J. COMMUN. DISORD. 24 (19911, 381-392

PREVALENCE OF ARTICULATORY DISORDERS OF DIFFERENT SOUNDS IN A GROUP OF FINNISH FIRST-GRADERS MAR1 J. QVARNSTRijM Kuopio

University

Central Hospital

M. TELLERVO LAINE University

of Kuopio

S. MARJATTA JAROMA Kuopio

University

Central

Hospital

Occurrence and type of articulatory speech disorders were studied in 157 7-year-old firstgraders found to have articulatory disorders at school and referred for further treatment to the Department of Phoniatrics, University Central Hospital. The control group consisted of all 130 first-graders in two elementary schools in Kuopio. About one third of the control group had articulatory speech disorders, one fifth of them expressing need for speech therapy. In both groups distortions of the /s/-sound were the most common disorders, distortions of the /r/-sound being rather uncommon and those of the Ill-, /d/- and /t/-sounds very rare. Occurrence of articulatory speech disorders did not vary systematically with sex nor was it associated with handedness. Some spontaneous correction of /s/-disorders occurred, while /r/-disorders were rather resistant to early treatment. The results suggest the need for reevaluation of differential diagnostics and timing of speech therapy during kindergarten and elementary school.

INTRODUCTION Finnish children have been reported to be able to produce all speech sounds, including the most diffkult ones (/t-L, /s/- and /d/-sounds), correctly by the age of 4-5 years (Sarmavuori, 1982). About 25% of Finnish 7-year-old first-graders have been observed to have articulatory speech disorders (Kilpinen, 1982). In a study of 8-year-old schoolchildren, Sonninen and Sonninen (1976) found that 34% had disorders of the /s/-sound and 8% had disorders of the /r/-sound. There is, however, little detailed information about the specific types of disorders. When the speech articulation of children who have not yet learned to read is evaluated, it is common to use articulation tests that contain picAddress correspondence Kuopio University Central

to Mari J. Qvarnstrom, Department of Phoniatrics, Hospital, SF-702101 Kuopio, Finland.

0 1991 by Elsevier Science Publishing Co., Inc. 655 Avenue of the Americas, New York, NY I0010

ENT-clinic,

381 0021~9924/91/$3.50

382

QVARNSTRiiM

ET AL.

tures of familiar objects, the names of which the children are to say aloud (Van Demark and Swickard, 1980; Kenney et al., 1984). Disorders of the different sounds are usually divided into substitutions, omissions, and distortions of the sound, .substitutions still being rather. common among students in the lower grades of elementary school (Eisenson and Ogilvie, 1971). To allow comparisons between our results and findings in other population groups, corresponding criteria were selected for this study. Possible associations between hand preference and occurrence of language disorders have been reported in several papers, but the role of speech disorders-especially articulatory disorders-has been discussed less (Arnold, 1970: Lebrun, 1983; Neils and Aram, 1986: Kertesz, 1989). The purpose of this study was to map the occurrence and type of articulatory disorders of different sounds in a group of Finnish-speaking first-graders according to age and sex. An additional aim was to determine the possible association between handedness and variation in articulation of speech sounds.

MATERIAL

AND METHODS

In Kuopio, a town in middle Finland with a population of 80,000, in the fall of 1986, 1060 children entered the first grade of elementary school and in the fall of 1987, 1046 children entered. All these children were screened for speech disorders by special teachers. In 1986, 198 children and in 1987, 185 children were found to have articulatory disorders of at least one sound. Thus, on an average, 18% of all first-graders had articulation problems severe enough to be referred for speech therapy when they started school. The subjects (Hospital referral group) included in this study were 157 children found to have articulatory speech disorders when screened at school. They were referred for detailed diagnosis and treatment to the Department of Phoniatrics, ENT-clinic, Kuopio University Central Hospital. The control group (First-grade sample group) consisted of all 130 tirstgraders in two elementary schools in Kuopio. Table 1 shows distribution of the subjects according to sex and history of previous speech therapy for both groups. Slightly more boys than girls were included among the hospital referral group, while in the control group (first-grade sample group) both sexes were almost equally represented. Of the first-graders in the hospital referral group, twice as many had had speech therapy during kindergarten as in the control group. In both groups the mean and median ages were 74 years (SD 4.3 months and 4.2 months, respectively). The age range was 2 years and 2 months for the hospital referral group and one year and five months for the controls. Of the first-graders in the hospital referral group, 95% were right-handed

