Multitaper Spectrum Analysis of Consonants Produced by Patients With Dentofacial Disharmonies.

PURPOSE: This study investigates differences in American English consonants produced by patients who present with various dentofacial disharmonies (DFDs), including severe overbites (Class II), underbites (Class III), and anterior open bites. Previous studies have found that patients with these malocclusion types all produce lingual sibilants and plosives with increased spectral center of gravity and increased spectral variance relative to controls. This result is puzzling since some DFD groups differ from controls in opposite ways, and it is also difficult to interpret because spectral moment measures are affected by a wide range of speech and nonspeech factors. METHOD: To better understand the articulatory basis of these differences, we apply articulatorily interpretable spectral measures derived from multitaper spectra. RESULTS: We find that all groups of DFD patients produce /s ʃ t tʃ/ with midfrequency spectral peaks that are less prominent than those of the control group, but peak frequency measures are largely the same across all groups. CONCLUSION: We conclude that the DFD patients differ more in sibilant noise source properties than in front cavity filter properties.

Impacts of Development, Dentofacial Disharmony, and Its Surgical Correction on Speech: A Narrative Review for Dental Professionals.

Speech is a communication method found only in humans that relies on precisely articulated sounds to encode and express thoughts. Anatomical differences in the maxilla, mandible, tooth position, and vocal tract affect tongue placement and broadly influence the patterns of airflow and resonance during speech production. Alterations in these structures can create perceptual distortions in speech known as speech sound disorders (SSDs). As craniofacial development occurs, the vocal tract, jaws, and teeth change in parallel with stages of speech development, from babbling to adult phonation. Alterations from a normal Class 1 dental and skeletal relationship can impact speech. Dentofacial disharmony (DFD) patients have jaw disproportions, with a high prevalence of SSDs, where the severity of malocclusion correlates with the degree of speech distortion. DFD patients often seek orthodontic and orthognathic surgical treatment, but there is limited familiarity among dental providers on the impacts of malocclusion and its correction on speech. We sought to review the interplay between craniofacial and speech development and the impacts of orthodontic and surgical treatment on speech. Shared knowledge can facilitate collaborations between dental specialists and speech pathologists for the proper diagnosis, referral, and treatment of DFD patients with speech pathologies.

Impacts of anterior-posterior jaw disproportions on speech of dentofacial disharmony patients.

BACKGROUND/OBJECTIVES: Articulation problems impact communication, development, and quality of life, and are diagnosed in 73-87% of patients with Class II Dentofacial Disharmony (DFD). We evaluated whether differences exist in stop (/t/ or/k/), fricative (/s/ or/ʃ/), and affricate (/tʃ/) consonant sounds of Class II DFD subjects, and whether extent of malocclusion correlates with severity of speech distortion. We hypothesized that Class II patients display milder distortions than Class III and anterior open bite (AOB), as Class II patients can posture into a Class I occlusion. MATERIALS/METHODS: Audio and orthodontic records were collected from DFD patients (N = 53-Class II, 102-Class III, 72-Controls) who were pursuing orthodontics and orthognathic surgery. A speech pathologist perceptually scored speech. Acoustic differences in recordings were measured using Spectral Moment Analysis. RESULTS: When Class II subjects were compared to controls, significant differences were found for the centroid frequency (M1) of the /s/ sound and the spectral spread (M2) of /t/, /tʃ/, and /s/ sounds, with pairwise significance for controls relative to Class II AOB and all Class II subjects. Class II AOB subjects had higher M1 and M2 values than patients with Class II closed bites and Class I controls for most sounds. When comparing across anterior-posterior (AP) groups, differences exist between controls, Class II and III DFD subjects for M1 of /t/, /tʃ/, and/ʃ/ and M2 for /t/, /tʃ/, /s/, and /ʃ/ sounds. Using linear regression, correlations between Class II and III severity and spectral measures were found for /t/ and /tʃ/ sounds. CONCLUSIONS/IMPLICATIONS: Class II and III patients have a higher prevalence of qualitative distortions and spectral changes in consonants compared to controls, but Class II spectral shifts are smaller and affect fewer sounds than in Class III and AOB cohorts. Linear correlations between AP discrepancy and spectral change suggest causation and that treatment may improve articulation problems.

