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

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

What causes autism?
May-June 2003

A paper on the etiology of autism spectrum disorders (Acosta & Pearl, 2003) was recently published in Current Neurology and Neuroscience Reports by two medical researchers at the Children's National Medical Center in Washington. This comprehensive review summarizes the advances in understanding why autism occurs that have been uncovered in the past decade. Acosta and Pearl posit that the best scientific evidence indicates that autism likely results from "genetically determined prenatal alterations in brain development." The genes suspected to be linked with autism have been discussed in a previous newsletter (April 2002) and continued advances in genetics are providing important clues about what happens during development that results in autism.

Neuroimaging research suggests that there is "abnormal regulation of brain growth" in individuals with autism (Acosta & Pearl, 2003). For example, one study found that children with autism aged 2 to 4 had larger brains with more cerebral and cerebellar white matter and more cerebral cortical grey matter than typically developing children of the same age (Courchesne et al., 2001). However, Carper and colleagues (Carper & Courchesne, 2000; Carper et al., 2002) found that children with autism gain substantially less grey and white matter in the frontal lobes from early to late childhood relative to typically developing children. Acosta and Pearl feel that current evidence points to abnormal timing and amount of brain growth and that growth in some areas may end prematurely.

Acosta and Pearl also point out research that has been carried out attempting to establish reliable correlations between viral infections and autism. Findings have been generally inconsistent with only congenital rubella being linked with autism though less than 1% of persons with autism are estimated as having had this condition (Fombonne, 1999). Acosta and Pearl also restate the findings of research on the putative link between the MMR vaccine and autism. As has been covered in previous newsletters (see Feb. 2003 and Oct. 2002 for more information), there is no established link between the vaccine and autism.

Acosta, M.T. & Pearl, P.L. (2003). The neurobiology of autism: New pieces of the puzzle.
Current Neurology and Neuroscience Reports, 3, 149-156.

Carper, R.A. & Courchesne, E. (2000). Inverse correlation between frontal lobe and cerebellum
sizes in children with autism. Brain, 123, 836-844

Carper, R.A., et al. (2002). Cerebral lobes in autism: Early hyperplasia and abnormal age effects.
Neuroimaging, 16, 1038.

Courchesne, E. et al. (2001). Unusual growth patterns in early life in patient with autistic
disorder. Neurology, 57, 245-254.

Fombonne, E. (1999). The epidemiology of autism: A review Psychological Medicine, 29, 769-786.

Readers' Forum

Many of the topics covered in this newsletter have been inspired by questions that have been brought to me by NECC staff and parents. Therefore, I'd like to introduce a new feature of the newsletter whereby you can send me any questions you have about autism research, treatments for autism, or applied behavior analysis. I will answer one or two questions per newsletter, depending on available space. Email your questions to William Ahearn.

Research at The New England Center

Editor's note: The New England Center for Children has recently attended the annual Association for Behavior Analysis convention in San Francisco. NECC staff presented 10 addresses, 2 workshops, and 7 posters. In this issue of the newsletter we are going to highlight some of the research projects that were presented as addresses by NECC staff. The first two papers were presented in a symposium on assessing and treating automatically reinforced behaviors like stereotypy. The first paper shows the results of assessments conducted by NECC's Intensive Instruction Program.

Stereotypy in Children with Autism at Program Entry and After One Year of EIBI: Comparison to Age Matched Typically Developing Peers. Jennifer Anderson, Nicole Gardenier, AMY GECKELER (presenter), William Holcomb, Rebecca MacDonald, Renee Mansfield and June Sanchez

Many children with autism engage in stereotyped and repetitive behavior. Decreasing stereotypy and increasing alternative or incompatible responses is often a primary goal for intervention. Research has shown that levels of stereotypy in young children with autism vary with age. Children who entered treatment at age 2 had lower levels of stereotypy than children who entered treatment at age 4. This study compared levels of stereotypy in 2-, 3-, and 4-year-olds with autism during structured and free-play activities when they entered treatment and one year later, and compared to age matched typically developing children. Inter-observer agreement (IOA) data were collected during the first 3 minutes of each 10-minute videotaped sample; mean IOA was 95.4% (range: 77% - 100%). Results from typically developing children indicate that levels of stereotypy remain low (below 10%) across all age groups. Results from the children with autism indicated that 2-year-olds (mean: 23%; range: 6 - 36%) and 4-year-olds (mean: 39%; range: 15% - 1%) at the beginning of treatment. After one year of EIBI, levels of stereotypy remained the same for 2-year-olds, decreased slightly for 3-year-olds (mean: 20%; range: 5% - 44%), and 4-year-olds showed the largest decrease (mean: 24%; range: 7% - 36%). Implications for early intervention for children with autism are discussed.

