Research in Autism Spectrum Disorders 7 (2013) 809–814

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Research in Autism Spectrum Disorders

Jo ur n al h o mep ag e: ht tp : / /ees .e ls evier .c o m/RA SD/d efau l t .asp

Autism spectrum disorders: Methodological considerations

for Early Intensive Behavioral Interventions

Johnny L. Matson *, Jina Jang

Louisiana State University, USA

A R T I C L E I N F O

Article history:

Received 15 December 2012

Accepted 24 January 2013

Keywords:

Autism spectrum disorders

Early intervention

Methodology

A B S T R A C T

Early Intensive Behavioral Intervention (EIBI) has become a cornerstone of early

intervention for young children with autism spectrum disorders (ASDs). As this field

has matured, the emphasis will need to shift from does it work to more specific and

tailored research topics. Increasing compatibility across studies will be critical.

Establishing more rigorous methods of group assignment and more systematic and

detailed descriptions of participants, and developing more up-to-date criteria and

methods of diagnosis will be needed. Also, providing more systematic and detailed

descriptions of treatment and more emphasis on staff training and treatment integrity will

be required. How methodology can be improved serves as the primary focus of the paper.

� 2013 Elsevier Ltd. All rights reserved.

Autism spectrum disorders (ASDs) have become a centerpiece for mental health, medical, and educational researchersworldwide (Kjellmer, Hedvall, Fernell, Gillberg, & Norrelgen, 2012; Lin, Chen, & Chou, 2012). The condition is consideredneurodevelopmental in origin and has a lifelong course (Gardiner & Iarocci, 2012; Kuhn & Matson, 2002; LoVullo & Matson,2009; Matson & LoVullo, 2008; Matson & Rivet, 2008; Matson, Mahan, Hess, Fodstad, & Neal, 2010; Nygren et al., 2012). Coresymptoms of communication, social deficits, and stereotyped and repetitive behaviors are evident and need to be assessedand treated (Horovitz & Matson, 2010; Matson & Wilkins, 2008, 2009; Matson, Smiroldo, & Bamburg, 1998; Matson, Leblanc,& Weinheimer, 1999; Matson, Dempsey, LoVullo, & Wilkins, 2008; Smith and Matson, 2010a, 2010b, 2010c).

Many other problems often co-occur with this condition including challenging behaviors, comorbid psychopathology,and physical delays and disabilities (Bahrami, Movahedi, Marandi, & Abedi, 2012; Gadow & Drabick, 2012; Matson & Kuhn,2001; Matson & Neal, 2009; Rojahn, Zaja, Turygin, Moore, & van Ingen, 2012; Rumpf, Kamp-Becker, Becker, & Kauschke,2012). Finally, rates of ASD have been rising (Matson & Kozlowski, 2011). For all of these reasons, this group of children hasbecome a focus for intervention.

Much has been done in the area of assessment to identify people with ASD (Edwards, Perlman, & Reed, 2012; Matson &Wilkins, 2008; Matson, Fodstad, & Dempsey, 2009; Matson et al., 2009c; Matson, Boisjoli, Hess, & Wilkins, 2010). Particularlyrobust efforts have been made with young children (Matson, Wilkins, & Gonzalez, 2008; Matson et al., 2009c). The idea is toidentify the condition and collateral behaviors and disorders as early as possible (LoVullo & Matson, 2009; Matson & Kuhn,2001; Matson et al., 1999; Poon, 2012; Smith & Matson, 2010a). Once this has occurred, efforts are then made to provide asmuch intervention as possible (Matson, Dempsey, & Fodstad, 2009; Strauss et al., 2012). The intervention is often as much as40 h a week, much of it is one-to-one, and heavy parental involvement is common (Wan et al., 2012). Medications are alsoadded to the intervention package in some cases, but best practice suggests that this should only occur later in life (Lunsky &

* Corresponding author at: Department of Psychology, Louisiana State University, Baton Rouge, LA 70803, USA.

E-mail address: johnmatson@aol.com (J.L. Matson).

1750-9467/$ – see front matter � 2013 Elsevier Ltd. All rights reserved.

http://dx.doi.org/10.1016/j.rasd.2013.01.006

J.L. Matson, J. Jang / Research in Autism Spectrum Disorders 7 (2013) 809–814810

Elserafi, 2012; Matson & Neal, 2009; Memari, Ziaee, Beygi, Moshayedi, & Mirfazeli, 2012; Singh, Matson, Cooper, Dixon, &Sturmey, 2005).

