A speech sound disorder (SSD) is defined as the presence of a problem with articulation and phonological processes in a child. This study analyzed the clinical characteristics of Korean patients with functional SSDs without any neuromuscular abnormalities.
The medical records of patients aged 36 to 72 months old who were diagnosed with SSDs were retrospectively reviewed. SSD patients who scored less than 85 in the U-Tap test were divided into two groups according to their receptive language scores on the Preschool Receptive-Expressive Language Scale (PRES)/the Sequenced Language Scale for Infants (SELSI).
Sixty-seven percent of patients with language impairment (LI) who were diagnosed with an SSD initially visited the hospital for a delay in language development (n=18, 66.7%). Among children with only an SSD, 26.7% (n=8) of the patients recognized it as a language developmental problem. All SSD patients had substitution errors in the onset of initial syllables (SSD, SSD+LI: 100%; typical development [TD]: 37.5%). Of particular note, SSD children with LI had more omission errors (55.6%) than patients with SSD only (16.7%). SSD patients had higher error rates than TD children in all consonants except for the glottal element (
A high percentage of children with SSD initially visited the hospital for the treatment of language development delays. Articulation tests are essential for children who suffer from language delay. Furthermore, since incorrect articulation can lead to delays in expressive language development, early interventions should be considered.
Inaccurate pronunciation is attributable to disorders of central and/or peripheral origin (articulation vs. phonologic disorders, respectively). Distinguishing between these types of disorders is challenging. The inability to correctly pronounce certain speech sounds beyond the age at which the sounds are usually learned (caused by an articulation or phonological disorder) is referred to as a speech sound disorder (SSD) [
A child’s speech-production skills develop during the cooing and babbling stages. Children usually attain phonological characteristics similar to those of adults by 3 to 5 years of age. A majority of Korean children can use most syllable structures proficiently by 4 years of age [
A Korean study reported that 2.5% of children had SSDs and 6.4% were at risk; however, the study lacked descriptions of the characteristics of SSDs in Korean-speaking children [
In this study, we investigated the clinical characteristics of Korean patients with functional SSDs. We excluded patients with neuromuscular abnormalities or abnormalities detected on brain magnetic resonance imaging (MRI). We specifically focused on differences based on the degree of LI and in comparison with children who showed typical development (TD).
We analyzed data of children aged 36 to 72 months, who underwent language tests at Jeonbuk National University Children’s Hospital between January 2016 and December 2020. The total number of participants was 974, of whom 410 were excluded because they had neuromuscular disorders (such as epilepsy or cerebral palsy), or electroencephalography- or brain MRI-documented abnormalities that may affect speech and language ability. We also excluded patients with tongue or oral cavity abnormalities. We defined an SSD as a U-Tap score <85 (below –1 standard deviation). Since the U-Tap score was low owing to a lack of language development, and not articulation impairment, in such cases, we excluded patients in whom the PRES score was not higher than the U-Tap score by 10 points or more. Finally, 57 patients were included in the study.
All children underwent the U-Tap test for pronunciation and PRES or SELSI screening to evaluate language development [
The U-Tap includes a total of 43 consonant tests (18 in the syllable onset, 18 in the nucleus, and seven in the coda). The score is expressed as a percentage of consonants that are correctly pronounced [
We investigated various clinical characteristics, such as the patient’s chief complaint, sex, age, gestational age at birth, birth weight, mode of delivery, number of siblings, duration of breastfeeding, head circumference, mean video or cellular phone exposure time per day, the timing of first word expression, and attention deficit-hyperactivity disorder, as predictor of language function in children. We compared clinical characteristics between the SSD and SSD+LI groups and TD group. We evaluated factors that affect U-Tap scores regardless of language ability. Differences in vulnerable consonants were also compared and analyzed. This study was approved by the Institutional Review Board (IRB) of Jeonbuk National University Hospital (IRB No.2021-05-053). Written informed consent by the patients was waived due to a retrospective nature of our study.
