Specific Language Impairment in Children with High-Functioning Autism Spectrum Disorder

Autism Spectrum Disorders (ASD) are among the most common neurodevelopmental disorders. According to the Centers for Disease Control and Prevention (CDC), studies in Asia, Europe, and North America have identified individuals with ASD with an average prevalence of about 1% (CDC, 2015). ASDs are typically diagnosed in early childhood, often at or before preschool age. However, there is no specific genetic test or clinical procedure for diagnosis. Diagnosis is based mainly on documented core impairments related to social interaction, communication, as well as restricted and repetitive behavior (American Psychiatric Association, 2013). In addition to impairments in the core symptom areas, many individuals with ASD also have impaired cognitive skills, atypical sensory behaviors, or other complex medical and psychiatric symptoms and conditions, such as seizure disorders, motor impairments, hyperactivity, anxiety, and self-injury/aggression. According to the DSM-5, individuals who meet the specified criteria are given the diagnosis of "autism spectrum disorder (ASD)" with one of three levels of severity. Level of severity is defined in terms of the amount of support needed in the area of social communication and with restricted, repetitive behaviors. The DSM-5 also recognizes severity may vary by context and fluctuate over time. Severity ratings are used for descriptive purposes only and not to diagnose or determine eligibility for services (APA, 2013).

Abnormal use of language (pragmatics), particularly in social communication and social interaction is the most striking feature of autism (Belkadi, 2006). However, the difficulties individuals with autism have with speech and language are very heterogeneous and could be contributed by a number of different factors (Gabig, 2011). Furthermore, individuals with autism frequently have deficits in paying attention to auditory information (Mody et al., 2013). They have to be trained to pay attention to sounds. Even when they are paying attention, they have difficulty in decoding what sounds mean and in matching them to words or thoughts.

Children with autism, especially those who require moderate to high level of support, often have difficulties with articulation (Gabig, 2011). This could be part of a broader problem of difficulty with oral-motor function. On the other hand, research has shown individuals with autism are better with paying attention and appreciating visual materials (Mody et al., 2013; Gabig, 2011). Therefore, the visual route is one way of getting access to their minds and giving them a way of expressing themselves.

Language Processing in the ASD Brain

Children with ASD can differ extensively in the extent of communication impairment. Up to fifty per cent of children with ASD are unable to speak throughout life (Groen, Zwiers, Van der Gaag, & Buitelaar, 2008). However, there is a subgroup who can communicate within the normal range of function.

There is also a subgroup of children with ASD who show deficits in certain aspects of language. They could be having problems in one or more of the following aspects: auditory processing, vocabulary production, perception of phonemes (the building blocks of words), higher-order semantics, syntax, pragmatics, or prosody (Rescorla & Safyer, 2013). Semantics refers to the meaning of words and this is the most common linguistic deficit in children and adolescents with ASD. Syntax means the language rules for combining words into phrases and sentences, and for understanding the relationship among words. Pragmatics is the implied meaning underlying a sentence, such as irony or satire. Prosody is the pitch, tone, rhythm, or intonation of a sentence (Groen et al., 2008). Some of these children would often communicate with reduced length sentences.

Research has shown impairment can occur in both the comprehension and production of language, however, there is greater impairment in comprehension (Belkadi, 2006; Hudry et al., 2010). These children have demonstrated reduced brain activation in prefrontal and temporal brain regions under scenarios that involve irony (Groen et al., 2008). They can also be impaired in their understanding of nonverbal cues from others. These nonverbal cues include discerning intentions and making rapid intuitive judgments of social context. Children with ASD who are high-functioning, are found to particularly have difficulty in recognizing negative facial expressions (Chapman & Baron-Cohen, 2006).

There are obvious differences in the brain structures between neurotypical children and children with ASD (Dawson, 2008). Functional imaging studies have found reduced activation in Broca’s area in contrast to Wernicke’s area. The reduced activation in Broca’s area could indicate a deficit in integrating the meaning of words within sentences, hence, impeding comprehension. The left lateralization, or specialization, of language processing seen in neurotypical children can also be reversed in children with ASD (Hodge et al., 2010). They are found to have larger language areas in the right cerebral cortex.

