Quantifying Language Development From Birth to 3 Years Using the Early Language Milestone Scale

(1)

Quantifying

Language

Development

From

Birth

to 3 Years

Using

the Early

Language

Milestone

Scale

James Coplan, MD*, and John R. Gleason, PhDt

From the *Depa,.ment of Pediatrics, State University of New York-Health Science Center, Syracuse, and the tDepartment of Psychology, Syracuse University

ABSTRACT. A point-scoring technique for the Early

Lan-guage Milestone Scale is described. Normative data based on the original 1982 cross-sectional sample and validation

data based on a separate longitudinal sample are

pre-sented. Mean Early Language Milestone Scale point

scores, standard deviations, and percentile equivalents for raw point scores are presented for all ages from birth

to 36 months. Correlations between point scores on the

Early Language Milestone Scale and scores on other

standardized developmental tests such as the Stanford-Binet Intelligence Scale, the Peabody Picture Vocabulary

Test, and the Illinois Test of Psycholinguistic Abilities

are presented. The clinical and research advantages of

this point-scoring technique are presented and compared

with the original pass/fail scoring method. Pediatrics

i990;86:963-97l; speech, kznguage, screening, otitis media.

ABBREVIATIONS. ELM Scale, Early Language Milestone Scale; REEL Scale, Receptive-Expressive Emergent Language Scale; SICD, Sequenced Inventory of Communication Development.

Five to ten percent of preschool children suffer

from disordered development of speech or

lan-guage.”2 Common causes of speech or language

impairment include hearing loss, mental

retarda-tion, developmental language disorders, autism, and

dysarthria.24 Therapeutic strategies and long-term

prognosis for speech or language delay differ widely,

depending on the nature of the specific underlying

disability. None of these disorders is curable.

None-theless, early intervention offers substantial

bene-fits in terms of improved functioning, academic

Received for publication Nov 2, 1989; accepted Mar 15, 1990. Reprint requests to (J.C.) Dept of Pediatrics, State University of New York-Health Science Center, 750 E Adams St, Syracuse, NY 13210.

management, genetic counseling, or anticipatory

guidance for parents taking the child’s disability

into account. Before intervention can be instituted,

however, a speech or language delay must first be

recognized. We therefore developed the Early

Lan-guage Milestone Scale (ELM Scale)5 as a screening

test of speech and language development from birth

to 36 months (48 months for intelligibility of

speech), so that speech/language-delayed children

could be detected by their primary care practitioner

and referred for formal diagnostic evaluation at the

earliest possible age.

The ELM Scale consists of 41 items in three

divisions, corresponding to different areas of

lan-guage function: auditory expressive, auditory

recep-tive, and visual. Auditory receptive abilities include

alerting and orienting to sound and following verbal

commands. Visual language milestones include

so-cia! smile, visual recognition of parents, visual

tracking, imitation and initiation of gesture games,

and index-finger pointing to signify desired objects.

Auditory expressive function is subdivided into

“content” (cooing, babbling, single words, two-word

phrases, vocabulary size, etc) and “intelligibility”

(clarity of speech, percentage of child’s speech

which is understandable by strangers) (Fig 1). The

majority of items on the ELM Scale can be scored

on the basis of parental report, with the option of

direct testing if the child fails by history; a few

items are elicited only by direct testing.

Derivation of the ELM Scale has been fully

de-scribed elsewhere.”4 In brief, the ELM Scale is

based on cross-sectional data derived from 191

low-risk subjects, 0 to 36 months of age, who were

recruited from the offices of several private

practi-tioners and from the pediatric outpatient

depart-ment at a university-based medical center. These

191 children will be referred to as the “normative

(2)

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Fig 1. Early Language Milestone Scale (ELM Scale) score sheet. Items are grouped into

three divisions: auditory expressive (AE), auditory receptive (AR), and visual (V). In the

auditory expressive division, this 12-month-old child failed item AE9 (first word) and AE8 (specific use of “mama” or “dada”). These item failures do not result in failure of the ELM

Scale screen as a whole, however, because fewer than 90% of 12-month-olds have attained these items at this age. A basal level in this division is attained with items AE7 to 5. In

the auditory receptive division, the same logic applies to failure of AR8 and AR7. However, the child also failed item AR6 (inhibits to “no”). Because AR6 has already been attained

by more than 90% of children the subject’s age, failure of this item results in failing the

ELM Scale screen as a whole. ELM Scale score sheet copyright PRO-ED; reproduced by

permission.

