Treatment of Core Symptoms of Autism Spectrum Disorder
Autism spectrum disorder (ASD) is defined by social and communication deficits and repetitive behaviors. This chapter discusses the core symptoms of ASD as well as how they are grouped and prioritized for treatment. Also included is a discussion of strategies that target these core symptoms.
KeywordsASD core symptoms Behavioral interventions Treatment
ASD is comprised of core deficits in social and communication skills and high levels of engagement in restrictive, repetitive behaviors and interests. To date, treatments based on the science of behavior analysis have been shown to be the most effective treatment of core symptoms of ASD (Odom, Boyd, Hall, & Hume, 2009). Further, the earlier these behavioral interventions are initiated, the better the treatment outcomes (Smith, Klorman, & Mruzek, 2015). This chapter provides an overview of treatment options for social skills, communication skills, and restrictive, repetitive behaviors and interests.
Deficits in social interaction and social communication are a core deficit of ASD (American Psychiatric Association, 2013). To meet the DSM-V diagnostic criteria for ASD, an individual must present with or have a history of deficits in (a) social-emotional reciprocity, (b) deficits in nonverbal communicative behaviors used for social interaction, and (c) deficits in developing, maintaining, and understanding relationships (American Psychiatric Association, 2013). This section surveys representative treatment options for a range of social interaction skills, starting from basic (i.e., eye contact and joint attention), intermediate (i.e., play skills), and advanced (i.e., perspective taking and lying). The following section details strategies for teaching communicative social skills in additional detail.
Basic Social Skills
One of the core deficits – that is identified as an early indicator – for individuals with ASD is lack of eye contact. Many individuals with ASD do not develop eye contact without specific training. Thus, eye contact is one of the first skills taught to learners in an early intensive behavior intervention (EIBI) program. Eye contact with both an instructor and instructional materials is a pivotal behavior in order to learn new skills and interact socially.
Several techniques have been developed to teach eye contact. Early behavior analysts used a verbal cue (e.g., “Look at me”) and a differential reinforcement and prompting procedures to bring eye contact under instructional control of the verbal cue (Foxx, 1977; Greer & Ross, 2007; Lovaas, 1981). Although eye contact can be successfully taught through this procedure, it is rather contrived and may not come under control of the appropriate antecedents and consequences, thus having little generality outside of the instructional activity. More recently, behavior analysts have shifted to teaching eye contact under natural contexts, such as embedded within discrete trial instruction (e.g., imitation, matching, etc.), mand training, and play.
Mand training, which takes advantage of a learner’s motivation, is one contextually appropriate context that can be used to increase eye contact and social initiations. Charlop-Christy, Carpenter, Le, LeBlanc, and Kellet (2002) taught three children with ASD to mand using the Picture Exchange Communication System (PECS; Frost & Bondy, 1994) and evaluated potential collateral effects related to social behaviors, such as eye contact and joint attention (JA). Following mand training, an increase in eye contact and JA, from 25% in baseline to 54% in intervention, was observed across all three participants. However, eye contact was not required during the mand to receive access to the requested item. More recently, Carbone, O’Brien, Sweeney-Kerwin, and Albert (2013) assessed the effectiveness of differential reinforcement to increase mands made with eye contact for a child with ASD. During baseline, all vocal mands were reinforced regardless of eye contact. Throughout baseline, the participant rarely made eye contact with the researcher while requesting. During treatment, the researcher withheld reinforcement (i.e., access to the item) until the participant made eye contact. Following the differential reinforcement procedure , percentage of mands with eye contact increased from a mean of 10% in baseline to a mean of 77%.
Ninci et al. (2013) also investigated the effects of a differential reinforcement with the addition of a prompting procedure to increase mands made with eye contact during play. The therapist attempted to manipulate the motivating operation for specific items/activities (e.g., catching the ball and waiting for the student to request the ball before returning it) in order to contrive opportunities for the participant to make requests. The intervention was effective in increasing requests made with eye contact for the participants and maintained at varying degrees following 3 months after the intervention. On the other hand, acquisition of mands made with eye contact increased at a quicker rate following the intervention with each therapist, thus demonstrating some evidence of generalization. The results of these studies demonstrate the possible utility of using natural social contexts combined with differential reinforcement and prompting procedures to increase eye contact.
More recently, O’Handley, Radley, and Whipple (2015) compared the effects of an intervention package, which consisted of social stories and video modeling, on the eye contact of six adolescents with ASD. Findings of this study indicated that using only social stories led to moderated improvements, but after video modeling was combined to social stories, participants demonstrated further improvements. Applying video modeling in isolation showed strong intervention effects, and combining social stories to video modeling contributed to minimal additional improvements.
The acquisition of eye contact may also be a prerequisite skill for teaching more advanced social skills such as joint attention (Ninci et al., 2013; Taylor & Hoch, 2008). Joint attention refers to a set of behaviors that involve the shared attention between a social partner and a stimulus, and attention could be shared by using various topographies. Some of the topographies may include shift in eye gaze, gestures, vocal or verbal communication using one or more words, or any combination of those (Rudy, Betz, Malone, Henry, & Chong, 2014). Joint attention skills are considered a pivotal skill in a child’s social and communication development (Adamson & Bakeman, 1984). Thus, joint attention should be one of the earliest social skills taught in a child’s EIBI curriculum.
