Lecture 2 - Models Of Child Language Disorders PDF

Models Of Child Language Disorders Lecture 2 Objectives What is a Language Disorder? Understanding Factors that Might Lead to Misdiagnosis Different Uses of Different Termonologies/Labels The Bottom Line Aspects And Mo...

Models Of Child Language Disorders Lecture 2 Objectives What is a Language Disorder? Understanding Factors that Might Lead to Misdiagnosis Different Uses of Different Termonologies/Labels The Bottom Line Aspects And Modalities Of Etiology of DLD Language Disorders Cognitive models of DLD Diagnostic Issues in DLD: DLD Relative To What? Comorbidity in DLD Are there subtypes of DLD? What is the Impact of Language Disorders on Daily living? How low can you go?  What is a Language Disorder? Language disorder has been defined by two different perspectives: naturalist & normative Naturalist perspective:  According to ASHA, language disorder is an impairment in comprehension and/or use of a spoken, written, and/or other symbol system; the disorder may involve the form, content, and use of language  Focuses on the deviation from the norm  E.g, low score on standarized assessments.  Pros: it covers a broad range of language behaviors across different modalities  Cons: doesn’t help the clinician decide what differences in language behavior constitute an impairment, or at what level of impairment intervention is needed Normative perspective:  According to Tomblin (2008), language disorder exists when the child’s level of language achievement results in unacceptable level of risk for undesirable outcomes. Language disorder is diagnosed when it interferes with the child’s ability to meet social expectations now or in the future.  Focuses on the impairment’s impact on the child’s overall development and abilities in his/her daily activities. Different Uses of Different Termonologies/Labels Different labels were used to describe children who have difficulties learning language.  Example: language delayed, language disorder, language impairment, specific language impairment, developmental language delay, developmental language disorder, etc., These differences cause confusion, difficulties to diagnose the problem, and lack of service equity (Ebbels, 2014) To have a label is important to identify children who are in need of services. However, depending on labels alone will not help in determining the appropriate services. Therefore, It is important to set specific criteria to diagnose the problem.  The CATALIZE In 2015 – 2017, CATALIZE which is an international group of researchers discussed different diagnostic issues regarding termonologies and diganostic criterias related to children’s langauge disorders. Results:  It is very important to reach into agreement in termonology/label and diagnostic criteria.  Language disorders can take different forms based on the child’s age and range of skills.  Language disorder in a 4-year olf child is different that language disorder in a 14-year old.  Language disorder occurs when the child has langauge problems receptively/expressively and these problems persist into middle childhood and beyond which significnatly impact the child’s social interactions an/or educational progress.  Developmental language disorder: is a heterogenous neurodevelopmental disorder that begins in early chidlhoos and persists into adulthood with no known differentiating conditions such as autism, cerebral plasy, epelipsy, or sensori-neural hearing loss (Bishop et al., 2016, 2017).  Language disorder associated with differentiating condition:  Co-occuring disorders: are impairments in cognitive, sensori-motor or behavioral domains that can co-occur with DLD and affect the severity of the impairment or the progress of intervention, but their cuasal relation ot language problems is unclear such as : ADHD, motor problems, dyslexia, speech problems, other adaptive behavioral and emotional disorders.  Developmental Language Disorder Qualifying for a diagnosis of developmental language disorder Developmental Language Disorder The problem arose The code we use to A significant in childhood communicate (e.g., deviation from the spoken or written) typical developmental trajectory Both naturalist (test scores) and normative (functional assessment) criteria are used Prevalence 7.4% Diagnostic Criteria for Children with Language Problems are: Aspects And Modalities Of Language Disorders Form Content Syntax Semantic Morpholog Vocabulary y knowledge phonology of objects & events Pragmatic Use Bloom & Lahey (1978)  Aspects & Modalities of Language Disorders Form:  Morphosyntax deficits are hallmark deficit in chidlren with DLD  Difficulty in using correct grammatical structure, and comprehending the meaning which is conveyed by syntax.  