The normative sample was predominantly middle

class. Half of the subjects in the normative sample were male; 80% of subjects were white and 20% nonwhite; 80% were private patients and 20% were

medically indigent. Nonwhite subjects were equally

divided between private and clinic settings. An

instruction manual was written, and two medical

students were trained in the administration of the

original field version of the ELM Scale. Each item

was scored by three methods: parental history (H),

direct testing (T), and incidental observation (0).

Parental history was usually adopted as the scoring method of choice, because this proved to be the

fastest and most reliable means of eliciting

infor-mation within the relatively brief time frame of a

screening encounter. Exceptions included certain

items of high stimulus value (orienting to a bell) or

complex auditory receptive items (retrieving objects

described by use, for example), which were only

elicited by testing.

Parents are known to be highly accurate

report-ers of their child’s current developmental status,

- Ca

when asked to respond to a series of forced-choice

questions about their child’s current abilities.6

Therefore, we asked parents “Does your child now,

or did he or she ever. . .?“ perform each language

milestone on the pilot version of the ELM Scale,

and a simple “yes/no” response was recorded. We

specifically avoided asking parents when the child

had attained each milestone. (The wording “did he

or she ever. . .?“ was included because some

lan-guage milestones are normally transient. For

ex-ample, once a child has advanced to polysyllabic babbling, he or she usually does not return to cooing

or monosyllabic babbling. A typical ELM question

would be “Does your child now, or did he or she ever, coo?”) For each ELM item, we calculated the percentage of subjects passing the item at

succes-sively older 1-month age intervals. We then used a

logistic model to fit a curve for percentage passing

each item X age. From these curves we read off the

ages by which 25%, 50%, 75%, and 90% of children

would be expected to pass each item. The resultant

(3)

pub-lished data based on longitudinal studies of lan-guage development.7’8

In devising a pass/fail scoring system for the ELM Scale, we selected the age by which 90% of

children in the normative sample had attained a

given language milestone as the cutoff age for

pass-ing that item. That is, the ELM Scale was deliber-ately set to flag the slowest 10% of children in terms of language acquisition. This was a

compro-mise between overidentification of normal children

vs underidentification of language-delayed children and was in agreement with the empiric observation that 5% to 10% of preschool children are, in fact, language impaired. To administer the ELM Scale, the examiner starts at the child’s age and works to the left (downward in age) in each division, admin-istering as many items as necessary until the child passes three consecutive items in that division (de-fined as the child’s “basal level” for that division). If the child attains a basal level in each division without failing any items that have already been attained by 90% or more of children his or her age, then the ELM Scale screen is passed (Fig 1). The average time required for administration by this technique is 1 to 3 minutes. Using this pass/fail scoring technique, the ELM Scale has been applied to high-risk2’3’9’3 and low-risk’4 populations. The ELM Scale has shown good to excellent sensitivity as a screening tool when compared with a variety of standardized tests of language or general intel-lectual development, including the Bayley Scales of

Infant Development,’5 the Stanford-Binet

Intelli-gence Scale,’6 the Peabody Picture Vocabulary Test,’7 the Receptive-Expressive Emergent

Lan-guage Scale (REEL Scale),’8 and the Sequenced

Inventory of Communication Development (SICD).’9 In a low-risk sample of 657 children, Walker et al’4 observed an overall failure rate on the ELM Scale of 8%, quite close to the built-in failure rate of 10% (children must pass ELM items that have already been attained by 90% of subjects their own age). In children older than 12 months of age, the ELM Scale demonstrated good to excellent agree-ment with the criterion measure, the SICD: the sensitivity of the ELM Scale was 100%, and the specificity was 68%, on an initial screen. If subjects were required to fail the ELM Scale on two succes-sive occasions using a screen-rescreen paradigm before being considered “positive,” the ELM Scale’s sensitivity fell to 88%, but with a commensurate rise in specificity to 83%. Walker et al discuss the relative merits of a single screen vs a screen-re-screen paradigm. For children younger than 12 months of age, they suggest that the ELM Scale might be superior to the SICD because of its greater

number of items and more-refined age norms.