There are two forms of joint attention, responding to joint attention bids and initiating joint attention bids. Responding to other’s joint attention bids could include changes in gaze direction or verbal responses. Initiating joint attention bids could include asking some else’s attention by pointing an item or emitting verbal words (e.g., saying “Look!”). Both forms of joint attention can be taught together as one complete joint attention skill or each form separately. Several techniques have been used to teach joint attention skills including differential reinforcement and prompting procedures (Taylor & Hoch, 2008), video modeling (Rudy et al., 2014), and social scripts with fading (Pollard, Betz, & Higbee, 2012).
The earliest form of joint attention, which emerges between 9 and 18 months for typically developing children, is nonverbal joint attention. Nonverbal join attention involves shifting eye contact between a stimulus and a familiar person (Adamson & Bakeman, 1984). Krstovska-Guerrero and Jones (2015) investigated the effects of a differential reinforcement and prompting procedure to teach young children (20–29 months) with ASD early forms of responding to joint attention bids and initiating joint attention bids. Joint attention skills can be generalized to similar conditions with the child’s mother and in novel contexts (e.g., responding to name). Appropriate initiations and responses to bids for joint attention continued 3 months following the intervention.
Taylor and Hoch (2008) used a least-to-most prompting procedure and natural consequences (i.e., social attention) to teach three children with ASD how to engage in three components of joint attention: (a) gaze shift from an object to an adult, (b) vocal response to joint attention bids, and (c) vocal initiations of joint attention bids. Following training on responding to joint attention bids, increase in gaze shift and vocal responses were observed, but vocal initiations did not increase until explicitly taught. Thus, teaching responding to joint attention bids does not guarantee generalization to initiating joint attention bids. Due to the complexity of joint attention, it may be important to break down the component skills (e.g., pointing and/or orienting, eye gaze shift, vocal and nonvocal comments/initiations) and teach each skill individually. In summary, teaching these pivotal skills, eye contact and joint attention, are of upmost importance to interventionists working with individuals with ASD. The way in which interventionists teach eye contact and JA can impact the generality of these skills.
Recently, Rudy et al. (2014) investigated the effects of video modeling on initiate bids for joint attention in children with ASD. Video model consisted of a 5-year-old girl and an adult dyad, and they demonstrate three components of joint attention bids: (a) pointing and/or orienting toward the object, (b) emitting a vocal statement (e.g., “Look, tree”), and (c) shifting eye gaze from the object to the therapist and back to the object. Results of this study implied that using video modeling alone was effective in teaching three components of joint attention bids to two participants, whereas the one student was required both video modeling and in vivo prompts to learn joint attention bids.
Intermediate Social Skills
Play is important for several aspects of child development , including gross motor skills, coordination, and language development (Garvey, 1990). Typically, children first explore and contact their environment through play. However, children with ASD often engage in repetitive and ritualistic behaviors (Harrop, McConachie, Emsley, Leadbitter, & Green, 2014) that can impede naturalistic play. Moreover, children with ASD could show difficulties in play activities due to the lack of motivation or understanding the basic rule of play (e.g., taking turns). They may not frequently initiate conversations or socially respond to others during play. Based on this necessity, three research-based teaching strategies were generally used to promote play skills in children with ASD: (a) video modeling, (b) visual activity schedules, and (c) social scripts and script fading.
In a recent study, MacManus, MacDonald, and Ahearn (2015) taught three children with ASD to engage in a variety of play responses with three different toy sets. The primary purpose of this study was to evaluate the effectiveness of video modeling and matrix training as a treatment package for increasing the generalized play behaviors of children with ASD. Researchers found that the percentage of scripted and recombined actions and vocalizations increased for all three participants after video modeling was introduced. Additionally, they found that generalization across toy sets occurred to some degree for all participants.
Visual activity schedules are considered as an evidence-based practice for individuals with ASD (Kight, Sartini, & Spriggs, 2015) that include a series of photos, images, and pictures, which can describe a sequence of skills or behaviors. Initially, adults physically guide schedule following and rapidly fade prompts until the child can independently complete the schedule (MacDuff, Krantz, & McClannahan, 1993). Activity schedules have been used to promote not only solitary play (Morrison, Sainato, Benchaaban, & Endo, 2002) but also peer play. For example, Brodhead, Higbee, Pollard, Akers, and Gerencser (2014) taught children with ASD to play hide-and-seek with peers using joint activity schedules. Participants successfully engaged in both hider and seeker roles and also generalized hiding and seeking locations.
Children with ASD often struggle with initiating and maintaining back-and-forth conversations (American Psychiatric Association [APA], 2013). Social scripting is another technology that specifically targets increasing spontaneous vocalizations (Krantz & McClannahan, 1993). Children with ASD are taught to engage in scripted phrases that fit a specific context. Once the child can readily engage in the scripted responses, the scripts are systematically faded until the child’s behavior comes under the control of stimuli in the natural environment. The broader goal of this intervention is for the child to engage in novel phrases in addition to those that were directly taught.