Clinical characteristics were summarized using means, standard deviations, and percentages. One-way analysis of variance, the Kruskal-Wallis test, and the chi-square test were used to compare differences in characteristics and U-Tap scores between the two SSD groups and the TD group. Multiple logistic regression analysis was performed to identify correlations between clinical characteristics and the U-Tap score. We performed the chi-square and Fisher exact tests to assess the significance of differences in the frequency of consonant errors among the three groups. All statistical analyses were performed using SPSS version 23.0 (IBM Corp., Armonk, NY, USA).
We quantified cases in which children had substitution, distortion, or omission errors in the 43 consonant tests. All patients with SSDs had substitution errors in the initial syllable onset position (SSD and SSD+LI: 100%; TD: 37.5%) (
Comparable results were obtained in a data analysis based on consonant phonemes and error types (
We investigated the clinical characteristics that were likely to be associated with the U-Tap score (
In this study performed in Korean preschool-aged children, we compared consonant errors between children with SSD and those with TD. SSD was commonly observed in boys (SSD: 80.0%; SSD+LI: 66.7%) (
Overall, compared with the TD children, those with SSDs experienced difficulties with most consonants, except the glottal element (
Clinical characteristics such as birth weight, mode of delivery, duration of breastfeeding, siblings, and head circumference did not affect the U-Tap score (
The clinical implications of these findings are as follows. (1) Many children diagnosed with SSDs initially sought medical attention for evaluation of delayed language development. Articulation tests are indicated in children who present with a major complaint of language delay. (2) Children with SSDs may occasionally present with concomitant expressive language delay; an early and accurate diagnosis and prompt initiation of treatment are necessary in such cases. (3) Children with SSDs tend to struggle even with pronunciation of easy consonants, and those with accompanying LI show a greater variety of errors than children with pure SSDs or TD. Therefore, both language function and articulation/phonological tests should be performed in all children with pronunciation problems and/or developmental language delays.
The limitations of this study are as follows. (1) We enrolled a limited number of preschool-aged children with SSDs; therefore, the small sample size is a drawback of this research. (2) A single language test was used in this study, and our results might not be generalizable across different languages. Large-scale studies are warranted in the future to investigate changes in expressive language function based on post-treatment improvement in articulation and prognosis in school-aged children.
No potential conflict of interest relevant to this article was reported.
Conceptualization: SJK. Data curation: MJH. Formal analysis: MJH. Methodology: MJH and SJK. Project administration: SJK. Visualization: MJH and SJK. Writing-original draft: MJH. Writing-review & editing: SJK.