The data of Walker et al comprise a subset of the

data collected on 4000 subjects by a multicenter research project funded by The Robert Wood

John-son Foundation to study physicians’ developmental

screening practices. In addition to undergoing screening with the ELM Scale, these 4000 subjects underwent screening with a brief two-item battery (“Are you concerned about your child’s hearing? Are you concerned about your child’s speech?”). Within this sample of 4000 children, 8% failed the ELM Scale (the same rate that had been observed by Walker et al in their subset of 657 subjects), whereas 2.5% failed the two-item screen. A ran-domly selected subset of the total population of 4000 children was never submitted to formal crite-non testing, however (Kagan J, PhD, personal com-munication 1988). Thus, it is impossible to calculate either the prevalence of language disability in this sample of 4000 subjects or the relative sensitivity of the ELM Scale vs the abbreviated two-item battery. However, the ELM Scale identified more than three times as many children with possible speech-language delay compared with the two-item screen (8% vs 2.5% failure rate), which almost certainly translates into greater sensitivity for the ELM than the two-item screen. Apparently, there-fore, although one must remain attentive to paren-tal concerns, it is not sufficient merely to ask whether the parent is worried about the child’s hearing or speech.

Additional data on the sensitivity and specificity of the ELM Scale have been provided by Black et al,’3 who administered the ELM Scale, the REEL Scale, and the Bayley Scales of Infant Development to 48 lower socioeconomic status infants at 14 months, with retesting on all three instruments at 18 months of age. Sixty percent of the mothers had

less than a high school education, an important

consideration in view of the ELM Scale’s depend-ence on parental accuracy as historian. Black et al found that performance on the ELM was signifi-cantly correlated with performance on the REEL and the Bayley at both 14 and 18 months. The ELM demonstrated a sensitivity of 86% and a specificity of 100%, correctly classifying 96% of

subjects as having normal vs delayed language

de-velopment. The ELM Scale detected more children at 14 months than either the REEL or the Bayley, and most of these children proved to be true posi-tives at follow-up. At the 18-month administration, correlation between the ELM and the Bayley was

.70 for expressive items and .81 for receptive items. The authors concluded that “in addition to its

strengths as a screening measure, the ELM was

also more sensitive in picking up language problems

at an earlier point in time than either the REEL or the Bayley.”

(4)

goal was to design a rapid screening tool yielding a

simple pass/fail rating rather than a language level

or language quotient. The subsequent acceptance of the ELM Scale has borne out the correctness of our original goal: the ELM Scale has been incor-porated into several standard reference textbooks of pediatrics2023 and has been favorably reviewed in the psychologic’3 and psychometric24 literature, as well as being endorsed by various authorities in language or early child development.25’26

Some-times, however, it is useful to be able to describe a

child’s language development in quantitative terms.

This may be true in high-risk settings such as neonatal intensive care unit follow-up clinics. Like-wise, for a child to be eligible for state or federally mandated remedial services, the child may have to be identified as so many months delayed, or as having a language quotient below a certain thresh-old value. The ELM Scale has been compared fa-vorably with other measures of early language de-velopment and has tighter age norms than some

instruments currently used as formal test measures.

However, the ELM Scale’s pass/fail scoring method

is sometimes a limiting factor in interpreting test

results. Therefore, we sought to devise an

alterna-tive, extended scoring technique for examiners

wishing to avail themselves of it, while leaving the

original pass/fail rapid scoring method intact for

screening purposes. The two scoring techniques have different purposes: the rapid scoring technique

is designed simply to detect children who fail the

ELM Scale and therefore are at risk for underlying language disability, whereas the extended scoring technique would provide additional information about the child’s language level and overall lan-guage proficiency which might be useful as part of a more formal diagnostic evaluation. The present

study had two phases: a normative phase and a

validation phase, both of which are reported below.

