ABSTRACT
Objective
To determine the prevalence of voice disorders, relationships between voice disorders and hypernasality, patterns of compensatory articulation disorders (CAD), acoustic characteristics, and associated factors in children with cleft palate with/without (CP ± L).
Method
The study consisted of 60 children with CP ± L, aged 7–12 years, who had undergone palate repair with/without cleft lip repair. Data were collected by evaluating voice quality using the GIRBAS scale (grade, instability, roughness, breathiness, asthenia, and strain). The Computerized Speech Lab (CSL) was used to evaluate the acoustic characteristics, including fundamental frequency (F 0), shimmer, jitter, and maximum phonation time (MPT). A Fiber Optic Laryngoscope (FOL) was utilized to conduct laryngeal investigations. Spearman's Rank Correlation statistics were used to investigate correlations.
Results
Prevalence of voice disorders in children with CP ± L was 30% (18/60 cases). Laryngeal examinations showed that 33.33% had exhibited vocal nodules, and 13.34% had vocal cord edema. Regarding assessments of acoustic characteristics, children with voice disorders displayed significantly higher jitter and shimmer values than those with normal voices (p < 0.05). (mean differences for jitter and shimmer /a:/ being −0.99 and −3.60), there were positive statistically significant relationships between voice disorders and severity of hypernasality at both the word and sentence levels (r = 0.46, r = 0.55); between voice disorders and the number of CAD patterns at both the word and sentence levels, (r = 0.30, r = 0.40).
Conclusion
The prevalence of voice disorders in children with CP ± L was 30%. The severity of voice disorders from the GIRBAS scores was significantly correlated to the severity of hypernasality and the number of CAD patterns.
Study Design
A cross‐sectional study.
Level of Evidence
2.
Keywords: cleft palate, compensatory articulation disorders, hypernasality, voice disorders
1. Introduction
Children with cleft palate, with or without cleft lip (CP ± L), still face significant speech and language disorders and velopharyngeal insufficiency (VPI) even after undergoing cheiloplasty and palatoplasty. VPI, where the soft palate fails to close tightly against the throat, allows air and sound to escape to the nasal cavity, persisting post‐surgery and resulting in articulation disorders and hypernasality. Voice disorders can be measured using various acoustic parameters that include shimmer (amplitude instability), jitter (frequency instability), and fundamental frequency (F0), all of which can provide critical insights into how voice disorders happen and the strain on vocal cords [1]. Voice disorders are often overlooked until they significantly interfere with daily communication.
In voice disorders, jitters refer to when variabilities are present in the frequency and pitch of one's voice; it is a crucial indicator of any irregularities in vocal cord vibration. Those, especially children with CP ± L, tend to exhibit higher jitter levels, which indicates poor or inadequate control over vocal pitch [1, 2, 3]. Conversely, shimmer is used to measure the variations in the amplitude of the voice, which means how loud or soft the voice is [1]. If there is high shimmer, this suggests that instability in vocal cord function is highly prevalent among those with vocal cord disorders. Lastly, fundamental frequency (F 0) refers to the basic pitch of the voice. For children with CP ± L generally present, the basic pitch is higher than their peers, which can result in speech difficulties caused by VPI [1, 2].
Voice problems are more common in children with cleft palate with or without a cleft lip (CP ± L), ranging from 5.5% to 41%, compared to the 6%–14% in other school‐aged children [4, 5, 6, 7, 8, 9]. This wide range in reported prevalence is partly because studies use different methods to identify voice disorders, such as subjective listening (GIRBAS) or objective CSL [1, 2, 10], which measures aspects like jitter and shimmer that indicate the severity of the voice issue [1, 2]. VPI, common in CP ± L, further strains the vocal cords and worsens voice problems, impacting children's communication, learning, social interactions, and potentially leading to feelings of isolation and low self‐esteem.