1. Lack of compatibility

A tempting issue when evaluating any treatment method is to assess outcomes across studies. Early Intensive BehavioralInterventions (EIBIs) is no exception to this trend. Meta-analysis, where effects are statistically compared across studies, isperhaps the most common of these. However, this method is not without controversy. For example, Eysenck (1978) referredto this procedure as mega-silliness. He suggested that meta-analysis basically consisted of adding apples and oranges;however, the procedure has continued to gain in popularity and is not generally considered to be the dominant methodologyfor synthesizing research (Aguinis, Pierce, Bosco, Dalton, & Dalton, 2011). We believe there are two primary reasons for thisdevelopment. First, individual studies are the building blocks for science. Studies must be replicable so that others can runstudies to confirm earlier findings. Over time, a body of data is developed and must be summarized. Then broaderconclusions can be drawn about efficacy and best practice applications and so on. Meta-analysis and general literaturereviews are in use because no better methods of summarizing data across multiple studies have emerged. As the extantliterature expands, so does the need for summary papers. Given that major improvements in synthesizing studies have notemerged, the current methods are likely to continue at least for the foreseeable future. One way to improve summaryoutcomes, however, is to aim for greater standardization in methodology and data reporting. Thus, we may not get to thegoal of comparing apples to apples, but perhaps apples to a mix of apples and oranges.

What follows is a description and analysis of some of the most problematic methodological issues in the EIBI literature.Numerous meta-analyses have already been published (see Kuppens & Onghena, 2012 for details). This topic is becoming solarge, that many facets of EIBI are open to study and debate. How EIBI affects major behavioral domains such as language,adaptive behavior, and performance on cognitive tasks are critical issues. Variations of the EIBI model, such as home versuscommunity programs and parent versus professional focused trainers must also be considered. Since there are manydifferent components of applied behavior analysis (ABA), different subtypes are used with different weekly intensity andoverall duration (e.g., weeks, months, or years). The time and difficulty in sorting all these factors will take time. However,the task will be made much easier if some basic methodological rules are followed.

Standardization was first addressed with respect to dependent variables used to evaluate the efficacy of EIBI (Matson,2007). Researchers pointed out that many studies did not use a core measure of ASD symptoms, yet authors were claimingimprovement in ASD. In the present review, we extend this discussion to include description of participants, criteria, andmethods of diagnosis, group assignments, and descriptions of treatment. Rather than to point out studies where omissionsare present, we will take the more positive approach of pointing out where authors have, in our view, gotten it right from amethodological point of view.

2. Group assignment

For establishing and working out specific intervention components at the outset of intervention development, single casedesigns are particularly good since they preserve resources. As topics evolve, however, economy of size begins to work in theopposite direction. As a technology matures, group studies with pretest–posttest data and no-treatment control groups arecompared to EIBI, and in some cases, other interventions become more critical for generalization, reliability, and validity ofthe methods. Group assignment becomes an issue in this case.

A number of factors are important and should be incorporated in establishing experimental and control groups in quasi-experimental pretest–posttest EIBI studies. The general point is that the groups must be as comparable as possible at pretest.Obviously, if a single case study design is used, this issue is mute since the participant is a ‘‘self-control.’’

As a general rule, random assignment to groups as described by Kaale, Smith, and Sponheim (2012) is to be preferred.However, this tactic assumes relative homogeneity between children on core symptoms of ASD, developmental milestones,challenging behaviors, and other factors that can impede treatment. Where considerable variability in these factors exists,yoking may be a preferred method of assignment (matching children as closely as possible in pairs, triplets, etc. is useddepending on whether there are two groups, three groups and so on). Prioritizing the variables for matching, we argue,should be based on their predictive ability on outcomes. Perry et al. (2011) note that developmental and diagnostic factorsfor EIBI programs are particularly pertinent.

Matching variables should be rank ordered. In addition to predictive value, discrepancies between individuals should alsobe factored into the matching process. For example, if predictor variable one has very small discrepancies across theprojected sample group, but major discrepancies are evident on predictor variable two, then the latter variable would be theprime match variable.