Across two studies, researchers taught three children with ASD to initiate conversation with peers and to respond to peer initiations. In the initial study, Wichnick, Vener, Keating, and Poulson (2010b) taught three children with ASD to initiate play and conversation. Participants were provided with ten plastic bags filled with two small toys. During treatment, seven of the bags also contained auditory scripts to prompt play initiations (e.g., “Let’s share toys”). Participants opened one of the bags, removed both toys, and handed the second toy to a play partner. If the bag contained a script, he/she also engaged in the scripted initiation. Before treatment, participants rarely made initiations during play; however, once treatment was introduced, the number of initiations increased and remained elevated after scripts were faded.
In a follow-up study, Wichnick, Vener, Pyrtek, and Poulson (2010a) taught participants to respond to the initiations made by peers . The participants and procedures were the same as those employed in the initial study. Participants were taught to engage in an appropriate response when another peer initiated play (e.g., “This is fun”). Before treatment, participants rarely responded to peer initiations; however, after treatment, the number of responses greatly increased. These responses were not limited to those specifically taught but also included novel responses.
Other researchers have also investigated the usefulness of a script training procedure to promote play-based conversations (Groskreutz, Peters, Groskreutz, & Higbee, 2015). Three children with ASD were directly taught three script frames to facilitate commenting about various play activities. The script frames were “I found the ____,” “I’m playing with the ____,” and “Look at this ____.” During treatment sessions, 15 scripts (five of each type of script frame) were placed on various components of the toy set. If 30 s elapsed and the participant did not make a comment, the researcher prompted a scripted response. After script training was introduced, the number of unique play comments increased for participants.
In summary, targeting conversation and play skills with children with ASD is extremely important, as one of the defining features of ASD is the deficit in social communication (APA, 2013). Video modeling, visual activity schedules, and social scripting are relatively simple interventions that can be employed to address these skill deficits. These interventions promote independence and generalization to novel responses, which can lead to more naturalistic social interactions.
Complex Social Skills
Despite the support for behavioral interventions in the treatment of social behaviors, there is much less support for the use of such interventions in teaching complex social behaviors (Ranick, Persicke, Tarbox, & Kornack, 2013). However, support for the use of behavioral principles in teaching complex social skills is emerging through the application of relational frame theory (RFT) , a post-Skinnerian approach to language and cognition development. RFT proposes that an individual’s ability to “derive stimulus relations is learned behavior” (Hayes et al., 2001, p. 22). That is, RFT advocates that the ability to relate things to one another is learned behavior. Though most research on RFT has been conducted on typically developing populations (Dymond, May, Munnelly, & Hoon, 2010), there is emerging support for the use of RFT to teach complex social behaviors to individuals with autism. For example, given that individuals with autism have deficits in the ability to understand verbal irony, Pexman et al. (2011) and Persicke, Tarbox, Ranick, and St. Clair (2013) evaluated the effects of a training package to teach children with autism to detect and respond to sarcasm. The training package included multiple exemplar training (MET) . MET involves training a behavior in the presence of multiple stimulus conditions in order to promote the generalization of behavior (Rosales, Rehfeldt, & Lovett, 2011). In this case, MET involves exposing the individual with autism to multiple opportunities to recognize and detect sarcasm. Instructor feedback was provided on the correctness of each opportunity to respond to sarcasm. Following the study, all three participants demonstrated mastery and maintenance of the skill of responding to sarcasm for up to 3 months after treatment.
A similar approach was used to teach children with autism to detect to and respond to deceptive statements. Ranick, Persicke, Tarbox, and Kornack (2013) argued that responding to deceptive statements is important because it may reduce the likelihood that individuals with autism fall victim to bullying. Using MET in a treatment package that also included rules, modeling, role-play, and feedback, Ranick et al. taught three children with autism to question deceptive statements that occurred during play situations. Following training, all three participants demonstrated mastery of responding to deceptive statements and were able to generalize that skill to novel examples of deception and their peers.
Using behavioral skills training (BST) , which involves instruction through modeling, instructions, rehearsal, and feedback in order to improve the skills of a learner in a given situation, Miltenberger (2012) and Bergstrom, Najdowski, Alvarado, and Tarbox (2016) taught three children to tell socially appropriate lies. The social skill of teaching appropriate lies is important because they allow an individual to avoid giving away a surprise, keep a secret during a game, and provide praise or support for a physical appearance that may be less than flattering (Bergstrom et al.). This intervention serves as another example of an effective strategy to teach complex social skills to individuals with autism.
Communication deficits are characterized by delayed or atypical development in the area of communication. Sturmey and Sevin (1994) observed that poor communication skills are at the core of most autism definitions. Indeed, current diagnostic criteria for ASD emphasize a profound impairment in verbal and nonverbal communication used for social interaction (American Psychiatric Association, 2013). The degree of this communication disorder can vary widely in individuals with ASD. Some children acquire speech and language slowly during the preschool years; estimates are that up to 50% can use phrased speech by the time they enter primary school (see Howlin, Magiati, & Charman, 2009). Another portion of about 30–50% experience a severe lack in the development of speech and language by the time they enter kindergarten (National Research Council, 2001; Tager-Flusberg & Kasari, 2013). These individuals are often described as “nonverbal” or only “minimally verbal” (Tager-Flusberg & Kasari, 2013). Interventions to promote communication, and speech and language in particular, therefore span a wider range of approaches including verbal and nonverbal communication modalities. The following is an outline of the most common contemporary communication interventions that are consistent with a behavioral paradigm of communication training and based on empirically validated principles of learning.