Children with Specific Language Impairment

Children with specific language impairment (SLI) show a significant deficit in spoken and written language that cannot be attributed to neurological damage, hearing impairment, or intellectual disability (Webster & Shevell, 2004). SLI is more prevalent than autism and affects approximately seven percent of all children. It is a longstanding condition with adverse effects on the child’s academic and social standing. Diagnosis is based on behavioral evaluation and research has shown that cause of the impairment is likely to have a genetic basis. Children with SLI is a heterogeneous group, and exhibit deficits in comprehension and/or production across any of the five language domains (i.e., phonology, morphology, syntax, semantics, pragmatics). Language disorders may persist across the lifespan, and symptoms may change over time. They exhibit problems in their ability to use grammatical morphemes, verbal inflection and rapid auditory processing. Some have impairment in one specific area, others might display problems in all the different areas. There would also be children who do not have spoken language disorder, but struggle with reading and written expression (Webster & Shevell, 2004).

For these children with SLI, there are usually deficits in morphological awareness (e.g., derivational morphemes, such as prefixes and suffixes, including inflectional morphology, such as plural, present progressive, and past tense markers). They would omit the use of function morphemes long after age-matched children with typical language development show consistent production of these elements (Dockrell, Ricketts, Palikara, Charman, & Lindsay, 2012). Errors occurred most often on verbs (especially verb endings, auxiliary verbs, and past tense marking of regular and irregular forms), function words (e.g., articles and prepositions), and pronouns. These errors occur more frequently as a result of omission rather than misuse. However, occurrence of both error types may be inconsistent. They would have problems judging grammaticality—identifying and correcting grammatical errors and identifying parts of speech. As a result, they have problems comprehending and using complex syntactic structures (Dockrell et al., 2012). It is also common to find them struggling with curriculum-related expository discourse production, and comprehending morphologically complex words that are common in academic subjects, especially at the higher levels.

Research has shown that children with SLI display abnormalities in neurodevelopment of their fronto-corticocerebellar circuits (Hodge et al., 2010). These circuits manage motor control and the processing of language, cognition, working memory, and attention. Neuroimaging studies have also shown brain structure and function abnormalities in Broca’s area, specifically the inferior frontal gyrus (IFG) language-association cortex (Hodge et al., 2010). As a result, language comprehension and processing in children with SLI are comparatively slower and less mature than age-matched children who are developmentally normal in their language functions.

The Relationship Between Autism and Specific Language Impairment

Autism and specific language impairment (SLI) are conventionally regarded as distinct disorders. The differential diagnosis is based on two observations (Hodge et al., 2010):

1. SLI is seen as isolated language impairments in the context of otherwise normal development, whereas in autism there is a triad of impairments, affecting communication, social interaction and behavioral repertoire.
2. The communication problems in these two conditions are different. Children with SLI have particular difficulty with structural aspects of language (phonology and syntax). On the other hand, abnormal use of language (pragmatics) is the most striking feature of autism.

However, this conventional view has been challenged on three counts. Firstly, research has shown that children with autism have structural language impairments similar to those in SLI (Hodge et al., 2010). Secondly, some children have symptoms intermediate between autism and SLI (Whitehouse, Barry, & Bishop, 2007; Leyfer, Tager-Flusberg, Dowd, Tomblin, & Folstein, 2008). Lastly, there is a high rate of language impairments in relatives of people with autism, suggesting etiological continuities between SLI and autism (Whitehouse, Barry, & Bishop, 2007). Hence, one could conclude that structural and pragmatic language impairments might be correlated but are separable consequences of common underlying risk factors.

More importantly, Hodge et al. (2010) established ASD and SLI children show abnormalities in neurodevelopment of fronto-corticocerebellar circuits that manage motor control and the processing of language, cognition, working memory, and attention. One could assume that a subgroup of children with ASD could also be struggling with language impairments that are similar with children with SLI. Language impairments are often more easily detected in children with ASD, with verbal expressions that demonstrate deficits in morphology and syntax (improper use of prefix and suffix, or the absence of proper grammar structure). However, with proper behavioral intervention and training, many of the children with high-functioning ASD, are able to communicate effectively, with the use of simple sentences, making it difficult to determine if there is truly a language impairment. Nevertheless, the language impairments exhibit readily in the school context, particularly in academic subjects where there is a high demand for comprehension of complex sentence structures, and that require higher cognitive functions of inference, critical reasoning and problem solving. The problem is especially exacerbated with written expressions.