Children with CP ± L often have higher F 0, jitter, and shimmer in their voices compared to typically developing children of the same age, particularly boys [1, 2, 3]. This suggests differences in their vocal acoustic characteristics. These children can adjust their pitch and loudness (related to F 0, jitter, and shimmer), which contributes to various compensatory behaviors and articulation difficulties. Boys with CP ± L tend to show more pronounced compensatory mechanisms due to physiological differences in vocal cord development, resulting in even higher values for these acoustic measures. These voice differences in children with CP ± L, such as increased hoarseness, breathiness, and hypernasality, are often linked to velopharyngeal insufficiency (VPI), which causes more air to escape through the nose and strain the vocal cords. Studies have also shown that children with CP ± L who use glottal stops as a compensatory articulation strategy tend to have higher F0, shimmer, and jitter, indicating increased tension in their vocal cords affecting vocal fold vibration [11, 12, 13].
The GIRBAS scale is a method for subjectively analyzing voice quality and mechanics [12]. Objective assessments using tools like the CSL provide crucial data on variations in voice frequency and loudness [14, 15, 16, 17]. The GIRBAS scale evaluates voice based on six perceptual features: Grade (G), Instability (I), Roughness (R), Breathiness (B), Asthenia (A), and Strain (S). CSL enhances this assessment by objectively measuring aspects like fundamental frequency (F 0), jitter, shimmer, and noise‐to‐harmonics ratio (NHR). CSL complements GIRBAS, as it can detect subtle vocal cord issues beyond what perceptual analysis alone might reveal. Speech therapists who use both subjective (GIRBAS) and objective (CSL) methods gain a more comprehensive understanding of a child's voice disorder, which is particularly beneficial for patients with CP ± L due to potential complexities affecting their vocal cords.
Most protocols provide lip correction at age 3 months and palatoplasty at 1 year of age for relief of the stigmas of facial abnormality and to expect normal function of speech production in most cleft lip and palate centers in Thailand. However, voice disorders are a common defect in children with CP ± L. It needs to explore acoustic characteristics, including jitter, shimmer, and F 0 among children with CP ± L, which are factors that are often overlooked when assessing speech disorders. Additionally, bridging gaps in existing literature about the relationship between voice disorders and hypernasality should be quantified. This new information provides data on the aforementioned relationship and impacts on voice quality, especially among children who have received surgery for CP ± L issues. These data might benefit the further prevention of voice disorders, treatment plans, and targeted monitoring strategies to improve voice quality care in speech therapy to reduce long‐term voice disorder risks.
The objectives of this study were to measure the prevalence of voice disorders in children with CP ± L and to investigate the relationship between acoustic parameters like jitter, shimmer, and frequencies with voice disorders.
2. Materials and Methods
To conduct this research, the study was first approved by the Human Research Ethics Review Board, Khon Kaen University, and Khon Kaen Hospital, Reference No. HE651061, which was approved on May 2, 2022. Upholding the highest ethical standards, a written consent form detailing every aspect of this study was distributed and signed by parents or caregivers of the children with CP ± L.
2.1. Population
Inclusion Criteria: This study included children between 7 to 13 years who had undergone cleft palate surgery (with or without cleft lip repair) at least a year prior to this study at Srinagarind Hospital and Khon Kaen Hospital, Khon Kaen, Thailand.
Exclusion Criteria: Children with CP ± L were excluded if they had any of the following conditions
Common cold and a runny nose
Intellectual disability
General developmental delay (GDD)
Reconstruction of VPI
Hearing impairment greater than 40 dB in both ears (a hearing test was performed using an audiometer (Interacoustics AC40) by an audiologist)
Speech disorders with other neurological speech disorders, such as slurred speech, cerebral palsy, and phonological abnormalities of /a:/, /u:/, and /i:/ (sounds assessed by a voice analyzer: CSL)
Sample Size: The sample size for this study encompasses a total of 60 volunteers. The infinite population proportion formula from Wayne W. Daniel's “Biostatistics: A Foundation for Analysis in the Health Sciences” (7th edition) [18] was used to calculate the sample size. This formula is written as n = Z [2][P(1‐P)]/d, where the values are:
n = required sample size
Z = Z‐value (1.96 for a 95% confidence level)
P = estimated proportion of the population with voice disorders (set at 19% based on previous data)
d = margin of error (set at 0.05 for this study)
This formula helped determine that a population size of 60 was sufficient for this study.
2.2. Research Tools
- Acoustic Analysis by Computerized Speech Lab (CSL) Model 4500
-
1.1Fundamental frequency (F 0)
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1.2Jitter
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1.3Shimmer
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1.4Maximum Phonation Time (MPT)
-
1.1
Perceptual assessments were performed by experienced speech‐language pathologists using the GIRBAS scale [12].
