palate

British Journal of Plastic Surgery (2001), 54, 290–293 © 2001 The British Association of Plastic Surgeons doi:10.1054/bjps.2001.3571

Association between velopharyngeal function and dental-consonant misarticulations in children with cleft lip/palate J. Pulkkinen, M.-L. Haapanen, J. Laitinen, M. Paaso and R. Ranta Cleft Centre, Department of Plastic Surgery, Helsinki University Central Hospital, Helsinki, Finland SUMMARY. We studied the association between velopharyngeal function and misarticulation of the dental consonants /r/, /s/ and /l/ in children with cleft lip/palate. We assessed 278 6-year-old Finnish-speaking non-syndromic children (115 girls, 163 boys) with isolated cleft palate (n:81), cleft lip/alveolus (n:82) or unilateral (n:84) or bilateral (n:31) cleft lip and palate. Auditory analysis of speech and velopharyngeal function, the presence of fistulae, previous velopharyngoplasty and speech therapy, as well as surgical technique and timing of primary palatal surgery were obtained from the hospital records. The misarticulations of the sounds /r/, /s/ and /l/ were evaluated in spontaneous speech by two experienced speech pathologists from the cleft team. Velopharyngeal function was categorised, on the basis of the effect on speech, into competent, marginal incompetent and obvious incompetent. Nasal grimace and distortions due to palatal fistulae were registered. The results indicated that velopharyngeal function was not significantly associated with misarticulation of any of the sounds /r/, /s/ and /l/ or their combinations in any cleft groups. The technique and timing of primary palatal surgery, the presence of fistulae and previous pharyngoplasty were not associated with misarticulations. On the basis of these results we conclude that dental-consonant misarticulations occur independently of velopharyngeal function, primary palatal surgical technique and timing of palatoplasty. © 2001 The British Association of Plastic Surgeons Keywords: velopharyngeal function, misarticulation, cleft palate, pharyngoplasty.

sound is a voiced trill, /s/ is a voiceless sibilant and /l/ is a voiced lateral consonant; they are quite similar to their British English counterparts. To control for possible misleading variables, the effects of sex, cleft type, method and timing of primary palatoplasty, palatal fistulae, earlier velopharyngoplasty and speech therapy were also studied.

The prevalence of dental-consonant articulatory errors is higher in cleft patients than in non-cleft patients.1–3 Our earlier studies have shown that, at the age of 6 years, 44% of cleft patients misarticulate at least one of the sounds /r/, /s/ and /l/; 41% distorted and 5% substituted (2% both distorted and substituted) at least one sound. The proportion of patients with at least one misarticulation increased significantly with increasing severity of the cleft. Misarticulations are significantly more often found in boys than in girls.1 The factors causing dental-sound misarticulations are not yet fully understood. Speech aerodynamics and breathing may be distorted in cleft patients.4 Dentoalveolar dysmorphology, in terms of the severity of the cleft, results in atypical cephalometric dimensions. This is associated with abnormalities in vocal-tract anatomy and may cause abnormal functioning and physiology during breathing and phonation.4,5 Alveolar fistulae, and the presence or absence of incisors, may also interfere with the ability to articulate. The pattern of speech development may also depend on factors such as previous velopharyngoplasty, the method of primary palatoplasty and existing hardpalate fistulae as well as social, psychomotor and psychodynamic factors and speech therapy. As far as we know, little research has focused on the correlation between velopharyngeal function and dental-sound misarticulations. Therefore, the aim of this study was to examine the relationship between velopharyngeal function and articulation of the Finnish dental consonants /r/, /s/ and /l/, normally produced by linguoalveolar contact. The /r/