DENTOFACIAL DISHARMONY PATIENTS' SIBILANTS DIFFER FROM CONTROLS' MORE IN SOURCE THAN FILTER PROPERTIES.

This study uses multitaper spectral analysis to examine the differences in consonants produced by patients who present with different dentofacial disharmonies (DFD) including severe overbites (Class II), underbites (Class III) and anterior open bites. Previous studies have found that patients with these malocclusion types all produce sibilants and plosives with increased spectral center of gravity and increased spectral spread relative to controls. This result is puzzling since some DFD groups differ from controls in opposite ways. To better understand the articulatory basis of these differences, we apply several spectral shape measures and find that all groups of DFD patients produce /s ʃ t tʃ/ with mid-frequency spectral peaks that are less prominent than those of the control group, but peak frequency measures are largely the same across all groups. This indicates that the DFD patients differ more in sibilant noise source than front cavity size.1.

Validating Spectral Moment Analysis as a Quantitative Measure of Speech Distortions in Speakers With Class III Malocclusions.

Purpose: This study examined the relationship between judged speech sound distortions and spectral moment metrics in speakers with Class III malocclusion. Methods: A quantitative online survey was distributed to 30 speech specialists (clinicians and/or students) and 100 lay listeners to judge the clarity of the sounds /s/, /ʃ/, /t/ and /k/ using a visual analog scale (VAS) from recordings of 11 Class III (underbite) Dentofacial Disharmony (DFD) patients and eight Class I controls. Patients and controls were grouped according to high, moderate, and low /s/-/ʃ/ first spectral moment differences. A linear mixed model was used to analyze the data. Results: VAS scale ratings increased as a function of decreasing spectral contrast for both groups of listeners. VAS ratings of speech specialists were more homogenous than lay listeners, and speech specialists rated distortions as less severe than lay listeners. Conclusions: Recordings of Class III DFD patients with low /s/-/ʃ/ first spectral moment differences were scored by listeners as having increased VAS scale ratings, indicative of more significant perceived speech-sound distortions. Spectral moment analysis appears to be a promising approach for characterizing speech of DFD patients and other craniofacial disorders.

Impacts of Skeletal Anterior Open Bite Malocclusion on Speech.

Introduction: Articulation problems are seen in 80-90% of dentofacial deformity (DFD) subjects compared with 5% of the general population, impacting communication and quality of life, but the causal link is unclear. We hypothesize there are both qualitative (perceptual) and quantitative (spectral) differences in properties of stop (/t/ or /k/), fricative (/s/ or /∫/), and affricate (/t∫/) consonant sounds and that severity of anterior open bite (AOB) jaw disharmonies correlates with degree of speech abnormality. Methods: To test our hypotheses, surgical orthodontic records and audio recordings were collected from DFD patients (n=39 AOB, 62 controls). A speech pathologist evaluated subjects and recordings were analyzed using spectral moment analysis (SMA) to measure sound frequency distortions. Results: Perceptually, there is a higher prevalence of auditory and visual speech distortions in AOB DFD patients when compared to controls. Quantitatively, a significant (p<0.01) increase in the centroid frequency (M1) was seen in the /k/, /t/, /t∫/, and /s/ sounds of AOB subjects compared to the controls. Using linear regression, correlations between AOB skeletal severity and spectral distortion were found for /k/ and /t/ sounds. Conclusions: A higher prevalence of qualitative distortion and significant quantitative spectral distortions in consonant sounds were seen in AOB patients compared to controls. Additionally, severity of skeletal AOB is correlated with degree of distortion for consonant sounds. These findings provide insight into how the surgical and/or orthodontic treatment of AOB may impact speech.

Orthognathic speech pathology: impacts of Class III malocclusion on speech.