Behavioral Intervention Principles Across Communication Modalities
To have the greatest benefit on the developmental trajectory, speech and language intervention should be started as early as the child is identified as having a difficulty; in addition, speech and language training should be integrated into any other type of intervention program that the individual is receiving.
Contemporary ABA-based approaches to speech and language intervention originated from Skinner’s (1957) analysis of verbal behavior (Sigafoos, O’Reilly, Schlosser, & Lancioni, 2007). According to Skinner, verbal behavior is reinforced by other people. For example, one can think of the direct act of opening a window (operant behavior) to breathe fresh air (reinforcement); the verbal behavior equivalent (saying, “open the window”) is only meaningful in the presence of a communication partner willing and able to react to and reinforce this communicative act. Verbal behavior includes any type of response form that will effectively modify a communication partner’s behavior. Natural speech is not always equivalent with verbal behavior, because speech is not automatically tied to the behavior of a listener. Echolalia, as an example, often results from automatic positive reinforcement (Sigafoos et al., 2009). On the other hand, any indirectly operated behavior that necessitates another person to mediate reinforcement is considered “verbal.” Therefore, verbal behavior can take many forms of communicative modalities such as vocalizations, writing, gestures, manual signs, exchanging pictures, or using a speech-generating device. In more depth, verbal behavior consists of several classes of verbal operants (see Sigafoos et al., 2009, for more information).
Based on the verbal behavior framework, communicative intervention aims at establishing a growing repertoire of proper communicative forms that will be used as mands, tacts, echoics, intraverbals, and autoclitics. Each of these verbal operants should be taught through direct instruction (Sundberg & Michael, 2001). Language interventions derived from Skinner’s analysis of verbal behavior show strong effectiveness for teaching the verbal operants outlined above. Skinner’s model emphasizes the function rather than the form of spoken language and underscores the importance of context (LaFrance & Miguel, 2014). By stressing function and context, this model provides clinicians with a viable tool to teach and shape speech and language, especially in cases where communicative repertoires are severely limited.
Interventions for the Verbal Individual
Behaviorally oriented speech and language programs for children that have communicative speech typically target four major aspects of speech-language development (Sigafoos et al. 2009). First, intervention often aims at increasing vocalizations and establishing imitative speech. Second, a general objective is to enlarge the learner’s vocabulary by (a) establishing new words and phrases, (b) enhancing the complexity of grammatical structures, and (c) developing the learner’s conversational skills. Third, intervention typically targets using the newly acquired speech forms in more functional and spontaneous ways; related content goals may include (a) establishing the spontaneous and generalized abilities to mand and tact, (b) transforming echolalic utterances into more meaningful functional speech, and (c) sustaining verbal behavior in general. Fourth, intervention aims to facilitate the various pragmatic aspects of verbal behavior, such as developing better articulation, expanding length of utterance, and fine-tuning prosody. It is critical to note that these four general intervention objectives are not mutually exclusive, and they are also not bound to any particular instructional sequence. Examples for evidence-based communication intervention programs that are firmly grounded in behavioral principles include the following examples.
Applied Verbal Behavior
Applied verbal behavior (AVB) programs (e.g., Greer & Ross 2008) incorporate behavioral procedures to teach verbal operants. AVB programs have proven to be effective in teaching children with ASD to acquire spoken words, produce questions, generate four-term sentences (verbs+colors+shape/size+labels), and respond to “what,” “how,” and “why” questions (Williams & Marra, 2011).
Pivotal Response Training
Another intervention program that has been used successfully to teach language to children on the autism spectrum is pivotal response training (PRT) (Koegel, Koegel, Harrower, & Carter, 1999). A “pivotal behavior” is considered one from which other behaviors originate. Based on principles of ABA blended with developmental approaches, PRT targets pivotal behaviors related to motivation, responsivity to multiple cues, self-management, and self-initiations. Creating a focus on these pivotal skills leads to ancillary gains in untargeted areas and ideally to generalized long-lasting improvements in language, behavior, and social outcomes. The comprehensive PRT program emphasizes consistent and coordinated programming across the child’s environments, including parents as much as possible (Park, 2013). Parents take on a major role in the treatment process and receive in-depth PRT training. This partnership model has parents outline clinically important treatment goals and intervention strategies that can be easily infused into their daily family schedule. During the treatment sessions, certain variables are manipulated in a natural language teaching context; for example, the clinician may use stimulus items that are functional and vary these, employ natural reinforcers, and reinforce any communicative attempt. The major use of PRT has been for the acquisition of early, very specific language skills; PRT has also been applied for increasing the frequency and spontaneity of utterances (Williams & Marra, 2011).
Interventions for the Minimally Verbal Individual: Augmentative and Alternative Communication
Individuals with ASD who do not develop sufficient natural speech or writing to meet their daily communication needs are candidates for intervention in the area of augmentative and alternative communication (AAC). Such individuals may show only pre-intentional communication, such as reaching for a desired item, or communication may show intent through behaviors such as pointing (Yoder, McCathren, Warren, & Watson, 2001). When speech does develop, it is often limited to unusual or echolalic verbalizations (Paul, 2005).
