Sensitivity of the Denver Developmental Screening Test in Speech and Language Screening

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Sensitivity

of the Denver

Developmental

Screening

Test in Speech

and

Language

Screening

Kathleen C. Borowitz, MS, CCC-SLP, and Frances P. Glascoe, PhD

From the Comprehensive Developmental Evaluation Center, Department of Pediatrics, Vanderbilt University, Nashville

ABSTRACT. A retrospective study was undertaken to determine whether the Denver Developmental Screening Test (DDST) language sector is a sensitive screen of speech and language development. Seventy-one children between 18 and 66 months of age with suspected devel-opmental problems were referred to screening clinics conducted by a child evaluation team. Each child was screened using the DDST (revised) and another screening measure of speech and language development. Statisti-cally significant differences were found between the

DDST language sector and the speech-language screening

in identification of expressive language and articulation problems. No significant difference was found with

re-ceptive language. The DDST failed to identify more than

one half of the children with expressive language and/or articulation problems. These results demonstrate that the DDST may fail to identify children with speech and language impairment. Professionals involved in develop-mental screening need to be advised of alternative speech

and language screening measures. Pediatrics 1986;78: 1075-1078; Denver Developmental Screening Test, speech and language development.

Since its development in 1967, the Denver

De-velopmental Screening Test’ (DDST) has become

the most widely used screening instrument for the preschool population and the most carefully scm-tinized.2’3 The test consists of four sectors that each screen a different area of development: personal-social, fine motor/adaptive, gross motor, and lan-guage. The test was designed to identify children at risk for delays in any of the areas screened.4 How-ever, criticism of the DDST has been directed at

the test’s low detection rate of children with mild

Received for publication Nov 7, 1985; accepted Feb 6, 1986. Reprint requests to (K.C.B.) Comprehensive Developmental Evaluation Center, Medical Center South, 2100 Pierce Aye, Nashville, TN 37232.

delays.57 Additionally, when used as a preschool

screening device, the DDST fails to accurately

iden-tify those children at risk for school failure.8

Al-though studies have addressed the DDST’s poor

sensitivity in identifying mildly delayed children, particularly those from disadvantaged back-grounds,6’7 little formal investigation of the test’s

content has been conducted.

Specifically, there have been few studies address-ing the language sector.9”#{176} Language may be the most important area to assess in a screening eval-uation as it has been repeatedly identified as a sensitive indicator of overall developmental status

and highly predictive of early school success.”’4 Given the importance of speech and language skills

in general development and school performance, a

retrospective study was undertaken to assess the

sensitivity of the DDST language sector. In this study, we examined the accuracy of the DDST

language sector in identifying children at risk for

speech and language delay and examined the test’s

ability to assess the three primary parameters of

speech and language development: receptive lan-guage, expressive language, and articulation.

SUBJECTS

Seventy-one children between 18 and 66 months of age were included in the study. All were referred to a multi-disciplinary child evaluation team from

the Department of Pediatrics of Vanderbilt

Univer-sity for developmental screening. Screening clinics

were held throughout the middle Tennessee region. The subjects were considered to be at high risk for developmental problems by the referring agencies.

Referral sources included the Department of

Hu-man Services, Public Health, Head Start, day-care and preschool centers, public schools, and

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1076 SPEECH AND LANGUAGE

deprived or abusive home environments, medical

problems, and suspected cognitive, motor, or speech and language delay. The groups consisted of 77% boys, 70% children from low-income families, and 82% white and 18% black children, which is reflec-tive of the Tennessee population.’5 None of the children had received speech and language therapy services, although 48% were enrolled in a day-care, preschool, or public school program at the time of screening.

