Gillian de Boer

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.

Application of Linear Discriminant Analysis to the Long-term Averaged Spectra of Simulated Disorders of Oral-Nasal Balance.

Objective Acoustic studies of oral-nasal balance disorders to date have focused on hypernasality. However, in patients with cleft palate, nasal obstruction may also be present, so that hypernasality and hyponasality co-occur. In this study, normal speakers simulated different disorders of oral-nasal balance. Linear discriminant analysis was used to create a tentative diagnostic formula based on the long-term averaged spectra (LTAS) of the speech stimuli. Materials and Methods Eleven female participants were recorded while reading nonnasal and nasal speech stimuli. LTASs of the recordings were run for their normal oral-nasal balance and their simulations of hyponasal, hypernasal, and mixed oral-nasal balance. The amplitude values (in decibels) were extracted in 100-Hz intervals over a range of 4 kHz. Results A repeated-measures analysis of variance of the normalized amplitudes revealed a resonance condition–frequency band amplitude interaction effect (P < .001). A linear discriminant analysis of the participants’ LTAS led to formulas correctly classifying 80.7% of the oral-nasal balance conditions. Conclusion The simulations produced distinctive spectra enabling the creation of formulas that predicted the oral-nasal balance above chance level. Future research with speakers with oral-nasal balance disorders will be needed to investigate the potential of this approach for the clinical diagnosis of disorders of oral-nasal balance.

Normative Nasalance Scores for Brazilian Portuguese Using New Speech Stimuli.

Objective: Normative data were established for newly developed speech materials for nasalance assessment in Brazilian Portuguese. Materials and Methods: Nasalance scores of preexisting passages (oral ZOO-BR, low-pressure oral ZOO-BR2 and NASAL-BR), new nasalance passages (oral Dudu no zoológico, oral Dudu no bosque, oral-nasal O cãozinho Totó and nasal O nenê) and Brasilcleft articulation screening sentences were collected from 245 speakers of Brazilian Portuguese, including 121 males and 124 females, divided into 4 groups: children (5-9 years), adolescents (10-19 years), young adults (20-24 years) and adults (25-35 years). Results: Across all nasalance passages, adult females scored on average 2 percentage points higher than males. Children scored 2-4 percentage points lower than older groups for the preexisting nasalance passages ZOO-BR and ZOO-BR2. Nasalance scores for the new nasalance passages were not significantly different from the preexisting passages. Scores for high-pressure sentences did not differ significantly from the oral nasalance passage Dudu no bosque. Conclusion: The nasalance scores for the new nasalance passages were equivalent to the preexisting materials. The new shortened and simplified nasalance passages will be useful for assessing young children. Normative scores for the Brasilcleft high-pressure sentences were equivalent to the new oral passage Dudu no bosque.

Tongue displacement and durational characteristics of normal and disordered Brazilian Portuguese liquids.

ABSTRACT The goal of the present study was to characterize normal and disordered Brazilian Portuguese liquids. The research hypotheses were that disordered liquid sounds would be characterized by (1) longer syllable and segment durations, (2) larger and more undifferentiated displacement of the tongue and (3) that the speech errors would show sub-phonemic differences depending on the target sound. The participants of this study were 11 children with phonological disorders and 9 control participants matched for age and educational background. The children’s tongue movement in the sagittal plane was recorded with ultrasound. The speech stimuli consisted of 3 repetitions of 5 words representing the four Brazilian Portuguese liquids /l/, /ʎ/, /ɾ/ and /ʀ/ in the context of the vowel /a/. A panel of four listeners transcribed each of the productions and classified them as correct or incorrect. The outcome measures were based on duration (syllable duration, ratio L/V) and tongue displacement (percentage average displacement, anterior displacement, posterior displacement). Based on mixed model analyses of variance, the first research hypothesis was confirmed for the /l/ and /ɾ/ targets, but not for the /ʀ/ and /ʎ/ targets. The second hypothesis was partially confirmed. The third hypothesis was confirmed. The research serves to illustrate the effects of phonological disorder on the phonetic realisation of Brazilian Portuguese liquid sounds.

Influence of Altered Auditory Feedback on Oral–Nasal Balance in Speech

Purpose This study explored the role of auditory feedback in the regulation of oral-nasal balance in speech. Method Twenty typical female speakers wore a Nasometer 6450 (KayPentax) headset and headphones while continuously repeating a sentence 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. An additional amplitude control group of 9 female speakers completed the same task while hearing themselves louder or softer in the headphones. Results A repeated-measures analysis of variance of the mean nasalance scores of the stimulus sentence at baseline, minimum, and maximum nasal feedback conditions demonstrated a significant effect of the nasal feedback condition. Post hoc analyses found 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 the 3 baseline feedback conditions. The amplitude control group did not show any effects of volume changes on nasalance scores. Conclusions Increased nasal feedback led to a compensatory adjustment in the opposite direction, confirming that oral-nasal balance is regulated by auditory feedback. However, a lack of nasal feedback did not lead to a consistent compensatory response of similar magnitude.

Influence of voice focus on tongue movement in speech

ABSTRACT The present study evaluated global aspects of lingual movement during sentence production with backward and forward voice focus. Nine female participants read a sentence with a variety of consonants in a normal condition and with backward and forward voice focus. Midsagittal tongue movement was recorded with ultrasound. Tongue height over time at an anterior, a central, and a posterior measurement angle was measured. The outcome measures were speech rate, cumulative distance travelled, and average movement speed of the tongue. There were no differences in speech rate between the different conditions. The cumulative distance travelled by the tongue and the average speed indicated that the posterior tongue travelled a smaller cumulative distance and at a slower speed in the forward focus condition. The central tongue moved a larger cumulative distance and at a higher speed in the backward focus condition. The study offers first insights on how tongue movement is affected by different voice focus settings and illustrates the plasticity of tongue movement in speech.