Characteristics of ASD Language Impairment

Children with high-functioning autism are generally fluent in their speech and possessed advanced vocabulary, good phonology, and syntax (rules of language). However, they struggle with receptive language, expressive language, nonverbal communication, and pragmatics (the social context of language). As a result, their work in the classroom is affected and they demonstrate a specific set of academic relative strengths (e.g., reading decoding, math calculations) and weaknesses (e.g., reading comprehension, math applications, written language).

However, there is a sub-group of children with high-functioning autism that do not possess the strengths in vocabulary, phonology, and syntax (Kjelgaard & Tager-Flusberg, 2001). In fact, they have significant language weaknesses and find it difficult to comprehend passages with complex sentence structure, and also to communicate their thoughts coherently. Their areas of weakness in language involve either receptive or expressive language, or both aspects. One key weakness I have observed in a group of adolescents with high-functioning autism that I teach, is in comprehension. This group of adolescents are between 15 and 17-year-old; they are all diagnosed with moderate or high-functioning autism. A majority of them are verbal and fluent in their speech and have little or no difficulty with reading. Observations made were although they are able to read a given passage fairly fluently, when asked to explain the meaning of sentences, some of them would provide explanations that are completely off the mark. A few others have great difficulty formulating sentences that express their ideas. This is especially true under stress and trying to solve complex problems.

One of the principal reason for the inaccurate comprehension is a relative weakness in abstract reasoning (Berninger & Richards, 2002). They tend to have a literal interpretation of expression, hence, they often misunderstand the subtler ideas in a message. Weakness in abstract reasoning also produce a tendency to over-simplify message in a communication, whether written or verbal. As a result, they tend to ignore or overlook the subtler, grey areas of a message. Other factors like struggles with emotional regulation (e.g., management of anxiety, frustration) and a tendency to become fixated on one minor aspect of a message also compromise accurate interpretation of information.A small group of them would also have visual-perceptual issues that would contribute to problems with visuospatial reasoning (Berninger & Richards, 2002). This would result in difficulty with the interpretation and understanding of symbolic and graphical representations. Research has also confirmed a small group of children with high-functioning ASD who also have language impairment are more prone to look at distractor images than those without language impairment (Haebig, Kaushanskaya, & Weismer, 2015).

Another area of struggle that they have stem from their weakness in pragmatics (Gabig, 2011). Pragmatics is the understanding of how to use language appropriately in social situations. In linguistics, distinction is made between sentence meaningandspeaker meaning. Sentence meaning is the literal meaning of the sentence, while speaker meaning involves determining the concept that the speaker is trying to convey. While children with high-functioning ASD may have little difficulty understanding and using sentence meaning, they often struggle with deriving and formulating speaker meaning. In other words, they could be strong in vocabulary, sentence structure, grammar, but have difficulty applying these language strengths to a social situation. Thus, it is common for them to struggle with differentiating the purposes (such as greeting, informing, demanding,promising, and making requests) in passages.

For those who are in the gifted range of intelligence, they often have the ability to use their strong rote memory to cover for weaknesses. They would memorize social protocols and patterns of successful communications. They would practice and over-learned communication and writing skills. This would help them to communicate relatively well. However, when it was appropriate to move to a different style, they would be lost and have difficulty with communicating fluently. Similarly, when context changes, they would also struggle with interpretation of messages. Nevertheless, they would be successful in giving the appearance of stronger language skills than they actually had. This is adequate for many social relationships, and academic tasks that do not require higher language abilities.

Most children with high-functioning autism tend to have very strong vocabulary, phonemic awareness, and reading decoding skills. Their strength in decoding translates into strengths in spelling, and sometimes writing mechanics (e.g., punctuation, capitalization). However, tasks that require abstract reasoning are difficult for them.As a result, reading comprehension is weakened because they have trouble deriving meaning from passages, especially when the themes are implicit. While they may include very interesting vocabulary and word choice in their writing, they struggle with organization and communication of complex ideas. This impairment would translate into difficulty with the interpretation of data, and passages with implicit theme, and in constructing complex sentences particularly in expository writing.

