Excerpted from Chapter 2 of CSBS DP Manual, by Amy M. Wetherby, Ph.D., CCC-SLP, & Barry M. Prizant, Ph.D., CCC-SLP.
Copyright © 2002 by Paul H. Brookes Publishing Co. All rights reserved..
The development of the CSBS DP was stimulated by the need to bridge the gap between current developmental literature and available standardized evaluation tools for young children. The national priority of early identification and intervention is reflected in the Education of the Handicapped Act Amendments of 1986 (PL 99-457) and the Individuals with Disabilities Education Act (IDEA) Amendments of 1991 (PL 102-119) and 1997 (PL 105-117). This legislation establishes a provision of funds to states choosing to develop and implement early identification and intervention services for infants and toddlers at high risk for or with a developmental delay from birth up to their third birthday, including children with delays in speech and language development. However, the early identification of children with communication or language disorders has posed a dilemma. The first symptom attended to by parents and professionals may be a delay in or failure to acquire language when other significant disabilities are not present. Because the normal range of first word acquisition is between 12 and 20 months of age, a child may not be referred for a language delay until at best 20–24 months but more typically after 30 months, especially in the absence of significant medical risks, cognitive impairments, or physical disabilities.
DEFINITION OF ASSESSMENT AND EVALUATION
The popular definition of assessment is the measurement of a child's knowledge, abilities, and achievement (Meisels, 1996). No clear boundary exists between assessment and intervention, but rather, assessment should be viewed as part of the intervention process. The purpose of assessment for young children is twofold: first, to identify or rule out the existence of a language or communication problem, and second, to understand the nature of the language problem in order to guide intervention decisions. The regulations stipulated in IDEA, however, distinguish between the terms evaluation and assessment.
Evaluation refers to the process used to determine a child's initial and continuing eligibility for services and includes screening, developmental evaluation, and diagnostic evaluation. Screening is the process of referral and identification of children who are at risk or high risk for developmental delays or disabilities or need an evaluation. Developmental evaluation is the process of confirming the presence or absence of a delay or disability and determining eligibility for services. Diagnostic evaluation is a more in-depth process of examining the nature of or classification of developmental delay or disability. IDEA requires that a multidisciplinary evaluation be used to determine initial eligibility of infants and toddlers for early intervention services.
Assessment refers to the ongoing procedures used to document the child's unique strengths and needs as well as the family's concerns, priorities, and resources regarding the child's development in order to plan intervention services (Crais, 1995). An assessment should provide information about a child's relative knowledge of specific skills across domains as well as guidelines for planning intervention. The tools and strategies used for evaluation will likely differ substantially from those used for assessment. Traditionally, an evaluation is conducted in a brief period of time using standardized, norm-referenced instruments. Assessment procedures usually entail multiple strategies and sources of information using criterion-referenced or curricular-based instruments and are ongoing.
WHY IS EARLY IDENTIFICATION IMPORTANT?
There is mounting evidence that intervention beginning during infancy or preschool has a greater impact on outcomes for children and families than providing services at school age (Barnett & Escobar, 1990). It is estimated that every dollar spent on early intervention can save $7.16 in later special education, crime, welfare, and other costs (Florida Starting Points, 1997). Despite federal mandates for early intervention, limitations in the identification process diminish children's access to services, and educators are not reaching most of the children and families who need help as early as they should (Meisels & Wasik, 1990). According to the 22nd Annual Report to Congress, 11% of school-age children received special education services (U.S. Department of Education, 2000). In contrast, only 4.9% of preschool children received special education, and only 1.6% of infants and toddlers received early intervention services. These statistics indicate a significant need to improve early identification of children who are likely to require special education at school age.
Recent advances in brain research show how the environment sculpts the young child's brain, as neurons form connections and mature in response to stimulation. The environment has the greatest potential to influence a child's developing brain during the first few years of life. Early experiences affect brain structure because the brain operates on a "use it or lose it" principle (Carnegie Task Force on Meeting the Needs of Young Children, 1994; Ounce of Prevention Fund, 1996). If a child does not have adequate emotional, physical, cognitive, and language stimulation, neurons can be lost permanently.