ARTICULATORY

SPEECH DISORDERS

Table 1. Distribution of Two Groups of Finnish First-Graders Sex, Previous Speech Therapy, and Handedness

Sex Girls Boys Previous speech therapy No Yes Information not available Handedness Right Left Not established

383

IN FIRST-GRADERS

According to

Hospital referral group (n = 157)

First-grade sample (n = 130)

n (%)

n (%)

67 (43) 90 (57)

67 (52) 63 (48)

64 (41) 92 (59)

1 (0)

90 (69) 37 (29) 3 (2)

149 (95) 7 (4)

117 (92) 9 (7)

1 (1)

I (1)

left-handed (Table 1); for 127 children of the first-grade sample the corresponding proportions were 92% and 7%, respectively. In this group information of the handedness was not available for three children. In 1% of the children in both groups, the handedness was not established. The first-graders of both groups were examined for articulatory speech disorders by the same experienced speech therapist. The children of the hospital referral group were examined at the Department of Phoniatrics and the children of the first-grade sample group at the health center of their school. First, so that the therapist could observe spontaneous speech, the child was interviewed about activities of daily living, school, and environment. The articulation test used was the Remes Articulation Test, which was developed for the Finnish language (Remes 1975a,b) and which consists of single-word items in a pictorial representation of familiar objects. The test words contain the Finnish consonants in various voweland consonant-cluster environments. After the articulation test, some complementary questions were asked. Articulatory disorders were classified according to the conventional classification based on disorders of different sounds (Van Riper, 1972) and divided into distortions, substitutions, and omissions of the sounds. Information about handedness, as well as about possible speech therapy before school age, was collected by interviewing the child and his/her parents when they visited the Department of Phoniatrics or the health center of the school. Chi-square or Fisher’s exact statistics were used to analyze differences in occurrence of articulatory speech disorders as well as handedness be-

and 4% were

QVARNSTRiiM

ET AL.

tween groups and between boys and girls. Multiple logistic regression functions were fitted to analyze the combined effects of age, sex, previous speech therapy, and handedness for occurrence of disorders of different sounds. For all analyses, a p-value of 5 0.05 (Z-values of at least 1.96) was considered statistically significant.

RESULTS Among the hospital referral group, 60% of the children had /s/-disorders and 38% had /r/-disorders (Table 2). Only I%-3% had problems with /I/-, Id/-, or /t/-sounds and none with other consonants or vowels. The disorders were mostly distortions of the sounds, substitutions of/s/-, /r/-, or /l/-sounds occurring in 1% of the children and omissions of /r/-sound in 1%. Among the first-grade sample group (Table 2) the most common articulatory disorders were also difficulties with the /s/- and /r/-sounds, in 3 1% and 7% of the children, respectively. Disorders of id/ and It/ occurred in about 1% of the children. All articulatory disorders in this group were distortions of the sounds.

Table 2. Frequency of Articulatory Speech Disorders Two Groups of Finnish-Speaking First-Graders

Sound M-Sound Correct Distortion Substitution /r/-Sound Correct Distortion Substitution Omission /l/-Sound Correct Distortion Substitution /d/-Sound Correct Distortion /t/-Sound Correct Distortion

of Different

Hospital referral group (n = 1.57)

First-grade sample (n = 130)

n (SC)

n (5%)

63 (40) 93 (59)

1 (1)

90 40

(69) (31)

0

(0)

121 9 0 0

(93) (7) (0) (0)

Sounds

in

PC’

.ooOO 97 (62) 57 (36) 2 (1)

I (1)

.I216 152 (97) 4

(2)

I (1)

130 (100) 0 (0) 0 (0) .8103

154 (98) 3 (2)

128 (99) 2 (2)

155 (99) 2 (1)

129

.6756

0 By xz test or Fisher’s exact fourfold

test

1

(99)

(1)

ARTICULATORY

SPEECH

DISORDERS

385

IN FIRST-GRADERS

Table 3. Frequency of Articulatory Speech Disorders of Different Sounds Two Groups of Finnish-Speaking First-Graders, According to Sex First-grade sample

Hospital referral group

Sound IS/

lrl III ldl It/

Boys

Girls (n = 67)

(n = 90)

n (%)

n (%)

42 (63) 19 (28) 0 (0) 1 (2) 1 (2)

y By x2 test or Fisher’s

52 41 5 2 1

(58) (46) (6) (2) (I)

exact fourfold

in

Boys

Girls (n = 67)

