A comparison of intensive behavior analytic and eclectic treatments for young children with autism

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Abstract

We compared the effects of three treatment approaches on preschool-age children with autism spectrum disorders. Twenty-nine children received intensive behavior analytic intervention (IBT; 1:1 adult:child ratio, 25–40 h per week). A comparison group (n = 16) received intensive “eclectic” intervention (a combination of methods, 1:1 or 1:2 ratio, 30 h per week) in public special education classrooms (designated the AP group). A second comparison group (GP) comprised 16 children in non-intensive public early intervention programs (a combination of methods, small groups, 15 h per week). Independent examiners administered standardized tests of cognitive, language, and adaptive skills to children in all three groups at intake and about 14 months after treatment began. The groups were similar on key variables at intake. At follow-up, the IBT group had higher mean standard scores in all skill domains than the AP and GP groups. The differences were statistically significant for all domains except motor skills. There were no statistically significant differences between the mean scores of the AP and GP groups. Learning rates at follow-up were also substantially higher for children in the IBT group than for either of the other two groups. These findings are consistent with other research showing that IBT is considerably more efficacious than “eclectic” intervention.

Introduction

Early intervention targets differences between the skills of children who have or are at risk for developmental delays and the skills of their typically developing peers. Those discrepancies may be small initially but are generally acknowledged to increase with the passage of time (e.g., Guralnick, 1998; Ramey & Ramey, 1998). Developmental trajectories are not fixed, however, even for children with known risk factors or disabilities. Instead, each child's progress can be influenced by many factors, such as experience. As Ramey and Ramey (1998) noted, “… a widespread hope for early intervention (is) … that children could be placed on a normative developmental trajectory and thus continue to show optimal development after early intervention ends” (p. 113). Accordingly, they posited a “zone of modifiability,” a period of time during which the precise developmental trajectory for children at risk is likely determined by the timing, intensity, and appropriateness of treatment. Convergent evidence supporting this hypothesis has come from a variety of sources. Longitudinal studies (e.g., the North Carolina Abecedarian Project, Infant Health and Development Program) demonstrated that the effects of early intervention on children at risk for developmental delay and mental retardation were evident when the children were 3 years old, and some gains were maintained into adolescence and adulthood (Campbell, Pungello, Miller-Johnson, Burchinal, & Ramey, 2001; Campbell, Ramey, Pungello, Sparling, & Miller-Johnson, 2002; for a review, see Ramey & Ramey, 1999). The likelihood that effective early intervention can produce lasting neurobiological as well as behavioral changes has been suggested by research showing that early experiences play a critical role in shaping brain architecture as well as brain function (Dawson & Fischer, 1994; Shore, 1997). Additionally, studies have shown that specific types of interactions with the physical and social environment can remediate some types of damage to the central nervous system (e.g., Hannigan & Berman, 2000). In a series of studies using mouse models of some mental retardation syndromes and neurological disorders, Schroeder, Tessel, and their colleagues demonstrated that behavior analytic discrimination training reversed abnormalities in brain structures and neurotransmitter levels as well as learning and behavior. Training was most effective when it began early in development (Loupe, Schroeder, & Tessel, 1995; Stodgell, Schroeder, & Tessel, 1996; Tessel, Schroeder, Loupe, & Stodgell, 1995; VanKeuren, Stodgell, Schroeder, & Tessel, 1998).

Findings from early intervention research indicate that treatment that is intensive, long in duration, and delivered directly to children (rather than just to their caregivers) produces better outcomes than treatment that lacks those elements (Ramey and Ramey, 1998, Ramey and Ramey, 1999). Few of those variables have been isolated and investigated in controlled studies, however. For example, despite the apparent relationship between the intensity of early intervention and outcome (e.g., Guralnick, 1998), there has been little experimental research on the effects of treatment intensity or duration. Nor has there been much research on the relation between type of early intervention and outcomes. Guralnick (1998) argued that the next generation of research in early intervention must progress beyond basic demonstrations of its effectiveness. There is a need for studies that delineate which aspects of early intervention are most efficacious, and for which populations. A better understanding of the optimal timing, intensity, duration, and type of intervention could benefit all children who have or are at risk for developmental delays. Given the reported recent increase in the number of children diagnosed with autism spectrum disorders, such issues may be particularly germane to this population (e.g., California Department of Developmental Services, 2003a; Yeargin-Allsop et al., 2003; but see Fombonne, 2001, Fombonne, 2003 for critiques of such reports). In addition, the cost of lifespan services for people with autism may be disproportionately higher than the cost of serving individuals with other disabilities (e.g., CDDS, 2002, CDDS, 2003b). Effective early intervention can substantially reduce those costs (Jacobson, Mulick, & Green, 1998). Therefore, there are several compelling reasons to examine outcomes produced by various types of early intervention for children with autism.