3. Description of participants

Developmental level and age have been discussed as important criteria for matching. Obviously then, such variablesshould be among the factors routinely defined and discussed in the EIBI literature. Very young children (2–5 years old) havereported IQ scores in some studies (see review by Peters-Scheffer, Didden, Korzilius, & Sturmey, 2011). However, reporting

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developmental quotients on tests such as the Bayley scales of Infant Development (Kelly-Vance, Needelman, Troia, & Ryalls,1999) and the Behavioral Assessment System for Children (BASC-2; Reynolds & Kamphaus, 2003, 2004) are to be preferredover IQ. Standardized intelligence tests do not produce stable test scores for young children and thus are not reliableparticipant variable(s). Additionally, there has been some confusion in the literature over what increased IQ scores frompretest to posttest mean. Perhaps all one can actually conclude is that scores increased. Suggesting that an increased scoredenotes increased IQ versus better attending skills, greater motivation to perform well, and a combination of these factors orother factors is an over-interpretation of the data at this point (Matson, 2007).

Another important factor that should be routinely addressed involves past treatment history of the child (Granpeesheh,Dixon, Tarbox, Kaplan, & Wilke, 2009). This factor is among the most important but is generally ignored in EIBI research. Pasttreatment history is so important because parents routinely use multiple interventions, often simultaneously. Additionally,the methods by which parents learn about and select treatments vary widely (Miller, Schreck, Mulick, & Butter, 2012). Pastefforts, if they produce effects may be detected and controlled at pretest by carefully matching across conditions and/or bystatistically covarying out uneven rates of performance across multiple dependent variables. More problematic is thepotentially steeper learning curve these interventions may produce by establishing factors that are not directly measuredsuch as sitting, attending, and other basic variables that affect the rate of skill acquisition in other areas. Additionally, whereother treatments are being provided simultaneously with EIBI, they produce noise in the methodological system andcomplicate the researchers’ ability to establish what works from what does not produce an effect.

Comorbid psychopathology, challenging behaviors, and serious health conditions such as seizures and cerebral palsy alsoneed to be evaluated. Where present, specifics on severity and frequency of symptoms should be reported in the study. Aconsiderable amount of EIBI resources are likely to be devoted to comorbid psychopathology and challenging behaviors. Thepotential for these factors to affect quality of life and absorb resources underscores the need to assess for these covaryingconditions within and outside the EIBI study itself. These data are underscored by a study noting that parents’ treatmentpriorities were highest in areas of greatest deficits or where their children were displaying emerging skills (Pituch et al.,2011).

4. Criteria and methods of diagnosis

There is a consensus among researchers and clinicians alike that ASD is a very heterogeneous condition. This facthighlights the need to provide the reader with detailed information on not only the severity and type of symptomspresentation, but the data these conclusions are based on, and who made these decisions. Optimally, consensus of more thanone professional, past history, observation, and standardized tests will be used in these determinations. Ben Itzchak andZachor (2009), Schreibman, Stahmer, Barlett, and Dufek (2009) and Strauss et al. (2012) provide good examples of methodsand measures that can be used to help in identifying core symptoms of ASD and collateral behaviors such as self-help skills,challenging behaviors, and comorbid psychopathology.

Different intensities and behavior analytic methods as well as primary targets for intervention will need to vary by child.The studies which will help to resolve these questions have not been conducted. A major goal of future EIBI research willfocus on this topic. Looking ahead in this way underscores the importance of providing detailed participants information.Without these data, it will be difficult to make important clinical decisions. Routinely, skill levels need to be discussed aspreviously noted. Age, gender, comorbid disorders, developmental level, race, and cultural data, treatment setting, andexternal stressors should be consistently reported.

5. Descriptive of treatments

One of the biggest problems with EIBI is that many parents and professionals view this treatment approach and ABA ingeneral as a monolith. In fact, ABA and EIBI relative to this review are constituted by a broad and varied number of proceduresdeveloped by many researchers over decades. Often, EIBI has been mislabeled as a singular accomplishment and categorizedaccordingly (e.g., Lovaas therapy). Many intervention components are involved in these treatments. These strategies date tolaboratory research aimed at establishing principles of how organisms learn, from rats and pigeons to people, and have beenin development for almost a century. EIBI strategies thus have a long heritage of basic and applied research on theexperimental analysis of behavior (e.g., Matson, 1977; Watson & Rayner, 1920; Wolf, Risley, & Mees, 1963). All of this dataunderscores the need for a detailed description of the intervention in any EIBI study.

