally higher for children with repaired cleft palate and normal VP function as compared to controls; however, a significant difference occurred only for low-pressure sentences ( p = .005).

CONCLUSION

Results partially support a pressure-sensitive theory of VP function in that some children with repaired cleft palate may achieve VP closure during the production of high-pressure consonants but fail to do so during the production of vowels and low-pressure consonants. Clinical implications are discussed.

Comparison of nasalance scores obtained with the nasometers 6200 and 6450

OBJECTIVE

The study had the goal of comparing the new Nasometer 6450 to the older model 6200 using synthetic test sounds and control participants. A particular focus of the investigation was on the test-retest variability of the instruments.

MATERIALS AND METHODS

The Nasometers 6200 and 6450 were compared using square wave test sounds. Six repeated measurements of oral, balanced, and nasal test stimuli were recorded from 25 female participants over an average of 35 days.

RESULTS

The synthetic test sounds demonstrated that the two nasometers obtained similar results for a range of frequencies. The results for the clinically normal participants revealed that nasalance scores from the two instruments were within 1-2 points, depending on the test sentence. Variability in scores increased with the proportion of nasal consonants in the sentence. Test-retest variability was between 6 and 8 points for more than 90% of the participants. Participants with higher nasalance scores for oral stimuli had higher between-session variability.

CONCLUSIONS

The Nasometers 6200 and 6450 should yield comparable results in clinical practice. Depending on the phonetic content of the test materials, clinicians should allow for a 6- to 8-point between-session variability when interpreting nasalance scores.

Nasometer 6200 Versus Nasometer II 6400: Effect on Measures of Nasalance

Objective :  This study compared measures of nasalance obtained using the Nasometer 6200 versus the Nasometer II 6400 in typically speaking young adult males and females for the nonnasal Zoo Passage, the phonetically balanced Rainbow Passage, and the Nasal Sentences. Design :  Participants read passages at a comfortable pitch and loudness twice while wearing Nasometer 6200 or Nasometer II 6400 headgear. The order of Nasometer system was counterbalanced across participants, and the order of the reading passage was randomized. Participants :  Participants consisted of 25 males (mean age = 21.22 years) and 25 females (mean age = 23.83 years). Main Outcome Measures :  The main outcomes measures were nasalance scores (%) obtained for each system × passage per participant. Results :  Results showed that the Nasometer 6200 and the Nasometer II 6400 differed significantly on mean nasalance for the Zoo Passage (mean difference = 7.15%) and the Rainbow Passage (mean difference = 3.05%) but not for the Nasal Sentences (mean difference = 0.77%). Intersystem correlations and measures of predictive accuracy indicated that the ability to predict Nasometer 6200 nasalance scores from Nasometer II 6400 scores was relatively weak. Conclusions :  In addition to such factors as age, gender, and regional dialect, normative nasalance expectations and normal versus disordered nasalance cutoff scores must be considered with full knowledge of the specific system that was used to acquire the nasalance data. Intrasubject changes in nasalance can only be validly assessed when test versus retest measurements have been acquired using the same nasalance system.

Normalization strategies for nasal acceleration to assess velopharyngeal function

Velopharyngeal function is essential for intelligible speech production, but can often be impaired. Current clinical care could be improved with the use of reliable and objective methods of assessment appropriate for home use. This paper explores the use of a combined nasal acceleration and acoustic sensor to assess velopharyngeal function. Speech production data in nasalized and non-nasalized contexts is recorded from N=6 healthy participants and three normalization strategies are assessed. Normalizing data to maximally nasal productions results in a reduction of between-speaker variability. Using a filtered speech signal can reduce the effects of intra-speaker variability caused be differences in loudness. The normalization strategies pursued show high discriminability of nasalization in vowels with an inexpensive sensor appropriate for home use.