AAC is defined as the supplementation or replacement of natural speech and/or writing using aided and/or unaided strategies . Blissymbols, pictographs, Sigsymbols, tangible symbols, and electronically produced speech are examples of aided AAC. Manual signs, gestures, and body language are examples of unaided AAC. The use of aided symbols requires a transmission device, whereas the use of unaided symbols requires only the body (Lloyd, Fuller, & Arvidson, 1997). Major types of AAC intervention for individuals on the autism spectrum include the following approaches.
Manual Signs, Gestures, and Total Communication
Manual signing was one of the first AAC strategies used with minimally verbal individuals with autism (Schlosser & Wendt, 2008). It was first trialed in the 1970s and has been applied successfully with this population for over 30 years. The term manual signs can indicate a natural sign language (e.g., American Sign Language aka ASL) or refer to the generation of manual signs as a code for a spoken language (Blischak, Lloyd, & Fuller, 1997).
Gestures are body movements or coordinated sequences of motor responses to represent an object, idea, action, or relationship omitting the linguistic features of manual signs. Examples for gestures include pointing or yes-no headshakes. Using gestures is a nonlinguistic form of unaided communication that develops early in life. Before the start of linguistic development, infants typically use gestures in symbol formation when communicating and interacting with communication partners (Loncke & Bos, 1997). Consequently, gestural development is an important precursor to later development of language skills (Morford & Goldin-Meadow, 1992). Individuals with ASD, however, rarely develop gestural use as an alternative communication strategy by themselves and need concerted intervention to acquire this skill (Loveland, Landry, Hughes, Hall, & McEvoy, 1988).
By the mid-1980s, an AAC approach emerged that combined manual signing with speech. This procedure is labeled as “total” or “simultaneous” communication (Mirenda & Erickson, 2000). Total communication emphasizes the use of the most appropriate communication strategy for the individual and is typically an adaptation of ASL. Research reports indicate increases in initiating communicative acts after manual sign training in children with ASD (Goldstein, 2002). Other studies showed improvements in early vocalizations or spoken words, while some research suggests limited productive use of manuals signs when taught to individuals with ASD. The majority of research does not support language progress beyond a few words when implementing manual signs; however, the total communication approach shows promising effects particularly for those children with autism who are minimally verbal and have poor verbal imitation (Williams & Marra, 2011). When implementing manual sign training, clinicians should be cautious about motor skill requirements on the individual with ASD. Possible motor apraxia may impede acquisition and production of a manual sign repertoire (Hilton, Zhang, White, Klohr, & Constantino, 2012; Isenhower et al., 2012). Related research suggests that manual signing can be part of a multimodal AAC system for individuals with ASD but that it should not be the only means of communication. A combination with other forms of AAC seems more beneficial (Williams & Marra).
Graphic Symbol Sets and Systems
Compared to manual signing, graphic symbols are a somewhat newer AAC mode for individuals with ASD. During the 1980s clinicians started to embrace the potential benefits of graphic symbols because of their non-transient nature (e.g., Mirenda & Schuler, 1988). Graphic symbols can be organized as sets or systems. Sets represent collections of symbols that do not have defined rules for their creation and expansion, while systems have an established rule repertoire (see Lloyd et al., 1997). Graphic symbols most often used in ASD include PCS, line drawings, colored photographs, and Premack (all sets) and blissymbols, orthography, and rebus (all systems) (Schlosser & Wendt, 2008). Graphic symbol sets and systems that are more iconic in nature (i.e., they demonstrate greater visual resemblance between symbol and referent) appear to be easier to learn (Kozleski, 1991).
Research suggests that graphic symbols are most effective for targeting mand skills (Schlosser & Wendt, 2008). Beyond manding, graphic symbols may be helpful as visual supports to facilitate transitioning activities (Dettmer, Simpson, Myles, & Ganz, 2000). Yet, the research base on graphic symbols has not reached a critical mass to draw conclusions whether one graphic symbol set/system may be preferable over others.
Speech-Generating Devices (SGDs)
SGDs are another viable option for minimally verbal individuals with autism. SGDs include dedicated electronic communication devices, talking word processors, and handheld multipurpose mobile devices (e.g., iPad®, iPod®, Android® tablets) equipped with AAC applications (apps). All of these have built-in technology that allows a user to communicate via digitized and/or synthetic speech. Digitized speech is generated by recording a human voice and converting it into an electronic waveform. The quality of digitized speech depends on the sampling rate used during the conversion process. SGDs and apps that apply higher sampling rates in general generate higher-quality speech output compared to those that rely on lower sampling rates. Recording quality may also be impeded by noisy environments, equipment quality, speaker age, and quality of the speaker’s natural voice (Drager & Finke, 2012).
Synthetic speech is generated by a text-to-speech algorithm built within the device that allows to produce an unlimited amount of spontaneous speech by converting alphabets, digits, words, and sentences into speech output. Intelligibility of high-quality text-to-speech engines can approach that of natural speech . Variables that influence synthetic speech quality include listening conditions, experience, and adjustment to the nature of synthetic speech and the particular listening tasks (Schlosser & Koul, 2015).