When manuals or curriculums are used, they should be referenced and made available free or for purchase. To the extentthat EIBI can be manualized, comparability of studies can be enhanced further. As a result, this approach should be endorsedwhere possible. The EIBI literature has advanced to a point where this strategy is now possible.

Even when techniques have been standardized, adjustments and modifications across and within children over time areinevitable. The discussion (or methods) section in manuscripts should note these changes and why they were necessary.Unfortunately, this rarely occurs. As a result, valuable knowledge on how to provide optimal EIBI treatment is being lost. Oneof the best and most descriptive treatment modifications was one of the earliest EIBI studies. Lovaas (1987) describes howlength of intervention, number of hours of treatment per week, and number of months of treatment varied based onoutcomes. In addition to length of treatment, the qualifications of the trainer, whether training is individualized, how many

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trainers are used per child and per groups, specific ABA procedures used, specific skills targeted, and proportion of time spenton each target behavior should be included.

6. Staff training and treatment integrity

One of the most neglected topics in EIBI studies pertains to monitoring if the treatment is being implemented correctly.An entire field has grown up around this topic. However, treatment integrity methods did not penetrate the EIBI literature toa major degree as of this writing. Often, treatments are poorly described or terms such as ABA are referenced as if this vast setof complex components and methods is one approach. Thus, at a minimum, the specific components of the interventionshould to noted, and a checklist needs to be developed to rate whether these components were employed accurately.

Hopefully, manualized methods will be developed in the future. These methods will help to insure accuracy, consistency,and uniformity of the treatment. Furthermore, comparing results across studies would be markedly enhanced. Manualizingprocedures also allow for standardized treatment integrity scaling methods. As a result, the same treatment integritymeasures could be used in multiple settings. This fact would justify spending time developing reliability and validity data onsuch measures.

How treatment integrity is affected by competing factors is not clear. At a minimum, the additional intervention shouldbe reported. Also, it would be interesting to know if children who receive EIBI alone fair better or if other interventions thatsimultaneously target core symptoms produce better results. Also, it is impractical to suggest that complementary therapieswill not be in place. Speech and physical therapy are examples of therapies that must be employed simultaneously with EIBIwhen needed.

Roberts et al. (2011) provide one good example of checking with parents about other concurrent interventions. Specificguidelines that emphasize a table or spread sheet on how many children are receiving concurrent treatments, who isreceiving which treatments, how much time per week children receive these treatments, how long children have receivedthese treatments, and who provided the treatment (e.g., parents, psychologists, etc.) would be helpful. We would like tounderscore that this topic needs a great deal of attention than it has received in the past.

7. Conclusions

At this point, EIBI and ABA in general, are well established interventions for young children with ASD. What is nowemerging consists of researchers looking at the many parameters that surround the topic. Variables such as staff versusparent mediation of treatment, the intensity of the intervention, factors that may help maintain treatment gains, and whatclient characteristics respond best to specific ABA methods all need additional consideration (Fava et al., 2011; Hayward,Gale, & Eikeseth, 2009; O’Connor & Healy, 2010). The challenge is to establish some level of uniformity in methodology as away to enhance compatibility across studies.

Methodological problems such as the lack of true control groups and poor to nonexistent follow-up data are common inthe literature. In the present review, we point out a number of other factors which are inconsistently and/or insufficientlyaddressed in the methodology sections of published studies. More uniform and comprehensive reporting of methods andmore systematic and detailed attention to methods and procedures are needed. These shortcomings are understandable andare due at least in part to the evolving nature of EIBI research. Initially, efforts were geared toward just making sure EIBIworked. That fact is now well established. As results, the focus now shifts to the myriad number of questions dealing withhow to improve, individualize, follow-up on, and streamline interventions. To accomplish these goals, further refinementsand more comprehensive reporting of methods and procedures are now required.

References

Aguinis, H., Pierce, C. A., Bosco, F. A., Dalton, D. R., & Dalton, C. M. (2011). Debunking myths and urban legends about meta-analysis. Organizational ResearchMethods, 14, 306–331.

Bahrami, F., Movahedi, A., Marandi, S. M., & Abedi, A. (2012). Kata techniques training consistently decreases stereotypy in children with autism spectrumdisorder. Research in Developmental Disabilities, 33, 1183–1193.

Ben Itzchak, E., & Zachor, D. (2009). Change in autism classification with early intervention: Predictors and outcomes. Research in Autism Spectrum Disorders, 3,967–976.

