Prevalence of specific language impairment in kindergarten children

A longitudinal investigation of reading outcomes in children with language impairments

This investigation examined the reading outcomes of children with language impairments (LI). A large subsample of children who participated in an epidemiologic study of language impairments in kindergarten (J. B. Tomblin, N. Records, P. Buckwalter, X. Zhang, E. Smith, & M. O'Brien, 1997) was followed into second and fourth grades. Participants' language, reading, and nonverbal cognitive abilities were assessed. Results indicated that children with LI in kindergarten were at a high risk for reading disabilities in second and fourth grades. This risk was higher for children with a nonspecific language impairment (nonverbal and language deficits) than for those with a specific language impairment (deficits in language alone). Children with LI in kindergarten who had improved in spoken language abilities by second and fourth grades had better reading outcomes than those with persistent language impairments. Also, children's literacy knowledge/ experience in kindergarten and their initial reading achievement in second grade were good predictors of subsequent reading outcomes.

Identification of early risk factors for language impairment

The current study is a population-based investigation of birth risk factors for school-identified specific language impairment (SLI). The sample consisted of 244,619 students (5,862 SLI) born in Florida between 1989 and 1990 who were in the Florida public school system at ages 6-7. Epidemiological measures of effect were used to investigate both individual- and population-level risk for SLI. Very low birth weight (VLBW), low 5-min Apgar score, late or no prenatal care, high birth order, and low maternal education were associated with highest individual-level risk. Low maternal education and having an unmarried mother was associated with the highest population-level risk. The results not only suggest who needs to be screened for a future developmental disability, but identify a group of children who are at-risk for an SLI placement in school. Early intervention services for these children may be the most effective approach to reducing the incidence of school-identified SLI.

The role of speed of processing, rapid naming, and phonological awareness in reading achievement

This study investigated the role of speed of processing, rapid naming, and phonological awareness in reading achievement. Measures of response time in motor, visual, lexical, grammatical, and phonological tasks were administered to 279 children in third grade. Measures of rapid object naming, phonological awareness, and reading achievement were given in second and fourth grades. Reading group comparisons indicated that poor readers were proportionally slower than good readers across response time measures and on the rapid object naming task. These results suggest that some poor readers have a general deficit in speed of processing and that their problems in rapid object naming are in part a reflection of this deficit. Hierarchical regression analyses further showed that when considered along with IQ and phonological awareness, speed of processing explained unique variance in reading achievement. This finding suggests that a speed of processing deficit may be an "extraphonological" factor in some reading disabilities.

Young children with specific language impairment and their numerical cognition

This study examined the enumeration and numerical reasoning levels of children with specific language impairment (SLI) compared to those of two groups of typically developing children: children matched for age (AM) and children matched for grammatical ability (GM). The children completed four numerical tasks: reproduction of sets, numerosity of sets, an addition/subtraction condition of the numerosity of sets, and transformation effects (conservation of number). Between-group analyses indicate that the children in the SLI group performed better than the children in the GM group for all set sizes of all tasks with one exception (set size 7 of the odd/subtract task) and performed more poorly than the children in the AM group for 7 of the 16 trials. There was a strong correlation of count range with the reproduction of sets task for the children with SLI, but not for the children in the other two groups. The AM group consistently used verbal counting to facilitate numerical problem solving. Conversely prompting the children with SU to use verbal counting while completing any of the numerical tasks resulted in a 50% decline in accuracy. Children need opportunities to strengthen numerical constructs, such as those enhanced through verbal counting. However, children with SLI also need opportunities to fortify their nonverbal enumeration and numerical reasoning without requiring the use of their deficit area.

A major susceptibility locus for specific language impairment is located on 13q21

Children who fail to develop language normally-in the absence of explanatory factors such as neurological disorders, hearing impairment, or lack of adequate opportunity-are clinically described as having specific language impairment (SLI). SLI has a prevalence of approximately 7% in children entering school and is associated with later difficulties in learning to read. Research indicates that genetic factors are important in the etiology of SLI. Studies have consistently demonstrated that SLI aggregates in families. Increased monozygotic versus dizygotic twin concordance rates indicate that heredity, not just shared environment, is the cause of the familial clustering. We have collected five pedigrees of Celtic ancestry that segregate SLI, and we have conducted genomewide categorical linkage analysis, using model-based LOD score techniques. Analysis was conducted under both dominant and recessive models by use of three phenotypic classifications: clinical diagnosis, language impairment (spoken language quotient <85) and reading discrepancy (nonverbal IQ minus non-word reading >15). Chromosome 13 yielded a maximum multipoint LOD score of 3.92 under the recessive reading discrepancy model. Simulation to correct for multiple models and multiple phenotypes indicated that the genomewide empirical P value is <.01. As an alternative measure, we also computed the posterior probability of linkage (PPL), obtaining a PPL of 53% in the same region. One other genomic region yielded suggestive results on chromosome 2 (multipoint LOD score 2.86, genomic P value <.06 under the recessive language impairment model). Our findings underscore the utility of traditional LOD-score-based methods in finding genes for complex diseases, specifically, SLI.

