Maggie E. Beard, M.A.
Doctoral Student/Project Director
School Psychology Program
The Ohio State University
Beard.164@osu.edu
Introduction
Speech and language skills are essential for academic success and learning, and children acquire these skills at various rates and ages. However, there are benchmarks for what is considered to be normal language acquisition, based on a child’s age and language development. Considering language is the basis of communication, it is foundational to reading, writing, listening, and speaking, but in the presence of impairment, it naturally affects the child’s ability to interact with others and learn. Likewise, children with language impairments may have difficulty understanding language, following directions, and choosing appropriate words to combine into comprehensive sentences.
Specific Language Impairment (SLI) is defined as an impairment of language comprehension, language production, or both, in the absence of general developmental delay (i.e., a normal IQ), neurological impairments, and autism (Schwartz, 2009). Approximately 8 out of every 100 children entering kindergarten will meet the criteria for Specific Language Impairment (NIDCD, 2011). A large number of these children who have trouble learning language are at further risk for ongoing and sustaining reading disabilities. Persistent language problems almost always affect an individual’s reading skills, which thus, significantly impacts learning. These problems, if not remediated, continue to impact a child’s ability to learn and flourish in key areas, and often puts them at risk for further developing language deficits. Subsequently, these language and reading problems will then often perpetuate into adulthood.
Specific Language Impairment (SLI) is one of the most common childhood learning disabilities. Thus, it is somewhat problematic that school psychology and educational journals have little to no information regarding speech and language impairment. School district speech-language pathologists are generally the schools’ professionals working to remediate children’s speech and language problems, so this may be a reason that we don’t often see peer-reviewed articles in school psychology and education journals regarding SLI. However, gaining a better understanding of language problems is extremely critical, and should require more attention from school psychologists because of its comorbidity with many other learning problems. School psychologists are instrumental in assessing and providing treatment and intervention outcomes for these problems, which is essential to the diagnosis and treatment of those affected. It is somewhat discerning that journals targeted at school psychologists have very little information regarding language difficulties, but that a variety of other disciplines have a multitude of published information. There a number of research studies suggesting that language difficulties are comorbid with a variety of other cognitive functions or disorders. The comorbidity rates for SLI, dyslexia, autism, and ADHD suggest that there is a necessary need for school psychologists to better understand the impairment and its overlapping symptoms with many other disabilities and disorders that school psychologists play a large role in diagnosing and designing intervention plans.
Etiology and Comorbidity of SLI
The causes for Specific Language Impairment are unknown, but several research studies show there is a strong genetic link, such that 50-70% have at least one other family member with SLI (Bishop, 2006). A variety of genetic studies have further investigated for evidence of linkage pertaining specifically to SLI. These genome-wide searches for regions that are inherited along with the disorder (linkage analyses) in families with language impairment have pointed to candidate regions on chromosomes 12, 13, 16, and 19, offering further support that SLI has a strong genetic link (Bartlett et al., 2004; Bishop, 2006; Paracchini, 2011; Rice, Smith, & Gayan, 2009).
Many children with reading problems also have spoken language problems. Estimates of comorbidity for SLI and dyslexia vary between 25 and 75% (McArthur, Hogben, Edwards, Heath, & Mengler, 2000). Many of the studies mentioned also found evidence for comorbidity among SLI, dyslexia, ADHD, and Autism (Bishop & Snowling, 2004; Flax et al., 2003; Hutchinson, Bavin, Efron, & Sciberras, 2012; Logan et al., 2011; Newbury et al., 2011). The same genes that are specific to SLI may share overlap with genes that are specific for Autism and dyslexia. This does not imply that all three are related, and that if you have one, you may have another. Instead it suggests the potential for shared etiology among each other, such that a child who has dyslexia may also experience problems developing appropriate language skills. For example, a child with dyslexia has trouble with printed words. This problem may exist as part of a larger language problem, or may occur independently. The comorbidity between SLI and Autism, as an added note, may also help to explain the difficulty that children with Autism have in terms of developing appropriate language skills and pragmatics. Something that we as school psychologists should keep in mind is the idea that there are overarching qualities among Autism, dyslexia, and SLI. Therefore, it is possible that the specific symptoms we might see a child eliciting may be mistaken for some other diagnosis or disorder. Thus, it is important that we have a better understanding of the overlap among disorders and specific symptoms.
Deficits in Language Learning
The major components of language, called linguistic features, are usually identified as semantics, grammar (syntax and morphology), pragmatics, and phonology. In addition to dividing language into linguistic features, language can be categorized according to the following linguistic systems: listening (receptive), organizing (integrating-mediating), and speaking (expressive). Bishop (2006) suggested that language is robust. Moreover, there are multiple routes to effective language acquisition, and that if one is blocked, another can be found. What is important, though, in the identification of SLI is that children, who had a single area of deficit, were less likely to be identified clinically as cases of SLI than those who had more than one deficit. There are numerous journals where a large body of the research is attributed to the cognitive components and mechanisms that are impacted for individuals that elicit common symptoms of SLI such as difficulty learning new vocabulary words, following directions, using correct grammar, auditory processing, and stuttering problems.
