CHAPTER III - Assessment Methods for Young Children With Communications Disorders - Continued
Screening Tests for Communication Disorders
Screening tests for communication disorders are intended to lead to a "yes" or "no" decision that a child either may have a communication disorder or is unlikely to have problems with communication. The intent of screening tests is not to arrive at a formal diagnosis. Instead, the goal of screening is to identify children who have an increased likelihood of a communication disorder and therefore need further in-depth assessment to establish the diagnosis.
Uses of screening tests for communication disorders
There are various approaches to screening for communication disorders in young children. Screening tests for communication disorders can be used to screen all children in a certain age group of the population or can be used more selectively to screen children where a heightened concern for a communication disorder has already been identified.
Many screening tests (or screening instruments), available through a variety of sources, claim to be useful in identifying children with communication disorders. Some of these screening tests have been evaluated using standard research studies while others have not.
Screening tests are most often used to determine if a child may have a communication disorder, usually as a next step when a concern has been identified. Sometimes screening instruments are used as a component in a formal diagnostic process. In addition, some screening tests that have numerical scores can be used to rate the severity of a communication problem compared to pre-determined normal values. These types of screening instruments may be used for conducting periodic monitoring of the child's progress and for assessing outcomes.
Evaluating the accuracy of screening tests
An ideal screening test would be inexpensive, simple to administer, and highly accurate in differentiating children with a particular condition from those who do not have the condition. In the real world, no perfect screening test exists for identifying children with communication disorders.
The accuracy of a particular screening test is indicated by determining its sensitivity and specificity.
- The sensitivity of an assessment method is the percentage of all persons with the condition that are correctly identified as having the condition (based on the reference standard). In other words, the sensitivity of a test is the percentage of all persons with the condition who have positive tests that correctly identify the condition (the true positive rate).
- The specificity of an assessment test is the percentage of all persons who do not have the condition (according to the reference standard) that are correctly identified by the tests as being free of the condition. In other words, the specificity of a test is the percentage of all persons who do not have the condition who have negative test results (the true negative rate).
Tests with high sensitivities tend to do a good job in identifying persons with the condition (so there are fewer false negative tests). Tests with high specificities do a good job in identifying persons who do not have the condition (that is they are very good at ruling out the condition, so there are few false positive tests). The higher the sensitivity of a screening test, the lower the false negative rate. The higher the specificity of a test, the lower the false positive rate.
The concepts of sensitivity and specificity are described in more detail in the methodology tables in Appendix A .
Screening tests reviewed for this guideline
Some of the following recommendations address individual screening instruments (or tests) that have been specifically designed to assess young children and which are currently available for use in the United States. All of these tests rely on historical information about the child's behavior (usually provided by a parent), direct observation of the child by a professional, or a combination of these methods.
Tests that rely on historical information may be in the form of checklists or structured interviews. Checklists such as the Language Development Survey (LDS) are lists of questions or vocabulary items to be completed by parents. The MacArthur Communicative Developmental Inventory (CDI) is a newer norm-referenced test of language development in children which relies on parent reports on a standardized questionnaire.
Tests that rely on direct observation of the child by a professional, such as the Early Language Milestone Scale (ELM), often prescribe specific ways for the examiner to elicit responses from the child and have a standardized method for scoring behaviors that are observed. The Clinical Linguistic Auditory Milestone Scale (CLAMS) was the only language assessment instrument reviewed that combined both historical information from parents and direct observation of the child.