Language development is one of the most critical school readiness skills. Children's capacity to talk and the size of their vocabulary when they enter kindergarten is predictive of success in school. Children with language problems in preschool are likely to face poor educational achievement at school age and are at increased risk to develop emotional and behavioral disorders (Baker & Cantwell, 1987; Prizant et al., 1990). Follow-up studies of preschoolers with speech and language problems consistently demonstrate persisting communication impairments in a substantial proportion of children and a high incidence of learning disabilities (Howlin & Rutter, 1987). Early intervention may prevent or decrease the severity of language delays in preschoolers, enhance school readiness, and increase later academic success in school.
Cumulative Effects of Poverty and Environmental Risk
Research on young children raised in poverty demonstrates the dramatic detrimental impact that impoverished environments can have on a child's capacity to learn to talk. Strong correlations exist among the amount of time that parents talk to their children, socioeconomic status, children's vocabulary, and children's IQ scores (Hart & Risley, 1992; Walker, Greenwood, Hart, & Carta, 1994). As documented by Hart and Risley (1992), children's capacity for learning language is solidified by age 3, and the cumulative effects of the environment are evident. By school age, children in poverty are more likely to have developmental disabilities and behavior problems and to require special education services than other children (Brooks-Gunn & Duncan, 1997; U.S. Department of Education, 2000). Educational programs beginning at 3–4 years of age cannot hope to overcome such vast differences in cumulative experience. Educators are challenged to find ways to intervene very early in children's lives to effectively enhance child development and affect school readiness.
LIMITATIONS OF FORMAL TOOLS
Although there has been a proliferation of research in infant communication and socioemotional development (Prizant & Wetherby, 1990), most formal tools used for evaluation and assessment of a child's communication and language have major limitations in their capacity to evaluate a child's spontaneous communication during natural interactions. Practitioners are faced with the challenge of identifying appropriate assessment instruments for young children to meet the goals of evaluation for early identification and assessment for intervention planning. Crais (1995) and Wetherby and Prizant (1992) identified several major limitations of the most frequently used formal communication assessment instruments for young children based on current theories of language development.
First, most formal instruments emphasize language milestones and forms of communication (e.g., number of different gestures, sounds, words, word combinations), rather than the social-communicative and symbolic foundations of language. Second, most instruments involving direct child assessment are primarily clinician directed, placing the child in a respondent role and limiting observations of spontaneous, child-initiated communication. Third, most instruments do not allow for the family to collaborate in decision making about the assessment process or to participate to the extent desired by the family; therefore, they are not family-centered. There is a critical need to move toward child-centered and family-centered assessment with infants, toddlers, and developmentally young children to ensure that evaluation and assessment practices yield meaningful measures.
In order to measure a child's communicative competence in natural interactions, language sampling has become widely used to supplement formal language tools for children who engage in conversation. Similarly, communication sampling can be used to supplement formal instruments for children functioning at preverbal or early verbal stages (Wetherby, Cain, Yonclas, & Walker, 1988; Wetherby & Prizant, 1989). The CSBS (precurser to the CSBS DP) was originally conceived as an informal procedure for sampling communication with preverbal children and was standardized and normed in response to the need for more naturalistic formal assessment measures. The implementation of IDEA makes it even more critical for clinicians to develop communication-sampling procedures to evaluate very young children.
HOW CAN WE FIND CHILDREN EARLIER?
A child's level of communication development may be the best indicator of a developmental delay. Delays or disorders in communication development are the most prevalent symptom in children with disabilities (Wetherby & Prizant, 1996). When serious health or physical impairments are not present, a delay in language development may be the first evident symptom that a child is not developing typically. A language delay may be the primary problem or reflect delays in other domains (i.e., socioemotional, cognitive, motor, sensory).