The impact of voice disorders on the quality of life was assessed by using The Thai Pediatric Voice Handicap Index (pVHI) [14, 19].
Self‐assessment for pharyngeal and laryngeal reflux symptoms (Reflux symptom index) was utilized (Thai version).
For the assessment of articulation disorders and resonance, we utilized the full standard articulation test (Thai Speech Parameters for Patients with Cleft Palate in a Universal Reporting System) [20].
In cases of hoarseness, a resident physician, an otolaryngologist, and an Ear, Nose, and Throat (ENT) specialist conducted laryngeal examinations using a flexible fiberoptic laryngoscope (FOL).
2.3. Assessments
Two experienced speech‐language pathologists (SLPs) with over 5 years of experience in cleft lip and palate and voice disorders used the GIRBAS scale to independently evaluate the voice quality of each child in an observation room. The children performed a maximum counting duration (MCD) task. Disagreements in scoring between the initial two SLPs were resolved by a third SLP with over 30 years of experience in the same field, who provided a consensus score. Articulation disorders and hypernasality were then assessed by employing the full standard articulation test [20] by two other SLPs, each with more than 10 years of experience working with cleft lip and palate. The articulation test results were classified as normal or error, including the CAD pattern. For hypernasality, scores were recorded at 5 levels under the criteria for hypernasality (−1, 0, +1, +2, +3) [21, 22].
Prior to recording, a researcher guided the child in practicing prolongation vowels /a/, /u/, and /i/ as long as possible. This was done after taking a deep breath with optimal or normal loudness and pitch via the following career phases: ‘Pai Nai Ma:’ for vowel /a:/, ‘Pai Jub Pu:’ for /u:/, and ‘Sa wat dee’ for /i:/. Each vowel was then recorded three times with a 1‐min interval duration, ensuring a comprehensive data collection process [23].
2.4. Data Analysis
The main form of data analysis for this study was statistical analysis. Using the IBM SPSS Statistics version 27.0 licensed to Khon Kaen University, a statistical analysis was conducted to analyze the differences in F 0, jitter, shimmer, MPT, and pVHI through independent‐samples t‐tests. Moreover, a Spearman's Rank was used to calculate correlation coefficients between variables. The statistical significance value was set to be p < 0.05 to ensure clarity and accuracy.
3. Results
General characteristics of the population: The general characteristics of the population in this study were 60 children, each with CPL. The mean age of this group was 9 years, with a range of 7–13 years. The gender distribution of this population was 66.70% of the boys (40/60) and 33.30% of the girls (20/60). General information about the volunteers is shown in Table 1.
TABLE 1.
General characteristics of children with CP ± L.
| Information (N = 60) | Numbers (%) |
|---|---|
| Cleft types | |
| Cleft palate | 13 (21.67) |
| Right unilateral cleft lip and palate | 11 (18.33) |
| Left unilateral cleft lip and palate | 17 (28.33) |
| Bilateral cleft lip and palate | 19 (19.67) |
| Uvular | |
| Structure | |
| Normal | 1 (1.70) |
| Short | 43 (71.70) |
| Bifid | 2 (3.30) |
| Absent | 14 (23.30) |
| Function | |
| Active | 29 (48.30) |
| Slightly movable | 30 (50.00) |
| None | 1 (1.70) |
| Fistula | |
| None | 48 (80.00) |
| Present | 12 (20.00) |
| Occlusions | |
| Class I | 19 (31.70) |
| Class II | 2 (3.30) |
| Class III | 38 (63.30) |
| Crossbite | 1 (1.70) |
| Underlying | |
| None | 53 (88.30) |
| Present | 7 (11.70) |
| Allergies | 4 (6.67) |
| Glucose‐6‐Phosphate Dehydrogenase (G6PD) | 1 (1.67) |
| Ventricular Septal Defect (VSD) | 1 (1.67) |
| Attention deficit hyperactivity disorder (ADHD) | 1 (1.67) |
| Having a history of hoarseness | 15 (25.00) |
| Behaviors | |
| Shout | 20 (41.70) |
| Bawl | 10 (20.80) |
| Clearing the throat | 4 (8.30) |
| Whispering | 9 (18.80) |
| Having a high‐pitched voice | 5 (10.40) |
| Total (N = 60) | 34 (56.70) |
The prevalence of articulation disorders was 98.33% (59/60 cases); children with CP ± L had shown CAD patterns, specifically 14/18 CAD patterns. The number of CAD patterns observed ranged from 0 to 5 patterns per case, with a median of 3 patterns at the word level, and from 0 to 6 patterns per case, with a median of 4 patterns at the sentence level.