Long term health and neurodevelopment in children exposed to antiepileptic drugs before birth

OBJECTIVE

To investigate the frequency of neonatal and later childhood morbidity in children exposed to antiepileptic drugs in utero.

DESIGN

Retrospective population based study.

SETTING

Population of the Grampian region of Scotland.

PARTICIPANTS

Mothers taking antiepileptic drugs in pregnancy between 1976 and 2000 were ascertained from hospital obstetric records and 149 (58% of those eligible) took part. They had 293 children whose health and neurodevelopment were assessed.

MAIN OUTCOME MEASURES

Frequencies of neonatal withdrawal, congenital malformations, childhood onset medical problems, developmental delay, and behaviour disorders.

RESULTS

Neonatal withdrawal was seen in 20% of those exposed to antiepileptic drugs. Congenital malformations occurred in 14% of exposed pregnancies, compared with 5% of non-exposed sibs, and developmental delay in 24% of exposed children, compared with 11% of non-exposed sibs. After excluding cases with a family history of developmental delay, 19% of exposed children and 3% of non-exposed sibs had developmental delay, 31% of exposed children had either major malformations or developmental delay, 52% of exposed children had facial dysmorphism compared with 25% of those not exposed, 31% of exposed children had childhood medical problems (13% of non-exposed sibs), and 20% had behaviour disorders (5% of non-exposed).

CONCLUSION

Prenatal antiepileptic drug exposure in the setting of maternal epilepsy is associated with developmental delay and later childhood morbidity in addition to congenital malformation.

Language and reading outcomes to age 9 in late-talking toddlers

Language and reading outcomes at 6 to 9 years of age were examined in a sample of 34 children who were late talkers as toddlers. The late talkers, who all had normal nonverbal ability and age-adequate receptive language at intake, were compared to a group of 25 typically developing children matched at intake (24 to 31 months) on age, socioeconomic status, and nonverbal ability. Late talkers performed in the average range on most language tasks by age 5. However, they had significantly poorer scores on most language measures through age 9. The groups did not differ in reading skills at age 6 or 7, but the late talkers were slightly less skilled in reading at ages 8 and 9. Findings suggest that slow early language development reflects a predisposition for slower acquisition and lower asymptotic performance in a wide range of language-related skills into middle childhood.

Behavioural analysis of an inherited speech and language disorder: comparison with acquired aphasia

Genetic speech and language disorders provide the opportunity to investigate the biological bases of language and its development. Critical to these investigations are the definition of behavioural phenotypes and an understanding of their interaction with epigenetic factors. Here, we report our investigations of the KE family, half the members of which are affected by a severe disorder of speech and language, which is transmitted as an autosomal-dominant monogenic trait. The cognitive manifestations of this disorder were investigated using a number of linguistic and non-linguistic tests. The aims of these investigations were to establish the existence of a 'core' deficit, or behavioural phenotype, and to explain how such a deficit during development might give rise to the range of other impairments demonstrated by affected family members. The affected family members were compared both with the unaffected members and with a group of adult patients with aphasia resulting from a stroke. The score on a test of repetition of non-words with complex articulation patterns successfully discriminated the affected and unaffected family members. The affected family members and the patients with aphasia had remarkably similar profiles of impairment on the tests administered. Pre-morbidly, however, the patients with aphasia had enjoyed a normal course of cognitive development and language experience. This benefit was reflected on a number of tests in which the patients with aphasia performed significantly better than the affected family members and, in the case of some tests, at normal levels. We suggest that, in the affected family members, the verbal and non-verbal deficits arise from a common impairment in the ability to sequence movement or in procedural learning. Alternatively, the articulation deficit, which itself might give rise to a host of other language deficits, is separate from a more general verbal and non-verbal developmental delay.

Relationship between a global rating of speech ability at the age of 3 yrs and a phonological screening 1 yr later: a prospective field study

OBJECTIVE

This study, which was carried out under routine conditions, evaluates the predictability of a global rating of children's speaking manner made by Child Health Centre nurses. The global rating was added to a formalized screening of 3-yr olds, which intended to identify severely language disabled children. This screening procedure is used in several Swedish counties and the participation rate is nearly 100%. The main questions of the study are: (i) can a global rating of speech ability in children, who have passed the 3-yr screening, predict the outcome of a new population screening 1 yr later? and if so (ii) what is the most efficient cut-off point?