Research into the effects of SGDs for minimally verbal individuals with ASD has evolved much later than for other AAC options (e.g., manual signing). Recently there has been increased research activity in this area, especially on the use of mobile technologies with AAC-specific apps; this is not an unsurprising trend in light of the current impact of mobile technologies on the AAC field (e.g., McNaughton & Light, 2013). The majority of studies document benefits from SGDs when these are used as part of treatment packages to target requesting skills or challenging behaviors (Schlosser & Koul, 2015). Some research has started to document effects on natural speech production and social-communicative behaviors in individuals with ASD (Kasari et al., 2014; Boesch, Wendt, Subramanian, & Hsu, 2013), but further investigations are warranted to draw more definite conclusions for clinical practice.
Instructional Approaches for Augmentative and Alternative Communication in Autism
To maximize the effects of AAC intervention, it is critical to put an effective instructional approach around the provision of AAC technology. Merely equipping the learner with AAC materials or devices will not automatically lead to improved communication. Incorporating behavioral learning principles into AAC intervention can be a powerful tool to create a proper instructional framework. Examples for evidence-based approaches are the picture exchange communication system and matrix training.
Picture Exchange Communication System (PECS)
The PECS has attained widespread use and popularity in the autism field during the last 20 years (Bondy & Frost, 1994). PECS is a manualized treatment for beginning communicators that uses behavioral strategies and a series of training phases to teach the use of graphic symbol cards for spontaneous communication with others. PECS involves six phases. In phase I: physical exchange, learners are taught to exchange a graphic symbol for a desired object. In phase II: expanding spontaneity, learners are taught to exchange a symbol with different communication partner across increasing distances. In phase III: picture discrimination, the task for the learner is to discriminate among symbols for requesting. Consequently, in phase IV: sentence structure, the learner is instructed to attach an “I want” symbol to a blank sentence strip, followed by the symbol for a desired item, and to exchange the sentence strip with a communication partner. In phase V: responding to “What do you want?,” the learner is required to respond immediately to a question prompt. Finally, phase VI: responsive and spontaneous commenting uses the acquired skills to develop responses to further questions (i.e., “What do you see?”) and spontaneous commenting (Bondy & Frost, 2001). Reviews of the PECS intervention literature indicate that the approach is successful in teaching initial communication skills and in some cases facilitated spoken language acquisition (Ganz, Davis, Lund, Goodwyn, & Simpson, 2012; Williams & Marra, 2011). For example, in a sample of 66 participants who received PECS intervention for over a year, 39 (59%) developed natural speech as a primary communication mode (Brunner & Seung, 2009).
Matrix training is a proper choice of instruction when learners possess an initial core lexicon of 40–50 symbols and begin to create symbol combinations. Matrix training can be implemented by using symbols in an AAC context (e.g., manual signs or graphic symbols) or by using spoken words. Matrix strategies use linguistic elements (e.g., nouns, verbs, etc.) presented in systematic combination matrices, which are arranged to induce generalized rule-like behavior. The learner is taught to combine a limited set of symbols in one semantic category with another set in a related semantic category to facilitate the acquisition of generalized combining of lexical items (Nelson, 1993). For example, a 2×2 matrix can be designed with two colors on one axis and two objects on the other axis, allowing four different color-object combinations. If two of the four combinations are taught, the learner may be able to generalize the skill to the untaught combinations. For example, if a child is taught to label “yellow apple” and “red pear,” the combinations “yellow pear” and “red apple” may emerge without direct instruction, a process that is known as “recombinative generalization” (Goldstein, 1983). Clinical research indicates that matrix training is effective in teaching action-object, graphic symbol combinations on a communication board for individuals with developmental disabilities including ASD (Nigam, Schlosser, & Lloyd, 2006). Successful intervention results have also been reported for teaching spelling, play-based behaviors , and enhanced expressive and receptive communication skills, although mostly for participants with developmental delay and/or intellectual disability (Chae & Wendt, 2012).
Restricted, Repetitive Behaviors and Interests
The final core symptom of ASD is restricted or repetitive behaviors, interests, or activities (American Psychiatric Association, 2013). To meet the DSM-V diagnostic criteria for ASD, an individual must present with or have a history of at least two categories of restricted, repetitive behaviors and interests (RRBI). RRBI categories include (a) stereotyped or repetitive motor movements, use of objects, or vocalizations (e.g., hand flapping, body rocking, lining up objects, echolalia or repetitive speech); (b) insistence on sameness, strict adherence to routines, or ritualistic verbal or nonverbal behavior (e.g., major distress related to changes in routines, transitions); (c) highly circumscribed or perseverative interests (e.g., intense focus or attachment to unusual objects, topics, or interests); or (d) hyper- or hyposensitivity to sensory input (e.g., indifference to pain, excessive sniffing of objects, licking objects, covering ears) (American Psychiatric Association, 2013). RRBI in individuals with ASD is heterogeneous and can take the form of a variety of motor, vocal, and ritualistic behaviors, which vary greatly in terms of form, frequency, and intensity. To assist in examining the etiology, trajectory, and treatment of RRBI, researchers have factored RRBI into two subgroups: lower-order and higher-order RRBI (Turner, 1999).
Lower-order RRBI are characterized by repetitive motor movements, vocalizations, or object manipulation, while higher-order RRBI relates to insistence on sameness, circumscribed perseverative interests, and rigid adherence to rules or rituals (Boyd, McDonough, , & Bodfish, 2012; Patterson, Smith, & Jelen, 2010).