SUBJECTS

Two sets of subjects were used. The first set of

subjects consisted ofthe 191 children in the original

normative sample, as described above. The second set of subjects, referred to hereafter as the “valida-tion sample,” consisted of 50 children drawn from a private pediatric group practice. Half were male. Any child with low birth weight, prior concerns about development, or who had sustained a major medical illness (eg, bacterial meningitis) was ex-cluded. Subjects in the validation sample were en-rolled at 9 months of age and were reexamined in a longitudinal fashion at 9, 18, 30, and 36 months of age. No subject in the normative sample also ap-peared in the validation sample, or vice versa. In-formed consent was obtained in all cases.

METHODS

Normative Phase

The extended scoring technique is based on each

child’s total point score on the ELM Scale. Norms

were derived by reanalysis of the original 1982 raw

data, which form the basis of the ELM Scale.

Starting at each child’s age, items to the left (down-ward in age) were scored until three consecutive

items in each division of the ELM Scale were passed

(the child’s basal level). The child was given full credit for any items below his or her basal level in each division. Then, returning to the child’s

chron-ologic age, items to the right (upward in age) were

scored until three items in a row were failed

(de-fined as the child’s “ceiling level”). It was assumed

that the child would be unable to pass any items

above his or her ceiling level; no credit was given for any of these items. (This is the same scoring convention used by other test measures such as the Peabody Picture Vocabulary Test.) Each item or

subpart of an item was valued at one point. The

child received credit for all items or subparts of

items successfully completed, plus credit for all

items below his or her basal level, yielding a total

point score (Fig 2).

For purposes of statistical analysis, subjects were grouped into age blocks: 0 to 2 weeks = newborn, 2

to 6 weeks = 1 month old, etc. (These are the same

age blocks that were used for the original 1982 data

analysis.) Total point scores were plotted against

age in months, and the resulting scatterplot was

then smoothed using a running lines smoother.27

This technique fits a moving straight line to

suc-cessive overlapping narrow windows of data in the scatterplot, yielding a smooth curve without

pre-supposing any specific type of functional

relation-ship (eg, polynomial) between point scores and age

at testing. Specifically, we assumed that point

scores would not show a simple linear relationship

with age, because the original placement of ELM Scale items was somewhat uneven, with greater

item density at some ages and less at others. This

was partly a consequence of the fact that language

development itself does not proceed in a uniform

fashion but tends to proceed in bursts marked by

“key ages” when many abilities are acquired almost

simultaneously.28

The running lines smoother produced a smoothed

mean point score, as well as an estimated standard

deviation about that mean, for each age from birth

to 36 months of age. For various reasons, including

the presence of floor and ceiling effects near the

ends of the age range, the distribution of point

scores at a given age can be quite skewed. Moreover,

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Fig 2. Early Language Milestone Scale (ELM Scale) score sheet demonstrates

point-scoring technique with a 12-month-old child. Examiner first works to the left, establishing a basal level in all three divisions of the ELM Scale. Examiner then works to the right, establishing a ceiling in each division. Total point score = sum of all items passed, plus

value of all items below basal level in each division. Point score for this child = 29, which

is between the 75th and 90th percentile for chronologic age. ELM Scale score sheet copyright PRO-ED; reproduced by permission.

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implies that at some ages, only a small number of

distinct scores will ever be obtained in actual

test-ing, making the estimated standard deviations dif-ficult to interpret. Therefore, we used the smoothed means and standard deviations to fit an estimated probability distribution at each age from birth to 36 months of age; we chose either a binomial, hypergeometric, or 3-binomial distribution, de-pending on the value of the estimated standard deviation. This yielded estimated probabilities of observing each of the various possible point scores at every age of testing. These probability distribu-tions were then used to convert observed raw point scores into percentile values at every age from birth to 36 months of age.