METHODS

The global ratings of the 3-yr olds were made using a 100 mm visual analogue scale (VAS). At the age of 4 yrs, 2065 globally rated children with no objections from the 3-yr screening participated in a second, well-established assessment. The purpose of this second screening was to identify not only severe but also moderate disability.

RESULTS

The mean VAS value of the global ratings was 62 mm. One-third of the ratings fell on the lower half of the scale. With a cut-off level set at < or =50 mm on the VAS two newly-identified, severely disabled children and 74% of the moderately disabled 4-yr olds were identified.

CONCLUSION

The results suggest that the global rating in connection to the 3-yr screening would serve as a useful tool for selective screening of 4-yr olds, and thus, reduce the work load.

Grammatical morphology deficits in Spanish-speaking children with specific language impairment

The focus of this study was the use of grammatical morphology by Spanish-speaking preschoolers with specific language impairment (SU). Relative to both same-age peers and younger typically developing children with similar mean lengths of utterance (MLUs), the children with SU showed more limited use of several different grammatical morphemes. These limitations were most marked for noun-related morphemes such as adjective-agreement inflections and direct object clitics. Most errors on the part of children in all groups consisted of substitutions of a form that shared most but not all of the targets grammatical features (e.g., correct tense and number but incorrect person). Number errors usually involved singular forms used in plural contexts; person errors usually involved third person forms used in first person contexts. The pattern of limitations of the children with SU suggests that, for languages such as Spanish, additional factors might have to be considered in the search for clinical markers for this disorder. Implications for evaluation and treatment of language disorders in Spanish-speaking children are also discussed.

Attention deficity/hyperactivity in SLI children increases risk of speech/language disorders in first-degree relatives: a preliminary report

Specific language impairment (SLI) or developmental dysphasia denotes the inability to acquire normal expression and/or comprehension of language in the absence of peripheral hearing impairment, neurological disorder, and mental retardation. The presence of attention deficit/hyperactivity in some SLI children has previously been documented. This family history study used 27 SLI families, identified through the parents from the Dysphasia Association, to examine the relationship between attention deficit/hyperactivity in SLI children and the risk to first-degree relatives. All SLI children were clinically diagnosed with speech/language disorder; medical records were searched for the presence of any of the exclusion criteria noted above. The 13 SLI children with medical record of attention deficit/hyperactivity had a significantly higher chance of having first-degree relatives with speech/language disorders than 14 SLI children without such record (15/27 and 4/46, respectively). This preliminary report suggests that additional study is warranted to investigate the relationship between speech/language disorders and attention deficit/hyperactivity in families of SLI children.

LEARNING OUTCOMES

As a result of this activity, the participant will be able to describe the SLI phenotype, its prevalence, and complexity and to recognize the relationship between comorbid attention deficit/hyperactivity in SLI children and the risk of speech/language disorder in their relatives.

Developing language skills of cocaine-exposed infants

OBJECTIVE

To assess whether there is an association of level of fetal cocaine exposure to developmental precursors of speech-language skills at 1 year of age, after controlling for confounding factors.

DESIGN

In a prospective, longitudinal, quasi-experimental, matched cohort design, 3 cocaine exposure groups were defined by maternal self-report and infant meconium assay: nonexposure (n = 131), heavier exposure (n = 66), >the 75th percentile for maternal self-report and >the 70th percentile of benzoylecgonine concentration, and all others as lighter exposure (n = 68). At 1 year of age, the Preschool Language Scale-3 was administered by examiners unaware of infant drug status.

RESULTS

Independent of confounding drug, medical, and environmental factors, more heavily exposed infants had lower auditory comprehension scores than nonexposed infants and lower total language scores than lighter and nonexposed infants. More heavily exposed infants were also more likely to be classified as mildly delayed by total language score than nonexposed infants. There were positive linear relationships between the concentration of benzoylecgonine in meconium and all outcomes and between maternal report of severity of prenatal cocaine use with poorer auditory comprehension indicating a relationship between amount of exposure and poorer outcomes.

CONCLUSIONS

This study documents significant behavioral teratogenic effects of fetal cocaine exposure on attentional abilities underlying auditory comprehension skills considered to be precursors of receptive language. Pediatricians are in a unique position to monitor early development of cocaine-exposed infants and make timely referrals for intervention.

Speed of processing in children with specific language impairment

The aim of the present study was to investigate the speed with which children with specific language impairment (SLI) respond on a range of tasks. Seventy-seven third-grade children participated in 10 different tasks (involving a total of 41 conditions), including nonlinguistic and linguistic activities. Mean response times (RTs) of children with SLI (n = 29) increased as a function of mean RTs of children with normal language (NLD, n = 29) under each of three different regression models; children with SLI responded more slowly across all task conditions, and also when linguistic and nonlinguistic tasks were analyzed separately. Children with nonspecific language impairment (NLI) were also included (n = 19). The results were similar to those for children with SLI, but the degree of slowing was greater. The results of the group analyses support the hypothesis that speed of processing in children with SLI is generally slower than that of children with normal language. However, some children with SLI do not appear to show deficits of this type.