RRBI Treatment Overview
RRBI have been reported to be the most difficult aspect of ASD for parents to manage (Bishop, Richler, Cain, & Lord, 2007) and present unique challenges for treatment. RRBI can negatively impact socialization (Watt et al., 2008), reduce access to and benefit from instruction, lead to stigmatization (Cunningham & Shriebman, 2008), and contribute to placement in restrictive settings (Boyd et al., 2012; Green et al., 2007; Honey, Rodgers, & McConachie, 2012). Not only do RRBI interfere with learning and social development, but interruption or blocking of RRBI has been shown to evoke additional challenging behaviors including tantrums, aggression, and self-injury (e.g., Hagopian & Adelinis, 2001). The best treatment outcomes for RRBI result from behavioral treatments based on the principles of operant conditioning (e.g., Boyd et al., 2012; Patterson, Smith, & Jelen, 2010). Behavioral treatments can be classified as antecedent interventions, consequence interventions, or combinations of antecedent and consequence interventions.
Antecedent treatments prevent RRBI through altering the environment, providing competing sources of stimulation and reinforcement, and reducing of motivation to engage in RRBI. Antecedent interventions often consist of focused intervention practices (Odom et al., 2009) which can be implemented in isolation or as part of a larger, comprehensive treatment package. Focused antecedent interventions for lower-order RRBI include teaching new skills or behaviors, noncontingent reinforcement (NCR), environmental enrichment, antecedent exercise, presession access to RRBI, and discrimination training.
Teaching New Skills
It has been posited that one reason individuals engage in RRBI is because they lack adaptive behaviors to access reinforcement (Boyd et al., 2012). By teaching appropriate leisure, play, and social interaction skills, researchers have shown that RRBI can decrease (Lanovaz, Robertson, Soerono, & Watkins, 2013). Loftin, Odom, and Lantz (2008) taught social interaction skills to three children with ASD. Intervention involved peer training, social initiation instruction, and self-monitoring. As social interaction skills improved, motor stereotypy decreased.
Noncontingent Reinforcement (NCR)
NCR involves systematically providing access to the maintaining consequence of challenging behavior on a fixed time-based schedule. For lower-order RRBI maintained by automatic reinforcement, NCR often involves access to stimulation matched to the properties of the RRBI (Piazza et al., 2000). For example, Rapp (2007) provided two boys with ASD who engaged in repetitive vocalizations noncontingent access to music and found repetitive language decreased. Ahearn, Clark, DeBar, and Florentino (2005) found that access to highly preferred toys that did not match the properties of the children’s RRBI also decreased RRBI. This suggests that if the properties of RRBI are not able to be identified or matched to the sources of stimulation (toys, music, etc.), then noncontingent access to highly preferred toys may be effective in reducing lower-order RRBI. Other research has shown that NCR is more effective in reducing lower-order RRBI when paired with consequence-based interventions (e.g., blocking RRBI) (Patterson et al., 2010).
Environmental Enrichment (EE)
EE is similar to NCR in that access to stimulation is provided irrespective of the individual’s engagement in RRBI (e.g., Vollmer, Marcus & LeBlanc, 1994). EE involves increasing the quantity or quality of reinforces within a setting. EE is effective at reducing RRBI when the reinforcing properties of the environment successfully compete with and become more valued than the automatic reinforcement obtained through RRBI (Rapp & Vollmer, 2005). For example, a teacher could conduct a preference assessment to identify a child’s preferred toys and activities (see Karsten, Carr, & Lapper, 2011, for guidelines for selecting an appropriate preference assessment). He or she could then identify times during the day when the child is likely to engage in lower-order RRBI and present the preferred toys and activities to the child during those times. Vollmer et al. (1994) found that when children with ASD were given access to their preferred items, lower-order RRBI decreased. However, for some individuals, EE may actually lead to an increase in vocal stereotypy. Van Camp et al. (2000) observed rates of hand flapping in a young boy and found that hand flapping was higher in the presence of preferred toys than when the child was alone without environmental stimulation. Given this variability in outcomes, it is important to evaluate the effects of environmental enrichment on RRBI for the individual prior to adopting the intervention whole scale.
Presession access to RRBI may also function to reduce the value of automatic reinforcement (e.g., Rapp & Vollmer, 2005; Rispoli et al., 2011). Lang et al. (2010) evaluated presession access as a treatment for repetitive object manipulation in four young children with ASD. When the children were given unrestricted access to engage in object manipulation immediately prior to a play intervention, they engaged in lower levels of object manipulation and increased levels of functional play during the subsequent play intervention session. Practitioners interested in preventing subsequent engagement in lower-order RRBI may schedule periods of unrestricted access to engage in RRBI prior to target tasks or activities.
Related to scheduling opportunities for individuals with ASD to engage in RRBI, research has shown that the use of visual and verbal cues can assist in signaling to the individual when it is appropriate to engage in RRBI and when it is inappropriate (Conroy, Asmus & Sellers, 2005). Such an intervention involves bringing RRBI under the control of a specific stimulus and then only presenting that stimulus when it is acceptable to engage in RRBI. For example, O’Connor, Prieto, Hoffmann, DeQuinzio, and Taylor (2011) evaluated a stimulus control procedure on repetitive motor and vocal behaviors in an 11-year-old boy with ASD. Through discrimination training, they taught the child that in the presence of a green card, he could engage freely in RRBI. However in the presence of a red card, RRBI was physically interrupted (e.g., manual guidance of his hands back to his lap, removal of preferred stimuli in the presence of repetitive vocalizations). When the child did not engage in RRBI in the presence of the red card, the researchers presented the green card, signaling that the RRBI would not be interrupted. Thus, this intervention involved a stimulus control procedure and reinforcement of the absence of RRBI with subsequent access to RRBI. This procedure was then generalized to the child’s school and community environments.