INTRODUCTION: Patients with dentofacial disharmonies (DFDs) seek orthodontic care and orthognathic surgery to address issues with mastication, esthetics, and speech. Speech distortions are seen 18 times more frequently in Class III DFD patients than the general population, with unclear causality. We hypothesize there are significant differences in spectral properties of stop (/t/ or /k/), fricative (/s/ or /ʃ/), and affricate (/tʃ/) consonants and that severity of Class III disharmony correlates with the degree of speech abnormality. METHODS: To understand how jaw disharmonies influence speech, orthodontic records and audio recordings were collected from Class III surgical candidates and reference subjects (n = 102 Class III, 62 controls). A speech pathologist evaluated subjects and recordings were quantitatively analysed by Spectral Moment Analysis for frequency distortions. RESULTS: A majority of Class III subjects exhibit speech distortions. A significant increase in the centroid frequency (M1) and spectral spread (M2) was seen in several consonants of Class III subjects compared to controls. Using regression analysis, correlations between Class III skeletal severity (assessed by cephalometric measures) and spectral distortion were found for /t/ and /k/ phones. CONCLUSIONS: Class III DFD patients have a higher prevalence of articulation errors and significant spectral distortions in consonants relative to controls. This is the first demonstration that severity of malocclusion is quantitatively correlated with the degree of speech distortion for consonants, suggesting causation. These findings offer insight into the complex relationship between craniofacial structures and speech distortions.

Lexicogrammatical skills in 2-year-old children with and without repaired cleft palate.

The purpose of the current research was to compare the lexical-grammatical skills of two-year-old children with and without repaired cleft palate (CP), accounting for the effect of variables such as vocabulary size at 18 months of age, maternal education level, and gender. Participants included 52 children with CP and 25 typically developing (TD) children. The CDI-WS was employed to measure vocabulary and grammatical skills. Significant differences were observed between the CP and TD groups with respect to the number of words, word forms (irregular nouns and verbs), word endings (overuse of plural (-s) and past tense (-ed) markers), the mean number of morphemes in their three longest utterances (M3L), and sentence complexity. In addition, compared to TD children, significantly smaller proportions of children with CP were observed to use words to talk about past and future events or use words to talk about an absent object. The difference between the CP and TD groups in terms of the size of vocabulary at 24 months of age remained statistically significant in the multivariable model. Among all predictors, the size of vocabulary at 18 months of age was identified as the most robust precursor of lexical and grammatical skills at 24 months of age. Gender was identified as a predictor of the M3L measure as an index for syntactic ability.

Development and Resolution of Nasal Fricatives in a Child with Repaired Bilateral Cleft Lip and Palate: A Case Report.

PURPOSE: This case report describes the development, characteristics, and resolution of anterior nasal fricatives (ANFs) - a learned maladaptive articulation error - in a young girl with repaired bilateral cleft lip and palate. METHOD: The girl was observed every two months from 12 to 24 months of age with follow-ups at 36, 48, and 67 months of age. RESULTS: At 12 months of age, the girl nasalized /b/ inconsistently and had mild conductive hearing loss. At 18 months of age, she exhibited audible nasal air emission on some plosives and used ANFs to replace /s/ and /z/, often with a nasal grimace. At 24 months of age, the child continued to experience mild conductive hearing loss, obligatory nasal air emission, and ANFs for /s/ and /z/. At 36 months of age, pressure-flow testing documented significant velopharyngeal (VP) dysfunction. The girl then used ANFs for /f/ and /s/, phonetically marked by different oral stops. At 48 months of age, although VP impairment continued, speech therapy largely eliminated ANFs. By 67 months of age, VP closure was nearly normal. CONCLUSIONS: Multiple factors including VP dysfunction, audible nasal air emission, and conductive hearing loss contributed to the development of ANFs. Clinical and etiological implications are discussed.

The Palatal Closure Efficiency (PaCE) Index: A New Speaker-Centered Aerodynamic Metric for the Evaluation of Velopharyngeal Function During Speech.

PURPOSE: Pressure-flow testing provides clinicians with estimates of velopharyngeal (VP) gap size during speech production. Traditionally, adequacy of VP function has been based on absolute area criteria. This clinical focus article provides a brief overview of pressure-flow testing and introduces the PaCE index, a speaker-centered metric to interpret findings. CONCLUSION: The PaCE index provides information on a speaker's ability to achieve VP closure during oral plosives relative to his/her own VP opening during a nasal consonant. This approach provides both clinicians and patients with more meaningful information to interpret pressure-flow findings for both diagnostic and treatment outcome purposes.