The most frequent compensatory articulation disorder (CAD) patterns observed were: at the word level, nasalized voiced pressure consonants (58.3%), velar substitutions (40%), and pharyngeal substitutions (25%); and at the sentence level, nasalized voiced pressure consonants (68.30%), velar substitutions (46.70%), and pharyngeal substitutions (30.00%). Additionally, phoneme‐specific nasal air emission and mid‐dorsum palatal articulation were each seen in 30.00% of patients. Glottal stops occurred in 11.6% of patients at the word level and 15.00% at the sentence level.
The resonance assessement of 60 children revealed 35% demonstrated normal resonance, while 28.33% exhibited mild hypernasality and 36.67% showed moderate hypernasality. Notebly, none of the participants displlayed severe hypernasality during evaluation.
For perceptual voice evaluation (GIRBAS Scale), it was reported that an abnormal voice quality (GIRBAS score > 0) was found in 30% of children in the study, as shown in Table 2. The children with CP ± L whose voice quality was abnormal using the GIRBAS scale were examined by an otolaryngologist using FOL. Fifteen of the 18 children were cooperative with FOL. Three of the 18 children with CP ± L were uncooperative with FOL after 3 trials of laryngoscope. The results of the remaining 15 children who completed FOL are shown in Table 3.
TABLE 2.
Percentage of perceptual analysis on GIRBAS scale.
| GIRBAS | Assessment results (severity levels) | Numbers (%) b |
|---|---|---|
| G | Normal (0) | 42 (70.00) |
| Mild (1) | 14 (23.30) | |
| Moderate (2) | 4 (6.70) | |
| I | Normal (0) | 56 (93.30) |
| Mild (1) | 4 (6.70) | |
| Moderate (2) | 0 (0.00) | |
| R | Normal (0) | 44 (73.30) |
| Mild (1) | 13 (21.70) | |
| Moderate (2) | 3 (5.00) | |
| B | Normal (0) | 46 (76.60) |
| Mild (1) | 10 (16.70) | |
| Moderate (2) | 4 (6.70) | |
| A | Normal (0) | 59 (98.30) |
| Mild (1) | 1 (1.70) | |
| Moderate (2) | 0 (0.00) | |
| S | Normal (0) | 57 (95.00) |
| Mild (1) | 3 (5.00) | |
| Moderate (2) | 0 (0.00) | |
| Normal GIRBAS a (0) | 42 (70.00) | |
| Mild GIRBAS a (1–6) | 16 (26.67) | |
| Moderate GIRBAS a (7–12) | 2 (3.33) | |
| Total GIRBAS a abnormal (more than 0) | 18 (30.00) | |
GIRBAS = Listening Voice Quality Assessment Score/(Grade (G), Instability (I), Roughness (R), Breathiness (B), Asthenia (A) and Strain (S)) [13].
N = 60.
TABLE 3.
The Laryngeal examinations.
| Laryngeal findings | Number (%) N = 15 |
|---|---|
| Normal | 3 (20.00%) |
| Muscle tension dysphonia (MTD) | 5 (33.30%) |
| AP contraction | 1 (6.70%) |
| Posterior Gap 1 mm | 1 (6.70%) |
| AP contraction with vocal cord edema | 1 (6.70%) |
| AP contraction, posterior Gap 1 mm with Vocal cord edema | 1 (6.70%) |
| Ventricular phonation/false vocal cord phonation | 1 (6.70%) |
| Vocal nodules | 5 (33.30%) |
| Bilateral | 3 (20.00%) |
| Unilateral | 1 (6.70%) |
| Pre‐vocal nodule | 1 (6.70%) |
| Vocal cord edema | 2 (13.30%) |
Abbreviation: AP, Anterior posterior.
