Robustness of lateral tongue bracing under bite block perturbation.

Lateral tongue bracing is a lingual posture in which the sides of the tongue are held against the palate and upper molars, and has been observed cross-linguistically. However, it is unknown whether lateral bracing makes adjustments to external perturbation like other body postures. The present study aims to test the robustness of lateral tongue bracing with three experiments. The first baseline experiment was an analysis of an electropalatogram database and the results showed lateral bracing being continuously maintained. The second experiment applied an external perturbation during speech production. A bite block was held between participants' teeth while intra-oral video was used to record contact between the sides of the tongue and upper molars during speech. The results indicated that lateral bracing was maintained most of the time during speech. The third experiment included simulations investigating the activation of tongue muscles relevant to lateral bracing at different degrees of jaw opening. The results show that bracing requires higher activation of bracing agonists and lower activation of bracing antagonists as jaw opening increases. Our results suggest that lateral tongue bracing is actively maintained and robust under external perturbation and further indicate it serves as an essential lingual posture during speech production.

F0-related head movement in blind versus sighted speakers.

This study investigated the relationship between head movement and fundamental frequency (F0) during speech by comparing continuous speech of congenitally blind and sighted speakers from YouTube videos. Positive correlations were found between F0 (measured in semitones) and vertical head movement for both speaker groups, with a stronger correlation for blind speakers. In addition, larger head movements and larger head movement per semitone ratios were observed for sighted speakers. These results suggest that physiological processes may account for part of the F0-related head movement and that sighted speakers use the visual modality to communicate F0 information through augmented head movement.

Nasalance-Based Preclassification of Oral-Nasal Balance Disorders Results in Higher Agreement of Expert Listeners' Auditory-Perceptual Assessments: Results of a Retrospective Listening Study.

OBJECTIVE: Reliable perceptual and instrumental assessment of oral-nasal balance disorders is a persistent problem in speech-language pathology. The goal of the study was to evaluate whether nasalance-based preclassification of oral-nasal balance disorders improves listener agreement. DESIGN: Retrospective listening study. SETTING: Tertiary university hospital. PARTICIPANTS: Fifty-four randomly selected recordings of patients with repaired unilateral cleft lip and palate (UCLP). Three experienced speech-language pathologists participated as expert listeners. INTERVENTIONS: Two listening experiments were based on nasalance scores and audio recordings of speakers with repaired UCLP. The speakers were preclassified as normal, hypernasal, hyponasal, or mixed based on their nasalance scores. Initially, the listeners determined the diagnostic category of the oral-nasal balance for 62 audio recordings (8 repeats). Six months later, they listened to 38 of the recordings (6 repeats) along with a spreadsheet indicating the nasalance-based categories for the oral-nasal balance. The listeners confirmed, or rejected and corrected, the nasalance-based preclassification. MAIN OUTCOME MEASURES: Intralistener, interlistener agreement, and agreement between listener categories and nasalance-based oral-nasal balance categories. RESULTS: In the first study, the agreement between the listeners' diagnostic category and the nasalance-based category was 45.1% and the interlistener agreement was 36.7%. In the second study, the agreement between the listeners' category and the nasalance-based category was 67.1% (75% agreement for the correct nasalance-based categories and 41.7% for the misclassifications), and the interlistener agreement was 85.4%. CONCLUSIONS: Preclassification of oral-nasal balance disorders based on nasalance scores may help listeners achieve better diagnostic accuracy and higher agreement.

Influence of Voice Focus Adjustments on Oral-Nasal Balance in Speech and Song.

OBJECTIVES: This study investigated the effect of training backward and forward voice focus adjustments on oral-nasal balance in speech and singing in typical speakers. METHODS: Twenty participants (10M/10F) aged 24.25 (SD 3.73) years read phonetically balanced, nasal and oral speech stimuli, and sang a song in both forward and backward voice focus conditions. A Nasometer 6450 was used to obtain nasalance scores in the different conditions. RESULTS: Results indicated that forward voice focus resulted in more nasality (p < 0.01) for the oral stimulus and song. Backward voice focus caused a decrease in nasality (p < 0.01) for the nasal stimulus, the phonetically balanced paragraph, and the song. During production of the song, males were more nasal in the forward voice focus condition than females (p = 0.01). CONCLUSIONS: Voice focus can influence oral-nasal balance in normal speakers. More research is needed to investigate whether voice focus adjustments could be helpful to speakers with oral-nasal balance disorders.

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.

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 tongue movement in speech.

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.

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.

Influence of Voice Focus on Oral-Nasal Balance in Speakers of Brazilian Portuguese.

OBJECTIVES: This study investigates whether a change in speaking voice focus affects the oral-nasal balance. The investigation was undertaken with different phonetic materials in speakers of Brazilian Portuguese, which features phonological and phonetic vowel nasalization. METHODS: Ten females read oral, balanced oral-nasal, and nasal loaded sentences in their normal voice, and with a backward focus and a forward focus. Nasalance scores were collected with a Nasometer 6400. RESULTS: A repeated measures ANOVA of the nasalance scores demonstrated a significant main effect of speaking condition (F(2, 18) = 12.87, p < 0.001). The mean nasalance scores across the stimuli in the backward focus and normal speaking conditions were 36.85% (SD 16.85) and 40.18% (SD 18.02), respectively, both significantly lower than the forward focus condition at 45.38% (SD 18.90). CONCLUSION: The results demonstrated that speaking focus influences oral-nasal balance in normal speakers. In future research, it should be investigated whether voice focus can also modify oral-nasal balance in hypernasal speakers with cleft palate and other disorders.