Social Behaviors of Children With Language Impairment on the Playground

Purpose: This pilot study examined the social behaviors of children with language impairment (LI) and their typical peers on the playground.

Method: Eight children with LI and their age-matched peers were videotape recorded for 45 minutes during morning and lunch recesses. Samples were divided into 5-second segments and coded according to the child’s behavior occurring during the segment. The behavior displayed during each interval was then coded into one of 37 subcategories. These subcategories were grouped into six general categories of (a) peer interaction, (b) adult interaction, (c) withdrawal, (d) aggression, (e) victimization, and (f) other.

Results: Significant differences were observed in the categories of peer interaction and withdrawal. Typical children spent significantly more time interacting with peers than did children with LI. Conversely, children with LI demonstrated significantly more withdrawn behaviors than did their typical peers. Analyses of effect size using ω 2 indicated that group membership accounted for approximately 30% of the variability in both of these types of playground behavior. No other significant differences were observed. These findings support the conclusions of researchers using teacher interview procedures, indicating that children with LI are more withdrawn than their typical peers at school.

Clinical Implications: Specific intervention targeting social language skills in playground contexts may be warranted to include children with LI in social interactions at recess.

The N400 component in parents of children with specific language impairment

Children with specific language impairment (SLI) often have a family history of language disorder. In this study, ERPs in response to a visual semantic priming task were recorded in parents of children with SLI. Despite equal performance, the ERPs displayed differences in language processing: larger N400 amplitudes indicated that the parents, especially the fathers, were less primed by the preceding context. Difference waveforms showed that the fathers of SLI children, contrary to controls, had less differentiated responses to congruent versus incongruent sentences. We propose that the N400 observations may be residual markers of past language deficiencies in the fathers. No differences in the N400 effect were found in the mothers of SLI children.

Concomitant Disorders in School-Age Children Who Stutter

Purpose: The purposes of this survey study were to (a) determine the number of children who stutter with verified concomitant phonological and language disorders, (b) determine the number of children who stutter with suspected concomitant phonological and language disorders, and (c) determine the type of treatment clinicians use with these children.

Method: A systematic sampling plan was used to obtain survey responses from 241 American Speech-Language-Hearing Association (ASHA)-certified, school-based speech-language pathologists from 10 states that were considered to have similar state verification criteria for fluency, articulation/phonology, and language disorders. Respondents were asked to provide information concerning verified and suspected concomitant disorders in children who stutter. They also were asked to select one of four types of intervention approaches suggested by Bernstein Ratner (1995) in treating concomitant disorders in stuttering (i.e., blended, cyclic, sequential, and concurrent).

Results: The speech-language pathologists reported on 467 children who stuttered. Of that total, 262 (56%) children had a fluency disorder only and 205 (44%) had a verified concomitant phonological and/or language disorder. A subgroup of children with verified fluency-only disorders were suspected of having a concomitant disorder. When treating a fluency and a concomitant phonological and/or language disorder, the majority of clinicians used a blended approach.

Clinical Implications: Using similar state verification guidelines, this survey showed that a large percentage of preschool through high school students possessed a verified fluency disorder and a phonological and/or language disorder. Thus, clinicians need to be aware of the strong possibility that school-age children who stutter might have a phonological disorder and/or a language disorder. Additionally, because the majority of respondents used a blended treatment approach when treating children with a fluency and a verified concomitant phonological and/or language disorder, it appears that many school-based clinicians believe it is best to address both problems simultaneously.

Language regression in childhood

Language regression is observed both in autistic regression and as part of acquired epileptic aphasia (Landau-Kleffner Syndrome). We prospectively identified 177 children with language regression at four major medical centers, and their clinical characteristics were recorded. Their mean age at regression was 22.8 months. The mean time-to-specialist referral was 38 months of age. Most children (88%) met criteria for autism or manifested autistic features. Males (P = 0.02) and children less than 3 years of age who regressed (P = 0.016) had a higher probability of developing autistic behaviors. Seizures were more common in children who regressed after they reached 3 years of age (P < 0.001), and children with seizures were less likely to have associated autistic regression (P < 0.001). Electroencephalogram abnormalities were reported in 37% of patients and were more common in children with seizures (P < 0.001). At last follow-up, language function was impaired in 88% of the children, although some improvement was noted in 57%. We conclude that the loss of previously acquired language at any age, even if that language only includes a few words or communicative gestures, is often associated with a more global regression in cognition and/or behavior and has serious implications for future function. Early identification and referral of these children is necessary to allow for diagnosis and intervention.