For acoustic Analysis using the CSL, it was found that boys significantly had lower F0 values compared to girls (p < 0.05) when the assessment was carried out for vowels /a:/, /u:/, and /i:/. For other key parameters like shimmer, jitter, and MPT, there were no variations in gender differences. For the MPT range, the study found that boys had a range of 2.12 to 11.65 s compared to girls, with a lower range of 2.30 to 10.28 s. When comparing normal and abnormal voice conditions, there were significant differences. children with voice disorders' MPT were shorter than children with normal voice (p < 0.05). Moreover, for children with voice disorders, the acoustic parameters such as jitter and shimmer increased (p < 0.05). The results are detailed in Table 4.
TABLE 4.
A comparison of voice characteristics between children with CP ± L with and without voice disorders.
| Computerized speech lab | N = 60 (normal = 42, voice disorder = 18) | Mean (SD) | Mean differences | 95% CI (lower–upper) | p | |
|---|---|---|---|---|---|---|
| F0 | /a:/ | Normal | 254.03 (34.75) | 10.29 | (−8.70) ‐ 29.27 | > 0.05 |
| Voice disorders | 243.74 (30.92) | |||||
| /u:/ | Normal | 282.51 (41.94) | 16.78 | (−5.20) ‐ 38.77 | > 0.05 | |
| Voice disorders | 265.92 (30.71) | |||||
| /i:/ | Normal | 279.98 (42.39) | 11.15 | (−6.66) ‐ 37.98 | > 0.05 | |
| Voice disorders | 264.32 (31.79) | |||||
| Jitter | /a:/ | Normal | 1.25 (0.70) | −0.99 | (−1.56) ‐ (−0.42) | < 0.01** |
| Voice disorders | 2.24 (1.51) | |||||
| /u:/ | Normal | 1.07 (0.40) | −0.25 | (−0.49) ‐ (−0.13) | < 0.05* | |
| Voice disorders | 1.30 (0.49) | |||||
| /i:/ | Normal | 1.02 (0.56) | −0.78 | (−1.14) ‐ (−0.42) | < 0.01** | |
| Voice disorders | 1.80 (0.56) | |||||
| Shimmer | /a:/ | Normal | 5.35 (1.99) | −3.59 | (−5.41) ‐ (−1.78) | < 0.01** |
| Voice disorders | 8.50 (3.48) | |||||
| /u:/ | Normal | 1.73 (0.64) | −0.51 | (−0.90) ‐ (−0.12) | < 0.01** | |
| Voice disorders | 2.24 (0.81) | |||||
| /i:/ | Normal | 3.20 (0.84) | −1.18 | (−2.02) ‐ (−0.34) | < 0.01** | |
| Voice disorders | 4.39 (1.62) | |||||
| MPT | /a:/ | Normal | 5.31 (1.98) | 1.09 | 0.05–2.13 | < 0.05* |
| Voice disorders | 4.22 (1.43) | |||||
| /u:/ | Normal | 5.77 (2.37) | 1.48 | 0.52–2.43 | < 0.01** | |
| Voice disorders | 4.29 (1.29) | |||||
| /i:/ | Normal | 5.61 (2.29) | 1.16 | 0.25–2.08 | < 0.05* | |
| Voice disorders | 4.45 (1.23) | |||||
Significant < 0.05.
Significant < 0.01.
The scores from the questionnaires, impact of voice disorders on quality of life (pVHI) which were completed by the parents or caregivers and the children with CP ± L found that there were differences between normal voice and voice disorders in terms of the physical conditions (mean difference = 2.83, 95% CI = 1.07–4.59), the emotional conditions (mean difference = 1.55, 95% CI = 0.26–2.84), and the total pVHI scores (mean difference = 5.80, 95% CI = 1.54–10.06). There were statistically significant differences in functional conditions between the group with normal voices and the group with abnormal voices.
According to the correlation between parameters, results revealed that the severity of hypernasality and CAD patterns had a higher correlation in children with voice disorders (GIRBAS score > 0) (p < 0.01) (Hypernasality and GIRBAS score r = 0.46, Hypernasality and Number of CAD patterns r = 0.55).
Correlations between CSL Measures and GIRBAS Score, the jitter and shimmer values displayed a positive correlation, with an overall GIRBAS score being higher. Conversely, the MPT assessment showed a negative correlation with the GIRBAS score, which signifies that those with severe voice disorders have shorter MPTs, are shown in Table 5.