(n = 63)

PU

n (%)

n (%)

PC1

.6484 .0426 .I333 1 .oooo

23 (34) 4 (6)

17 (27) 5 (8)

.4736 .9237

1.oooo

0

(0)

1 (2) 0 (0)

0

(0)

1 (2) I (2)

-

1.0000 .9753

test

For the /s/- and /r/-sounds, the differences in occurrence of disorders of different sounds between the groups were statistically significant (Table 2). In both groups girls had more articulatory disorders of the /s/-sound than boys did, but the differences were not statistically significant (Table 3). On the other hand, in both groups boys had more disorders of the /r/sound than girls did. However, the difference was statistically significant only in the hospital referral group. Disorders of the /l/-sound were found only in boys, while Id/- and /t/-disorders were equally rare in both sexes. Different articulatory speech disorders can be expressed as combinations in individuals. In the hospital referral group, 87% of the children had a disorder of one or more sounds. Of the girls 79% and of the boys 92% had articulatory disorders. In the first-grade sample group the total number of subjects with at least one articulatory speech disorder was 33Y0, 36% of the girls and 30% of the boys. Most of the children in both groups were right-handed (Table 1). According to sex, in the hospital referral group 96% of the girls were righthanded and 3% left-handed, while in 2% the handedness was not established. In the same group 94% of the boys were right-handed and 6% left-handed. In the first-grade sample 91% of the girls and 94% of the boys were right-handed, and the percentages of left-handed children were 9% and 5%, respectively. For 2% of the boys in the first-grade sample handedness was not established. In neither group was the difference between boys and girls statistically significant. The relationship between handedness and articulatory speech disorders is shown in Table 4. In the hospital referral group all children with no articulatory speech disorders were right-handed. All left-handed children in this group, 5% of the total, had an articulatory disorder of at least one sound. In the first-grade sample group 91% of the children with no articulatory speech disorders were right-handed and 8% were left-handed. The

QVARNSTRiiM

ET AL.

Table 4. Relationship Between Handedness and Occurrence of Articulatory Speech Disorders in Two Groups of Finnish-Speaking First-Graders Hospital referral

First-grade articulatory

group disorder

articulatory

sample disorder

Handedness

None (n = 20) n (%‘I

2 One (n = 137) II (%)

None (n = 79) n (%)

2 One (n = 48) n (5%)

Right Left Not established

20 (100) 0 (0) 0 (0)

129 (94) 7 (5) I (I)

71 (90) 7 (9)

46 (96) 2 (4)

P”

I (1)

.5405

0 (0) .4380

” By x’ test or Fisher‘s exact fourfold test.

corresponding proportions of the children with at least one articulatory disorder were 95% and 5%, respectively. The differences within groups did not reach statistical significance. Multiple logistic regression functions showed that among children of the hospital referral group none of the studied variables (age, sex, previous speech therapy, and handedness) was associated with occurrence of disorder of the /s/-sound (Table 5). In the first-grade sample group (Table 6) occurrence of the /s/-disorder was negatively related with age. This implies that the risk of having the acoustical /s/-disorder decreased with increasing age in a group of first-graders with an age range of about 2 years. There was a positive and significant relationship between occurrence of disorders of the It-l-sound and previous speech therapy (Tables 7 and 8), indicating that disorders of the /r/-sound evidently are rather resistant to speech therapy.

Table 5. Relationship Between Acoustical /s/-Disorder Sex, Age, Previous Speech Therapy and Handedness Group, as Estimates of Logistic Model Variable

Sex (female = 0. male = I) Age (months) Previous speech therapy (no = 0. yes = I) Handedness (O-2)

Regression coefficient

(no = 0, yes = I) and in the Hospital Referral

S.E.

.17776

~ .OlS94 ~ .00248 - .34025

.02000

.46318

.38921

.I8048

Regression coeffcient/S.E. - .08965 p.12413 - I .88522 I I9006

ARTICULATORY

SPEECH

DISORDERS

IN FIRST-GRADERS

Table 6. Relationship Between Acoustical /s/-Disorder Sex, Age, Previous Speech Therapy and Handedness Sample Group, as Estimates of Logistic Model Variable Sex (female = 0, male = 1) Age (months) Previous speech therapy (no = 0, yes = 1) Handedness (O-2)

Regression coefficient

Sex (female = 0, male = 1) Age (months) Previous speech therapy (no = 0, yes = I) Handedness (O-2)

Sex (female = 0, male = 1) Age (months) Previous speech therapy (no = 0. yes = 1) Handedness (O-2)

S.E.

