News and Notes about Scientific Research on Autism and other Developmental and Behavioral Disorders

Editor: Bill Ahearn, Ph.D., BCBA
Director of Research, New England Center for Children

Recent Advances in the Study of Brain Development in Children with Autism

In a recent review of studies of brain development in children with autism, Eric Courchesne (2004) describes two converging lines of research that have revealed a good deal of information about abnormal brain growth related to this disorder. Head circumference is accepted as a sound measure of brain volume. Several studies have found that children with autism tend to have normal or slightly smaller than typical head circumference at birth (e.g., Courchesne et al., 2003). However, from 6-14 months of age head circumference increases rapidly and excessively in children with an autism spectrum disorder (ASD) with very little growth from then through the 28th month. So it is assumed that brain growth occurs earlier and rapidly in children with an ASD, but also slows or shuts down too early. Head circumference changes more gradually and is more evenly distributed across the first two years of life in typically developing children.

Magnetic resonance imaging (MRI) investigations have confirmed and extended the results obtained by measuring head circumference. For example, Sparks and colleagues (2002) found that the brain volume of children with an ASD at 3-4 years of age was significantly larger when compared to typically developing children. This study also noted that the size of specific regions of the brain, the cerebrum, cerebellum, and amygdala, were all larger for children with an ASD than in typically developing children. Other regions of the brain, such as the occipital lobes, however, have been found to be similar in the typically developing and ASD populations, indicating that the brain is not uniformly enlarged (Carper et al., 2002). Courchesne (2004) and others speculate that this neurodevelopmental abnormality contributes to many of the behavioral manifestations of autism spectrum disorders. One of these regions, the cerebellum, is thought to be involved in perception, language, and emotion. Abnormal development in the cerebellum likely underlies difficulties observed in these areas in persons with autism. Clearly much more work is to be done to confirm and extend these results, but Courchesne is hopeful that these lines of research will help to clarify the prenatal factors that lead to this abnormal brain growth regulation in children with ASDs.

Carper, R.A., Moses, P., Tigue, Z.D., & Courchesne, E. (2002). Cerebral lobes in autism: Early hyperplasia and abnormal age effects. Neuroimage, 16, 1038-1051.

Courchesne, E. (2004). Brain development in autism: Early overgrowth followed by premature arrest of growth. Mental Retardation and Developmental Disabilities Research Reviews, 10, 106-111.

Courchesne, E., Carper, R., & Akshoomoff, N. (2003). Evidence of brain overgrowth in the first year of life in autism. Journal of the American Medical Association, 290, 337-344.

Sparks, B.F. et al. (2002). Brain structural abnormalities in young children with autism spectrum
disorder. Neurology, 59, 184-192.

Research Activities at NECC

With the beginning of a new school year and the start-up of a number of new projects associated with the grant awarded to the Shriver Center and NECC by the National Institute of Child Health and Human Development (as described in the last newsletter), I wanted to review some of the types of research activities that take place at the school. Receiving grant funding provides us with extra resources for specific projects, but the majority of the research activities that take place here are done in the context of our daily teaching and behavioral programming. NECC has always strived to improve the services it delivers to students and one of the main avenues for this has been through supporting research. Many of the standard teaching procedures and behavioral assessment techniques we use on a daily basis have been developed through research conducted either here or by our colleagues in the field of applied behavior analysis.

Many of our students have severe problem behavior that is difficult to manage. Applied behavior analysts have developed specific assessment procedures that help to determine the specific cause or causes of problem behavior. These assessment procedures are commonly referred to as functional analyses. Functional analysis is a frequently used assessment at NECC that allows us to develop intervention programs that meet an individual’s needs. As a clinical tool, functional analysis helps to identify the situations in which a student will and will not engage in problem behavior. Once the analysis is complete, we often test new behavioral programming in a controlled setting to make certain that it will be effective. Pelios, Morren, Tesch, and Axelrod (1999) found that those clinicians who reported using functional analysis were much less likely to use intrusive interventions than those who did not. Therefore, these techniques are very important and are considered to be the best way to develop treatments for severe problem behavior.

Research at NECC is certainly not limited to treating problem behavior. There has been a particular emphasis on developing effective ways of motivating our students during instruction. Program Director Rick Graff has established a flourishing line of research geared towards determining effective reinforcers for students. Many types of preference assessments are commonly used at NECC and are part of our standard practices for determining the types of motivational systems we use with our students. In previous newsletters (e.g., Winter 2004), I have described some of the research that has influenced our discrete-trials training procedures. We continually evaluate skill acquisition programming in an attempt to develop the best teaching strategies for each teaching situation and for each student. Some of these evaluations involve comparing different ways of delivering instruction with the goal of determining which will lead to the most rapid learning.

Most of these projects that I have just mentioned occur as part of our standard service delivery. Each student is unique and we strive to find the programming that best suits his or her needs. Sometimes when conducting assessments, we discover information that is useful not only for the student we are working with but have implications for better serving other students. For this reason, it is very important to us to be able to disseminate our findings to others. Just as we learn from our colleagues, they benefit from our experiences. To accelerate our understanding of effective intervention for individuals with developmental disabilities, we hope that all of our parents, colleagues, and friends share our goal of determining the best clinical and educational practices. One significant way of contributing to this goal is by consenting to allow your children to participate in research taking place at NECC and to allow us to share the knowledge we gain by working with your children with others.