TABLE 5.
The relationship between compensatory behaviors and sound quality.
| Correlations | 95% confidence intervals (2‐tailed) (Lower–upper) | Spearman's rho | Significance (2‐tailed) | |
|---|---|---|---|---|
| Total GIRBAS and hypernasality | Word level | 0.16–0.62 | 0.46 | < 0.01** |
| Sentence level | 0.31–0.72 | 0.55 | < 0.01** | |
| Total GIRBAS and number of CAD patterns | Word level | 0.10–0.50 | 0.29 | < 0.05* |
| Sentence level | 0.17–0.60 | 0.40 | < 0.01** | |
| Total GIRBAS and number of articulation disorders | Word level | (−0.26) to 0.25 | 0.07 | 0.59 |
| Sentence level | (−0.23) to 0.33 | 0.12 | 0.36 | |
| Total GIRBAS scale and MPT/a:/ | (−0.51) to (−0.01) | −0.27 | < 0.05* | |
| Total GIRBAS scale and Jitter/a:/ | 0.17–0.64 | 0.42 | < 0.01** | |
| Total GIRBAS scale and Shimmer/a:/ | 0.32–0.69 | 0.53 | < 0.01** | |
| Total GIRBAS scale and Jitter/i:/ | 0.30–0.66 | 0.48 | < 0.01** | |
| Total GIRBAS scale and Shimmer/i:/ | 0.17–0.67 | 0.43 | < 0.01** | |
| Total GIRBAS scale and MPT/u:/ | (−0.47) to (−0.01) | −0.28 | < 0.05* | |
| Total GIRBAS scale and Shimmer/u:/ | 0.05–0.55 | 0.32 | < 0.05* | |
| Hypernasality and Shimmer/a:/ | Word level | (−0.09) to 0.44 | 0.18 | 0.17 |
| Sentence level | 0.09–0.56 | 0.27 | < 0.05* | |
| Hypernasality and MPT/i:/ | Word level | (−0.61) to (−0.05) | −0.31 | < 0.05* |
| Sentence level | (−0.56) to (−0.06) | −0.27 | < 0.05* | |
| Hypernasality and MPT/u:/ | Word level | (−0.65) to (−0.15) | −0.37 | < 0.01** |
| Sentence level | (−0.66) to (−0.01) | −0.34 | < 0.01** | |
Significant < 0.05.
Significant < 0.01.
Hypernasality at both the word and sentence levels was significantly correlated with the MPT of /i:/ and /u:/ (p < 0.05) and with a negative correlation (r = −0.31, r = −0.27, r = −0.37, and r = −0.40), which indicated that there was more severe hypernasality and a shorter MPT. Hypernasality at the sentence level showed statistically significant results and had a mildly correlated relationship with the shimmer of /a:/ (r = 0.27, p < 0.05). From the articulation test, 14 CAD patterns were found. The correlation was analyzed using the percentage of the expected cell count statistics. Pearson Chi‐squares were used if the values were less than 5 (< 20%). Fischer's exact test was used if the values were greater than 5 (> 20%). The Patterns of CAD, which were found to have statistically significant positive relationships with voice disorders (GIRBAS > 0), are shown in Table 6.
TABLE 6.
The relationship of voice disorders and pattern of compensatory articulation disorders.
| CAD | Normal (N = 42) | Voice disorders (N = 18) | Pearson Chi‐square a | p | |
|---|---|---|---|---|---|
|
Word level Velar substitution |
None | 29 (48.30%) | 7 (11.70%) | = 4.77a | < 0.05* |
| Present | 13 (21.70%) | 11 (18.30%) | |||
|
Sentence level Velar substitution |
None | 26 (43.30%) | 6 (10.00%) | = 4.13a | < 0.05* |
| Present | 16 (26.70%) | 12 (20.00%) | |||
|
Word level Nasalized voiced pressure consonant |
None | 21 (35.00%) | 4 (6.70%) | = 4.00a | < 0.05* |
| Present | 21 (35.00%) | 14 (23.30%) | |||
|
Sentence level Nasalized voiced pressure consonant |
None | 18 (30.00%) | 1 (1.70%) | = 8.10a | < 0.05* |
| Present | 24 (40.00%) | 17 (28.30%) | |||
|
Sentence level Phoneme‐specific nasal air emission |
None | 33 (55.00%) | 9 (15.00%) | = 4.90a | < 0.05* |
| Present | 9 (15.00%) | 9 (15.00%) | |||
Pearson Chi‐square. Expected count more than 5 (20%).