Production of English finite verb morphology: a comparison of SLI and mild-moderate hearing impairment

The performance on production of finite verb morphology of 19 children (ages 5;9-10;7) with mild-moderate sensorineural hearing impairment (SNH) was compared with that of 14 children with specific language impairment (SLI) (ages 7;2-10;9) and age-matched and language-matched control groups. On average, the SNH group outperformed the SLI group and was comparable to controls. However, a subset of the SNH group (n = 6) was impaired on one or both of these tasks. Degree of hearing loss or age of receiving hearing aids was not directly related to performance, but other language measures were. The subset was also significantly younger than the rest of the SNH group, suggesting that acquisition of finite verb morphology may be delayed in children with hearing impairments. Verb regularity had no effect on performance of any group, but word frequency and phonological complexity did exert an influence. The findings are discussed in relation to causative theories of SLI.

Estimating the Risk of Future Reading Difficulties in Kindergarten Children: A Research-Based Model and Its Clinical Implementation

PURPOSE

Speech-language pathologists have the skills and knowledge needed to play an important role in the early identification of children who are at risk for reading difficulties. Whereas research has identified language and other factors that may be predictive of future reading problems, studies have not provided the statistical models and classification data needed for the implementation of early identification programs. In this paper, we report the results of a longitudinal study that examined kindergarten predictors of second-grade reading outcome.

METHOD

Six hundred and four children were given a battery of language, early literacy, and nonverbal cognitive measures in kindergarten as part of an epidemiologic study of language impairments in children. Follow-up testing of reading achievement was completed in second grade. Participants were divided into those children with and without reading difficulties.

RESULTS

Findings indicated that five kindergarten variables (letter identification, sentence imitation, phonological awareness, rapid naming, and mother's education) uniquely predicted reading outcome in second grade.

CLINICAL IMPLICATIONS

A logistic regression formula and classification data based on these results are provided. Suggestions are offered concerning how this information could be used in an early identification and intervention program for children who are at risk for reading difficulties.

Speech and language screening for audiologists

Speech and language screening by audiologists is not new, although few audiologists screen speech and language, which should be an integral component of the audiological evaluation. This article considers ASHA's views about speech and language screening by audiologists, screening tests available to audiologists, and the training of audiologists to screen speech and language.

The New Peabody Picture Vocabulary Test—III:

This article examines whether changes in the ethnic minority composition of the standardization sample for the latest edition of the Peabody Picture Vocabulary Test (PPVT-III, Dunn & Dunn, 1997) can be used as the sole explanation for children's better test scores when compared to an earlier edition, the Peabody Picture Vocabulary Test-Revised (PPVT-R, Dunn & Dunn, 1981). Results from a comparative analysis of these two test editions suggest that other factors may explain improved performances. Among these factors are the number of words and age levels sampled, the types of words and pictures used, and characteristics of the standardization sample other than its ethnic minority composition. This analysis also raises questions regarding the usefulness of converting scores from one edition to the other and the type of criteria that could be used to evaluate whether the PPVT-III is an unbiased test of vocabulary for children from diverse cultural and linguistic backgrounds.

KEY WORDS: vocabulary, multicultural assessment, standardized tests, Peabody Picture Vocabulary Test, test bias

Follow-up of children with early expressive phonology disorders

Fifty-two children identified at age 4 to 6 years as demonstrating a moderate to severe expressive phonology disorder were followed to the third and fourth grades. Children were classified into two groups based on the presence of an early phonology disorder in isolation (P) or the presence of a phonology disorder with other language problems (PL). At follow-up, articulation measures failed to differentiate the groups; however, the PL group performed more poorly than the P group on measures of phoneme awareness, language, reading decoding, reading comprehension, and spelling. The P group demonstrated poor spelling skills relative to their reading and language abilities, suggesting residual spelling weaknesses in these children. The PL group reported more nuclear family members with speech-language disorders and with reading disorders than the P group. Findings support previous research linking early language disorders with later reading difficulties.

The relationship between language and reading. Preliminary results from a longitudinal investigation

This longitudinal study investigated the relationship between language and reading from three perspectives. First, we examined the reading and writing outcomes of children identified with spoken language impairments (LIs). Second, the early language abilities of children identified as poor readers were investigated. Finally, reading and language abilities were treated as continuous variables and the developmental relationship between them was studied. In general, the results indicated that language abilities (both phonological processing and oral language) significantly contributed to achievement in the early stages of reading (2nd grade) and had an even stronger effect as children acquired greater reading proficiency (4th grade).