Emergence of Prevocalic Stop Consonants in Children With Repaired Cleft Palate.

Purpose This study determined the time course of the emergence of prevocalic stop consonants in young children with cleft palate following surgical repair. Method A total of 120 children in four cohorts from three institutions were followed from 12 to 24 months of age: (a) 24 with repaired cleft lip and palate (CLP), (b) 36 with repaired cleft palate only (CP), (c) 33 without clefts but with histories of frequent otitis media and ventilation tubes (OM), and (d) 27 typically developing (TD) children without clefts or OM. Emergence of prevocalic stops and symbolic language skills were determined during administration of the Communication and Symbolic Behavioral Scales Developmental Profile. Parametric survival models were fitted with and without covariates-recruitment site, gender, maternal education level, middle ear status, language ability, and age at surgery for children with clefts-to describe the time course of the emergence of prevocalic stops. Results The estimated age at which 80% of children demonstrated prevocalic stop emergence was 15.0, 15.3, 18.9, and 21.8 months for TD, OM, CP, and CLP groups, respectively (p < .001, unadjusted model). Both CP and CLP cohorts had a significantly longer time to stop emergence than either the TD or OM cohorts, even after adjusting for covariates. Abnormal middle ear status, lower symbolic language ability, and older age at palatal surgery were significantly associated with delayed stop emergence. Conclusions Survival model estimates show that four out of five children with repaired cleft palate will achieve emergence of prevocalic stop consonants by 19-22 months of age, corresponding to 9-12 months following palate repair. Clinical implications are discussed.

Alveolar Backing in 3-Year-Old Children with and without Repaired Cleft Palate: Preliminary Findings Related to Cleft Type and History of Otitis Media.

OBJECTIVE: The purpose of this preliminary study was to determine if cleft type and/or history of otitis media with effusion (OM) contribute to backing of /t/ and/or /s/ in young children with and without repaired cleft palate. METHOD: Participants were 39 children (mean age=36 months, range 34 to 41). Ten children had repaired unilateral cleft lip and palate (CLP), nine had repaired cleft palate only (CP), twelve had no clefts but histories of OM, and eight were typically-developing (TD) without clefts or OM history. All children were video and audio recorded during administration of the Goldman-Fristoe Test of Articulation-3 (GFTA-3). Standard scores of articulation, frequency of alveolar backing, and first spectral moments of the /t/-/k/ and /s/-/ʃ/ phonetic contrasts were obtained. RESULTS: Children with CLP had lower GFTA-3 scores than both TD (p=.012) and OM (p=.001) groups. Fisher's Exact test showed that significantly more children with CLP backed alveolar targets, mostly /s/, than children with CP (p=.020). Children with CLP also had (a) reduced /t/-/k/ spectral difference compared to TD children (p=.016) and (b) reduced /s/-/ʃ/ spectral difference compared to both children with CP (p=.010) and children with OM (p=.018). Children with OM had reduced /t/-/k/ spectral difference compared to TD children (p=.009). CONCLUSIONS: Cleft type contributes to alveolar backing and reduced spectral contrast of /s/-/ʃ/ in 3-year-old children with repaired cleft palate. History of OM affects spectral contrast of /t/-/k/ in non-cleft children. Etiology and clinical implications of alveolar backing are discussed.

Lexical Selectivity of 2-Year-Old Children With and Without Repaired Cleft Palate Based on Parent Report.

OBJECTIVE: To determine vocabulary and lexical selectivity characteristics of children with and without repaired cleft palate at 24 months of age, based on parent report. PARTICIPANTS: Forty-nine children with repaired cleft palate, with or without cleft lip (CP±L; 25 males; 21 cleft lip and palate, 28 CP only), 29 children with a history of otitis media (OM) and ventilation tubes (21 males), and 25 typically developing (TD) children (13 males). MAIN OUTCOME MEASURE(S): Parent-reported expressive vocabulary was determined using the MacArthur Communicative Development Inventory: Words and Sentences. RESULTS: Vocabulary size was reduced for children with repaired CP±L compared to children in the TD group (P = .025) but not the OM group (P = .403). Mean percentage of words beginning with sonorants did not differ across groups (P = .383). Vocabulary size predicted sonorant use for all groups (P = .001). CONCLUSIONS: Children with repaired CP±L exhibit similar lexical selectivity relative to word initial sounds compared to noncleft TD and OM peers at 24 months of age, based on parent report.