There is a growing body of research indicating that prelinguistic abilities predict later language abilities. By their first birthday, children usually do not produce true words but can share attention and emotion and communicate intentionally using a variety of gestures and speech-like sounds that have shared meanings with caregivers (Bates, 1976; Bates, O'Connell, & Shore, 1987; Stern, 1985). The readability of children's signals, coupled with contingent social responsiveness, facilitates successful acquisition of communication (Dunst, Lowe, & Bartholomew, 1990; Tronick, 1989). Typically, by their second birthday children use and understand hundreds of words, construct sentences, and engage in simple conversations. Linguistic communication begins when vocabulary growth accelerates, typically at about 19 months (Bates et al., 1987; Bloom, 1993). The dramatic changes in language abilities that occur from 1 to 2 years are reflected in the transition from prelinguistic to linguistic communication.
Although most children develop their first words between 12 and 15 months, it is common practice to wait until a child is at best 18–24 months, but usually at least 30 months of age and still not talking, to refer the child for an evaluation. The challenge for service providers determining whether to make a referral for a developmental evaluation is twofold. First, many children who are late in talking catch up on their own and need to be distinguished from children who will have persistent language problems. Second, children with delayed language skills need to be identified even earlier before language develops.
There is wide variation in the age and rate of acquisition of linguistic communication; however, this variation is strongly associated with prelinguistic development. A strong association has been found between children's prelinguistic gestures and sounds, communicative functions, comprehension of words, and use of objects in play at 1 year and language skills at 2 and 3 years (Paul, 1991; Paul & Jennings, 1992; Paul, Looney, & Dahm, 1991; Rescorla & Goosens, 1992; Thal & Tobias, 1992; Thal, Tobias, & Morrison, 1991; Wetherby et al., 1988). Many children are late in learning to talk, and many of these children do not need early intervention services. About 15% of 24-month-olds are late talkers with no other obvious delays (i.e., having fewer than 50 words or no word combinations; Rescorla, 1989, 1991). About half of these children show persisting problems in language development at age 3; the other half catch up with their peers spontaneously without intervention (Paul, 1991; Rescorla & Schwartz, 1990; Thal et al., 1991).
Research on preschoolers with language delays has important implications for distinguishing between children who will catch up spontaneously from those whose language problems are likely to persist. (For a review of this research, see McCathren, Warren, & Yoder, 1996; Olswang, Rodriguez, & Timler, 1998; Wetherby & Prizant, 1992.) These studies have identified a collection of language predictors that are prelinguistic indicators of later language development and promise earlier and more accurate identification. The following seven language predictors have been identified:
Emotion and eye gaze
Rate and function of communication
Use of gestures
Use of sounds
Use of words
Understanding of words
Use of objects
These studies have demonstrated that children delayed only in the use of words are very likely to catch up on their own while children who are delayed also in several or many of the other predictors are likely to have persisting problems. Instead of waiting for children to start using words, evaluating these language predictors is a promising solution to improve early identification.
The literature reviewed previously suggests that a child's profile of communicative and symbolic abilities, even prior to the emergence of words, may be a sensitive indicator of the likelihood of subsequent difficulties in communication and language development. The findings for young children who show persisting language impairments indicate that measures of vocabulary alone are insufficient for early identification. Multiple measures across communicative and symbolic domains are necessary for earlier identification and differentiation of children who will outgrow their delay, from those children who have specific versus more pervasive social or cognitive impairments. That is, a child who shows expressive language delays at 2 years and also shows delays in one or more of the other language predictors would be at a much higher risk than a child who demonstrates expressive language delays only.
These findings suggest greater urgency in initiating intervention that addresses delays, not only in expressive language, but also in other communicative and symbolic parameters. Because it is not yet possible to consider delays in expressive language for children younger than 18 months, it is even more critical to measure other parameters of communication and symbolic development in children younger than 18 months. Furthermore, patterns of strengths and weaknesses in the language predictors should provide critical information contributing to the early identification of a developmental disability. This empirical and theoretical framework forms the basis of the CSBS DP.