Clinical Application of a New Approach to Identify Oral–Nasal Balance Disorders Based on Nasalance Scores

Objective: A new approach to classify oral–nasal balance disorders based on instrumental measurements was developed based on linear discriminant analysis (LDA) of nasalance scores of simulated oral–nasal balance disorders by de Boer and Bressmann. The current study aimed to apply the newly developed functions to clinical data to investigate the applicability of this new approach. Design: Retrospective diagnostic accuracy study. Setting: Tertiary university hospital. Participants: Fifty-five Dutch-speaking Flemish children (age 4-12 years) with normal (n = 20), hypernasal (n = 18), hyponasal (n = 12), or mixed nasality (n = 5). Interventions: Nasalance scores of an oral and a nasal text were used to calculate 3 sets of LDA function scores. Predicted classification was consecutively based on the function values of the group centroids originally determined by de Boer and Bressmann and adapted LDA functions and group centroids based on clinical data. Main Outcome Measures: Discriminatory power of the linear discriminant formulas. Results: Based on the original LDA functions, 56% of the speech samples matched the perceptual classification. Applying a correction factor for age and language differences resulted in a 67% correct classification, although 83% of the hyponasal samples were ranked as “normal resonance.” Rederivation of the LDA functions based on current clinical data resulted in an 80% correct classification. Conclusions: The new approach of classifying oral–nasal balance disorders based on a combination of nasalance scores was promising. However, further clinical research is needed to refine the LDA functions and group centroids before clinical application is possible.

Influence of Altered Auditory Feedback on Oral-Nasal Balance in Song

OBJECTIVES This study explored the role of auditory feedback in the regulation of oral-nasal balance in singing in trained singers and non-singers. STUDY DESIGN Experimental repeated measures study. METHODS Twenty non-singers (10M/10F) and 10 female professional singers sang a musical stimulus repeatedly while hearing themselves over headphones. Over the course of the experiment, the nasal level signal in the headphones was increased or decreased so that the participants heard themselves as more or less nasal. Nasalance scores in the different phases of the experiment were quantified using a Nasometer 6450. RESULTS A repeated measures analysis of variance demonstrated a significant main effect for singing condition F(5, 135) = 3.70, P < 0.05, and multiple comparison tests demonstrated that the nasalance scores for final baseline and the maximum and minimum nasal feedback conditions were all significantly lower than the first baseline (all comparisons P < 0.05). CONCLUSION There were no differences between the singers and non-singers. All participants had lower nasalance scores in response to both increased and decreased nasal signal level feedback.

Normative Nasalance Scores for Middle-Aged and Elderly Speakers of Brazilian Portuguese

Objectives: This study establishes normative nasalance values for middle-aged and elderly Brazilian Portuguese-speakers and investigates age and gender effects across the life span. Methods: Nasalance scores were obtained from 62 middle-aged (45–59 years) and 60 elderly (60–79 years) participants with normal speech for 3 nonnasal, 1 phonetically balanced, and 2 nasal-loaded test sentences using the Nasometer II 6400. The data were combined with a published data set of 237 speakers in 4 groups: children (5–9 years), adolescents (10–19 years), young adults (20–24 years), and mature adults (25–35 years). A repeated-measures analysis of variance was used to investigate differences between the stimuli by gender and age groups. Results: There were statistically significant effects of stimulus, gender, and age group, as well as a stimulus-age group interaction effect and a gender-age group interaction effect. The females’ mean nasalance scores were higher than those of the males. The mean nasalance scores for the child, adolescent, and young and mature adult speakers were significantly lower than those for the elderly speakers, and the children’s scores were significantly lower than those of the middle-aged speakers. Conclusion: Higher nasalance scores among middle-aged and elderly speakers may indicate physiological changes affecting oral-nasal balance in speech across the life span.

Influence of Voice Focus on Oral-Nasal Balance in Speech

OBJECTIVES The concept of voice focus describes the relationship of the vocal tract length on the perceived brightness or darkness of the speakers voice. The present study explored the impact of adjustments of the voice focus on oral-nasal balance. The vocal tract settings in question were backward focus (retracted tongue, wide pharynx, and lowered larynx) and forward focus (fronted tongue, constricted pharynx, and raised larynx). The backward focus condition was expected to decrease nasalance scores and the forward focus condition was expected to increase nasalance scores. STUDY DESIGN Experimental repeated-measures study. METHODS Sixteen females aged 23.78 (standard deviation 1.99) produced oral and nasal test sentences with a backward focus and a forward focus. Audio recordings and nasometry measurements were made. Nine of the participants completed the task successfully. RESULTS In a repeated-measures analysis of variance, the nasalance scores were compared across stimuli, speaking condition, and repetition. There was a main effect for stimuli (F = 109.37, P < 0.0001). In a follow-up analysis of variance we found a condition effect for the nasal stimulus (F = 17.91, P < 0.0001). For the nasal stimulus, the nasalance scores of the backward focus were lower, and the nasalance scores of the forward focus were higher than in the normal condition. CONCLUSIONS Changing the voice focus influenced oral-nasal balance more when the velopharyngeal port was open. Future studies should explore the possible treatment potential of voice focus for patients with hypernasality.