Vocabulary Growth From 18 to 24 Months of Age in Children With and Without Repaired Cleft Palate.

Purpose This study investigated vocabulary growth from 18 to 24 months of age in young children with repaired cleft palate (CP), children with otitis media, and typically developing (TD) children. In addition, the contributions of factors such as hearing level, middle ear status, size of consonant inventory, maternal education level, and gender to the development of expressive vocabulary were explored. Method Vocabulary size of 40 children with repaired CP, 29 children with otitis media, and 25 TD children was measured using the parent report on MacArthur-Bates Communicative Development Inventories: Words and Sentences (Fenson et al., 2007) at 18 and 24 months of age. All participants underwent sound field audiometry at 12 months of age and tympanometry at 18 months of age. A multiple linear regression with and without covariates was used to model vocabulary growth from 18 to 24 months of age across the 3 groups. Results Children with CP produced a significantly smaller number of words at 24 months of age and showed significantly slower rate of vocabulary growth from 18 to 24 months of age when compared to TD children (p < .05). Although middle ear status was found to predict vocabulary growth from 18 to 24 months of age across the 3 groups (p < .05), the confidence interval was large, suggesting the effect should be interpreted with caution. Conclusions Children with CP showed slower expressive vocabulary growth relative to their age-matched TD peers. Middle ear status may be associated with development of vocabulary skills for some children.

Obligatory Nasal Turbulence as a Trigger for the Development of Posterior Nasal Fricatives in a Child With Repaired Cleft Palate.

Posterior nasal fricatives (PNFs) are unusual articulations that occur in some children with and without cleft palate. The etiology of PNFs is unclear. A young girl with repaired cleft palate is described who exhibited inconsistent obligatory nasal turbulence during production of stops at 2 years of age. At 3 years of age, she exhibited various phonological processes and used PNFs to replace sibilants and affricates. Pressure-flow testing showed a relatively small velopharyngeal area during production of stops. These observations are consistent with obligatory nasal turbulence triggering the development of PNFs as an unusual phonological process, perhaps facilitated by reduced hearing.

Vocal Loudness as Contributory to the Occurrence of Obligatory Posterior Nasal Turbulence.

Two cases are presented that show increased loudness as contributory to the occurrence of audible posterior nasal turbulence as an obligatory symptom. Case 1 was an 18-month-old boy with repaired cleft palate who exhibited sporadic posterior nasal turbulence with velar flutter that was associated with increased loudness. Case 2 was a 4-year-old boy with repaired cleft palate who exhibited relatively frequent posterior nasal turbulence with velar flutter that was associated with pervasive and excessive loudness. Following 3 therapy sessions, loudness was reduced and audible nasal turbulence was eliminated. Clinical implications are discussed.

Velopharyngeal Status of Stop Consonants and Vowels Produced by Young Children With and Without Repaired Cleft Palate at 12, 14, and 18 Months of Age: A Preliminary Analysis.

Purpose: The objective was to determine velopharyngeal (VP) status of stop consonants and vowels produced by young children with repaired cleft palate (CP) and typically developing (TD) children from 12 to 18 months of age. Method: Nasal ram pressure (NRP) was monitored in 9 children (5 boys, 4 girls) with repaired CP with or without cleft lip and 9 TD children (5 boys, 4 girls) at 12, 14, and 18 months of age. VP status was categorized as open or closed for oral stops and vowels in three contexts-consonant-vowel syllables, vowel-consonant-vowel syllables, and isolated vowels-on the basis of the presence or absence of positive nasal ram pressure. Results: At 12 months of age, TD children produced 98% of stops and vowels in syllables with VP closure throughout the entire segment compared with 81% of stops and vowels for children with CP (p < .0001). There were no significant group differences at 14 or 18 months of age. Conclusions: TD children exhibit consistent VP closure for stop consonants and vowels at 12 months of age. Some children with repaired CP do not achieve consistent closure until 14 months of age, approximately 3 to 4 months following palate repair.