There is considerable empirical evidence that early intensive behavior analytic intervention produces large and lasting functional improvements in many children with autism. Although a number of behavior analysts have been documenting the effectiveness of behavior analytic intervention for individuals with autism since the early 1960s (e.g., Ferster & DeMyer, 1961; Wolf, Risley, & Mees, 1964; see also Matson, Benavidez, Compton, Paclawskyj, & Baglio, 1996), a study by Lovaas (1987) was singular for documenting substantially improved functioning in a sizeable proportion of children who received comprehensive, intensive, long-duration behavior analytic intervention starting before they reached 4 years of age. Nine of 19 children in that study who received early intensive behavior analytic treatment for at least 2 years had cognitive and language test scores in the normal range by the age of 6–7 years and completed first grade without special instruction. In contrast, few gains were made by children with autism in two control groups who received either 10 h of behavior analytic treatment per week or typically available community services over the same time period. A follow-up study found that the “best outcome” children from the Lovaas (1987) study continued to function normally into adolescence (McEachin, Smith, & Lovaas, 1993).

Several studies of comprehensive, intensive behavior analytic treatment for young children with autism spectrum disorders have been published prior to and since the Lovaas (1987) study. Collectively, these studies have documented the efficacy of intensive behavior analytic intervention, both center-based (e.g., Eikeseth, Smith, Jahr, & Eldevik, 2002; Fenske, Zalenski, Krantz, & McClannahan, 1985; Harris, Handleman, Gordon, Kristoff, & Fuentes, 1991) and home-based (e.g., Anderson, Avery, DiPietro, Edwards, & Christian, 1987; Birnbrauer & Leach, 1993; Smith, Groen, & Wynne, 2000; Weiss, 1999). In several studies, standardized test data indicated that cognitive functioning, language skills, and academic performance approached or exceeded normal levels in many children who received at least 2 years of early intensive behavior analytic treatment (for a review, see Green, 1996, Smith, 1999). Instruments such as the Vineland Adaptive Behavior Scales also detected substantial improvements in adaptive functioning (Anderson et al., 1987; Birnbrauer & Leach, 1993; Smith et al., 2000, Weiss, 1999). Similar outcomes have been documented in systematic case studies in which independent evaluators used objective measurement instruments to track children's progress (Green, Brennan, & Fein, 2002; Perry, Cohen, & De Carlo, 1995). Finally, parents whose children received intensive behavior analytic intervention showed high satisfaction and reduced stress over the course of treatment in comparison to parents whose children did not receive intensive behavior analytic intervention (Anderson et al., 1987; Birnbrauer & Leach, 1993; Smith et al., 2000).

Although all published studies of early intensive behavior analytic treatment demonstrated that many children made substantial gains, outcomes varied within and across studies. The proportions of intensively treated children who achieved normal or near-normal functioning, more modest improvements, and relatively small improvements varied from study to study (Green, 1996, Smith, 1999). For instance, a smaller percentage of children in the Smith et al. (2000) study were able to function independently in regular classrooms post-treatment than was reported by Lovaas (1987), and no children were reported to be enrolled in general education settings without supports in the Anderson et al. (1987) and Birnbrauer and Leach (1993) studies. Those studies differed in several important ways from the Lovaas (1987) study, however. None involved the 40 h of intensive treatment per week that was provided to the experimental group in the Lovaas (1987) study. Additionally, participants in those studies had lower pre-treatment language and IQ scores and received intervention for a shorter period of time than their counterparts in the Lovaas (1987) study. There were also methodological differences across studies: some were quasi-experimental while others used true experimental designs, and few assigned participants to groups randomly (see Green, 1996, Kasari, 2002, Rogers, 1998, Smith, 1999). Indeed, although some partial and systematic replications of the Lovaas (1987) study have been published, so far no full replications (40 h of treatment per week for a minimum of 2 years; multiple outcome measures; at least one control group) have appeared in the literature. Nevertheless, as an aggregate, the published studies offer compelling evidence that many children with autism who received early intensive behavior analytic treatment made substantial gains.