Regression coefficient/S.E.

.20369 .02489 .21698

- 1.22710 - 2.20756 I .09848

- .36161

.40494

- .89300

Regression coefficient

,I6038

(no = 0, yes = 1) and in the Hospital Referral

S.E.

.19231

Regression coefficientk4.E.

- .00482 .91777

.02127 .20882

.83399 - .22642 4.39513

- .09578

.32354

- .29614

Table 8. Relationship Between Acoustical /r/-Disorder Sex, Age, Previous Speech Therapy and Handedness Sample Group, as Estimates of Logistic Model Variable

(no = 0, yes = 1) and in the First-Grade

- .24994 - .05494 .2383S

Table 7. Relationship Between Acoustical /r/-Disorder Sex, Age, Previous Speech Therapy and Handedness Group, as Estimates of Logistic Model Variable

387

Regression coefficient -.I7208 - .03796

(no = 0, yes = I) and in the First-Grade

S.E.

Regression coefticient/S.E.

1.63874

.38425 .04920 .5.5154

- .44783 - .77154 2.97122

.I4782

.49649

.29773

QVARNSTRijM

ET AL.

DISCUSSION The subjects in this study were ordinary first-grade children from the Kuopio elementary schools. Socioeconomic background, including educational level of the parents, was not determined in this study. However, all schools in Finland are public schools, and all socioeconomic groups are represented in each school district. In the hospital referral group, it is possible that educational level of the parents might have had an influence on accepting the referral to the hospital. In general, Finnish children at the preschool or kindergarten level are referred for speech therapy if they have severe articulatory speech disorders. To discover any articulatory disorders severe enough to need treatment, all first-graders are screened by special teachers in fall during their first year at school. All special teachers are trained to diagnose and treat speech disorders and difficulties in reading and writing. However, the criteria used to estimate which articulatory disorders need treatment may vary among urban and rural municipalities for both children not at school yet and schoolchildren. The size of the elementary schools varies, resulting in differing resources for speech therapy. These differences in resources affect the criteria used to select children for treatment. Therefore in the present sample the criteria for referring first-graders for further treatment may have varied somewhat from one special teacher to another. In Finnish-speaking population, girls have more s-disorders, mainly mild or moderate, and boys have more r-disorders, usually severe enough to need treatment (Laine et al., 1987). During the actual study, the children in both groups were diagnosed by the same experienced speech therapist using the same method for all diagnoses. The environment during the examination of both groups was peaceful and quiet. Thus, the procedure to diagnose the articulatory disorders in the present study was the same for all children. All articulatory disorders found in the present population group were disorders of the Is/-, It-l-, /I/-, Id/-, or itl-sound, most commonly those of the Is/or /r/-sound. Almost all disorders were distortions, but there were also some substitutions and omissions. According to Powers (1971), substitutions and omissions are common among kindergarten children, but in school-age children articulatory disorders are mainly distortions. If categorized according to severity, omission is the most severe and distortion the least severe type of articulatory disorder (Shelton and McReynolds, 1979). In fact, omissions and substitutions may be an intermediate stage in the motor maturation of normal speech articulation. Interestingly, some omissions and substitutions were found in the hospital referral group, while in the first-grade sample group there were only distortions of some consonants. In the first-grade sample group one third of the children had articulatory