Improving the positive predictive value of screening for developmental language disorder

In a previous study, we reported the results of an early language screening program in which 306 children were screened using a parent-report questionnaire sent through the mail (Klee et al., 1998). A sample of the children screened were given clinical evaluations within a month of screening (n = 64) and again 1 year later (n = 36). Although the screening program correctly identified 91% of 2-year-olds with language delay, it produced a large number of over-referrals. In the present study we examine a revised screening criterion designed to reduce the number of false positives. The revised criterion generated fewer positive screens overall than the original and resulted in improved specificity (96% vs. 87%) and positive predictive value (77% vs. 51%), while maintaining the high sensitivity (91%) and negative predictive value (98%) of the original criterion. We also propose a screening score based on the new criterion, designed to inform the process of deciding which children to bring in for further evaluation.

Nonword repetition performance in school-age children with and without language impairment

This study examined nonword repetition performance in a population-based sample of school-age children. A total of 581 second graders who were participating in a longitudinal, epidemiologic investigation of specific language impairment (SLI) were administered the Nonword Repetition Task (NRT) developed by Dollaghan & Campbell (1998). Performance was examined according to second-grade diagnostic category, presence/absence of language impairment, and treatment status. Results indicated that children with language impairment, as well as those in intervention, exhibited deficient nonword repetition skills compared to normal language controls. Findings also confirmed that the NRT is a culturally nonbiased measure of language processing. Results from likelihood ratio analyses indicated that NRT performance, though not sufficient on its own, may provide a useful index to assist in ruling in or ruling out language disorder.

An assessment battery for identifying language impairment in African American children

This investigation compares the performances of 24 African American children, diagnosed as language impaired (LI) and receiving school-based language therapy, to 2 groups of typically developing peers (N = 48) on 5 traditional types of language assessment measures. Three of the measures were derived from child-centered free play language sample analyses and included average length of communication units (MLCU), frequencies of complex syntax, and numbers of different words. Two of the measures examined language comprehension and included responses to requests for information in the form of Wh-questions and responses to probes of active and passive sentence constructions. The performances of the group of children with language impairments were significantly lower on each measure than that of chronological age matched African American children who were typically developing. Sensitivity and specificity of the battery appeared excellent. The findings are discussed in terms of the potential of these informal language measures to contribute to a culturally fair assessment protocol for young African American children.

Redefining the survival of the fittest: communication disorders in the 21st century

OBJECTIVES

To determine the economic effect on the US economy of the cost of caring for people with communication disorders as well as the cost of lost or degraded employment opportunities for people with such disorders, including disorders of hearing, voice, speech, and language.

STUDY DESIGN

Survey of available historical and contemporary governmental and scholarly data concerning work force distribution and the epidemiology of disorders of hearing, voice, speech, and language.

METHOD

Analysis of epidemiological and economic data for industrialized countries, North America, and the United States.

RESULTS

Communication disorders are estimated to have a prevalence of 5% to 10%. People with communication disorders may be more economically disadvantaged than those with less severe disabilities The data suggest that people with severe speech disabilities are more often found to be unemployed or in a lower economic class than people with hearing loss or other disabilities. Communication disorders may cost the United States from $154 billion to $186 billion per year, which is equal to 2.5% to 3% of the Gross National Product.

CONCLUSIONS

Communication disorders reduce the economic output of the United States, whose economy has become dependent on communication-based employment. This trend will increase during the next century. The economic cost and the prevalence rates of communication disorders in the United States indicate that they will be a major public health challenge for the 21st century.

Language disorders: a 10-year research update review

OBJECTIVE

To review the past 10 years of research in child language or communication disorders, which are highly prevalent in the general population and comorbid with childhood psychiatric disorders.

METHOD

A literature search of 3 major databases was conducted. The child language literature, describing the domains of language development--phonology, grammar, semantics, and pragmatics--is reviewed.

RESULTS

Disorders of grammar, semantics, and pragmatics, but not phonology, overlap significantly with childhood psychiatric disorders. Receptive language disorders have emerged as high-risk indicators, often undiagnosed. Language disorders and delays are psychiatric risk factors and have implications for evaluation, therapy, and research. However, they are often undiagnosed in child mental health and community settings. The research has focused mostly on monolingual English-speaking children.

CONCLUSION

Awareness of basic child language development, delay, and deviance is crucial for the practicing child and adolescent psychiatrist, who must diagnose and refer relevant cases for treatment and remediation. Future research needs to address the growing language diversity of our clinical populations.

Academic outcomes in children with histories of speech sound disorders

Tests of phonology, semantics, and syntax were administered to 52 preschool children (19 girls and 33 boys, age 4-6 years) with moderate to severe speech sound disorders. The children's performance on these tests was used to predict language, reading, and spelling abilities at school age (age 8-11 years). Language impairment at school age was related to poor performance on preschool tests of syntax and nonsense word repetition, while reading impairment was predicted by poor performance in all preschool test domains (phonology, semantics, and syntax). In contrast, spelling impairment was predicted by deficits in preschool tests of phonological processing as measured by the Word Discrimination subtest of the Test of Language Development - Primary 2. Family history for speech and language disorders did not predict language, reading, or spelling impairment at school age. However, family history for reading disorders was a good predictor of school-age spelling difficulties.

