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

Retraction of Suggested Autism MMR Link

In 1998, Andrew Wakefield and 12 colleagues published a study consisting of a series of case reports in The Lancet tentatively suggesting a link between the Measles-Mumps-Rubella (MMR) vaccine and autism. This paper reported that symptoms of gastrointestinal difficulties and autism emerged in several children following MMR vaccination and that the parents of these children associated the vaccine with the onset of difficulties. Anecdotal report, such as parents correlating the onset of these symptoms with the delivery of the injection, is typically not accepted as scientific evidence, though such reports can lead to productive research that systematically investigates the caregiver observations.

As has been reported numerous times in our Newsletter, the suggested link between the MMR vaccine and autism has been thoroughly investigated by many well-respected autism researchers and no confirming evidence has emerged. For example, Fombonne and Chakrabarti (2001) did an extensive survey of the potential link between autism and the MMR vaccine and found that there was no evidence for a relation. The most definitive study to date was conducted by Danish researchers (Hviid et al., 2003) who looked at nearly three million children that received either a vaccine containing thimerosal or the same vaccine without this preservative and found that the rates of autism were not higher in the group that received vaccines with thimerosal. Some have said that thimerosal damages the gut, however, Taylor and his colleagues (2002) in a study with nearly 500 children with an autistic spectrum disorder (ASD) found no relation between the MMR and bowel problems. Looking specifically at gut problems in persons with autism, Black, Kaye and Jick (2002) found that children with ASD were no more likely to have a gastrointestinal problem than their age-matched peers.

In February the results of an investigation into the original Wakefield et al. (1998) study was published in The Sunday Times (London) by Brian Deer. Deer's report uncovered that Wakefield was paid over $100,000 by a group of lawyers and parents prior to conducting his research. This group was seeking to sue vaccine manufacturers and wanted Wakefield to provide a link between the MMR and autism. Several of the children in the study were not routine referrals as was suggested in The Lancet but were sent to the Royal Free Hospital by one of the lawyers for this group. The article also stated that the Royal Free Hospital's ethics committee approved the research conducted but the Deer investigation uncovered that the study was not even reviewed by an ethics committee. This scandal has resulted in 10 of the study's co-authors retracting the suggestion of a link between MMR and autism (Mayor, 2004). The finding that the MMR autism link was never solidly grounded in fact may lead to greater public confidence in this and other vaccines. However, it is quite daunting to consider the amount of funding that has been channeled into investigating this claim. There are many other promising areas of research into the etiology and treatment of autism that could have greatly benefited from these resources.

Black, C., Kaye, J., & Jick, H. (2002). Relation of childhood GI disorders to autism: Nested
case-control study using data from the UK General Practice Research Database. British
Medical Journal, 325, 429-421.

Fombonne, E. & Chakrabarti, S. (2001). No evidence for a new variant of measles-mumps-rubella-induced autism. Pediatrics, 108, E58.

Hviid, A., Stellfeld, M., Wohlfahrt, J., & Melbye, M. (2003). Association between thimerosal-containing vaccine and autism. Journal of the American Medical Association, 290, 1763-1766. 1.

Taylor, B. et al. (2002). MMR vaccination and bowel problems or developmental regression in children with autism: Population study. British Medical Journal, 324, 393-396.

Mayor, S. (2003). Authors reject interpretation linking autism and MMR vaccine. British Medical Journal, 328:602 (13 Mar). doi:10.1136/bmj.328.7440.602-c.

Wakefield et al. (1998). Ileal-lymphoid-nodular hyperplasia, nonspecific colitis, and Pervasive
developmental disorder in children: An early report. Lancet, 351, 637-641.

For more information on Brian Deer visit: http://briandeer.com/mmr-lancet.htm

Immunization Safety Review Released

The Institute of Medicine has released the results of its final review of the suggested relation between the MMR vaccine or the preservative thimerosal and autism. A committee of public health experts reviewed all published and unpublished studies related to this controversy and concluded that scientific evidence indicates that these proposed relations should be rejected. The committee also suggested that future research should be channeled into more promising areas.