Pelios, L., Morren, J., Tesch, D., & Axelrod, S. (1999). The impact of functional analysis methodology on treatment choice for self-injurious and aggressive behavior. Journal of Applied Behavior Analysis, 32, 185-195.

Readers’ Forum

Email your questions to William Ahearn.

Q: Our son engages in stereotypy very often. What causes stereotypy and what can
we do about it?

Stereotypy, though it is a common problem behavior in persons with autism, occurs with typically developing persons, individuals with developmental disabilities, and people with mental health problems. The best information we have as a field about why stereotypy occurs is somewhat straightforward. Brian Iwata, who serves as consultant to NECC, and his colleagues at the University of Florida have conducted a very large-scale study of stereotypy (Conners, Iwata, Hanley, Goff, Zhou, & Cole, 2000). They were interested in determining the cause(s) of stereotypy. They found that over 95% of the individuals they assessed had stereotypy because the stereotypic movements themselves are reinforcing (we summarize this with the term automatic reinforcement). This warrants a bit of unraveling. Stereotypic behavior involves a motor response, like hand-flapping. That motoric movement feels good though in some instances it seems to relieve discomfort. People tend to do things repeatedly that feel good like twirling their hair, scratching an itch, or rubbing their eyes. Stereotypic behavior can appear very awkward and sometimes can interfere with learning. Most typically developing children engage in stereotypy. However, as they age these behaviors are either replaced by other more reinforcing play skills, decrease because of social consequences (like reprimands), or some combination of the two. People with autism often do not develop these alternative play skills and can be relatively indifferent to social consequences. If other behaviors are not learned to replace stereotypy, then stereotypy may become one of the most likely things the person will spend their time doing. Automatically reinforced behaviors can be very difficult to treat. In fact, older persons with developmental disabilities that are in residential settings often have very high levels of stereotypy. One reason why this may occur is that they are not being taught other behaviors that are reinforcing or they have very limited access to things they like to do.

We have collected data in our preschool that implies that the older a child is when they first enter intensive behavioral instruction, the higher the level of stereotypy they are likely to have and the further away they are from the level of stereotypy we see in typically developing children. Our general treatment procedures involve a multi-faceted approach to these problems. We attempt to redirect stereotypic behavior, teach play skills, and if necessary, we will find other more appropriate behavior to teach the child to engage in to access the form of sensory input that stereotypy provides (e.g., vocal stereotypy produces sound, if we cannot redirect, we might teach them how to use a walkman to listen to sounds they like). A few researchers have reported that stereotypy can also occur as a means of getting attention and as a means for escaping from unpleasant situations but these reports are clearly in the minority. Here at NECC, we attempt to analyze each individual's behavior without assumptions but we realize that stereotypy is likely occurring because of the sensory input produced by the behavior.

Conners, J., Iwata, B.A., Hanley, G.P., Goff, G.A., Zhou, L., & Cole, A. (2000). Structural and functional analysis of noninjurious stereotypic behavior. Paper presented at the Association for Behavior Analysis Conference, Washington, D.C., September.

Research at The New England Center for Children

Editor’s note: The New England Center for Children has two articles that have recently been accepted for publication and I have included abstracts of those studies below. The first study describes a comparison of two teaching techniques commonly used during discrete trial training. It was found that the delayed cue procedure, which involves the fading of teacher prompts, was generally more effective than the exclusion procedure. The second study involved a treatment procedure for stereotypy. In this study it was found that providing continuous access to activities that did not match the sensory consequences presumably maintaining stereotypy produced low levels of stereotypy.

Clark, K.M. & Green, G. (2004). Comparison of two procedures for teaching dictated- word/symbol relations to learners with autism. Journal of Applied Behavior Analysis, 37.

The efficacy of exclusion and delayed cue procedures for establishing novel dictated- word/symbol relations with 2 boys with autism was compared using computerized match-to-sample (MTS) procedures. Acquisition of the relations under the two training conditions was compared via an alternating treatments design. The delayed cue procedure was more efficacious than the exclusion procedure in 4 of 5 comparisons across participants.

Ahearn, W.H., Clark, K.M., DeBar, R., & Florentino, C. (in press). On the role of preference in response competition. Journal of Applied Behavior Analysis.

A duration-based preference assessment was used to identify items that produced high levels of engagement and low levels of stereotypy. When evaluated in treatment, stimuli that both matched and that did not match the sensory consequences hypothesized to maintain the participant’s stereotypy effectively competed with its occurrence. It is suggested that preference, as measured in duration-based assessment, can be as significant as sensory match for interventions that function to facilitate responses that compete with automatically reinforced behavior.

Web Resources

• For information about The New England Center or to access and electronic version of this or previous NECC Research Newsletters, visit our Web site www.necc.org.

• For information about autism, visit the National Library of Medicine’s autism site www.nlm.nih.gov/medlineplus/autism.html.

• For information about applied behavior analysis in the treatment for autism visit www.behavior.org.

• For science-based information on biomedical treatments and theories in autism visit www.autism-biomed.org.

• For information on health issues in general visit the World Health Organization www.who.int.

• For professionally-screened information on health care (including some treatments for autism and other developmental disabilities), visit www.quackwatch.com.

• For information on the Berkshire Association for Behavior Analysis and Therapy, visit www.karsina.us/babat/.

• For information on the Association for Behavior Analysis, visit www.abainternational.org.

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