While the ability to write is related to the ability to speak, writing and speaking are supported by entirely different parts of the brain. According to new research from Rice University, Johns Hopkins University and Columbia University (2015), writing and speaking are supported by different parts of the brain. This applies to not just motor control of the hands and mouth but in the high-level aspects of word construction. Furthermore, they also found it is possible to injure the section of the brain responsible for speech but leave the part responsible for writing unharmed, and vice versa.

Findings from the research has implications for children with ASD, particularly the high-functioning group who are verbal. Although it appears written language should be dependent on spoken language, since the ability to write develops only after speech, but once we learn to write, our brains develop specialized mechanisms for written language, even for high levels of language processing. This would imply that children with high-functioning ASD might be struggling with writing impairment, even if they have little or no problems with speech. Hence, in the classroom, it is common to observe some children who are able to provide fluent verbal replies to inferential question, but are unable to reproduce the same answer in written expression. These children often require additional prompting, or even specific instructions on the mechanics of writing, like where they should be writing, how do they begin the answer and what they should be writing down. There appears to be difficulty translating from verbal expression to written expression.

Another key factor that could explain the inability to develop adequate writing skills is deficits in executive functioning. Berninger and Richards (2002) refer to basic academic skills in terms of the neuropsychological systems through which language is expressed: Language by ear (listening); language by mouth (speaking); language by eye (reading), and language by hand (writing). Writing develops over a longer developmental trajectory than the other language systems, and requires the greatest involvement of frontal lobe functions (executive functions and working memory) for success (Berninger & Richards, 2002). Therefore, relatively skilled writing does not develop until late adolescence. Most importantly, one needs to remember that writing is not the mirror image of reading, nor is it a mere motor act. It is a complex process that involves all the processes in executive functioning (Berninger & Richards, 2002; Graham, Harris, & Olinghouse, 2007). As defined by Graham, Harris, and Olinghouse (2007, p. 217):

Executive functioning involves the conscious, purposeful, and thoughtful activation, orchestration, monitoring, evaluation, and adaptation of strategic resources, knowledge, skills, and motivational states to achieve a desired goal. This involves analysis (e.g., sizing up the demands of the situation), decision making and planning (e.g., selecting or devising a plan of action), attentional control (focusing and maintaining attention as well as inhibiting interfering behaviors), coordination of cognitive resources, and flexible application (e.g., adjusting plans and goals to meet changing situations).

The complexity of the task requires writers to not only be able to apply their skills and knowledge, but also to be flexible in the coordination of resources available to them, and in their strategic processing (i.e., mental operations for planning, drafting and revising) (Graham et al., 2007). Given the language impairments and other conditions faced by children with autism, writing complex prose that demand higher cognitive abilities would not come easily and readily without structured and specific training over a significant time period.

Conclusion

There is significant variability in language functioning in verbal children with high-functioning autism (Gabig, 2011). Variation is seen in oral language functioning, reading ability and writing ability. There are some who possess excellent phonetic decoding ability yet poor comprehension, while others struggle with phonetic decoding of unfamiliar words, hence, difficulties with reading comprehension (Gabig, 2011). Research has shown that language ability is not necessarily dependent on IQ (Kjelgaard & Tager-Flusberg, 2001). There are children with lower IQ who possess language skills within the normal range, and children with impaired language skills but whose IQ are within the high range (Kjelgaard & Tager-Flusberg, 2001).

This significant variability in the comprehension and use of language has compelling implications for the academic success of school-age children with high-functioning autism. These children are often found within the regular classroom, and are faced with the same demands made by the general education curriculum, as with age-matched typical children. High-Functioning children with autism are faced with increasingly more complex discourse processing demands as each grade progresses (Gabig, 2011). The language of the curriculum often is complex and abstract. Hence, children with high-functioning autism are faced with the dual challenge of increasing competence in the language used in social control and interaction, and complex academic discourse. There are additional cognitive-linguistic demands on the child with high-functioning autism in the classroom (Gabig, 2011). Therefore, there is a need to look into a proper system of language-training, specifically for children with high-functioning autism and language impairment in the general education classroom. The system of training has to be individualized and continuous, starting from the lower grades, so as to allow for early intervention and training of the executive functions, to better prepare them for the cognitive-linguistic demands at higher academic level. As there is significant variation in the language ability of children with high-functioning autism, more research needs to be conducted to examine the specific strengths and weaknesses, and impact on academic learning. Interventions on the school level can benefit from a more specific profiling of the language needs of these children.

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