Patients and methods We studied 278 out of 280 consecutive Finnish-speaking children with adequate cephalometric and occlusal data born between 1980 and 1988, years varying in the numbers of the different types of clefts (Table 1). Two subjects out of the 280 were excluded because we had inadequate data on velopharyngeal function. All the children were treated at the Cleft Centre, Department of Plastic Surgery, Helsinki University Central Hospital. Only patients with no documented persistent hearing deficiency, no known syndrome or associated anomaly possibly affecting speech, no psychomotor retardation and no language-related cognitive disabilities were included in the study. The cleft palates were closed at a mean age of 1.4 years (s.d.:0.38 years; range: 0.7–2.1 years) using a one-stage closure of the cleft palate with either the Veau–Wardill–Kilner V–Y pushback (n:62) or the Cronin modification (n:130).6 In four boys with bilateral cleft lip and palate, the cleft palate was closed using a Shweckendiek modification. In 109 children the cleft palate was closed before the age of 1.5 years 290

Association between velopharyngeal function and dental-consonant misarticulations

(mean: 1.2 years; s.d.:0.13 years; range: 0.7–1.5 years) and in 87 children at the age of 1.5 years or later (mean: 1.8 years; s.d.:0.16 years; range: 1.5–2.1 years). None of the children had had orthodontic treatment. The patients attended regular follow-up examinations at a mean age of 6.1 years (s.d.:0.23 years; range: 5.4–7.0 years). The methods have been described in more detail in a previous paper.1 Table 1 shows the distribution of patients by type of cleft and sex, previous speech therapy, velopharyngoplasty and the presence of fistulae. The speech data were obtained from hospital records, including the speech data obtained from perceptual (auditory) analyses made by one of the two experienced speech pathologists from the cleft team. Misarticulations of the sounds /r/, /s/ and /l/ were evaluated in spontaneous speech.7 Sounds were categorised into correct sounds and misarticulations; the misarticulations were further categorised into distortions and substitutions. The distortions included sounds produced by deviated place or manner of articulation (e.g. palatalisation, lateralisation, interdental sound production, lack of trill in the /r/ sound). The sounds produced instead of the target phoneme were recorded for the substitutions. Specific signs of velopharyngeal incompetence (VPI) were not included in the misarticulations studied. Speech characteristics associated with VPI were registered for all of the sounds. Those were: 1: nasal air emissions; 2: hypernasality; 3: weakness of pressure consonants; and 4: compensatory articulations (glottal, lingual, pharyngeal stops and nasal and laryngeal fricatives). Each parameter was judged to be either absent or present. Nasal air emission was recorded as present if it was heard more than twice in one examination. Hypernasality was present if it was heard constantly or temporarily in a specific phonetic context, i.e. in high vowels or in the approximants. Weakness of plosives was present if it was associated with the pronunciation of pressure consonants on at least two occasions during the examination. The degree of

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velopharyngeal competence was assessed, according to a three-point scale, in terms of the combination of registered perceptual speech signs. A scale value of 0 indicated velopharyngeal competence, a value of 1 indicated marginal velopharyngeal competence including cases with temporary signs of VPI, e.g. hypernasality in high vowels, or mild, occasional nasal air emissions noted in association with pressure consonants. A scale value of 2 indicated obvious VPI, including cases with constant hypernasality with or without constant nasal air emission, noted typically in association with pressure consonants, as well as cases with weakness of plosives and compensatory articulation. The effects of residual oronasal fistulae were identified and excluded from the categorisation of the misarticulations studied. Audible nasal air emission with or without nasal grimace and retracted articulation were taken into account for differential diagnostic purposes. The inter-judge agreement in the assessment of speech characteristics of velopharyngeal function and psychomotor development ranged from 91.3% to 94.2%. The data for each patient’s /r/, /s/ and /l/ sounds were evaluated simultaneously by the two speech pathologists; the categorising of distortions and substitutions was based on a 100% consensus between them. The data were entered into a computer and analysed using NCSS 6.0 for Windows. Pearson’s chi-squared or Fisher’s exact statistics were calculated to test for differences between the parameters being compared. For all analyses P:0.05 was accepted as significant. Results The occurrences of misarticulation of /r/, /s/ or /l/ or their combinations were statistically compared to velopharyngeal competence, marginal velopharyngeal competence and obvious VPI. No significant differences were observed (Table 2). In later comparisons marginal and obvious VPI subgroups were combined.