ARTICULATORY

SPEECH DISORDERS

IN FIRST-GRADERS

389

disorders of one or more sound. In previous studies frequency of articulatory disorders among Swedish-speaking first-graders was 3 1% (Alstam-Malcus et al., 1976) and among Finnish-speaking 8-year-olds 34% for the /s/-sound and 8% for the /r/-sound (Sonninen and Sonninen, 1976). Among Finnish-speaking young adults the frequency of all articulatory disorders has been reported to be 31%, 18% of which are severe enough to require treatment (Laine et al., 1987). In her study of Finnish secondgraders (excluding the mildest articulatory errors), Herajarvi (1968) also reported the same frequency. Interestingly, in this sample special teachers found 18% of all first-graders to have an articulatory problem needing treatment. The present and previous studies indicate that about one third of the 7- to 8-year-old children in Scandinavian population groups have an articulatory disorder of at least one sound, slightly less than one fifth revealing articulatory disorder severe enough to need treatment. In several studies, including the present one, the frequency of articulatory disorders has been reported to decrease with age (Leske, 1981). Milisen (1971) reported that 12%-15% of English children from kindergarten through the fourth grade had serious articulation defects and that, owing to spontaneous improvement, in grades five to eight the percentage was only 4.5%. Alstam-Malcus et al. (1976) studied a group of Swedish first-graders and found that a year later the articulatory disorder remained in only half of the cases. In the other half articulation had improved spontaneously without therapy. Kilpinen (1982) reported that 25% of 7-yearold Finnish-speaking children had articulatory speech disorders, whereas among young Finnish-speaking adults the percentage of subjects with moderate to severe distortion of at least one sound was 18% (Laine et al., 1987). In the present control group (the first-grade sample), which represented normally developing first-graders, the frequency of /s/-sound disorders decreased with advancing age; but no such change was discernible for the /r/-sound. On the other hand, /r/-disorders seemed to be rather resistant to speech therapy given during preschool or kindergarten. These findings indicate, on the one hand, spontaneous correction of /s/disorders and, on the other hand, poor response to early treatment of /r/disorders and raise the question as to whether differential diagnostics and timing of speech therapy for children should be re-evaluated. In some studies boys have been found to have more articulatory disorders than girls do. Kenney et al. (1984) studied 4-year-old preschool children with normal development and found that boys produced about twice as many articulatory errors as girls did. The girls had more distortions and omissions, and the boys had more substitutions of sounds. With regard to different sounds, boys made more errors in all sounds except /s/ and /f/. According to Beitchman et al. (1986), 36% of 5-year-old kindergarten boys and 30% of girls in the same age have speech problems. In a study of young Finnish-speaking adults Laine et al. (1987) found no

390

QVARNSTRiiMETAL.

significant difference between the sexes, although women tended to have more distortions of the /s/-sound and fewer distortions of the /r/-sound than men did. Children with severe language disorders have been found to be nonright-handed more often than children with mild language disorders (Neils and Aram, 1986). Articulatory disorders and delayed language development are known to be diagnostic features in, for example, MBD-syndrome (Minimal brain dysfunction) (Rasmussen et al., 1983) and speech dyspraxia (Arnold, 1970; Gordon and Grimley, 1974; Snowling and Stackhouse, 1983). In 7-year-old Swedish schoolchildren (Rasmussen et al., 1983) left-handedness was three times as common among children with MBD-syndrome as among those without MBD. Articulatory speech disorders combined with dyspraxia and/or MBD have been found to be difficult to correct even with long-term and intensive speech therapy, because of a basic problem in speech fine movements or in sensory-motor dysfunction (Gordon and Grimley, 1974; Rasmussen et al., 1983; Snowling and Stackhouse, 1983). Children with dyspraxia and MBD are also at risk for behavioral and learning problems (Gillberg et al., 1983). In our sample, the relationship between handedness and occurrence of articulatory speech disorders was not statistically significant. However, all left-handers in the study group (the hospital referral group) had a disorder of at least one sound. Speech movements and variation in place of articulation of speech sounds in these data will be reported separately. During the second phase of this longitudinal study it will be interesting to see whether these children have problems with reading or writing during the first three years at school.

SUMMARY About one third of a series of first-graders had articulatory speech disorders, all of which were distortions of medioalveolar consonants in the Finnish language. Parallel to other linguistic areas, distortions of the /s/sound were the most common disorders, distortions of the /r/-sound being rather uncommon and those of the /I/-, Id/-, and /t/-sounds very rare. About one fifth of the first-graders were referred by special teachers for further treatment. Relatively, /r/-disorder was clearly more often an indication for referral for treatment during speech screening at school. The present results indicate that occurrence of articulatory speech disorders did not vary systematically with sex, nor was it associated with handedness. Some spontaneous correction of /s/-disorders occurred, but disorders of the /r/-sound were rather resistant to early treatment. In conclusion, these and previous results suggest the need for reevaluation of differential diagnostics and timing of speech therapy during kindergarten and elementary school.

ARTICULATORY

This study

SPEECH DISORDERS

was supported

by the grants

391

IN FIRST-GRADERS

from the University

of Kuopio, from Foundation.

the Academy

of Finland. and from the North Savo Fund of Finnish Cultural

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Englewood