In contrast, there is little objective empirical evidence regarding the efficacy of non-behavior analytic intervention models such as Treatment and Education of Autistic and Related Communication Handicapped Children (TEACCH; e.g., Schopler, 1997) or developmental approaches, such as the Colorado Health Sciences Program (Rogers & DiLalla, 1991; Rogers, Herbison, Lewis, Pantone, & Reis, 1986). Of the total of 15 early autism intervention outcome studies evaluated in three separate reviews, only five were evaluations of what the authors characterized as non-behavior analytic treatments. Reported treatment effects consisted of small mean gains in standardized test scores (e.g., IQ, language) or changes in developmental levels on measures not widely employed to assess children with autism; all had serious methodological limitations. Further, no studies comparing early intensive behavior analytic treatment directly with TEACCH, Colorado Health Sciences, or any other comprehensive treatment model have been published to date (Kasari, 2002, Rogers, 1998, Smith, 1999). Several studies, however, have compared outcomes of intensive behavior analytic treatment with those resulting from standard interventions that are typically provided to children with autism through public early intervention and special education programs. In the Lovaas (1987) study, the 41 participants in control groups 1 and 2 were described as receiving treatments consisting of “resources in the community such as those provided by small education classes.” Control group 1 also received behavior analytic treatment for 10 h per week. Few gains were documented for children in those groups over the course of 2 or more years of treatment. Similarly, a comparison group of children in the study by Smith et al. (2000) who were enrolled in public schools for 10 to 15 h per week made little improvement.

Recently Eikeseth et al. (2002) compared the effects of intensive behavior analytic treatment with equally intensive and relatively well-specified “eclectic” treatment that is similar to the type of intervention that many children with autism receive in public schools and some private programs. These investigators studied the effects of intervention provided for 28 h per week for 1 year on children with autism who were 4–7 years of age when they entered treatment. Thirteen children received behavior analytic intervention, while 12 other children received intensive treatment using a combination of methods including discrete trial training, TEACCH-based procedures, and sensory integration therapy. All children received 1:1 treatment from therapists who all had similar educational backgrounds and training. Each therapist received weekly consultation from behavior analysts. Additional training was provided to parents and therapists of children in the intensive behavior analytic treatment group. After 1 year the children in the behavior analytic treatment group performed substantially better on standardized measures of cognitive, language, and adaptive functioning than the children in the intensive “eclectic” treatment group. For example, children in the behavior analytic treatment group gained an average of 17 points on standardized measures of cognitive functioning. At follow-up, seven children in the behavior analytic treatment group achieved scores in the normal range of functioning, while only two children in the “eclectic” treatment group produced scores in the normal range. These results suggested that the type, rather than the intensity, of treatment accounted for the outcomes produced by intensive behavior analytic treatment.

“Eclectic” intervention like that provided to children in the comparison group in Eikeseth et al. (2002) study is widely available to children with autism enrolled in public early intervention and special education programs. Yet little evidence about the efficacy of that approach has appeared in the research literature to date. The study described here was a prospective analysis of the effects of three different early intervention approaches on young children with autism spectrum disorders. Interim (14 months) outcomes for children who participated in an intensive behavior analytic treatment program were compared with those of children who received intensive “eclectic” intervention in classrooms designed exclusively for children with autism and children in non-intensive, generic early intervention programs.

Section snippets

Referral and selection

The participants were 61 children diagnosed with autistic disorder or pervasive developmental disorder—not otherwise specified (PDD-NOS). Potential participants were referred by non-profit agencies (“regional centers”) under contract with the State of California Department of Developmental Services to provide case management for individuals with developmental disabilities. Referred children were screened for the following eligibility criteria: (a) diagnosis of autistic disorder or PDD-NOS

Intake

At intake there was clear evidence of developmental delay in all three groups of children. For most skill domains, the mean standard scores for all three groups were substantially below 100, and the mean learning rates were well below the normal rate of 1 year of development per year of age (see Table 4). As might be expected, delays were most prominent in receptive and expressive language skills, with mean standard scores in all three groups close to 50, and mean learning rates of about .5 age

Discussion

Young children with autism or PDD-NOS who received intensive behavior analytic treatment (IBT) for about 14 months outperformed comparable children who received “eclectic” intervention services for the same period of time on virtually every follow-up measure. In most cases the differences in mean scores were substantial and statistically significant. Our analyses corrected for the parents’ level of education and for the children's ages at diagnosis. No direct correction was made for the age at

Acknowledgements

The authors are grateful to Valley Mountain Regional Center Region 6 Autism Connection, and California State University, Stanislaus for supporting this research; to Shannon Brackett, Beth LeBrun, Schelley McDonald, Marie Overmyer, and Yasman Dianat for assistance with data collection; and to the children and families who participated in the study. Preliminary reports of this research were presented at the international conference of the Association for Behavior Analysis, Venice, Italy, November

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