Significant < 0.05.
4. Discussion
Prevalence of voice disorders by perceptual voice evaluation (GIRBAS Scale) in children with CP ± L aged 7–13 was 30% (18/60), which is higher compared to Thai studies, where the prevalence was reported to be between 19.13% and 25% [8, 9]. This finding aligns with international research, where prevalence rates between 5.5% and 41% were observed [4, 5, 6, 7, 8, 9], Children with VPI may use pharyngeal or laryngeal production as a place of articulation. Thus, these patients are at risk for voice disorders. Studies show that more subglottic pressure during talking leads to hyperfunction of the larynx. Robinson and Otteson reported a 5.5% prevalence of hoarseness in the cleft palate population. The laryngoscopic findings showed vocal fold nodules and edema, or mucosal thickening of the vocal folds in the children with hoarseness, such as the study by Timmons, Wyatt, and Murphy (2010), which reported that the prevalence of voice disorders in children with cleft palate was 34% [4]. It is important to note that prevalence can vary based on the assessment tools used, the age range, and the specific type of cleft lip and palate.
The study used FOL to directly view the larynx (voice box), pharynx (throat), and sometimes even the nasal passages when perceptual voice assessments suggested an issue (GIRBAS score greater than 0). While stroboscopy is a useful technique for seeing vocal cord movement and details that were not visible with regular examination and provides more benefit and information than FOL, it was not the focus of this study as the goal was to assess vocal cord structure. Additionally, stroboscopy is more expensive, difficult to perform on children, and time‐consuming. The process of examination needed a shorter duration for young children. For this particular study, stroboscopy was not required for examining the larynx. As a result, anatomical abnormalities that might not manifest in voice symptoms could potentially go undetected, contributing to underdiagnosis. The FOL findings in this study showed that 33.33% (5/15 cases) of children with voice disorders had functional voice disorders, which is higher than the 11% rate found in another study [1]. Aside from this, the study noted that 46.67% (7/15 cases) were found to have laryngeal diseases, a rate that exceeds the 11% to 27.4% found in international studies [1, 24]. Therefore, these results indicate the need for early screening for accurate and thorough diagnosis. Awareness of early detection of voice disorders should be a concern for further treatment.
For voice and acoustic: The study's findings were broken down based on the CSL analysis findings, jitter and shimmer elevation, and compensatory behavior to reduce hypernasality. For the CSL analysis, the study noted that children with CP ± L who suffered voice disorders had shorter MPT, when compared to children without voice disorders. Moreover, the shorter MPTs seen differed from the typical children's duration, which indicated that those with voice disorders had less muscle control and faltered respiratory dynamics [25, 26]. Regarding jitter and shimmer elevation, it was noted that children with voice disorders had high values. The jitter rates were reported to be 0.81 ± 0.11 in boys and 0.82 ± 0.18 in girls, while shimmer values were elevated at 1.51 ± 0.16 for boys and 1.77 ± 0.31 for girls. The findings signified that voice disorders occur at earlier stages and detection; it could lead to compensatory articulation strategies being formulated to compensate for VPI. Elevated jitter and shimmer levels were indicators of compensatory articulation that children with CP ± L tend to exhibit more compensatory behaviors, like an increase in vocal strain for the purpose of mitigating VPI [1, 2, 3].
Several patients with CP ± L and VPI had CAD. The current study agrees with previous studies that found a high risk of CAD compared to the normal population. The rate of voice disorders was 30%, which puts this study's found prevalence in the range of previous studies that had a prevalence of 5.50% to 41%. Even though a previous study showed no relationship between VPI and hoarseness [7], this study suggests that individuals with CP ± L are prone to dysphonia because they often overwork their vocal cords to compensate. This overuse can lead to muscle tension dysphonia (MTD) and potentially develop into vocal cord nodules, polyps, swelling (edema), and other issues. While the soft palate (velum) is key for proper velopharyngeal (VP) function, the back of the throat (posterior pharyngeal wall) helps compensate for any VP gap in those with VPI. When these muscles cannot fully close the VP gap, leading to hypernasality, individuals use compensatory strategies. These include speaking louder, emphasizing oral sounds, tensing vocal cords for a softer or higher voice to reduce nasality, or using glottal stops to compensate for poor VP closure. These behaviors all increase the risk of developing voice abnormalities.
