In the book Children with Specific Language Impairment, Professor Laurence B. Leonard of Purdue University, explains how scientists, during the last 200 years, have studied children whose deficits in spoken language ability could not be attributed to neurological damage, hearing impairment, or intellectual disability. (Leonard, 2014). Additionally, Professor Leonard denotes that the most common name to describe the aforementioned condition is Specific Language Impairment (SLI).
Language impairment is one of the most common childhood disorders and affects approximately 7% of this population. “SLI cannot be attributed to hearing loss, low nonverbal intelligence, or neurological damage” (Leonard, 2014). The disorder is commonly detected during the few years of a person's life and it is common for people who have experienced SLI during their childhood, to still suffer certain deficiencies in this area, as adults.
As is to be expected, SLI greatly impacts reading and therefore, disturbs the learning process. As occurs with these types of conditions, it is best to treat them as soon as possible so as to avoid affecting a child’s development during their school years. Working on language deficiencies during preschool years is imperative, as it facilitates growth and improvement in language facilities. Specialized programs have been designed to improve language development and they allow that regular children to act as role models for children with SLI (NIDCD, National Institute on Deafness and Other Communication Disorders, 2017). Other options are related to speech-language therapies provided by speech pathologists.
Another option for individuals with SLI is the use of Applied Behavior Analysis (ABA). ABA is used to replace socially maladaptive behaviors by more appropriate ones and is an equally effective alternative to treat specific language impairment. ABA “is a scientific approach for discovering environmental variables that reliably influence socially significant behavior and for developing a technology of behavior change that takes practical advantages of those discoveries” (Heward, 2014). In simple words, Behavior Analysis (BA) delves into the principles that explain how learning processes occur and how human behavior works. These principles are governed by positive reinforcement; when a behavior is followed by a reward, there is a greater likelihood that such behavior will be repeated more frequently in the future. Through the pass of the years, researchers have found and perfected new techniques for increasing positive and appropriate behaviors and decreasing behaviors that can affect and/or delay learning. (Speaks, 2016).
Thus, ABA is the best-known scientific approach and educational strategy to help children with Autism Developmental Disorder (ASD). “Over a thousand studies reporting on ABA-based assessment and treatment techniques have been published since the 1960’s…these controlled studies have strong internal validity as they use experimental designs that permit one to conclude that the intervention was responsible for the change in behavior (Kennedy Krieger Institute, 2016)”. Verbal Behavior (VB) therapy, which is a fundamental branch of ABA, has been effective in the treatment of children with autism, a condition characterized by language deficits; hence, it is appropriate to hypothesize that these strategies can also be effective in the treatment of children with SLI. The aforementioned and other aspects will be discussed more rigorously later in this review.
Conceptual Framework
Examining SLI further, highlights that the condition is a language disorder that delays the correct acquisition of language abilities in children who do not have hearing difficulties or other developmental disabilities.
SLI is one of the most common childhood learning disabilities, affecting approximately seven to eight percent of children in kindergarten. The impact of SLI continues to adulthood. Others name that SLI acquires are Developmental Language Disorder, Language Delay, or Developmental Dysphasia. It is one of the most common childhood learning disabilities (NIDCD, National Institute on Deafness and Other Communication Disorders, 2017)
Although causes of SLI are unknown, recently it has been discovered to have a closely related genetic aspect. Children with SLI are more likely than those without SLI to have parents and siblings who also present difficulties and delays in speaking. In fact, 50 to 70 percent of children with SLI have at least one other family member with the disorder. (NIDCD, National Institute on Deafness and Other Communication Disorders, 2017)
SLI has been described by two classes of premises including either a deficit specific to grammar, or a non-linguistic processing impairment. According to the Procedural Deficit Hypothesis (PDH), SLI can be mostly explained by the unusual development of brain structures that form the procedural memory system. This system favors the learning and execution of motor and cognitive skills. Recent evidence reveals this system intervenes in important aspects of grammar. PDH suggests that an important proportion of individuals with SLI presents irregularities in this brain network, causing the impairments of the linguistic and non-linguistic functions that depend on it. On the other hand, functions such as lexical and declarative memory, which depend on other brain structures, are expected to remain largely spared.
It is argued that the data support the predictions of the PDH, and particularly implicate Broca's area within frontal cortex, and the caudate nucleus within the basal ganglia. Finally, broader implications are discussed, and predictions for future research are presented. It is argued that the PDH forms the basis of a novel and potentially productive perspective on SLI. (Ullman & Pierpont, 2005)
As per the National Institute on Deafness and Other Communication Disorders, children with SLI are frequently late to talk and may not produce words until the age of two. What can happen at the age of 3 is that they begin to speak but are not understood. They have difficulties to acquire new vocabulary and establish conversations. Consequently, they may encounter difficulties using verbs.