Edwards, D. J., Perlman, A., & Reed, P. (2012). Unsupervised Categorization in a sample of children with autism spectrum disorders. Research in DevelopmentalDisabilities, 33, 1264–1269.

Eysenck, H. J. (1978). An exercise in mega-silliness. American Psychologist, 33, 517.Fava, L., Strauss, K., Valeri, G., D’Elia, L., Arima, S., & Vicari, S. (2011). The effectiveness of a cross setting complementary staff- and parent-mediated early intensive

behavioral intervention for young children with ASD. Research in Autism Spectrum Disorders, 5, 1479–1492.Gadow, K. D., & Drabick, D. A. (2012). Symptoms of autism and schizophrenia spectrum disorders in clinically referred youth with oppositional defiant disorder.

Research in Developmental Disabilities, 33, 1157–1168.Gardiner, E., & Iarocci, G. (2012). Unhappy (and happy) in their own way: A developmental psychopathology perspective on quality of life for families living with

developmental disability with and without autism. Research in Developmental Disabilities, 33, 2177–2192.Granpeesheh, D., Dixon, D., Tarbox, J., Kaplan, A., & Wilke, A. (2009). The effects of age and treatment intensity on behavioral intervention outcomes for children

with autism spectrum disorders. Research in Autism Spectrum Disorders, 3, 1014–1022.Hayward, D., Gale, C., & Eikeseth, S. (2009). Intensive behavioral intervention for young children with autism: A research-based service model. Research in Autism

Spectrum Disorders, 3, 571–580.Horovitz, M., & Matson, J. L. (2010). Communication deficits in babies and infants with autism and pervasive developmental disorder-not otherwise specified

(PDD-NOS). Developmental Neurorehabilitation, 13, 390–398.

J.L. Matson, J. Jang / Research in Autism Spectrum Disorders 7 (2013) 809–814 813

Kaale, A., Smith, L., & Sponheim, E. (2012). A randomized controlled trial of preschool-based joint attention intervention for children with autism. Journal of ChildPsychology and Psychiatry, 53, 97–105.

Kelly-Vance, L., Needelman, H., Troia, K., & Ryalls, B. O. (1999). Scales of infant development and play-based assessment in two-year old at-risk children.Developmental Disabilities Bulletin, 27, 1–15.

Kjellmer, L., Hedvall, A., Fernell, E., Gillberg, C., & Norrelgen, F. (2012). Language and communication skills in preschool children with autism spectrumdisorders: Contribution of cognition, severity of autism symptoms, and adaptive functioning to the variability. Research in Developmental Disabilities, 33,172–180.

Kuhn, D. E., & Matson, J. L. (2002). A validity study of the Screening Tool of Feeding Problems (STEP). Journal of Intellectual and Developmental Disability, 27, 161–167.

Kuppens, S., & Onghena, P. (2012). Sequential meta-analysis to determine the sufficiency of cumulative knowledge: The case of early intensive behavioralInterventions for children with autism spectrum disorders. Research in Autism Spectrum Disorders, 6, 168–176.

Lin, J.-D., Chen, Y.-C., & Chou, Y.-C. (2012). Longitudinal analyses of geographic differences in utilization rates of children with developmental delays whoparticipation in early intervention services. Research in Developmental Disabilities, 33, 1757–1762.

Lovaas, O. I. (1987). Behavioral treatment and normal educational and intellectual functioning in young autistic children. Journal of Consulting and ClinicalPsychology, 55, 3–9.

LoVullo, S. V., & Matson, J. L. (2009). Comorbid psychopathology in adults with autism spectrum disorders and intellectual disabilities. Research in DevelopmentalDisabilities, 30, 1288–1296.

Lunsky, Y., & Elserafi, J. (2012). Antipsychotic medication prescription patterns in adults with developmental disabilities who have experienced psychiatric crisis.Research in Developmental Disabilities, 33, 32–38.