METHODS

The DDST (revised) and a separate speech and language screening evaluation were administered to all subjects on the same day. The DDST was

ad-ministered by a licensed psychologist or psychologic

examiner. Standard administration and scoring of

the DDST were used, resulting in a pass, fail, or questionable score for each of the four sectors of the test.’6 All subjects received pass or fail scores on the language sector of the DDST. A brief speech and language evaluation of ten to 15 minutes was performed by a certified speech and language pa-thologist blind to the DDST results. The speech

and language evaluation consisted of items from

the Preschool Language Scale (PLS)’7 and a clinical assessment of spontaneous language use. The PLS is a well-accepted measure oflanguage development that provides separate scores for receptive and ex-pressive language. Receptive language refers to the

child’s ability to hear, understand, and process

lan-guage. Expressive language refers to both the vo-cabulary content and the grammatic complexity of language that the child produces. The expressive

subtest of the PLS also includes articulation items, assessing a child’s production of sounds, vocal qual-ity, and speech intelligibility. Clinical assessment of spontaneous language use included a rating of speech intelligibility, analysis of syntactic complex-ity, and calculation of mean length of utterance, which were all based on expected language mile-stones.’8 Scoring criteria for speech and language screening were in accordance with speech and

lan-guage certification requirements derived from the

Education for All Handicapped Children Act (PL 94142).1920 Children received a failing score in

ex-pressive or receptive language when their perform-ance in each area was less than or equal to 70% of their chronologic age. A failing score in articulation was given when intelligibility was reduced due to sound errors inconsistent with the child’s chrono-logic age.21’22

Results of the DDST language sector were corn-pared to results of the speech and language evalu-ation. Due to dichotomous data and skewed distri-butions, data were compared using the Wilcoxon

matched pairs signed ranks test. P < .05 was con-sidered significant.

RESULTS

DDST results were first compared to speech and

language evaluation results in each of the three areas assessed: articulation, expressive language, and receptive language (Table 1). Sixty children were identified as having problems in articulation through brief speech and language evaluation. Only 28 of these failed the DDST language sector. A statistically significant difference was found be-tween the two measures with regard to articulation. Fifty-six children showed delays in expressive lan-guage on speech and language evaluation. Only 30 of these children failed the DDST language sector, again resulting in a significant difference between the two measures. Receptive problems were de-tected in 36 children on speech and language eval-uation. Twenty-five of these children failed the

DDST language sector. No significant difference

was found with receptive language.

DDST results were then compared to speech and language evaluation results without differentiation of the language areas. Results showed a significant difference between the number of children identi-fled by each of the screening methods. Sixty-five children (92%) failed the speech and language eval-uation due to a delay in one or more of the three areas assessed. Only 30 children (42%) failed the

DDST language sector. More than half of the chil-dren (35 of 65) in need of further speech and

language evaluation were not detected by the

DDST. The sensitivity of the DDST was not

af-fected by the child’s age; at 1 year intervals between 18 and 66 months, the DDST consistently

under-detected language problems (Table 2).

Twenty-seven of the 35 children who had passed the DDST language sector but failed the brief speech and language evaluation received subse-quent full speech and language evaluations through the public school system, Headstart, or a private

Denver Developmental Screening Test (DDST) Results Using a Wilcoxon Matched Pairs Ranked Signs Test*

Speech/ No. (%) of Deficits Z Value

Language Detected by: Deficit Speech/

Language Language Screening Sector

Any 65 (92) 30 (42) -5.16t Articulation 60 (84) 28 (39) -4.49t Expressive 56 (79) 30 (42) -4.56t Receptive 36 (51) 25 (34) -1.24

* N = 71. tP<.001.

at Viet Nam:AAP Sponsored on September 7, 2020 www.aappublications.org/news

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TABLE 2. Comparison of Speech-Language and the Denver Developmental Screening Test (DDST) Lan-guage Sector Results Using a Wilcoxon Matched Pairs Ranked Signs Test Controlling for Age

Age No. of No. (%) of Deficits Z Value

(mo) Children Detected by:

Speech/ DDST Language Language Screening Sector 18-30 12 10 (83) 5 (42) 31-42 21 19 (90) 10 (48) 43-54 26 24 (92) 9 (35) 55-66 12 11 (91) 5 (42)

*P< .005.

agency. All but one of these children qualified for speech and language services and were enrolled in therapy.