Prevalence of speech delay in 6-year-old children and comorbidity with language impairment

We estimate the prevalence of speech delay (L.D. Shriberg, D. Austin, B. A. Lewis, J. L. McSweeny, & D. L. Wilson, 1997b) in the United States on the basis of findings from a demographically representative population subsample of 1,328 monolingual English-speaking 6-year-old children. All children's speech and language had been previously assessed in the "Epidemiology of Specific Language Impairment" project (see J. B. Tomblin et al., 1997), which screened 7,218 children in stratified cluster samples within 3 population centers in the upper Midwest. To assess articulation, the Word Articulation subtest of the Test of Language Development-2: Primary (Newcomer & Hammill, 1988) was administered to each of the 1,328 children, and conversational speech samples were obtained for a subsample of 303 (23%) children. The 6 primary findings are as follows: (a) The prevalence of speech delay in 6-year-old children was 3.8%; (b) speech delay was approximately 1.5 times more prevalent in boys (4.5%) than girls (3.1%); (c) cross-tabulations by sex, residential strata, and racial/cultural backgrounds yielded prevalence rates for speech delay ranging from 0% to approximately 9%; (d) comorbidity of speech delay and language impairment was 1.3%, 0.51% with Specific Language Impairment (SLI); (e) approximately 11-15% of children with persisting speech delay had SLI; and (f) approximately 5-8% of children with persisting SLI had speech delay. Discussion includes implications of findings for speech-language phenotyping in genetics studies.

Maternal education and measures of early speech and language

The present study was designed to determine whether 4 measures of children's spontaneous speech and language differed according to the educational level of the children's mothers. Spontaneous language samples from 240 three-year-old children were analyzed to determine mean length of utterance in morphemes (MLUm), number of different words (NDW), total number of words (TNW), and percentage of consonants correct (PCC). A norm-referenced, knowledge-dependent measure of language comprehension, the Peabody Picture Vocabulary Test-Revised (PPVT-R), was also included for purposes of comparison with the spontaneous measures. Three levels of maternal education were compared: less than high school graduate, high school graduate, and college graduate. Trend analyses showed statistically significant linear trends across educational levels for MLUm, NDW, TNW, and PPVT-R; the trend for PCC was not significant. The relationship of maternal education and other sociodemographic variables to measures of children's language should be examined before using such measures to identify children with language disorders.

Fourteen-year follow-up of children with and without speech/language impairments: speech/language stability and outcomes

This report concerns the speech and language outcomes of young adults (N = 242) who participated in a 14-year, prospective, longitudinal study of a community sample of children with (n = 114) and without (n = 128) speech and/or language impairments. Participants were initially identified at age 5 and subsequently followed at ages 12 and 19. Direct assessments were conducted in multiple domains (communicative, cognitive, academic, behavioral, and psychiatric) at all three time periods. Major findings included (a) high rates of continued communication difficulties in those with a history of impairment; (b) considerable stability in language performance over time; (c) better long-term outcomes for those with initial speech impairments than for those with language impairments; and (d) more favorable prognoses for those with specific language impairments than for those with impairments secondary to sensory, structural, neurological, or cognitive deficits. These general conclusions held when either a liberal or a more stringent criterion for language impairment was employed. Some of these findings are consistent with those from earlier follow-up studies, which used less optimal methods. Thus, the present replication and extension of these findings with a sound methodology enables greater confidence in their use for prognostic, planning, and research purposes.

Local norming of the test of adolescent/adult language-3 in the Ottawa Speech and Language Study

The young adult norms for the Test of Adolescent/Adult Language-3 (TOAL-3; D. Hammill et al., 1994) are based only on individuals who pursued postsecondary education, a restriction that renders the norms inappropriate for many clinical and research purposes. This research note details the rationale, methods, and results of a local norming of the TOAL-3 spoken language subtests, based on participants from the Ottawa Speech and Language Study (C. J. Johnson et al., 1999). The resulting Ottawa norms represent the full range of young adult language abilities and, therefore, can be used with caution for some clinical and research purposes.

Bound-morpheme generalization by children with SLI: is there a functional relationship with accuracy of response to training targets?

We investigated whether limited bound-morpheme generalization (BMG) by preschool children with SLI is functionally related to limited learning of training targets (words, affixed forms). Thirty children with SLI and 30 age-/gender-matched controls participated in the study. Production probes revealed a dissociation between learning and generalization performance. In addition, the number of children who achieved criterion-level BMG increased abruptly during an additional instructional experience with new training targets. These findings suggest that positive evidence of a bound morpheme's generalizability to different vocabulary stems benefits BMG. Furthermore, they suggest that limited BMG reflects problems not with the storage or access of specific trained facts but with the extraction and extension of the linguistic pattern (e.g., regularity, "rule") instantiated in the learning targets.