Higher-order RRBI involve perseverative or circumscribed interests and insistence on sameness. As such, antecedent interventions are designed to expand interests and enhance flexibility. One approach with emerging research support is to capitalize on perseverative interests through a strength-based approach. Perseverative interests have been embedded into instruction via instructional materials (Adams, 1998), social interaction topics (Baker, Koegel, & Koegel, 1998), and play (Boyd, Conroy, Mancil, Nakao, & Alter, 2007). For example, Baker et al. compared the effects of perseverative interest embedded in social games on the social interactions with three children with ASD. The children’s restricted interests included facts about the United States, Disney characters, and children’s movies. When the socially appropriate games were centered on the child’s perseverative interest (such as playing tag on a giant map of the outline of the United States), social interaction increased for all three participants and generalized to social interactions with topics outside of perseverative interests.
Functional Communication Training (FCT)
FCT has shown promise in the treatment of challenging behavior associated with ritual interruption (e.g., Kuhn, Hardesty, & Sweeney, 2009). Rispoli et al. (2014) evaluated FCT to teach three young boys with ASD and higher-order RRBI to appropriately request access to their preferred ritual. When the children requested appropriately, they were permitted to engage in the ritual. When they engaged in challenging behavior, the ritual was terminated. To reduce the time spent engaged in the ritual, the participants were taught to only request access to the ritual once a visual timer had elapsed. Using this signaled delay to reinforcement, the children were able to tolerate interruption of rituals for up to 1 min. For one child, results generalized occurred across rituals.
Differential Reinforcement (DR)
DR procedures involve providing poorer quality or less quantity of reinforcement for RRBI and greater quality and quantity of reinforcement for either appropriate behaviors or the absence of RRBI. A target criterion for RRBI or a replacement response is established and systematically reinforced. Taylor, Hoch, and Weissman (2005) implemented a differential reinforcement procedure with a 6-year-old girl with ASD who engaged in vocal stereotypy. The teacher told the child that if she played quietly until the timer rang, she could have access to musical toys (toys matched to the reinforcing properties of vocal stereotypy). A card with the word “Quiet” and a digital timer set and placed in view of the child. Results showed that when the differential reinforcement procedure was in place, vocal stereotypy decreased. Differential reinforcement can also be used to increase variability of behaviors (Miller & Neuringer, 2000). For example, a child who engages with toys in the same manner each day would be reinforced for engaging with toys in different ways (Boyd, McDonough, Rupp, Khan, & Bodfish, 2011).
Punishment procedures for RRBI include response cost, response interruption and redirection, and sensory extinction. Response cost involves removing access to a desired object or activity contingent upon RRBI. For example, a child who is earning tokens to exchange for a preferred activity may lose a token each time she engages in RRBI (Lapime & Dittcher, 2014). Response interruption and redirection involves manually preventing repetitive motor movements or verbally interrupting repetitive vocalizations (Ahearn et al., 2007). Response blocking is related to response interruption, but rather than blocking the RRBI itself, access to reinforcement obtained by the RRBI is prevented (Rapp & Vollmer, 2005). This is referred to as sensory extinction. Rincover, Newsom, and Carr (1979) hypothesized that a child who spun plates on hard surfaces was doing so to hear the sound the plate made when it clattered against the table. The researchers covered the table with a soft material to block the sound of the plate spinning. With this sensory extinction procedure, plate spinning decreased, and the authors were able to introduce new appropriate play skills which allowed the child to access similar auditory reinforcement.
Although punishment procedures for RRBI are common in practice, they have not been shown to be effective in maintaining reductions over RRBI over time (Cunningham & Schreibman, 2008) and may serve to increase RRBI when punishment procedures are not in place (Rapp & Vollmer, 2005). There are also ethical concerns that arise when implementing punishment procedures, and such procedures can lead to aggressive behaviors or instructional environments taking on aversive characteristics (Rapp & Vollmer). It is recommended that punishment procedure be incorporated into treatment packages that include antecedent and reinforcement procedures.
The above sections outline strategies for the treatment of core symptoms of ASD. Though the type of treatment differs depending on the needs of each learner, one commonality between treatment options is that effective treatments are based on the principles of behavior analysis. To date, no other forms of treatment have reported the positive results obtained by behavioral interventions for individuals with ASD. Because there are a number of alternative treatments for ASD (see Foxx & Mulick, 2016), it is important for consumers to appraise alternative treatments, as some treatments may be harmful or counterproductive to treatment goals (Brodhead, 2015). Finally, when implementing behavior-analytic treatments for individuals with ASD, it is of great importance that treatment is designed, implemented, and supervised by qualified professionals. In some cases, the input of multiple professionals may be necessary, as treatment of social skills, communication, and repetitive behaviors are separate areas of expertise. Failure to provide proper oversight of the implementation of behavioral procedures may result in less than adequate treatment of core symptoms of ASD.
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