Determining the Relationship Between Executive Functioning and Repetitive Behaviors for Children with ASD vs. Typically Developing.

Transcription

1 Cohen, 1 Determining the Relationship Between Executive Functioning and Repetitive Behaviors for Children with ASD vs. Typically Developing Nyack High School Justin Cohen

2 Cohen, 2 Acknowledgements I would like to thank both my science research teachers I ve had, Mrs. Kleinman and Ms. Foisy. They ve been a huge help, and provided plenty of support and guidance throughout this whole endeavor. I also would like to thank my mentor, Dr. Rebecca Jones in assisting me in the lab.

3 Cohen, 3 Abstract This study looked at the relationship between executive functioning and repetitive behaviors for children with autism and for typically developing children. It was hypothesized that increased executive functioning would be associated with a decreased amount of repetitive behavior. To test the child s executive functioning, the HTKS task was used, and to measure repetitive behaviors, the RBS-R survey was utilized. To analyze what happened to this relationship as the children aged, both the typically developing and ASD groups were broken down into two age groups: early school and preschool. There was no statistically significant relationship found between the two scores for either the typically developing nor the ASD group. However, this study did succeed in, showing for the first time, a statistically significant difference in HTKS scores for children with autism compared to that of typically developing children.

4 Cohen, 4 Table of Contents Introduction. 6 Methodology... 8 Results Conclusion. 14 Discussion.. 14 References.. 16

5 Cohen, 5 Lists of Figures and Tables Table 1: Description of Participants... 8 Table 2: Age Group Breakdowns... 9 Figure 1: HTKS Scores for Children With Autism and Typically Developing Children. 1 Figure 2: RBS-R Scores for Children with Autism and Typically developing Children..11 Figure 3: Comparing HTKS and RBS-R Scores for Children With Autism 12 Figure 4: Comparing HTKS and RBS-R Scores for Typically Developing Children..13

6 Cohen, 6 Introduction Over the past 4 years, there has been a ten fold increase in the diagnoses of Autism Spectrum Disorder (ASD). ASD affects over 3 million Americans and over 1 million individuals worldwide. In the United States, 1 in 68 children are diagnosed with an autism spectrum disorder. Autism is roughly 4.5 times more common in boys than girls, and often times people diagnosed with autism have a hard time fitting in with society (Howlin, et al., 24). It s often very challenging for a person with autism to find and hold a job. Also, the costs for raising a child with autism are tremendous. On average, a family can end up having to spend an extra $4, a year on therapies and treatments compared to that of a typically developing child. The reason for the recent increase in the diagnoses of autism is not completely known, however it is thought that this is due to improved diagnosis protocols and environmental factors such as heavy metals like lead and mercury (Croen, et al., 22). Autism is a disorder in brain development; it is a specific disorder among the autistic spectrum. Its severity can vary from low functioning to high functioning. Although all children with autism usually have a deficit in social skills, other areas such as language and cognitive ability can vary widely. Children with autism also tend to have difficulty with verbal and non verbal communications, motor coordination, attention, repetitive behaviors and more. Symptoms of autism usually begin to manifest between 24 and 36 months of age (Mandell, et al., 25). Recent research suggests that there is no singular cause for autism. In fact, it s likely there are multiple causes, from gene mutations to environmental factors. A significant difficulty that children with autism have is with their Executive Function (EF) skills. EF is a set of skills that helps get things accomplished such as estimating how much time a project will take to complete. Most children with autism show diminished EF. Often times a test called Head Toe Knee Shoulder (HTKS) is used to measure a child s EF (Ponitz, et al., 29). During an HTKS test, a child is first asked to touch their head and toes. During the

7 Cohen, 7 second trial of the test the child is asked to touch their head when the adult says to touch their toes and vice versa. Therefore, the child must inhibit their intuitive response, which is to follow what the adult is saying, and to use EF skills in order to remember the instructions. For the third trial, both the knees and shoulders are thrown into the mix and the child has to touch their shoulders after hearing knees and touch their knees after hearing shoulder. The number of correct responses is recorded and a composite score created. This test demonstrates the child s ability to show self control and a working memory of the instructions and thus their EF skills (Kidwell, 212; Lan, et al., 211). However, this is the first study to use the HTKS test with children with autism. Repetitive behaviors are also a known action associated with autism. It is not uncommon for children with autism to participate in ritualistic behavior such as hand flapping, rocking, and head banging. A common tool to measure a child s repetitive behavior is the RBS-R (Repetitive Behavior Scale - Revised). It s a questionnaire that the child s guardian fills out and the guardian is asked to rank the severity of a specific behavior on a scale from -4 (Lam, et al., 26). This test will yield a composite score that is very useful in determining how much repetitive behaviors play a role in that child s life. The goal of this study is to find a connection between HTKS scores and RBS-R scores. It is hypothesized that there will be a stronger trend between the scores for children with autism compared to that of TD children. Particularly, higher HTKS scores will yield lower RBS-R scores for children with autism, and for TD, the connection will be similar just less clear. There is a reason to believe this hypothesis to be true because a higher HTKS score shows an increase in EF and thus a better ability to control oneself and participate in less repetitive behaviors. Also, this study aims to look at what happens to this trend between the scores as both groups age from preschool to early school.