Validation Phase

Subjects in the validation sample were tested with the ELM Scale in a longitudinal fashion at 9, 18, and 30 months, and point scores were calculated exactly as previously described for the normative sample. At 30 months of age these subjects also underwent testing with the Peabody Picture Vocab-ulary Test-Revised, and at 36 months they were

tested with the Stanford-Binet Intelligence Scale

and selected subtests from the Illinois Test of Psy-cholinguistic Abilities.29

RESULTS

Normative Phase

In the normative sample, a steady increase in point score with age was demonstrable (Table 1; Fig 3). Floor and ceiling effects were apparent at the extremes of the age range covered by the ELM Scale: before 1 month of age it is impossible to fail the ELM Scale because none of the items has yet been attained by 90% or more of subjects.

Con-versely, many subjects older than the age of 30

months passed all ELM Scale items, making it

impossible to discriminate percentile equivalents for point scores above the 75th percentile. For most purposes, however, the question of greatest interest will be whether the child is significantly delayed, ie, below the 5th percentile for age; this could readily be traced from 2 through 36 months of age (Fig 4).

Validation Phase

(6)

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Age (months)

The normative sample for the ELM Scale

con-sists of 191 subjects, balanced for racial composition and sex, most of whom were middle class. The size of the ELM Scale normative samples compares favorably with two of the most commonly used speech/language assessment tools, the SICD and

the REEL Scale, which were based on 252 children

and 50 children, respectively. The data in the nor-mative sample were collected cross-sectionally, whereas the data in the validation sample reported

herein were gathered and analyzed longitudinally;

the close agreement between these two sets of data

serves as an interval cross-check on the validity of

the original cross-sectional ELM Scale norms.

Fur-thermore, the longitudinal data presented here showed good external validity when compared with previously published measures of language devel-opment. In addition to validating the ELM Scale

itself, this agreement with external norms makes

any theoretical concern about selection bias in the

original normative sample unlikely.

Standard deviations were slightly smaller and mean point scores were slightly higher in the vali-dation sample than in the original normative sam-ple, probably because the validation sample was drawn entirely from one predominantly middle

class private practice and was therefore somewhat

agreement with predicted values from the norma-tive sample (Table 2; Fig 3). The ELM Scale score at 30 months in the validation sample correlated well with the 30-month Peabody Picture

Vocabu-lary Test score and with scores at 36 months on the

Stanford-Binet Intelligence Scale and the Illinois Test of Psycholinguistic Abilities (Table 3). The point-scoring system required determination of a ceiling as well as a basal level for each child, effec-tively doubling the number of items that must be given; there was a commensurate increase in time required for administration of the ELM Scale (2 to 5 minutes, vs 1 to 3 minutes for the pass/fail scoring method). Additional data from the validation sam-ple are reported elsewhere.3#{176}

TABLE 1. Early Language Milestone Scale Scores in

the Normative Sample*

Age N Observed Smoothed Smoothed

Mean Mean SD

0 3 4.0 1.9 2.2

1 17 4.1 4.8 3.0

2 15 8.1 80 2.9

3 9 11.8 11.3 2.7

4 17 14.2 13.9 2.7

5 6 15.2 15.4 2.4

6 17 16.8 16.9 2.5

7 7 19.1 19.3 2.5

8 7 21.9 21.8 2.4

9 14 23.2 23.0 2.1

10 5 23.4 24.0 2.3

11 2 25.5 25.3 2.3

12 7 25.6 26.4 2.1

13 7 28.0 27.4 2.2

14 1 32.0 28.6 2.4

15 4 30.8 29.0 2.8

16 3 28.7 30.3 3.0

17 3 29.0 31.4 3.3

18 4 31.5 32.1 4.2

19 3 34.0 33.1 4.4

20 3 34.0 35.3 5.2

21 2 37.0 36.8 5.5

22 1 42.0 39.0 5.6

23 1 31.0 40.6 5.5

24 4 45.0 42.4 6.2

25 0 . . . 42.5 7.3

26 2 43.5 43.8 7.2

27 1 54.0 45.0 7.2

28 1 46.0 45.6 7.2

29 0 . . . 47.2 6.7

30 0 . . . 48.4 6.4

31 6 46.8 49.3 6.1

32 0 . . . 50.8 5.6

33 0 . . . 51.9 5.0

34 2 54.0 52.5 4.9

35 3 54.0 54.3 3.7

36 2 55.5 56.1 2.1

4 Age is given in months (0 = newborn to 2 weeks, 1

month = 2 to 6 weeks, etc); N = number of subjects.