Of those children who did fail the DDST language

sector, 93% showed articulation problems, 80% showed receptive language problems, and 100% showed expressive language problems. Additionally, 70% of the children in this group also failed at least one other sector of the DDST.

DISCUSSION

The results of this study demonstrate that the

language sector of the DDST is an insensitive screen for speech and language deficits. The test failed to identify more than half of those children in need of specific speech and language interven-tion. The DDST’s poorest identification rate was associated with articulation and/or expressive

lan-guage deficits. Although the DDST does not include

any measure of articulation, many health profes-sionals rely solely on this test for developmental screening. It is, therefore, important to determine the sensitivity of the DDST in detecting any speech and language deficit.

The insensitivity of the DDST to speech and language development can be attributed to the

rel-atively few items in the language sector, the lack of articulation assessment, and the minimal amount of expressive language production required to pass those items assessing expressive skills. Only one item, “defines 6 words,” requires an answer of greater than two words in length. This item does not appear on the test until the 6-year level. Al-though no items directly measure the adequacy of articulation, one item, “uses plurals,” indirectly as-sesses the use of /s/ in the final position of words. It is, therefore, possible for a 5-year-old child using only two-word combinations and demonstrating a severe articulation delay to pass the language sector ofthe DDST.

Children failing the DDST language sector were

likely experiencing pervasive language development

problems as the majority showed deficits in all three language parameters measured. Most of these chil-dren were at risk for delays in other areas of

devel-opment because they also failed at least one other sector of the DDST. These results support previous findings that the DDST reliably identifies children

demonstrating significant delays but often fails to detect those children demonstrating mild delays.

Professionals now using the DDST should in-dude additional methods to assess speech and lan-guage development. It is suggested that attempts be made to elicit more conversational speech from children during the administration of the test. At-tention should be given to both the child’s length of utterance and speech intelligibility. Children passing the DDST language sector when the health care provider or parent have concerns about speech

and language development should be reassessed with another measure specifically designed for

speech and language screening. Efficient measures presently available for children up to 36 months of

age include the Receptive-Expressive Emergent

Language Scale (REEL)23 and the Early Language Milestone Scale (ELM).24 The REEL is a parent interview form, and the ELM combines parent

in-terview with direct testing. Both are intended for

use by primary care physicians. For children 3 to 7 years of age, the Speech and Language Skills sub-test, and the General Knowledge and

Comprehen-sion subtest from the Brigance Diagnostic Inven-tory of Early Development25 are suggested. Both subtests involve direct testing as well as teacher and/or parent interview. Although the Brigance

Inventory is most commonly used by school

sys-tems, the suggested subtests could provide a brief and easy method of screening for primary care physicians.

Articulation screening can quickly be completed

through the Denver Articulation Screening Exam

(DASE).26 The DASE involves the simple

proce-dure of the child repeating words spoken by the examiner and was designed to be used by non-speech and language professionals who may have limited knowledge of normal articulation develop-ment. The DASE includes a method for rating

speech intelligibility and also provides specific

guidelines for articulation development through the 6-year level. Additional information on accurate screening methods and guidelines for referral are available through community speech and language specialists.

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1078 SPEECH AND LANGUAGE

sectors may require more comprehensive evalua-tion.

CONCLUSION

The DDST may fail to reliably identify children

in need of further speech and language evaluation. Specifically, the DDST does not appear to be sen-sitive to expressive language and articulation skills.

Future investigation might evaluate changes in the DDST’s sensitivity and specificity given minor modifications of the language sector such as requir-ing more talking from children and rating articu-lation. Such modifications may improve not only the DDST’s detection of speech and language

prob-lems, but also other mildly handicapping condi-tions.

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1986;78;1075

Pediatrics

Kathleen C. Borowitz and Frances P. Glascoe

Screening