The Vineland Adaptive Behavior Scales (VABS), a general developmental test that is sometimes used to screen for communication disorders, is also included in the screening recommendations. The VABS is a norm-referenced test that assesses adaptive behavior by directly questioning the parents, using a standard questionnaire and interview protocol.
|Note: For children less than 24 months of age, screening tests are limited in their ability to differentiate children with receptive language problems from children who have normally developing language skills.|
General Principles of Screening for Communication Disorders
|Evidence Ratings : [A] = Strong [B] = Moderate [C] = Limited [D1] = Opinion/Studies do not meet criteria [D2] = Literature not reviewed|
General principles of screening tests
- It is important to recognize that even screening instruments that are easy to administer usually require the experience of a qualified professional (knowledgeable about communication disorders in young children) to interpret results and counsel parents. [D2]
- It is recommended that screening for communication disorders include use of:
- open-ended questions
- informal checklists
- formal checklists
- formal screening instruments
- observation of parent child communicative interactions in a naturalistic setting [D1]
- If screening for communication disorders is done with a formal checklist or questionnaire, then one of the following tests is recommended, which can be completed by parents with support as necessary:
- Ages and Stages Questionnaire (ASQ)
- Language Development Survey (LDS)
- MacArthur Communicative Development Inventories (CDIs) [D1]
- If there is heightened concern about a possible communication disorder in a young child, it may be useful for professionals to use a formal screening instrument for communication disorders, such as:
- Clinical Linguistic Auditory Milestone Scale (CLAMS)
- Early Language Milestone Scale (ELM-2)
- Receptive-Expressive Emergent Language Scale (REEL) [B]
Interpretation of screening test results
- If a screening instrument suggests a possible communication disorder, further assessment is needed to determine whether a disorder exists and to establish a diagnosis. [D2]
- If a screening instrument suggests that a communication disorder is not likely, it is still important to assess the child for other developmental or medical problems that may have caused the initial concern. [D2]
- It is important to remember that not all children with communication disorders can be identified early. Because the time of onset and severity of symptoms vary, it is recommended that screenings be repeated at various age levels when concerns for communication disorders persist or become apparent. [D1]
- It is recommended that parents be advised of the limitations of screening tests for communication disorders. Some children who have a communication disorder will pass a screening test whereas some children who fail the screening test do not necessarily have a communication disorder. [D2]
- In interpreting results of screening tests for communication disorders, it is recommended that:
- if a child scores below the standard cut-off, that this alert the examiner to the need for further assessment. A standard cut-off is a clinically accepted set of criteria to separate passing or failing scores on the screening test
- if a child scores above the standard cut-off and there are other indications of a possible communication disorder, then the child's progress continue to be monitored and periodic follow-up be scheduled [D2]
|Evidence Ratings : [A] = Strong [B] = Moderate [C] = Limited [D1] = Opinion/Studies do not meet criteria [D2] = Literature not reviewed|
Clinical Linguistic Auditory Milestone Scale (CLAMS)
The Clinical Linguistic Auditory Milestone Scale (CLAMS) was developed to screen for language delays in young children between birth and 3 years of age. The test uses standardized methods for obtaining information from parent report and from direct interaction between the examiner and the child. The CLAMS is designed to be administered by a physician in an office setting.
The CLAMS includes both parent report and activities to elicit specific responses from the child. The test determines if a child has specific language skills or abilities that have been found to be present in most typically developing children at set chronological ages.
- The CLAMS may be useful as a screening test that can be used in physicians' offices to identify communication disorders in young children. [B]
- Because of its high specificity, the CLAMS is most useful for confirming normal language development in children from 14 to 36 months of age. [B]
- The CLAMS may be useful as a screening test to identify expressive language delays in children age 25-36 months, but is less useful for this purpose in children younger than 25 months old because of its decreased sensitivity. [B]
- The CLAMS may have limited usefulness in identifying children 14 to 36 months of age with receptive language delays. [B]
Early Language Milestone (ELM) Scale
The Early Language Milestone (ELM) Scale was developed for use in the pediatrician's office for a brief screening of a child's language abilities. Responses are obtained from a combination of parental report, examiner observation, and direct testing. There is a revised version available, the ELM-2.