Table 1 Number of patients with each type of cleft by sex, misarticulations of /r/, /s/, /l/ or their combinations, obvious or marginal velopharyngeal incompetence (VPI), previous velopharyngoplasty, previous speech therapy and fistulae Cleft type CP CL(A) UCLP BCLP Total

Boys

Girls

Total

Misarticulations

VPI

Velopharyngoplasty

Speech therapy

Fistulae

36 49 54 24

45 33 30 7

81 82 84 31

32 19 49 22

34 8 34 7

10 0 13 10

27 4 33 12

11 0 28 13

163

115

278

122

83

33

76

52

CP: cleft palate only; CL(A): cleft lip with or without cleft alveolus; UCLP: unilateral cleft lip and palate; BCLP: bilateral cleft lip and palate.

Table 2 Statistical comparison of patients with and without misarticulation of the sounds /r/, /s/, /l/ and any one of them between the subgroups with velopharyngeal competence (VPC), marginal velopharyngeal competence (mVPC) and obvious velopharyngeal incompetence (oVPI) /r/

VPC (n:195) versus mVPC (n:63) VPC (n:195) versus oVPI (n:20) VPC (n:195) versus mVPC;oVPI (n:83)

/s/

/l/

P

χ2

P

χ2

P

χ2

0.400 0.352 0.755

0.709 0.867 0.098

0.743 0.453 0.952

0.103 0.562 0.004

0.222 1.000 0.348

1.491 0.048 0.882

No significant differences (P:0.05) were observed.

/r/ or /s/ or /l/ P χ2 0.224 0.859 0.345

1.476 0.031 0.892

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Figure 1—Occurrence of /r/, /s/ and /l/ misarticulations associated with velopharyngeal incompetence (VPI) and velopharyngeal competence (VPC) in 6-year-old children according to the type of cleft.

There was no significant difference in velopharyngeal function between boys and girls in any cleft group. Thus, boys and girls were combined in later comparisons. Although the velopharyngeal-competence group included more misarticulations than the VPI group, the only significant difference was observed in the bilateral-cleft-lipand-palate group, where all /s/ disorders were in the velopharyngeal competence group. The timing and method of primary palatal repair and the presence of residual fistulae were not significantly correlated with the presence of misarticulations in any of the cleft groups (P90.05). Subjects with no previous speech therapy had significantly fewer misarticulations (P:0.002) than those who had had speech therapy before the age of 6 years. However, speech therapy was not significantly correlated with velopharyngeal function (P:0.205). Patients who had had previous velopharyngoplasty did not differ from those who had not (P:0.162) in terms of the frequency of misarticulations. Figure 1 shows the frequency of /r/, /s/ and /l/ misarticulations associated with VPI and velopharyngeal competence in 6-year-old children according to the type of cleft. Discussion Children with cleft palate are prone to severe speech problems. In addition to problems with resonance and pressure consonants they also very often have dentalconsonant misarticulations.1,8 VPI results directly or compensationally in specific speech characteristics, which can usually be eliminated by plastic surgery and/or speech therapy. However, dental-consonant errors are quite resistant to therapy.1,2,9 They are known to be associated with occlusal or cephalometric abnormalities10 and aerodynamic problems,11 but so far there has been no analysis of the relationship between velopharyngeal function and dental-consonant misarticulations. This information is important for evolving adequate treatment. Dental misarticulations impair speech intelligibility and may cause psychosocial problems, and their treatment accounts