Smoothed means and SDs calculated by running lines

scatterplot smoother.

Fig 3. Early Language Milestone Scale smoothed mean

scores (closed circles), ±1 SD (heavy line) and ±2 SD

(light line), as obtained in the cross-sectional normative

sample. Mean scores for subjects in the longitudinal

validation sample at 9, 18, and 30 months are

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(7)

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Fig 4. Percentile values for Early Language Milestone Scale (ELM Scale) point scores from birth to 36 months of age. Ordinate = age in months; abscissa = ELM Scale point

scores. Curves plotted on graph are the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentile equivalents for the corresponding point scores.

TABLE 2. Comparison of Early Language Milestone Scale (ELM Scale) Point Scores at

9, 18, and 30 Months From the Cross-sectional Normative Sample and Scores Obtained

at the Same Ages in the Longitudinal Validation Sample*

ELM Scale Point Scores 9 Months 18 Months 30 Months

Normative sample (N = 191) 23.0 (2.5) 32.1 (4.0) 48.4 (6.4) Validation sample (N = 50) 23.6 (1.6) 34.4 (2.2) 51.2 (3.8)

* Results are given as mean (SD).

less heterogeenous than the normative sample. The

differences were slight, however (never more than

0.5 SD based on 1982 norms), suggesting that

so-cioeconomic status did not exert a major impact on

response patterns to ELM Scale items. It is also noteworthy that Black et al’3 found excellent

agree-ment between the Bayley Scales of Infant

Devel-opment and the ELM Scale in a predominantly lower socioeconomic group of subjects. Thus, the ELM Scale appears to yield stable results among

subjects of both middle and lower socioeconomic

status.

The correlation between the 30-month ELM and

the 30-month Peabody Picture Vocabulary Test in

the validation sample addresses the issue of

con-current validity of the ELM, augmenting the data

of Black et aP3 and Walker et al.’4 The ELM Scale

scores in the validation sample at 30 months

dem-onstrated good predictive validity relative to

per-TABLE 3. Product-Moment Correlation Between

30-Month Early Language Milestone Scale (ELM Scale)

Score and 30-Month Peabody Picture Vocabulary Test

(PPVT), 36-Month Stanford-Binet, and 36-Month

Illi-nois Test of Psycholinguistic Abilities (ITPA Scores)*

PPVT Stanford-Bi- ITPA

(30 net (36 mo) (36

mo) mo)

ELM Scale (30 mo) .51 .66 .55

* All correlations significant at P < .0001 level.

formance on the Stanford-Binet and Illinois Test

of Psycholinguistic Abilities at 36 months.

Long-term predictive validity of infant test scores is

generally poor, except in the case of neurologically impaired subjects.31’32 For example, in normal

sub-jects the correlation coefficient between Bayley

Scales of Infant Development scores at 18 months

(8)

In-telligence Scale at age 6 years is only .2.’ The shorter the test-retest interval, however, the greater the correlation coefficient, with 6-month test-retest intervals during infancy generally yielding correla-tion coefficients in the range of #{149}5#{149}31Thus, the

correlation coefficient of .66 between the 30-month ELM and the 36-month Stanford-Binet compares favorably with extant data on predictive validity of test scores in normal toddlers.