Distribution of proportions of errors according to type and consonant category in children with typical development (TD), speech-sound disorders (SSD), and SSD+language impairment (LI). (A) It is the onset error of initial syllable and (B) is the error of the middle of words on all SSD patients, (C) and (D) show the error probability for each consonant group regardless of the error type. B, bilabial; N, nasal; G, glottal; VP, velar plosive; AP, alveolar plosive; AF, alveolar fricative; PA, palatal affricate; L, liquid.
Clinical characteristics of SSD patients
Characteristic | SSD | SSD+LI | TD | |
---|---|---|---|---|
Sex | 30 | 27 | 16 | |
Male | 24 (80.0) | 18 (66.7) | 10 (62.5) | 0.369 |
Female | 6 (20.0) | 9 (33.3) | 6 (37.5) | |
Age (mo) | 45.3±8.7 | 46.4±7.7 | 49.2±7.8 | 0.293 |
Visiting route | ||||
Parents | 17 (56.7) | 12 (44.4) | 8 (50.0) | 0.003 |
K-DST screening | 10 (33.3) | 14 (51.9) | 2 (12.5) | |
Other | 3 (10.0) | 1 (9.1) | 6 (37.5) | |
Chief complaint | ||||
DLD | 8 (26.7) | 18 (66.7) | 3 (18.8) | |
Articulation problem | 14 (46.7) | 5 (18.5) | 1 (6.3) | 0.001 |
GDD | 0 | 3 (11.1) | 0 | |
Routine check-up | 8 (26.7) | 1 (3.7) | 4 (25.0) | |
Other | 0 | 0 | 8 (50.0) | |
Mode of delivery | ||||
Vaginal | 19 (63.3) | 14 (51.9) | 9 (56.3) | 0.677 |
Cesarean section | 11 (36.7) | 13 (48.1) | 7 (43.8) | |
Gestational age (wk) | 37.9±3.2 | 39.2±1.7 | 38.6±2.5 | 0.197 |
Weight at birth (kg) | 3.1±0.7 | 3.2±0.6 | 3.0±0.5 | 0.657 |
Sibling (n) | 1.9±0.5 | 1.9±0.6 | 1.9±0.3 | 0.930 |
Breastfeeding duration (mo) | 4.8±4.7 | 5.0±6.5 | 5.1±7.3 | 0.435 |
Head circumference | ||||
<–2 SD percentile | 3 (10.0) | 5 (18.5) | 1 (6.3) | 0.583 |
–2 SD≤ HC <–1 SD | 1 (3.3) | 2 (7.4) | 2 (12.5) | |
–1 SD≤ HC <0 | 10 (33.3) | 5 (18.5) | 6 (37.5) | |
0≤ HC <1 SD | 12 (40.0) | 10 (37.0) | 7 (43.8) | |
1 SD≤ HC <2 SD | 4 (13.3) | 4 (14.8) | 0 | |
≥2 SD | 0 | 1 (3.7) | 0 | |
Screen time (/day) | 1.8±1.5 | 2.7±2.3 | 1.2±0.9 | 0.011 |
First word utterance (mo) | 14.6±6.1 | 15.7±6.5 | 13.1±4.1 | 0.425 |
ADHD | 4 (13.3) | 5 (18.5) | 2 (12.5) | 0.817 |
Receptive language (score) | 102.7±11.1 | 67.5±11.0 | 99.0±9.0 | <0.001 |
Expressive language (score) | 91.7±14.3 | 64.0±13.9 | 94.9±11.4 | <0.001 |
U-Tap score (score) | 63.2±12.0 | 48.9±13.2 | 94.8±4.9 | <0.001 |
Values are presented as number (%) or mean±standard deviation.
SSD, speech sound disorder; LI, language impairment; TD, typical development; K-DST, Korean Developmental Screening Test for infants and children; DLD, developmental language delay; GDD, general developmental delay; SD, standard deviation; HC, head circumference; ADHD, attention deficit-hyperactivity disorder; U-Tap, Urimal Test of Articulation and Phonation.
Statistical differences of consonant errors in SSD patients and TD children
Variable | Substitution |
Distortion |
Omission |
Total |
||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
SSD | SSD+LI | TD | SSD | SSD+LI | TD | SSD | SSD+LI | TD | SSD | SSD+LI | TD | |||||
Onset of initial syllable | ||||||||||||||||