The study found children with CP ± L are at a higher risk of developing various voice disorders compared to normal children [27, 28]. Correlation between hypernasality and voice quality was reported to be moderate and positive, indicating the premise that as hypernasality increases, voice quality decreases. Moreover, the study also noted a pattern between hypernasality and CAD, as patients with severe hypernasality were reported to have a higher number of compensatory articulation disorder patterns. Correlation between a higher GIRBAS score and the number of CAD patterns signified that voice disorders were more common among children with higher CAD patterns. For CAD patterns, the most common patterns were velar substitution, nasalized voiced pressure consonants, and phoneme‐specific nasal air emission that all of which contribute to voice disorders. Furthermore, children with CP ± L exhibit various compensatory behaviors, such as the tone in which they speak shifting from being loud to soft, as this is a mechanism to manage VPI. Although shifting tone can address the issue of resonance, it can lead to more problems arising, such as a strain on vocal cords, and cause voice disorders to worsen [28, 29]. CSL findings confirmed that children with higher GIRBAS scores had increased jitter and shimmer, while MPT was negatively correlated with voice quality.
The clinical implications and recommendations suggested that early diagnosis can lead to better intervention. This was extremely prevalent for children with severe voice disorders, especially for those who have CP ± L. Speech and langugae patholgists should conduct regular screenings to detect early stages of voice disorders before these children exhibit compensatory behavior patterns. If early detection is not conducted, it will lead to long‐term vocal strain and the behaviors becoming ingrained. Furthermore, the findings had implications for the need for there were more comprehensive voice assessments to be carried out that include a combination of assessment mechanisms, like perceptual and acoustic ones, that can fully evaluate voice quality in children with CP ± L. Further supplementing these assessments with tools like the CSL analysis and the GIRBAS scale can provide a more comprehensive evaluation of perceptual and objective components of voice disorders. Finally, children with CP ± L should be continuously monitored for changes in hypernasality, voice quality, and compensatory behaviors over time. If these abnormality patterns are observed there will be strategies to prevent severe voice disorders from occurring and can facilitate the improvement of the child's communication abilities.
The information of this study proves important and significant in the detection of children who need special attention, constant monitoring, and a differentiated approach in speech therapy. Interventions should also involve not only the enhancement of the loudness of the voice and ringing quality but also the reduction of vocal stress. Explaining to parents and caregivers the risks of developing compensatory behaviors will go a long way in preventing and/or reducing the cases of severe voice disorders in children with CP ± L.
5. Conclusion
Prevalence of voice disorder was 30%. The findings of this study affirm that children with CP ± L have compromised levels of voice quality; they also observed that more severe hypernasality and the presence of increased numbers of CAD patterns were associated with more severe voice disorders in children. Lastly, compensating strategies that included speaking louder or utilizing certain syllables and phonations to decrease nasality were employed, leading to hoarseness. It was demonstrated that these hypernasality and CAD patterns exert excess tension on the vocal folds, thus contributing to voice disorders.
Conflicts of Interest
The authors declare no conflicts of interest.
Acknowledgments
The funding for this study was granted by the Research and Graduate Studies of Khon Kaen University and The Center for Cleft Lip, Cleft Palate, and Craniofacial Deformities at Khon Kaen University in conjunction with the Tawanchai Project (The Tawanchai Center). (Grant Number TWG6416). Faculty of Medicine, Khon Kaen University supported a research assistant (Grant no. AS 66006).
Funding: This work was supported by Faculty of Medicine, Khon Kaen University supported for research assistant, AS 66006; Research and Graduate Studies of Khon Kaen University and The Center for Cleft Lip, Cleft Palate, and Craniofacial Deformities at Khon Kaen University in conjunction with the Tawanchai Project (The Tawanchai Center), TWG6416.
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