Difficulty in using different grammatical inflectional morphemes such as: past tense, gender or number marker, etc.,  Usinf verbs is difficult  Use nominative pronouns like: he, she, they; rather than acusative words (e.g., him, her, them)  Difficulty using complex sentences such as: WH-questions, passive, subject-verb agreement etc.,  Errors in speech production and phonological awareness Content:  Acquire their 1st words later than their typically developing peers  Semantic knowledge less in-depth.  Limited knowledge about word meaning such as: synonyms, antonyms, etcs.,  Word finding difficutly Use:  Difficulties telling a coherent narratives  Difficulties integrating language and context  Difficulties understanding abstract and ambiguous language  Difficulties understanding other’s opinions or mind  Diagnostic Issues in DLD: DLD Relative To What? When assessing a child’s language, would you compare his language ability relative to his Chronological age OR Mental age (cognitive ability) or both?  Diagnostic Issues in DLD: DLD Relative To What? When assessing cognitive ability, clinicians use tests that assess non-verbal cognitive ability such as problem solving. What is the problem with cognitive referencing?  Lahey (1990):  it is not appropriate to compare results of tests that were not constructed to be comparable.  Difficult to decide which part of nonlinguistic cognition should be assessed.  ASHA (2000)  Different combinations of tests (e.g., morphology, syntax, vocabulary relative to IQ) can yield different recommendations for the same child Other Arguments Arguments against using cognitive referencing:  Longitudinal studies of children with language disorders have reported instability of nonverbal ability scores.  Many children used their linguistic abilities to solve the non-verbal tests.  Other studies suggested that children with DLD who have low IQ score can still benefit from therapy services.  Denial of services based on low IQ scores is not consistent with principles of IDEA. Diagnostic Issues: HOWEVER Mental age discrepancy can help in:  Providing guidelines to help determine the goals of intervention  Getting a general idea of a child’s developmental level through standardized tests and other measurement tools that addressed his behaviors can help in determining the reasonable behaviors to target in the intervention program.  Build an evidence-based regarding response to treatment. Are there subtypes of DLD? Subgroups may change overtime as shown in longitudinal studies (nature of disorder change) vocabulary morphology pragmatics CATALISE (2017) suggested describing strengths and weaknesses and not using terminology for subgroups What is the Impact of Language Disorders on Daily living? To determine whether the child requires speech-language services, we can’t just rely on the results of standardized tests! Why? Tests are not always available for:  All age groups  All languages  All aspects of language Normative position (Tomblin, 2008): language disorders must involve significant deficits relative to environmental expectations.  meanning a deficit big enough to be noticed by ordinary people such as parents and teachers. What might be a problem with that perspective? What is the Impact of Language Disorders on Daily living? Diagnostic frameworks/ sources defining disorders  DSM-5 (APA, 2012) diagnostic statistical Manual of mental health disorders  ICD-11 international classification of diseases (WHO, 2018). Both stress the importance of considering the impact of language disorder on daily living.  Other organizations/classifications: ASHA See table 1.2 p. 11 How low can you go? Where do you set the cut off? Impairment can be defined as deviation from average performance. Standardized tests fulfil this role nicely; they measure a set of skills in a large number of children drawn from the general population and set normative scores based on the average performance of those children. How low can you go? What about children with uneven profiles of language? (production, comprehension) Understanding Factors that Might Lead to Misdiagnosis: Differentiating problems related to poverty  Poverty does not cause language disorder but does introduce risk factors that affect acquisition of higher-level language and literacy skills. Differentiating problems related to cultural-linguistic diversity → dialects, and different culture’s influence Assessing spoken language in children who are dual language learners → bilingualism The Bottom Line Diagnosing language disorders is not direct or exact easy! There is still controversy and inconsistency about who gets the diagnosis and services. It is important for a clinician to remember: 1. There is no right answer; as there is no standard diagnostic test that is universally accepted. 