Matson, J. L. (1977). Simple correction for treating on autistic boy’s encopresis. Psychological Reports, 41, 802.Matson, J. L. (2007). Determining treatment outcome in early intervention programs for autism spectrum disorders: A critical analysis of measurement issues in

learning based interventions. Research in Developmental Disabilities, 28, 207–218.Matson, J. L., & Kozlowski, A. M. (2011). The increasing prevalence of autism spectrum disorders. Research in Autism Spectrum Disorders, 5, 418–425.Matson, J. L., & Kuhn, D. E. (2001). Identifying feeding problems in mentally retarded persons: Development and reliability of the screening tool of feeding

problems (STEP). Research in Developmental Disabilities, 22, 165–172.Matson, J. L., & LoVullo, S. V. (2008). A review of behavioral treatments for self-injurious behaviors of persons with autism spectrum disorders. Behavior

Modification, 32, 61–76.Matson, J. L., & Neal, D. (2009). Psychotropic medication use for challenging behaviors in persons with intellectual disabilities: An overview. Research in

Developmental Disabilities, 30, 572–586.Matson, J. L., & Rivet, T. T. (2008). Characteristics of challenging behaviours in adults with autistic disorder, PDD-NOS, and intellectual disability. Journal of

Intellectual and Developmental Disability, 33, 323–329.Matson, J. L., & Wilkins, J. (2008). Nosology and diagnosis of Asperger’s syndrome. Research in Autism Spectrum Disorders, 2, 288–300.Matson, J. L., & Wilkins, J. (2009). Psychometric testing methods for children’s social skills. Research in Developmental Disabilities, 30, 249–274.Matson, J. L., Smiroldo, B. B., & Bamburg, J. W. (1998). The relationship of social skills to psychopathology for individuals with severe or profound mental

retardation. Journal of Intellectual and Developmental Disability, 23, 137–145.Matson, J. L., Leblanc, L. A., & Weinheimer, B. (1999). Reliability of the Matson evaluation of social skills in individuals with severe retardation (MESSIER). Behavior

Modification, 23, 647–661.Matson, J. L., Dempsey, T., LoVullo, S. V., & Wilkins, J. (2008). The effects of intellectual functioning on the range of core symptoms of autism spectrum disorders.

Research in Developmental Disabilities, 29, 341–350.Matson, J. L., Wilkins, J., & Gonzalez, M. (2008). Early identification and diagnosis in autism spectrum disorders in young children and infants: How early is too

early? Research in Autism Spectrum Disorders, 2, 75–84.Matson, J. L., Dempsey, T., & Fodstad, J. C. (2009). The effect of Autism Spectrum Disorders on adaptive independent living skills in adults with severe intellectual

disability. Research in Developmental Disabilities, 30, 1203–1211.Matson, J. L., Fodstad, J. C., & Dempsey, T. (2009). What symptoms predict the diagnosis of autism or PDD-NOS in infants and toddlers with developmental delays

using the Baby Infant Screen for aUtism Traits. Developmental Neurorehabilitation, 12, 381–388.Matson, J. L., Wilkins, J., Sharp, B., Knight, C., Sevin, J. A., & Boisjoli, J. A. (2009). Sensitivity and specificity of the Baby and Infant Screen for Children with aUtIsm

Traits (BISCUIT): Validity and cutoff scores for autism and PDD-NOS in toddlers. Research in Autism Spectrum Disorders, 3, 924–930.Matson, J. L., Boisjoli, J. A., Hess, J. A., & Wilkins, J. (2010). Factor structure and diagnostic fidelity of the Baby and Infant Screen for Children with aUtIsm Traits-Part

1 (BISCUIT-part 1). Developmental Neurorehabilitation, 13, 72–79.Matson, J. L., Mahan, S., Hess, J. A., Fodstad, J. C., & Neal, D. (2010). Progression of challenging behaviors in children and adolescents with autism spectrum disorders

as measured by the autism spectrum disorders-problem behaviors for children (ASD-PBC). Research in Autism Spectrum Disorders, 4, 400–404.Memari, A. H., Ziaee, V., Beygi, S., Moshayedi, P., & Mirfazeli, F. S. (2012). Overuse of psychotropic medications among children and adolescents with autism

spectrum disorders: Perspective from a developing country. Research in Developmental Disabilities, 33, 563–569.Miller, V. A., Schreck, K. A., Mulick, J. A., & Butter, E. (2012). Factors related to parents’ choices of treatments for their children with autism spectrum disorders.

