© Borgis - Postępy Nauk Medycznych 1/2013, s. 51-57
*Monika Suchowierska, Monika Rupińska
Wczesna intensywna terapia behawioralna u dzieci z autyzmem – teoria i badania
Early Intensive Behavioral Intervention (EIBI) for children with autism – theory and research
Department of Psychology, University of Social Sciences and Humanities, Warszawa, Poland
Head of Department: Ewa Trzebińska, PhD
Autyzm jest jednym z najpoważniejszych zaburzeń rozwoju. Mimo iż schorzenie to jest cały czas określane jako „enigma” ze względu na brak jednoznacznych odpowiedzi na wiele pytań z nim związanych, to jednak ponad 50 lat badań klinicznych zaowocowało pokaźnym zasobem wiedzy nt. oddziaływań terapeutycznych. Wiemy już, że wczesna intensywna terapia behawioralna prowadzi do znaczących pozytywnych zmian w funkcjonowaniu poznawczym, społecznym i emocjonalnym dzieci z autyzmem. W obecnym artykule opiszemy główne założenia behawioralnej teorii autyzmu, scharakteryzujemy wczesną intensywną terapię behawioralną i przytoczymy wyniki badań nad jej efektywnością oraz podamy wytyczne dla pracowników służby medycznej, którzy mogą w swojej praktyce mieć do czynienia z dziećmi z autyzmem.
Autism is a pervasive developmental disorder that is a life-long disability. Although autism is called an “enigma” because many questions still remain unresolved, more than 50 years of treatment research resulted in a substantial body of knowledge on effective methods of therapy. Scholarly work shows that Early Intensive Behavioral Intervention (EIBI) can lead to significant and clinically important changes in an autistic child’s cognitive, social and emotional functioning. In the present article, we will describe tenets of behavioral approach to autism, characterize therapy based on applied behavior analysis, summarize research on EIBI, and conclude with guidelines for health care providers as well as a list of institutions in Poland that offer behavioral intervention to children with autism.
Autism is a pervasive developmental disorder defined behaviorally and characterized by impairments in three areas: social interaction, reciprocal verbal and nonverbal communication and the range of interests and activities (1). Although recognition of this disorder may have its origins in Jean-Marc Gaspard Itard’s description of the “wild boy of Aveyron” from 1801 (2), the first formal account of autistic individuals was published by Leo Kanner in 1943. The current definition of autism, although consistent with the deficits observed in Kanner’s original group of children, has been refined and broadened. Nowadays, persons with autism are considered to have one of the neurodevelopmental disorders that have such wide range of behavioral consequences and severity that they are collectively referred to as pervasive developmental disorders (PDDs) in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, Revised Text (1).
Autism is one of the most severe developmental disorders. It is also often called an “enigma” due to the fact that so far scientists have found no answers to many questions related to the disorder. Nevertheless, nearly 70 years which have passed since the first systematic description of children with autism, and over 50 years devoted to the application of behavioral techniques to solving human problems, have brought forth a substantial body of knowledge about effective methods of helping autistic people. This knowledge is well grounded thanks to, among other factors, the fact that the theory of autism and behavioral therapy is entrenched in empirical research, while the combination of theory and research reflects clinical practice.
Scholarly research shows that early intensive behavioral therapy can lead to significant and clinically important changes in an autistic child’s cognitive, social and emotional functioning (3-5). A survey of about 500 publications on the use of methods based on the applied behavior analysis (ABA) has shown that behavioral techniques are effective in teaching children with autism as well as in their adaptation to independent life (6). What is more, behavioral therapy is recommended by government organizations in the USA and Europe (7, 8) as the leading form of treatment administered to children with autism. The behavioral approach includes a few different “variants” which differ in the techniques they use and in the logistics of the services they offer (9-11). However, what the programs offering behavioral therapy have in common is the fact that they view autism not as a hypothetical construct but as a set of behavioral deficits and excesses, and that they apply the learning theory to their therapeutic work (12).