Editor's note: This next paper was specifically focused on showing effective interventions for children who engage in vocal stereotypy (vocalizations that are not contextually appropriate). Both treatments discussed are commonly used interventions here at NECC.

Treating Vocal Stereotypy with Response Redirection and Stimulus Competition. WILLIAM H. AHEARN (presenter), Kathy Clark, Bo-In Chung, Nicole Gardenier and Rebecca MacDonald

Vocal stereotypy is a particularly difficult form of stereotypy to treat. Certain established techniques for treating other stereotypies such as response blocking are difficult to use with vocal responses. The present study will present functional assessment of vocal stereotypy showing that this response class is most often automatically reinforced or multiply controlled. Then, effective treatment procedures for several children will be presented. One of the treatments involves response interruption and redirection to appropriate speech. This procedure was assessed with 3 children in an ABAB design. Response redirection decreased vocal stereotypy for all participants and an increase in appropriate speech was observed for some participants. A second treatment procedure, sensory competition, will be presented for 3 children. This treatment was evaluated in a multi-element design. It was found that items that matched the sensory consequence of the child's vocal stereotypy (i.e., auditory stimulation) were only occasionally more effective than high preference items that did not match the perceived sensory consequences of vocal stereotypy. This indicates that preference may be equally or more significant than sensory modality when using competition procedures.

Editor's note: This paper was part of a symposium on teaching play skills to children with autism. Becky MacDonald and her colleagues have developed video modeling techniques that they have used to teach appropriate play with specific activities and reciprocal play with peers.

Using Video Modeling to Teach Play and Social Skills to Children with Autism and Typically Developing Peers. REBECCA MACDONALD (presenter), Ruth Debar, Amy Geckeler, Renee Mansfield, Christine O'Flaherty and Shelly Cota

One approach to fostering play skills in young children with developmental disabilities is the direct teaching of developmentally relevant play activities. In this approach, the activities that are targeted for intervention are derived from developmental assessment. Accordingly, the target activities are not based on what can be done with toys, but what a child is ready to understand about objects, people, and events. As a result, the toys are used in ways that support the target activities derived from developmental assessment. The teaching procedures follow a least-to-most prompting model, which builds upon child-directed procedures that capitalize on the child's attention to the toys available for play, and then guiding that attention to a target activity. It is argued that such an approach supports links between and among developmental domains that go beyond learning to play. The presentation and discussion will include videotaped examples from different studies of how the approach was used with children with autism.

Editor's note: The next paper was part of a symposium on training careproviders. The work presented was conducted at the Marcus Institute by Eileen Roscoe. Eileen joined NECC last year and is the staff intensive unit's Assistant Director of Research (see Feb. 2003 newsletter for a description of some other research conducted by Eileen).

Evaluating the Relative Effects of the Discriminative and Motivational Properties of Performance Feedback in the Implementation of Stimulus Preference Assessments. EILEEN ROSCOE (presenter), Wayne Fisher, Ashley Glover and Valerie Volkert

Performance feedback has facilitated the acquisition and maintenance of a wide range of behaviors (e.g., health-care routines, seat-belt use, client transfer techniques, conducting preference assessment), and most researchers have attributed the effectiveness of performance feedback to (a) its discriminative functions, (b) its reinforcing functions, or (c) the combination of its discriminative and reinforcing functions. However, few researchers have assessed the critical components responsible for the effectiveness of performance feedback. In this study, we attempted to evaluate the relative contribution(s) of the discriminative and reinforcing functions of performance feedback by comparing a condition in which the discriminative functions were maximized and the reinforcing functions were minimized (i.e., performance-specific instructions/ no tangible reinforcement) with one in which the reinforcing functions were maximized and the discriminative functions were minimized (i.e., tangible reinforcement/ no performance-specific instructions). The effects of these two conditions on the acquisition of skills involved in conducting two commonly used preference assessments (i.e., the paired-choice and the multiple-stimulus without replacement assessments) were compared using a within-subject design that combined elements of a multiple-baseline design and a multielement design. Results showed that acquisition of these skills occurred primarily in the performance-specific instruction/ no tangible reinforcement condition, suggesting that the delivery of performance-specific instructions was critical to skill acquisition, whereas the delivery of tangible reinforcers had little effect.