for a large proportion of the costs of speech therapy, especially in cleft patients. The children with VPI did not have more frequent dental-consonant errors than the children with velopharyngeal competence. Thus, these results indicate, for the first time, that dental-consonant misarticulations do not significantly depend on VPI. There was no significant difference between the subgroups with and without a velopharyngeal flap in the distribution of dental-consonant errors. Thus, the errors are not likely to be due to persisting faulty articulatory manoeuvres originally induced by velopharyngeal insufficiency before the flap operation. The articulatory errors were not dependent on the timing or the method of primary palatal repair, which further confirms their independence of velopharyngeal function. Since VPI cannot explain dental-consonant misarticulations, other possible reasons for their presence should be examined and specifically treated. An important conclusion of this study is that dental-consonant errors in cleft patients are a separate error category. The treatment of dental-consonant errors could be planned independently of the treatment of VPI. Some features specific to VPI may, of course, also occur in association with dental-consonant misarticulations, but according to our results dental-consonant misarticulations are not significantly related to velopharyngeal function, whether competent or not. Our results have important implications for the treatment of cleft-palate patients. When various techniques of primary palatal repair are compared in terms of speech outcome, the results should not be biased by non-specific factors such as dental-consonant misarticulations. So far there have been no studies on the effect of the treatment of dentofacial dysmorphology on the production of dental consonants. As the surgical treatment of cleft palate is not correlated with dental-consonant misarticulations, and as these may be associated with dentofacial dysmorphology, it is important to focus future research on the diagnosis and treatment of dentofacial dysmorphology.

Association between velopharyngeal function and dental-consonant misarticulations

Acknowledgements This study was supported by the Emil Aaltonen Foundation.

References 1. Laitinen J, Haapanen M-L, Paaso M, Pulkkinen J, Heliövaara A, Ranta R. Occurrence of dental consonant misarticulations in different cleft types. Folia Phoniatr Logop 1998; 50: 92–100. 2. Qvarnström MJ, Laine MT, Jaroma SM. Prevalence of articulatory disorders of different sounds in a group of Finnish first-graders. J Commun Disord 1991; 24: 381–92. 3. Van Demark DR, Morris HL, Vandehaar C. Patterns of articulation abilities in speakers with cleft palate. Cleft Palate J 1979; 16: 230–9. 4. Mayo R, Warren DW, Zajac DJ. Intraoral pressure and velopharyngeal function. Cleft Palate Craniofac J 1998; 35: 299–303. 5. Warren DW, Drake AF, Davis JU. Nasal airway in breathing and speech. Cleft Palate Craniofac J 1992; 29: 511–19. 6. Heliövaara A, Rintala A, Ranta R. One-stage closure of isolated cleft palate with the Veau–Wardill–Kilner V to Y pushback procedure or the Cronin modification. Scand J Plast Reconstr Surg Hand Surg 1993; 27: 49–54. 7. Remes K. Artikulaatiotesti. Kuvakortisto puheenkehityksen ja äännevirheisyyden tutkimiseen ja tarkkailuun. Helsinki: Koulun Erityispalvelu Oy, 1975. 8. Haapanen M-L. Factors affecting speech in patients with isolated cleft palate: a methodic, clinical and instrumental study. Scand J Plast Reconstr Surg Hand Surg 1992; Suppl. 26.

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9. Luotonen M. Early speech development, articulation and reading ability up to the age of 9. Folia Phoniatr Logop 1995; 47: 310–17. 10. Laine T. Associations between articulatory disorders in speech and occlusal anomalies. Eur J Orthod 1987; 9: 144–50. 11. Laitinen JM, Sarmas R, Haapanen M-L, Ranta R. Speech and breathing aerodynamics, oral somatosensoric sensibility, and strength of tongue muscles correlated with articulation of the Finnish /r/-sound in subjects with and without oral clefts. Med Sci Res 1998; 26: 813–15.

The Authors Joonas Pulkkinen DDS, Special Dentist Marja-Leena Haapanen MD, PhD, Chief Phoniatrician Jaana Laitinen DDS, PhD, Dentist Marjukka Paaso BA, Speech Therapist Reijo Ranta DDS, PhD, Chief Orthodontist Cleft Centre, Department of Plastic Surgery, Helsinki University Central Hospital, Töölö Hospital, PO Box 266, FIN-00029 HUS, Finland. Correspondence to Joonas Pulkkinen. Paper received 28 January 2000. Accepted 22 January 2001, after revision. Published online 4 April 2001.