- The ELM Scale may be useful for identifying 24 month-old children who have normal expressive language development because of its high specificity. [B]
- The ELM Scale may be less useful for identifying children with the possibility of expressive language delays at 24 months because of its decreased sensitivity. [B]
Language Development Survey (LDS)
The Language Development Survey (LDS) was originally designed to be completed by parents in a clinical setting, but it can also be mailed to parents. It is a test of expressive language designed to identify language delay in 2 year-old children. The LDS consists of a one-page vocabulary checklist of about 300 words, plus a question asking about combining two or more words into phrases. If a 2 year-old child has fewer than 50 words or no word combinations, the child is considered to have a language delay.
- The LDS may be useful in identifying children 24 months of age who have a possible communication disorder. [B]
- If a child at 24 months has less than a 50 word vocabulary or has no word combinations, further assessment is needed. [B]
MacArthur Communicative Developmental Inventories (CDIs)
The MacArthur Communicative Developmental Inventories (CDIs) are norm-referenced tests of language development in children and are based on parent reports on a standardized questionnaire. They are intended to describe typical language development in children from 8 to 30 months of age. There are two formats, one for children age 8 to 16 months old and another for children age 16 to 30 months. Parents complete a standardized questionnaire asking about various aspects of nonverbal and verbal communication.
- The CDIs are useful to aid in the recognition of children with possible communication disorders who would benefit from further assessment from 8 to 30 months of age. [B]
- If the child is from a family where Spanish is the primary language, the Spanish version of the CDIs may be particularly useful. [B]
- It is important to remember that the CDIs are intended as screening instruments and not as tools to make a formal diagnosis. [B]
Vineland Adaptive Behavior Scales (VABS)
The Vineland Adaptive Behavior Scales (VABS) is a norm- referenced instrument that assesses a child's adaptive behavior by means of an interview with the child's primary caregiver. The VABS assesses adaptive behavior in the domains of receptive and expressive communication, daily living, socialization, and motor skills.
- A low score on the Vineland Adaptive Behavior Scales may be useful in identifying children under the age of 3 who have a possible communication disorder. [B]
- If a child has a low score on the Socialization Domain scale on the Vineland Adaptive Behavior Scales or similar general developmental test, it may be reflective of an underlying communication disorder. [B]
Additional Screening Recommendations Based on Instruments Not Evaluated in the United States
The following recommendations are based on a review of the scientific literature evaluating the efficacy of three assessment instruments that are not readily available to U.S. clinicians.
The assessment instruments evaluated include an auditory processing test, an interactive test, and the Preschool Language Checklist. These are all research tests developed for screening young children in community language studies in Great Britain.
The results of the British studies are useful for supporting some general recommendations about the use of language screening instruments.
Auditory Processing Questionnaire:
The auditory processing questionnaire was developed to identify auditory problems and language delay in nine month old infants at a routine screening test for hearing in a community setting in Great Britain. The brief questionnaire asks parents about their child's responses to sounds and understanding of speech.
Screening Tests Using A Sample of Language:
A test using a sample of language was developed for a community study in Great Britain to screen the language of children between the ages of 30 and 34 months. The test can be given by health visitors during routine developmental assessments. The screening test assesses both comprehension and expression using pictures and doll play materials.
Preschool Language Checklist (PLC):
The Preschool Language Checklist (PLC) was developed as a postal questionnaire for use in a community research study in Great Britain to screen the language of 3 year-old children. The PLC includes 12 questions: 11 questions on the child's receptive and expressive language, and one question asking if the child had been assessed for a hearing problem.
|Evidence Ratings: [A] = Strong [B] = Moderate [C] = Limited [D1] = Opinion/Studies do not meet criteria [D2] = Literature not reviewed|
- Screening tests and parent questionnaires, when interpreted by professionals with expertise in assessing children under the age of 3 with communication disorders, may provide information that is useful in helping to identify children with communication disorders. [B]
- Asking parents about their child's responses to sounds and understanding of speech may be useful for identifying children with possible communication disorders. [B]
- A sample of language produced or elicited in a play setting may be useful as a screening method to identify children under the age of 3 who have a possible communication disorder. [B]
- In using a screening test, it is important to remember that using different pass/fail cut-off levels will yield different sensitivity and specificity. [B]