Moreover, some research studies have suggested that there is a high heritability for cognitive traits and disorders including verbal and nonverbal IQ, language skills (Stromswold, 2001), and reading ability (Harlaar et al., 2005). Longitudinal and cross-sectional case-control studies consistently show a relationship between early childhood language impairments and reading impairments (such as dyslexia) later in life (Catts et al., 2002; Snowling et al., 2000), with some experts proposing that SLI and reading impairment represent various manifestation of an underlying linguistic disability. Furthermore, children with language impairment show slowed processing speeds across a wide variety of linguistic and nonlinguistic tasks (Miller, Kail, Leonard, & Tomblin, 2001; Miller & McCardle, 2011). Much of the research identifies areas of strengths and weaknesses for individuals with SLI. It is problematic to really identify and pinpoint characteristics that make diagnosis of the disorder distinctly different from other disorders and impairments because they all share common overlap for many of the symptoms they just manifest themselves in various ways across a variety of disciplines and functions.
SLI Interventions
Several research studies have provided interventions aimed at improving different deficit areas in children with SLI. A variety of interventions have been identified to specifically target some of the more common SLI deficit areas such as working memory (Archibald & Gathercole, 2006; Holmes, Gathercole, & Dunning, 2009; Klingberg, Forssberg, & Westerberg, 2002; Riches, 2012), vocabulary knowledge (Munro, Lee, & Baker, 2008), phonology (Skibbe, Justice, & Bowles, 2011), semantics (Bragard, Schelstraete, Snyers, & James, 2012), narratives (Swanson, Fey, Mills, & Hood, 2005), and grammar and syntax (Leonard, Miller, & Owen, 2000). The areas of language that are affected vary from individual to individual and over time within each individual. Therapy goals are generated on an individual basis, and are reassessed over time and adjusted accordingly.
With regard to interventions, they are specifically designed to follow the normal acquisition of language skills to ensure that the individual has the appropriate prerequisite skills required for teaching or improving the new language components. Intervention goals also vary depending on age and functionality. Preschool children generally focus on conversation skills, but also work to increase skills that will be necessary for classroom interaction and basic aspects of language, in addition to the acquisition of literacy skills. Elementary school-aged children address more complex aspects of language tied to school-related needs. Older children often work on aspects such as understanding their textbooks, constructing well-organized papers, and understanding complex uses of language such as multiple-meaning words and figurative languages such as similes, metaphors, and idioms (Clegg, Hollis, Mawhood, & Rutter, 2005). Identifying successful interventions is somewhat problematic because there is still much to understand regarding SLI and the common characteristics and traits that comprise the disorder. The lack of research in school journals within this area also suggests that schools need to play a more significant role in providing interventions for children with language problems.
Conclusion
Language difficulties are associated with a wide range of disabilities, including hearing impairment, broad cognitive delays or disabilities, and autism spectrum disorders. Specific Language Impairment is differentiated from these other disorders because impacted individuals do not experience global developmental delays. Instead SLI individuals have normal functioning in all areas except for language. Specific Language Impairment puts individuals at a risk for future academic problems because it can be an accumulation of underdevelopment language development like semantics, grammar, pragmatics and phonology. Also, listening, organizing, and speaking skills are all impacted when individual’s experience deficits in as many as one or more of the following areas.
To further illustrate, there is a multitude of research to suggest that Specific Language Impairment is attributed to a specific set of genes and chromosomes. There is also a great deal of overlap between symptoms for SLI, dyslexia, Autism, and ADHD, further suggesting gene overlap among these disorders or impairments impacting language production and comprehension. Interventions are designed to address specific individual needs and functionality. They are aimed at improving language skills and are designed to help the individual learn to find alternative ways to compensate for deficit areas.
There is a great deal of information and research to support the various components of language that are impacted by SLI. There is also a great deal of evidence to offer support that there are specific genes that contribute to SLI and that the impairment is highly heritable among other related family members. Additionally, there is evidence that interventions are designed to effectively target problems associated with the language impairment. However, there is little information to show the methods that are yielding the most significant and effective treatment gains for SLI interventions.
Also there is little information to help professionals better understand and differentiate SLI from other cognitive disabilities and related disorders. Additionally, there is a great deal of comorbidity between SLI and other disorders like dyslexia, Autism, and ADHD, thus there is a necessary need to understand the differences across all and the overlap within to decrease the chances for misdiagnosis. In doing so, it is both important and necessary for school psychologists and SLPs to work together to specifically identify symptoms and diagnosis for individuals that may have a great deal of overlap. For example, say a child is seen by an SLP for receptive, expressive, or mixed language deficits. The SLP works with the child to improve specific language skills. The child may also be struggling with reading or other academic subjects due to the underlying language problems. Without effective communication across school professionals the child may only receive intervention to target the language problems, which may not necessarily address the reading problems. Additionally, the child may have a form of dyslexia that could be overlooked if one does not understand the comorbidity between the two types of impairments. Thus, it is very important that we address these issues in the literature and research that is readily available to school psychologists and vice versa for SLPs so that they understand the comorbidity between various issues enabling them to make clear and distinct determinations for diagnosis and treatment.
References
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Maggie E. Beard., M.A., is a 4th year Ph.D student in the School Psychology Department at The Ohio State University. She has several work experiences including Project Director for two NIH studies looking at language impairment in family pedigrees and a study investigating the genetic and environmental influences for reading, math, language, ADHD, and related cognition. She has also worked at Nationwide Children's Hospital in the Pediatric NeuroPsychology unit as an extern and currently serves as the Lead Mental Health Consultant for HeadStart. Her research and professional interests center around the development of language and reading skills, cross-battery assessment, mental health in the schools, and issues of social justice.