The Institute of Medicine's full report can be found at:
http://www4.nationalacademies.org/news.nsf/isbn/030909237x?opendocument

E.K. Shriver Center and NECC Investigators Awarded Grant

The National Institute of Child Health and Human Development approved a new Program Project grant for funding. The project is titled: Behavioral Allocation & Choice Processes in Mental Retardation: Basic Research & Applications. There are four projects included in the five-year grant. The first project will look into an individual's sensitivity to several aspects of the environment, for example the presence or absence of a teacher, and how this affects skill performance. The Shriver Center's Bill McIlvane and Karen Lionello-DeNolf will serve as investigators for this research. The second project will examine variables that affect motivation with a focus on identifying the most effective procedures for developing reinforcement systems. NECC's Bill Ahearn and the Shriver Center's Bill Dube are the investigators for this project. The third project will investigate how aspects of the environment come to control behavior. The Shriver Center's Richard Serna and Bill McIlvane will lead these studies. The last project will investigate how aspects of social interaction affect behavior. This project's lead investigators are Bill Dube and NECC's Becky MacDonald. The bulk of the research for these projects will be conducted at The New England Center. We will have more on this collaborative effort as the studies get underway.

Readers' Forum

Email your questions to Bahearn@necc.org.

Q: Our son has autism and we want to have more children. What is the chance of us having another child with autism?

A: This question is particularly difficult to answer for a number of reasons.
Though autism is assumed to be inherited, it is thought that the genetic process
underlying it is complicated and typically not isolated to a specific gene (see Muhle, Trentacoste, & Rapin, 2004 for a thorough review of the genetics of autism). Autism is sometimes related to the presence of another medical condition like fragile X syndrome. Fragile X syndrome involves an abnormality on the X chromosome and the gene associated with it has been identified. However, at least 90% of cases of autism are not linked to a specific medical condition. Estimates of the likelihood of an affected family having another child with autism have been reported to be between 2-8% (Muhle, Trentacoste, & Rapin; Simonoff, 1998). This means that there is somewhere around a 1 in 20 chance of a couple having another child with autism. This risk is much higher than the one faced by a couple with an unaffected child but is much lower than the risk faced by a couple whose child's autism is associated with a known medical condition of genetic origin such as fragile x syndrome or tuberous sclerosis (Simonoff). If a family is interested in assessing the risk of having a child with a genetic disorder, it may prove useful to consult a genetics counselor. The role of a genetics counselor is to provide unbiased information about genetic disorders and predispositions. Anyone interested in learning more about genetics counseling should visit the MedlinePlus: Genetic Counseling website at

http://www.nlm.nih.gov/medlineplus/geneticcounseling.html

Muhle, R., Trentacoste, S.V., & Rapin, I. (2004). The genetics of autism. Pediatrics, 113(5), e472-486.

Simonoff, E. (1998). Genetic counseling in autism and pervasive developmental disorders. Journal of Autism and Developmental Disorders, 28(5), 447-456.

Research at The New England Center

Editor's note: The New England Center for Children has recently published an article in Research in Developmental Disabilities on the topic of measuring stereotypic behavior in children with autism. Also, the Autism Association in New South Wales, Australia reprinted the Reader's Forum from our last edition in their Keynotes newsletter. The RIDD article by Nicole Gardenier, Becky MacDonald, and Gina Green compares two general methods for observing this problem behavior. Stereotypy is often difficult to accurately measure because the duration of episodes of this behavior can vary greatly. It was found that momentary time sampling provides the most accurate estimates of the level of occurrence of this behavior. This is an important finding because partial-interval recording is the more widely used data collection technique.

Gardenier, N.C., MacDonald, R., & Green, G. (2004). Comparison of direct observational methods for measuring stereotypic behavior in children with autism spectrum disorders. Research in
Developmental Disabilities, 25, 99-118

We compared partial-interval recording (PIR) and momentary time sampling (MTS) estimates against continuous measures of the actual durations of stereotypic behavior in young children with autism or pervasive developmental disorder-not otherwise specified. Twenty-two videotaped samples of stereotypy were scored using a low-tech duration recording method, and relative durations (i.e., proportions of observation periods consumed by stereotypy) were calculated. Then 10, 20, and 30s MTS and 10s PIR estimates of relative durations were derived from the raw duration data. Across all samples, PIR was found to grossly overestimate the relative duration of stereotypy. Momentary time sampling both over- and under-estimated the relative duration of stereotypy, but with much smaller errors than PIR (Experiment 1). These results were replicated across 27 samples of low, moderate and high levels of stereotypy (Experiment 2).

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 http://www.karsina.us/babat/.

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




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