Acoustic-temporal aspects of stop-plosives in the speech of Persian-speaking children with cleft lip and palate.

PURPOSE: The main objective was to examine temporal parameters of stop-plosives in Persian-speaking children with repaired cleft lip and palate (CLP). METHOD: Eleven children with repaired bilateral CLP and 20 typically-developing children participated in the study. Stop-gap duration (SGD) and voice-onset time (VOT) were measured based on digital waveform and spectrographic displays. RESULT: Separate linear mixed model analyses showed significantly longer SGDs for children with CLP for all plosives in word-mid and final positions. Furthermore, children with CLP tend to produce longer VOTs for all voiceless plosives. CONCLUSION: Persian-speaking children with repaired CLP prolong stop-gap segments, similar to findings reported for English-speaking children with CLP. Prolonged segments may be due to an active strategy to increase oral air pressure and/or improve perceptual accuracy of speech segments.

Age and Phonetic Influences on Velar Flutter as a Component of Nasal Turbulence in Children With Repaired Cleft Palate.

OBJECTIVE: The purpose of this study was to determine the influence of age and selected phonetic factors on velar flutter as a component of nasal turbulence in children with repaired cleft palate. PARTICIPANTS: A total of 30 children with repaired cleft palate with or without cleft lip ranging in age from 4 to 13 years (mean, 8.6 years; standard deviation, 2.4 years) who exhibited nasal turbulence characterized by velar flutter participated in the study. MEASURES: The headset of a nasometer was used to record the children producing multiple repetitions of consonant-vowel (CV) syllables that contrasted the stops /p/ and /t/ with the fricatives /f/ and /s/ and the high-front vowel /i/ with the low mid-central vowel /Λ/. All targeted consonants were coded relative to the presence of flutter using both perceptual and spectral criteria. Percentages of syllables coded for flutter were calculated as a function of consonant and vowel types. Intra-and interjudge reliability of coding was high. RESULTS: Percentages of syllables with velar flutter ranged from a high of 100% to a low of 4% among the participants. A Spearman rank-order correlation between age and percentage of syllables with flutter was nonsignificant. Mantel-Haenszel tests for repeated measures indicated that flutter occurred more often during production of syllables containing /i/ (62%) when compared with /Λ/ (50%) (P = .029). CONCLUSIONS: Velar flutter as a component of nasal turbulence varies widely among children with repaired cleft palate. CV syllables with high vowels appear to trigger velar flutter more often than syllables with low vowels.

Aerodynamic and Laryngeal Characteristics of Place-Dependent Voice Onset Time Differences.

OBJECTIVE: To investigate aerodynamic and laryngeal factors associated with place-dependent voice onset time (VOT) differences. METHODS: The speech materials were /p∧, t∧, k∧/, each produced 15 times by 10 adult English speakers in the carrier phrase "say __ again". The sound pressure level was targeted within a ±3 dB range. Intraoral air pressure (Po) was obtained using a buccal-sulcus approach. VOT, Po, maximum Po declination rate (MPDR), duration of the laryngeal devoicing gesture (LDG), occlusion duration, and the duration of the Po drop to baseline (atmosphere) to the onset of voicing (PDOV) were determined for each stop. RESULTS: VOT was longer for the alveolar and velar stops compared to the bilabial stop. A constant LDG was observed for all stops regardless of place of articulation. Occlusion duration, however, was significantly shorter for the alveolar and velar stops compared to the bilabial stop. Aerodynamically, Po was greatest for the velar stop, intermediate for the alveolar stop, and smallest for the bilabial stop. MPDR index showed a slower rate of Po drop for the velar and alveolar stops compared with the bilabial stop. PDOV was found to be longer for /p/ than /t/ and /k/. CONCLUSION: Findings provide empirical evidence for the inter-related roles of Po, rate of Po change, and laryngeal factors in place-dependent variations of VOT.