Application of linear discriminant analysis to the nasometric assessment of resonance disorders: a pilot study.

Objective : Nasalance scores have traditionally been used to assess hypernasality. However, resonance disorders are often complex, and hypernasality and nasal obstruction may co-occur in patients with cleft palate. In this study, normal speakers simulated different resonance disorders, and linear discriminant analysis was used to create a tentative diagnostic formula based on nasalance scores for nonnasal and nasal speech stimuli. Materials and Methods : Eleven female participants were recorded with the Nasometer 6450 while reading nonnasal and nasal speech stimuli. Nasalance measurements were taken of their normal resonance and their simulations of hyponasal, hypernasal, and mixed resonance. Results : A repeated-measures analysis of variance revealed a resonance condition-stimuli interaction effect (P < .001). A linear discriminant analysis of the participants' nasalance scores led to formulas correctly classifying 64.4% of the resonance conditions. When the hyponasal and mixed resonance conditions with obstruction of the less patent nostril were removed from the analysis, the resultant formulas correctly classified 88.6% of the resonance conditions. Conclusion : The simulations produced distinctive nasalance scores, enabling the creation of formulas that predicted resonance condition above chance level. The preliminary results demonstrate the potential of this approach for the diagnosis of resonance disorders.

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.

Application of Linear Discriminant Analysis to the Nasometric Assessment of Resonance Disorders: A Pilot Study.

Objective : Nasalance scores have traditionally been used to assess hypernasality. However, resonance disorders are often complex, and hypernasality and nasal obstruction may co-occur in patients with cleft palate. In this study, normal speakers simulated different resonance disorders, and linear discriminant analysis was used to create a tentative diagnostic formula based on nasalance scores for nonnasal and nasal speech stimuli. Materials and Methods : Eleven female participants were recorded with the Nasometer 6450 while reading nonnasal and nasal speech stimuli. Nasalance measurements were taken of their normal resonance and their simulations of hyponasal, hypernasal, and mixed resonance. Results : A repeated-measures analysis of variance revealed a resonance condition-stimuli interaction effect (P < .001). A linear discriminant analysis of the participants' nasalance scores led to formulas correctly classifying 64.4% of the resonance conditions. When the hyponasal and mixed resonance conditions with obstruction of the less patent nostril were removed from the analysis, the resultant formulas correctly classified 88.6% of the resonance conditions. Conclusion : The simulations produced distinctive nasalance scores, enabling the creation of formulas that predicted resonance condition above chance level. The preliminary results demonstrate the potential of this approach for the diagnosis of resonance disorders.

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.

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.

Analysis of oral-nasal balance after intensive speech therapy combined with speech bulb in speakers with cleft palate and hypernasality.

OBJECTIVE: To evaluate the efficacy of the combination of a speech bulb with an intensive speech therapy program in hypernasal participants with cleft palate. METHODS: Twenty hypernasal speakers with cleft palate (12 females and 8 males, median age 28.45 years), who were wearing speech bulbs underwent an intensive speech therapy program of 45 sessions over 3 weeks. Three experienced speech-language pathologists rated the participants' speech recordings before and after intensive speech therapy, with and without the speech bulb. Nasometric recordings and long-term averaged spectra were also analyzed using repeated-measures ANOVAs. RESULTS: The ANOVA of the hypernasality ratings showed significant effects of therapy [F (1,19) = 15.97; p < .001], speech bulb [F(1,190 = 28.54, p < .001] and a therapy -speech bulb interaction effect [F(1.19) = 22.30, p < 0.001]. The most favorable listener ratings of hypernasality were obtained post-therapy when participants were wearing their speech bulbs. Without the speech bulb, intensive speech therapy by itself did not result in a significant improvement. With speech bulb, nasalance scores for high [F (1,19) = 14.07, p < .001] and low pressure [F (1,19) = 14.84, p < .001] sentences were significantly lower post-therapy, providing preliminary evidence that an intensive speech therapy program may enhance the effect of a speech bulb. Before and after comparisons of individual nasalance profiles demonstrated variable improvement in 15 participants, no progress in 2 participants and more severe hypernasality after therapy in 3 participants. Long-term averaged spectra corroborated the findings of the perceptual analysis. Based on a frequency bin from 201 to 300 Hz, there was a significant within-subject effect for with and without speech bulb [F(1, 18) = 4.54, p = .047] as well as for before vs. after session [F (1,18) = 7.14, p = .015]. CONCLUSION: The speech bulb in combination with intensive speech therapy resulted in improved oral-nasal balance for the majority of participants. More research is needed to investigate long-term outcomes as well as individual factors contributing to therapy success.

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.

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 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 speaker's 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.