Bilabial plosives | 5 (16.7) | 12 (44.4) | 0 | 0.002 | 2 (6.7) | 0 | 1 (6.3) | 0.398 | 1 (3.3) | 10 (37.0) | 0 | <0.001 | 7 (23.3) | 14 (51.9) | 1 (6.3) | 0.004 |
Nasal | 3 (10.0) | 6 (22.2) | 0 | 0.089 | 2 (6.7) | 1 (3.7) | 0 | 0.550 | 2 (6.7) | 7 (25.9) | 0 | 0.021 | 7 (23.3) | 14 (51.9) | 0 | 0.001 |
Glottal | 1 (3.3) | 2 (7.4) | 1 (6.3) | 0.787 | 0 | 0 | 1 (6.3) | 0.164 | 1 (3.3) | 1 (3.7) | 0 | 0.747 | 2 (6.7) | 3 (11.1) | 2 (12.5) | 0.769 |
Velar plosives | 10 (33.3) | 11 (40.7) | 0 | 0.013 | 7 (23.3) | 2 (7.4) | 1 (6.3) | 0.135 | 2 (6.7) | 10 (37.0) | 0 | 0.001 | 13 (43.3) | 17 (63.0) | 1 (6.3) | 0.001 |
Alveolar plosives | 6 (20.0) | 12 (44.4) | 2 (12.5) | 0.038 | 4 (13.3) | 6 (22.2) | 1 (6.3) | 0.346 | 1 (3.3) | 11 (40.7) | 0 | <0.001 | 10 (33.3) | 18 (66.7) | 3 (18.8) | 0.004 |
Alveolar fricative | 26 (86.7) | 24 (88.9) | 5 (31.3) | <0.001 | 8 (26.7) | 11 (40.7) | 2 (12.5) | 0.134 | 2 (6.7) | 3 (11.1) | 0 | 0.378 | 30 (100) | 27 (100) | 7(43.8) | <0.001 |
Palatal affricate | 28 (93.3) | 22 (81.5) | 2 (12.5) | <0.001 | 9 (50.0) | 6 (22.2) | 3 (18.8) | 0.655 | 1 (3.3) | 8 (29.6) | 0 | 0.001 | 30 (100) | 25 (92.6) | 5 (31.3) | <0.001 |
Liquid | 15 (50.0) | 10 (37.0) | 0 | 0.001 | 3 (10.0) | 0 | 0 | 0.106 | 2 (6.7) | 9 (33.3) | 0 | 0.003 | 20 (66.7) | 19 (70.4) | 0 | <0.001 |
Onset of middle syllable | ||||||||||||||||
Bilabial plosives | 4 (13.3) | 16 (59.3) | 0 | <0.001 | 1 (3.3) | 5 (18.5) | 0 | 0.046 | 1 (3.3) | 2 (7.4) | 0 | 0.478 | 5 (16.7) | 20 (74.1) | 0 | <0.001 |
Nasal | 2 (6.7) | 3 (11.1) | 0 | 0.378 | 3 (10.0) | 1 (3.7) | 0 | 0.321 | 4 (13.3) | 9 (33.3) | 0 | 0.016 | 7 (23.3) | 12 (44.4) | 0 | 0.005 |
Glottal | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | ||||
Velar plosives | 12 (40.0) | 18 (66.7) | 1 (6.3) | 0.001 | 7 (23.3) | 8 (29.6) | 0 | 0.059 | 3 (10.0) | 11 (40.7) | 0 | 0.001 | 15 (50.0) | 24 (88.9) | 1 (6.3) | <0.001 |
Alveolar plosives | 6 (20.0) | 15 (55.6) | 1 (6.3) | 0.001 | 8 (26.7) | 4 (14.8) | 0 | 0.064 | 2 (6.7) | 7 (25.9) | 0 | 0.021 | 13 (43.3) | 20 (74.1) | 1 (6.3) | <0.001 |
Alveolar fricative | 28 (93.3) | 26 (96.3) | 5 (31.3) | <0.001 | 5 (16.7) | 5 (18.5) | 3 (18.8) | 0.977 | 0 | 2 (7.4) | 0 | 0.173 | 30 (100) | 27 (100) | 7 (43.8) | <0.001 |
Palatal affricate | 25 (83.3) | 22 (81.5) | 1 (6.3) | <0.001 | 9 (30.0) | 10 (37.0) | 1 (6.3) | 0.084 | 0 | 0 | 0 | 29 (96.7) | 25 (92.6) | 2 (12.5) | <0.001 | |
Liquid | 5 (16.7) | 4 (14.8) | 0 | 0.231 | 2 (6.7) | 3 (11.1) | 0 | 0.378 | 13 (43.3) | 16 (59.3) | 2 (12.5) | 0.011 | 20 (66.7) | 23 (85.2) | 2 (12.5) | <0.001 |
Values are presented as number (%).
SSD, speech sound disorder; TD, typical development; LI, language impairment.
Correlations between clinical factors and the U-Tap score (
Variable | U-Tap score |
---|---|
Sex | 0.261 |
Age | 0.016 |
Mode of delivery | 0.698 |
Gestational age | 0.203 |
Weight | 0.320 |
Siblings | 0.527 |
Breastfeeding duration | 0.860 |
Head circumference | 0.320 |
Screen time | 0.752 |
First word utterance | 0.887 |
ADHD | 0.403 |
Receptive language | 0.769 |
Expressive language | 0.001 |
U-Tap, Urimal Test of Articulation and Phonation; ADHD, attention deficit-hyperactivity disorder.