Research in Autism Spectrum Disorders, 6, 87–95.Nygren, G., Sandberg, E., Gillstedt, F., Ekeroth, G., Arvidsson, T., & Gillberg, C. (2012). A new screening programme for autism in a general population of Swedish

toddlers. Research in Developmental Disabilities, 33, 1200–1210.O’Connor, A., & Healy, O. (2010). Long-term post intensive behavioral intervention outcomes for five children with autism spectrum disorder. Research in Autism

Spectrum Disorders, 4, 594–604.Perry, A., Cummings, A., Geier, J. D., Freeman, N. L., Hughes, S., Managhan, T., et al. (2011). Predictors of outcome for children receiving intensive behavioral

interventions in a large, community-based program. Research in Autism Spectrum Disorders, 5, 592–603.Peters-Scheffer, N., Didden, R., Korzilius, H., & Sturmey, P. (2011). A meta-analytic study on the effectiveness of comprehensive ABA-based early intervention

programs for children with autism spectrum disorders. Research in Autism Spectrum Disorders, 5, 60–69.Pituch, K. A., Green, V. A., Didden, R., Lang, R., O’Reilly, M. F., Lancioni, G. E., et al. (2011). Parent reported treatment priorities for children with autism spectrum

disorders. Research in Autism Spectrum Disorders, 5, 135–143.Poon, K. K. (2012). Challenging behaviors among children with autism spectrum disorders and multiple disabilities attending special schools in Singapore.

Research in Developmental Disabilities, 33, 578–582.Reynolds, C. R., & Kamphaus, R. W. (Eds.). (2003). Handbook of psychological and educational assessment of children: Personality, behaviors, and context (2nd ed.). New

York, NY: The Guilford Press.Reynolds, C. R., & Kamphaus, R. W. (2004). BASC-2: Behavioral assessment system for children (2nd ed.). Circle Pines, MN: American Guidance Service.Roberts, J., Williams, K., Carter, M., Evans, D., Parmenter, T., Silove, N., et al. (2011). A randomized controlled trial of two early intervention programs for young

children with autism: Centre-based with parent program and home-based. Research in Autism Spectrum Disorders, 5, 1553–1566.Rojahn, J., Zaja, R. H., Turygin, N., Moore, L., & van Ingen, D. J. (2012). Functions of maladaptive behavior in intellectual and developmental disabilities: Behavior

categories and topographies. Research in Developmental Disabilities, 33, 2020–2027.Rumpf, A. L., Kamp-Becker, I., Becker, K., & Kauschke, C. (2012). Narrative competence and internal state language of children with Asperger Syndrome and ADHD.

Research in Developmental Disabilities, 33, 1395–1407.Schreibman, L., Stahmer, A. C., Barlett, V. C., & Dufek, S. (2009). Brief report: Toward refinement of a predictive behavioral profile for treatment outcome in children

with autism. Research in Autism Spectrum Disorders, 3, 163–172.Singh, A. N., Matson, J. L., Cooper, C. L., Dixon, D., & Sturmey, P. (2005). The use of risperidone among individuals with mental retardation: Clinically supported or

not? Research in Developmental Disabilities, 26, 203–218.

J.L. Matson, J. Jang / Research in Autism Spectrum Disorders 7 (2013) 809–814814

Smith, K. R., & Matson, J. L. (2010a). Behavior problems: Differences among intellectually disabled adults with co-morbid autism spectrum disorders and epilepsy.Research in Developmental Disabilities, 31, 1062–1069.

Smith, K. R., & Matson, J. L. (2010b). Psychopathology: Differences among adults with intellectually disabled, comorbid autism spectrum disorders and epilepsy.Research in Developmental Disabilities, 31, 743–749.

Smith, K. R., & Matson, J. L. (2010c). Social skills: Differences among adults with intellectual disabilities, co-morbid autism spectrum disorders and epilepsy.Research in Developmental Disabilities, 31, 1366–1372.

Strauss, K., Vicari, S., Valeri, G., D’Elia, L., Arima, S., & Fava, L. (2012). Parent inclusion in Early Intensive Behavioral Intervention: The influence of parental stress,parent treatment fidelity and parent-mediated generalization of behavior targets on child outcomes. Research in Developmental Disabilities, 33, 688–703.

Wan, M. W., Green, J., Elsabbagh, M., Johnson, M., Charman, T., & Plummer, F. (2012). Parent–infant interaction in infant siblings at risk of autism. Research inDevelopmental Disabilities, 33, 924–932.

Watson, J. B., & Rayner, R. (1920). Conditioned emotional reactions. Journal of Experimental Psychology, 3, 1–14.Wolf, M., Risley, T., & Mees, H. (1963). Application of operant conditioning procedures to the behavior problems of an autistic child. Behavior Research and Therapy,

1, 305–312.