Ivar Lovaas and Tristam Smith (13) have described four tenets of their theory in the article „A comprehensive behavioral theory of autistic children: Paradigm for research and treatment”. First, behavior of people with autism does not differ from behavior of other people, and it obeys the basic principles of behavior. When reinforcement and extinction are applied, the learning curves of people with autism are very similar to those of other people. The range of reinforcers, which is at first very scanty for autistic people, can be effectively broadened by the application of procedures which combine initially neutral stimuli (such as praise) with primary reinforcers (such as food) or with other, already established reinforcers (such as toys). Learning difficulties can be lessened by discrimination training, especially during imitation and match-to-sample exercises in the educational programs.
Second, people with autism have several behavioral deficits and excesses rather than one central disfunction whose correction would lead to general and extensive improvement. This assumption is based mainly on the results of research on generalization, which demonstrates clearly that people with autism show the high specificity of their behavior rather than its generalization. Transfer of skills from one kind of behavior to another or from one stimulus to another is possible, but only after the teaching procedures have been planned carefully and generalization has been included in the therapy. This assumption is reflected in clinical work very clearly: therapists should build for a given child a “pyramid of skills”, beginning at the base – one brick after another – teaching more complicated skills on top of what has already been learnt.
Third, people with autism can learn in an environment which is specifically adjusted to their needs. This environment should only differ so far from normal surroundings as to be “functional”, i.e. understood and predictable for an autistic person. Often the modifications include making certain stimuli more distinct (for instance by uttering simpler statements to the child), making use of motivational systems and of visual stimuli (such as pictures) supplementing auditory stimuli.
Fourth, the difficulty autistic people have with functioning in the normal environment and their success in the special environment show that autism ought to be regarded as a disorder consisting of maladjustment of the neural system to the typical living conditions, rather than as a disease which can be cured. Therefore, therapeutic work should rely primarily on creating special conditions for a child with autism, where they shall be able to function well and learn, and only secondarily on gradually accustoming them to life in the typical environment, where they may also support themselves with certain assistive technology (such as using a communication board while shopping).
To sum up, Lovaas & Smith (13) propose that autistic people ought to be regarded, especially when it comes to therapeutic work, not as “different, abnormal, and standing out”, but rather as being on the same continuum of functioning as other people, only at its end. Therefore the task of behavioral therapists is to “move” autistic people in the direction of the center of this continuum, by working systematically on individual deficits and excesses.
Effective intervention is an even more urgent issue, when one takes into consideration the epidemiological reports concerning the frequency of pervasive developmental disorders. The review of the range of prevalence estimates for autism and other PDDs comes from a series of publications by Fombonne (14-18). In the last article, Fombonne reports the occurrence of PDDs in children under the age of 8 years to be of the order of 60 to 70 per 10,000 children. Several factors could have contributed to an increased prevalence of autism, but most likely this change is probably attributable to improved detection and changes in diagnostic criteria. Regardless of the underlying reasons, the issue of early identification of and intervention in autism is of paramount importance.
Early Intensive Behavioral Intervention (EIBI) is a form a comprehensive treatment based on principles of applied behavior analysis and administered to children with autism. According to Green, Brennan & Fein (19) it is characterized by: 1) individualized and comprehensive programing of educational goals, 2) use of behavioral techniques, 3) close supervision of service delivery by individuals trained in the ABA, 4) programing of therapeutic goals based on knowledge of developmental milestones, 5) close collaboration with the parents in planning and conducting the therapy, 6) initially teaching the child on a one-to-one basis in a natural environment, with a gradual transition to a group setting, 7) intensive teaching (i.e., 20-30 hours per week, all year round), 8) extended duration (i.e., at least 2 years in most cases), and 9) early start of intervention (i.e., before the child turns 3 years old). EIBI has been shown to be effective and has been classified by Rogers and Vismara (20) as a “well established” treatment based on the criteria for empirically-validated treatments (21). Below, we present three publications that provide evidence for the recommendation that EIBI should be a treatment of choice for children with autism. Two of them are meta-analyses and one is an experimental study.