2. The diagnosis process depends highly on the integration of information from different resources by the clinician. 3. The clinician’s training and experience allow the balancing of test scores with additional input from significant others (i.e., parents or caregiver) appraisals about the child’s abilities in different context. 4. That’s what it means to be a SPEECH-LANGUAGE PATHOLOGIST ☺ Etiology of Developmental Language Disorders What is the cause of DLD? Is it one cause? If you knew the cause, would you have a clear idea about his language ability? Etiology of DLD Biological Factors Environmental Cognitive Factors Behavioral Features Etiology of DLD  Etiology of DLD/ Biological Factors Genetic Factors  DLD tends to run in families, Do you think it is because they share the environments or genes?  Twin studies (monozygotic vs dizygotic) established that DLD is heritable  On chromosome 7 – FOXP2, (CNTTNAP2 gene associated with language deficits in a number of neurodevelopmental disorders).  On chromosome 16q: associated with non-word repetition.  The risk is increased when variants occurs on multiple genes: gene ATP2C2 and CMIP  Keep in mind genes do not encode specific behaviors.  Genes identified to be associated with DLD were also associated with other neurodevelopmental disorders such as autism, ADHD, dyslexia, ID. Etiology of Developmental Language Disorders Neurobiological Factors in DLD Language in the brain: Brain’s development:  Starts in utero-continues through adolescence  Synaptic pruning: the elimination of underused connections- this leads to functional representation and results in “localization” of information processing. E.g., processing language.  Language areas in the brain in DLD children do not show gross lesions, but there are subtle structural or functional brain differences in DLD children.  DLD children may show differences in the following areas in the brain:  Inferior frontal  Temporal  Inferior parietal  White matter tracts connecting these areas  Atypical patterns of asymmetry in language cortex  fMRI- hypoactivation in language areas in DLD relative to comparison group. Etiology of Developmental Language Disorders / Environmental Factors Environmental factors alone do not cause DLD. SES: Children from poor SES have delayed language development.  SES is mediated by maternal education which influences quantity and quality of child-mother interactions. Environment may be genetically influenced (may be a reflection of parental language impairment) Cognitive models of DLD Auditory processing Limited processing capacity Procedural deficits  Cognitive models of DLD Auditory Processing  Chiat (2001): difficulties in perceiving brief and rapidly presented sounds lead to problems in perceiving and categorizing meaningful phonemic contrast thus leading to language learning problems.  That may explain the selective impairments in grammatical processing as many grammatical markers are unstressed.  Auditory processing deficits are more common in DLD but Not all children with DLD have auditory processing deficits and not all children with auditory processing deficits have DLD.  Targeting auditory skills in intervention does not improve other aspects of language in DLD children. Cognitive models of DLD Limited Processing Capacity  Limited capacity to hold information while processing perceptually challenging input could impact language development.  Performance on working memory tasks and phonological short term memory tasks (NWR) provide evidence of a limited capacity system in DLD.  However, we must be cautious in interpreting poor performance on verbal working memory tasks Cognitive models of DLD Procedural Deficits  Procedural memory: involves a slow and gradual learning process in which the skill becomes automatic by time. It is important for rule-based learning such as grammar.  Declarative memory: involves processing of names, dates, places, facts, etc., It underlies knowledge-based learning such as vocabulary.  DLD children have deficit in procedural memory system and therefore depend on declarative memory.  A matter of debate Cognitive models of DLD - Conclusion A single cognitive factor cannot explain the different language profiles of DLD children. Targeting the underlying cognitive processes in therapy did not result in a greater improvement in language compared to directly targeting language behavior.  Comorbidity in DLD Language disorders rarely occur in isolation Comorbidity refers to a situation where a child may experience two or more disorders simultaneously  Independent causal origins  Causally related Questions???