Editor's note: The next paper was part of a symposium on treating pediatric feeding disorders.

Preventing Escape Prevention. WILLIAM H. AHEARN (presenter)

Escape prevention procedures such as physical guidance and non-removal of the spoon have been well validated as effective interventions for feeding problems. However, there is less documentation on effective interventions for deficient patterns of food intake that do not utilize escape prevention. This paper will present three procedures for treating food selectivity that did not involve preventing escape from food. The first is an errorless fading procedure in which a previously rejected food was subsequently consumed following a decrease in the texture of a preferred food to a puree. A small amount of the non-preferred food was added to the preferred food and the amount of the non-preferred food was gradually increased until the child accepted the non-preferred food alone. The second procedure involves adding condiments to rejected food to produce acceptance of those foods. The effect of adding condiments was evaluated in an ABAB/multiple baseline design. Last, the effects of repeatedly and systematically exposing a child to foods will be presented. A pre- and post-exposure evaluation of this procedure is presented and exposure led to improved acceptance of previously rejected foods.

Editor's note: The next two papers were conducted by NECC staff that collaborate with our research partners from the Shriver Center/UMASS medical school. Atli Magnusson, the presenter of the second paper, won an outstanding student paper award for his research.

Stimulus Function and Observing Behavior in a Laboratory Model of Stimulus Overselectivity. CHATA DICKSON (presenter), Kathleen M. Clark, Sharon Wang, and William V. Dube

This study investigates stimulus overselectivity in individuals with developmental disabilities using a delayed matching to multiple samples (DMTS) task. Previous research has shown that overselective stimulus control may be influenced by recent rates of reinforcement (Dube & McIlvane, 1997). The previous study did not, however, determine whether observing behavior was correlated with stimulus control, as predicted by the literature on observing behavior (e.g., Mulvaney, Hughes, Jwaideh, and Dinsmoor, 1981). Subjects in the current study display overselectivity on the DMTS task. Automated apparatus presents stimuli and records matching-to-sample responses; eye movements are recorded with an eye-tracking system. Simple-discrimination training will establish reinforcement histories for four stimuli, two S+ and two S-. In DMTS testing to follow, sample stimuli will consist of one S+ and one S- stimulus. After a reversal of S+ and S- functions in the simple-discrimination context, the DMTS tests will be repeated. The data of interest from DMTS tests will include analyses of both stimulus control and observing durations. Data collection is in progress. If the results show differential observing of S+ and S-, they will document a relation between observing and restricted stimulus control. On the other hand, if the results show equal observing of S+ and S-, then they will reveal an experimental dissociation of observing and attending.

Topography of Eye Movements Under Select and Reject Control. ATLI MAGNUSSON (presenter), William V. Dube, Chata Dickson and Murray Sidman

Responding on discrimination tasks can be under Select or Reject stimulus control. Select control occurs when a response to the discriminative stimulus (Sd) results in reinforcement, and Reject control occurs when a response away from the discriminative stimulus results in reinforcement. Given consistent Reject or Select control in matching-to-sample tasks, it is possible to measure differences in responding with some test for stimulus equivalence; outcomes on reflexivity, transitivity, and equivalence tests are opposite under Reject versus Select control (Carrigan and Sidman, 1992; Johnson and Sidman, 1993). This paper reports an experiment asking if observing behavior might also be different under Select and Reject control. This question arises because research on observing behavior in simple discrimination has shown that observing responses are more frequent for stimuli correlated with reinforcement (Sd) than stimuli correlated with extinction (e.g., Case & Fantino, 1989). In conditional discrimination, the Sd is the correct comparison under Select control, but it is the incorrect comparison under Reject control. In the experiment, automated apparatus presented stimuli and recorded matching-to-sample responses; eye movements were recorded with an eye-tracking system. Results from two participants showed that eye movements toward the incorrect comparison were relatively more frequent under Reject than Select control.

Student Research at NECC

On July 30th from 2 to 6 pm, NECC will be holding a student research poster session. The poster session is held to provide and opportunity for students in one of our Masters programs to present their work, receive constructive feedback, and to gain experience presenting research. This year NECC's Parents and Friends group will sponsor awards for outstanding projects. Many students use this forum to practice before presenting at a regional conference such as the Berkshire Association for Behavior Analysis and Therapy (BABAT - held annually in Amherst, MA) or a national conference such as ABA, which will be held in Boston next May.

Web Resources

For information about the New England Center, 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 http://www.karsina.us/babat/.

For information on the Association for Behavior Analysis, visit http://www.abainternational.org/.




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