Typical errors that a 5-year-old child with SLI would make include dropping the “s” from the end of present-tense verbs, dropping past tense, and asking questions without the usual “be” or “do” verbs. For example, instead of saying “She rides the horse,” a child with SLI will say, “She ride the horse.” Instead of saying “He ate the cookie,” a child with SLI will say, “He eat the cookie.” Instead of saying “Why does he like me?”, a child with SLI will ask, “Why he like me?” (NIDCD, National Institute on Deafness and Other Communication Disorders, 2017)
As was mentioned at the beginning of this paper, it is common for parents to seek the help of speech and language therapists, who apply several techniques to treat this deficiency in language. The most common interventions are directly related to grammatical exercises and using imitation and elicitation methods. However, nowadays there are much more practical and effective methods, such as teaching in natural environments to elicit conversations that may be of interest to the student and not imposed by the therapist; work in small groups to develop children's social use of language, and the involvement of parents in all these interventions is use as a fundamental piece to help the students to move forward. Additionally, the use of computer-based interventions is helpful since the use of new technology greatly increases the possible strategies, exercises, tools, etc. ultimately, these tools allow to assess clinical efficacy of the interventions.
As mentioned earlier, ABA and VB therapies are very suitable for treating children with SLI. When speaking about behavior, we referred to something that can be observed, measured, and recorded. ABA methods are used to support persons in several ways such as to increase behaviors through reinforcement procedures; to teach new skills by providing systematic instructions; to preserve positive behaviors such as self-control; to generalize learned behaviors in restricted or controlled environments to new environments and with other people; to control certain circumstances under which interfering behaviors occur; and finally to reduce maladaptive behaviors such as aggressive, self-injurious, and repetitive behaviors (The Center for Autism and Related Disorders CARD , 2016). The effectively way in which ABA/VB therapy influence human behavior allows these techniques to be used to increase verbal behavior in children with SLI.
The essential elements of ABA/Verbal Behavior programs include teaching procedures that are based on standard ABA methodology such as the use of reinforcement, prompting, fading, and shaping. A language assessment is conducted in the first place, followed by the design of an intervention support plan based on Skinner’s (1957) analysis of verbal behavior. Linguistic targets from typically developing guide both, assessment and intervention plan. Ultimately, behavior analysis and Skinner’s study of verbal behavior are used to conduct the language acquisition process. (Sundberg, 2015)
Broadly speaking, this is how ABA/VB programs can be useful in the development of verbal behavior in children with SLI. A review of some of the existing scientific literature on these themes is presented below.
Review of Research Literature
The National Institute on Deafness and Other Communication Disorders (NIDCD) supports a different researches to investigate the genetic foundations of SLI, the nature of the language deficits that trigger it, and alternative ways to diagnose and intervene children with it.
Genetic research is one of the investigations supported by the NIDCD. A mutation in a gene on chromosome 6, named the KIAA0319 gene was recently discovered and it seems a crucial element in SLI. Mutation has proven to be fundamental in learning disabilities such as dyslexia, autism, and speech sound disorders; all of them related to speech deficits. Such elements show that struggles in learning language might be coming from the same genes that causes difficulties with reading and understanding printed text.
On the other hand, NIDCD also support bilingual research, which have allowed the search for alternative ways to assess students who speak English as a second language. The main reasons for initiating these investigations in order to find alternative ways of evaluation are that the standardized tests used in schools to screen for language impairments are designed attending typical language development milestones in English. In the case of bilingual children, they are more likely to score in the at-risk range on these tests and it can be difficult to differentiate between students who are having issues to learn a new language and children with real language impairments.
NIDCD also support diagnostic research. One of the greatest challenges for researchers today is to be able to detect if there are early developmental indicators that could predict language difficulties, allowing an early identification and intervention with these children. This could be very beneficial, not only for children with SLI, but also for children with ASD. Both groups have shortcomings in starting to communicate with spoken language, comprehension, and in general present significant communication difficulties that inhibit their regular development in society.
Overall, NIDCD continue funding researches focused on discovering risk markers related to SLI and ASD that could indicate future problems in speech and communication. Some of the strategies followed by the investigators are data collection using behavioral, eye-tracking, and neurophysiological measures, as well as general measures of cognitive and brain development. The research includes tracking a group of children until they are 3 years old to check if there are signs that are specific to SLI or ASD or that could predict the development of either disorder. The results of research as described, allow the possibility of developing new approaches to early screening and diagnosis for SLI and ASD (NIDCD, National Institute on Deafness and Other Communication Disorders, 2017).