Performances of At-Risk, African American Preschoolers on the Peabody Picture Vocabulary Test-III

This study examined the performance of 59 at-risk, African American preschoolers on the Peabody Picture Vocabulary Test-III (PPVT-III, Dunn & Dunn, 1997). The subjects were considered at-risk based on low-income status and/or social status variables such as family density and teenage parents. A mean standard score of 91 and a standard deviation of 11 were achieved by these children. Although these scores are below those reported for the PPVT-III standardization sample, the performance spread resulted in a normal distribution of scores. Differences in performance based on gender and income were not apparent, but level of education of the primary caregiver significantly influenced performance. The findings indicate that unlike the Peabody Picture Vocabulary Test-Revised (PPVT-R, Dunn & Dunn, 1981) the PPVT-III is a culturally fair instrument that is appropriate for use with this population.

Tense over time: the longitudinal course of tense acquisition in children with specific language impairment

Tense marking in English is relatively late appearing and is especially late for children with Specific Language Impairment (SLI). Little is known about the full course of acquisition for this set of morphemes. Because tense marking is a fundamental property of clause construction, it is central to current theories of morphosyntax and language acquisition. A longitudinal study is reported that encompasses the years of 2;6-8;9 years for typically developing children (N = 43) and 4;6-8;8 years for children with SLI (N = 21). The findings show that a diverse set of morphemes share the property of tense marking; that this set is not mastered until age 4 years in typically developing children and after 7 years for children with SLI; that acquisition shows linear and nonlinear components for both groups, in a typical S-shaped curve; and that nonsyntactic measures are not predictors of growth (including nonverbal intelligence, vocabulary size, and mother's education), whereas initial MLU does predict rate of acquisition. The findings are consistent with a model of Optional Infinitives (OI) for typically developing children (cf. Wexler, 1994, 1996) and Extended Optional Infinitives (EOI) for children with SLI. This model hypothesizes incomplete specification of features of tense that are represented in the grammar.

Neural basis of an inherited speech and language disorder

Investigation of the three-generation KE family, half of whose members are affected by a pronounced verbal dyspraxia, has led to identification of their core deficit as one involving sequential articulation and orofacial praxis. A positron emission tomography activation study revealed functional abnormalities in both cortical and subcortical motor-related areas of the frontal lobe, while quantitative analyses of magnetic resonance imaging scans revealed structural abnormalities in several of these same areas, particularly the caudate nucleus, which was found to be abnormally small bilaterally. A recent linkage study [Fisher, S., Vargha-Khadem, F., Watkins, K. E., Monaco, A. P. & Pembry, M. E. (1998) Nat. Genet. 18, 168-170] localized the abnormal gene (SPCH1) to a 5. 6-centiMorgan interval in the chromosomal band 7q31. The genetic mutation or deletion in this region has resulted in the abnormal development of several brain areas that appear to be critical for both orofacial movements and sequential articulation, leading to marked disruption of speech and expressive language.

Look who's talking: a prospective study of familial transmission of language impairments

Language impairments have been hypothesized to have a genetic component. Previous studies of the familial aggregation of language impairments have relied on a retrospective approach based on parental/self-reported history of language development. This study examined familial aggregation prospectively, by investigating language acquisition and cognitive development in the younger siblings and offspring of individuals with well-defined language impairments. It was predicted that children with a positive family history for language impairments would be more likely to show delays in language acquisition than would age- and gender-matched controls. Similar delays were not expected in nonlinguistic domains, such as conceptual, gestural, or general cognitive development. Ten children with a positive family history and 10 age- and gender-matched controls were tested. Analyses of linguistic and cognitive assessments at 16 to 26 months confirmed the predictions. Children with a family history of language impairments had lower receptive and expressive language scores than controls, with 50% of them scoring at least 1.5 SD below the mean for their age. At the same time, performance on a number of tasks that did not rely on language abilities did not differ as a function of family history. These results indicate that children with a positive family history for language impairments are at risk for language delay; the results also support a familial component to language impairments.

Epidemiology of specific language impairment: prenatal and perinatal risk factors

The prenatal and perinatal risk factors likely to be associated with specific language impairment (SLI) were examined in this study. A review of existing research showed that there have been few studies on this topic. Among children with SLI, greater rates of near relatives with language learning problems has been found. Data obtained from a case-control study of 177 children with SLI and 925 children without sensory, developmental disorders, or language impairment were studied using a parental questionnaire concerning exposures during the prenatal and perinatal period for the index children. Differences between the children with SLI and controls were found for parental characteristics regarding education, positive history of language and learning problems, tobacco smoking, and breast feeding. No support was found for elevated rates of maternal exposure to disease or occupational chemical substances.