In the last 30 years meta-analysis has been accepted in the social and health sciences as a very useful and helpful research methodology to quantitatively integrate the results from different studies. In a meta-analysis results of every study are quantified by means of an effect-size index (e.g. standardized mean difference), enabling us to give the study results in the same metric (22, 23). Typically, in meta-analysis two tests are conducted: test of homogeneity (using the Q-statistic and I2) and effect size (using e.g. Hedges’s g) (22). The Q-statistic test only informs us about the presence or absence of heterogeneity. The I2 reports on the extent of such heterogeneity (between-study variance).
First meta-analysis was conducted by Edelvik et al. (24). The selection of studies for this meta-analysis involved eight inclusion criteria:
– the participants received behavioral intervention,
– the participants receiving EIBI were on average between 2 and 7 years old when the treatment started,
– the participants were diagnosed with autism or PDD-NOS,
– a full-scale measure of intelligence (IQ) and/or a standardized measure of adaptive behavior such as the Vineland Adaptive Behavior Scales (VABS) were used,
– the duration of intervention was between 12 and 36 months,
– the study was a group study, not a case study,
– the study included either a control or a comparison group,
– the results were published in a peer-reviewed journal.
Nine research reports met all inclusion criteria, so additional detailed information was obtained by contacting the authors of each study (provide the age, IQ, and adaptive behavior scores for the participants). Not all authors collected both IQ and Adaptive Behavior Composite (ABC) data. Additionally, the authors measured intelligence with various tests (e.g. Bayley Scales of Infant Development, Wechsler Preschool and Primary Scale Intelligence-Revised etc.). If the participant scored on a test below the norm, researchers calculated a ratio IQ score by dividing the obtained mental age with chronological age and multiplying by 100. All of the tests have been validated for children with pervasive developmental disorders. All studies used the VABS (Vineland Adaptive Behavior Scale) for measuring the adaptive behavior. The content and scales of the VABS were organized within a four domain structure: communication, daily life, socialization and, for children younger than 6 years old, motor skills (24, 25). The VABS is the best available instrument for assessing adaptive behavior in children with pervasive developmental disorders and/or mental retardation.
Results. The Q-statistic was not statistically significant for either the IQ or the ABC score (24). This result suggested that all of the studies could be combined into one common effect measure (the studies’ results are homogeneous). Edelvik et al. also calculated the between-study variance for the IQ and for the ABC score. The score for either the IQ and the ABC score have a very low rate of heterogeneity (10.66% and 17.65%), and these data suggest that relatively small proportions of variance were explained by between-study variance. Then the authors were able to use a fixed effects model for computing the overall effect size. One study (26) included a control group and a comparison group. Edelvik et al. (24) thus calculated a separate effect size for these groups and the total number of effect sizes for IQ was ten (from the nine studies included) and for the ABC it was eight (from the seven studies included).
The range of the standardized mean change effect size for IQ was g = 0.69 to g = 1.74. The overall effect size for the IQ change was large (g = 1.103) and suggests EIBI is a very effective intervention method for increasing the IQ scores for young children with autism. For the ABC change the range of the effect sizes was g = 0.13 to g = 1.22. The overall mean effect size for the ABC change was medium (g = 0.66), and suggests the EIBI is a moderately effective intervention method for increasing the ABC in young children with autism. All of these estimates of the effect size were statistically significant.
Another meta-analysis was computed by Reichow & Wolery (27) and included both descriptive and statistical analyses (effect size analyses and a meta-analysis). The authors used seven inclusion criteria:
– the study was based on the University of California at Los Angeles Young Autism Project (UCLA YAP) model,
– the participants receiving EIBI were less than 84 months old at the beginning of the treatment,
– the children were diagnosed with pervasive developmental disorders,
– the duration of the intervention was greater than or equal to 12 months,
– at least one child outcome measure was reported,
– experimental research designs or quasi-experimental research designs was utilized,
– results were published in English in a peer-reviewed journal.
In summary, 13 research reports (14 samples – one study compared two arrangements of EIBI: clinic-coordinated EIBI and parent-coordinated EIBI) met all inclusion criteria and were analyzed by the authors.
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Płatny dostęp do wszystkich zasobów Czytelni Medycznej
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