The user of the ELM Scale now has two scoring techniques available. Because of its brevity, the pass/fail scoring technique remains ideally suited to rapid screening of large numbers of low-risk subjects. The point-scoring technique presented here offers the user the option of describing a child’s

language development in a more quantitative

fash-ion, expressing the child’s language level as a per-centile score for his or her chronologic age or in terms of standard deviations above or below the mean for age. This scoring method will be advan-tageous in high-risk settings such as neonatal in-tensive care unit follow-up clinics, child develop-ment clinics, audiology clinics, Head Start pro-grams, etc, where the increased prevalence of underlying speech and language disability justifies the increased investment in developmental testing. The extended scoring technique will also permit more direct comparison between ELM Scale per-formance and performance on other tests that yield a point score, scaled score, or developmental quo-tient. Finally, the point-scoring method will be useful as a research tool, permitting a more fine-grained description of language than a simple “pass” or “fail.” For example, hearing loss in the first 12 months of life may be deleterious to speech and language development33’34 Until now, however,

researchers studying early language development

have had to rely on language tests with overly broad age ranges for specific language milestones (eg, “birth to 4 months,” “4 to 8 months”),33 tests of general cognitive development containing very few

language items in the first 24 months of life,33 or

language tests that cannot even be administered to

children younger than 24 months of age.34 The point-scoring system for the ELM Scale will now enable investigators to describe global language

de-velopment from birth to age 3 years in a

quantita-tive fashion. This will permit exploration of other

research questions: For example, might children

with recurrent otitis media show transient but prog-nostically significant speech/language delay in the first 24 months of life which is now being over-looked because of the difficulty until now in quan-tifying language development at that young age?

Furthermore, by using the original pass/fail scoring

system in a complementary fashion to the point-scoring method, it will be possible to analyze the

specific pattern of item failures. For example, will children with frequent otitis media demonstrate a reduction in their global ELM Scale score (point-scoring method) while retaining normal acquisition of visual milestones such as index-finger pointing (pass/fail analysis of individual items)?

When evaluating the developmental status of children in the first 2 years of life, there has histor-ically been a tradeoff between the desire to limit

assessment to only those items that are reliably

reproducible in a test setting vs a need to know about some developmental areas even if only by parental report. This has been particularly true of early language development, where a performance frequently cannot be elicited from the child in a testing situation. Because many items on the ELM Scale are scored primarily on the basis of parental report, the examiner is still dependent on the avail-ability of an accurate historian. This limitation also applies to other test measures in the first 24 months of life, to some degree. For example, some items on the Bayley Scales of Infant Development or the SICD can also be passed by parental report. In a

sense, therefore, the ELM Scale and other

devel-opmental scales in the first 2 years oflife sometimes depict what the parents say the child does, rather than what the child is actually observed to do.

Parents are usually accurate reporters of their

child’s current level of developmental function, however, and parental estimates are almost always more accurate than pediatricians’ guesswork about

a child’s developmental level.35’36 To some degree,

the ELM Scale seeks to formalize parental report-ing, either on a pass/fail or quantitative point-score

basis. Therefore, the ELM Scale should be thought

of as a semiquantitative measure of language

de-velopment, depending as it does on parental report.

Furthermore, no test instrument can provide a qualitative analysis of language development.

Therefore, all children who are suspected of being

language impaired should undergo formal assess-ment of language by trained clinicians. The point-scoring system for the ELM Scale described herein

will be of benefit, however, in terms of leading to

appropriate referrals, quantifying the magnitude of a child’s speech/language delay, or quantifying a child’s language progress over time.

SUMMARY

A point-scoring technique for the ELM Scale has

been presented. Point scores in a longitudinal

val-idation sample showed good agreement with

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as the Peabody Picture Vocabulary Test and the Stanford Binet Intelligence Scale. It is now possible to express a child’s score on the ELM Scale as a percentile value for chronologic age or in terms of standard deviations from the mean for age. This scoring technique will be useful in research or

high-risk clinical settings where a more refined

descrip-tion than a simple pass/fail system is desired. The

original pass/fail rapid scoring technique for the

ELM Scale is still available and remains the most appropriate scoring technique for screening large numbers of low-risk subjects.

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1990;86;963

Pediatrics

James Coplan and John R. Gleason

Milestone Scale

Quantifying Language Development From Birth to 3 Years Using the Early Language

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