8 Cohen, 8 Methodology The data from the participants in this study were all stored in the database at Weill Cornell Medical College. The data for each participant was recorded at different times and each participant had individually chosen variables recorded. Many of the children in this study went to the facility to receive treatments and therapies. To be admitted to any of the programs at WCMC, the child must go through a battery of tests, often including the RBS-R and others. Sometimes included in these tests was the HTKS task but not as often as the others. Data for typically developing children was also recorded at WCMC for a control and participants were usually paid a stipend. To retrieve the data specifically for this study, the database was sorted through, only retrieving participants who meet these criteria: months of age, had scores for the HTKS task and RBS-R and either diagnosed with autism or typically developing. Table 1 shows the breakdown of the participants used for this study. N Age Average (months) age SD for age VIQ Average VIQ SD for VIQ NVIQ Average NVIQ SD for NVIQ ASD TD Table 1: Description of Participants After retrieving and organizing the data from the participants, the groups were then further divided by age. Since there are many more participants in the typically developing group than in the autistic group, to just cut the groups by the average age would not yield the most

9 Cohen, 9 statistically stable results. Because there were a more limited amount of participants in the autistic group, the median age for that group was found and that s where the line was drawn between the age groups. By doing this, the same number of children with autism were in each age group. This was the best way to maximize the number of participants in each group; that separating age was 59 months. Any participant 59 months or younger was placed in the preschool group, and all participants older than 59 months were placed in the early school group. The breakdown of this group can be seen in Table 2. N Age (months) ASD Preschool ASD Early School TD Preshool TD Early School Table 2: Age Group Breakdowns Next, to analyze the difference in HTKS scores for children with autism and typically developing, 3 bar graphs were created. The first graph was for all participants, ASD vs. TD. The other 2 graphs were broken down by age; one was for preschool and the other was for the early school aged children. For comparing RBS-R scores between the two groups, the same 3 graphs were created. Then to address the hypothesis, the HTKS and RBS-R scores were compared directly. A total of 6 line graphs were constructed to analyze the relationship. The first group of 3 graphs was for the ASD group only. One graph looked at the trend for the whole group and the other 2 were dissected further into the age groups. Similarly 3 graphs were constructed for the TD group. To determine the statical significance of each correlation, independent t-tests were run to get p values.

10 Cohen, 1 Results Figure 1: HTKS Scores for Children With Autism and Typically Developing Children 27.5 HTKS ASD vs. TD ASD TD P< ASD Early School TD P> ASD Preschool TD P>.5 The graphs in Figure 1 looked at the relationship between HTKS scores for children with autism and typically developing children. The top graph shows that children with autism score statistically significantly lower on the HTKS test compared to that of typically developing children. However, that trend dissipates when the two groups are divided into the age groups, evident by the two lower graphs.

11 Cohen, 11 Figure 2: RBS-R Scores for Children with Autism and Typically developing Children 4 RBS-R ASD vs. TD RBS-R Score Total Preschool ASD 5 TD P<.1 Early School RBS-R Score Total RBS-R Score Total ASD TD P<.1 ASD TD P<.1 The graphs in Figure 2 are comparing RBS-R scores for children with autism and typically developing. This relationship has been well documented and it is known that children with autism exhibit much more repetitive behavior compared to that of typically developing children. These graphs further prove this statement by showing a statistically significant difference in RBS-R scores between the two groups. Also this trend prevails even when broken down by age.

12 Cohen, 12 Figure 3: Comparing HTKS and RBS-R Scores for Children With Autism ASD HTKS vs. RBS-R RBS-R Score Total Preschool RBS-R Score Total P>.5 P>.5 Early School RBS-R Score Total P>.5 The graphs in Figure 3 look at the relationship between HTKS and RBS-R scores for Children With Autism. No statistically signifiant relationship between the scores was found when looking at all the children with autism, nor was there a statically signifiant relationship in either of the age groups.

13 Cohen, 13 Figure 4: Comparing HTKS and RBS-R Scores for Typically Developing Children 5 TD HTKS vs. RBS-R RBS-R Score Total P>.5 Preschool Early School RBS-R Score Total P>.5 RBS-R Score Total P>.5 The graphs in Figure 4 examined the relationship between HTKS and RBS-R scores for typically developing children. No statistically signifiant relationship between the scores was found when looking at all the typically developing children, nor was there a statically signifiant relationship in either of the age groups.

14 Cohen, 14 Conclusion: As evident by the large p values, no statistical significance was found between HTKS and RBS-R scores for either children with autism or typically developing children in any age group. Also, children with autism statistically scored lower on the RBS-R compared to that of typically developing children, which was also expected and consistent with other studies. However, children with autism did statistically score lower on the HTKS task compared to that of typically developing children. This was consistent with the hypothesis, but was also the first analysis to show that there is a statically significant difference in HTKS scores between the two groups. Discussion: The idea of expecting a child who has higher EF to exhibit less repetitive behaviors does seem to be sound, however the data suggest that there is no correlation between the scores. There are several reasons to account for this. One is that the sample size was fairly small and the TD group far out weighed the ASD group, perhaps yielding an unreliable statistical analysis. In the future, this procedure could be repeated with more participants to get a more accurate depiction of the trend. Also, it is not very accurate to compare HTKS and RBS-R scores for TD children because they tend to not score at all or perhaps have very small composite scores on the RBS-R. This is because TD children tend not to depict repetitive behaviors because then they may be categorized as not typically developing. It is, however, possible that there truly is no trend between EF skills and repetitive behaviors. A possible explanation for the no trend is that the neural-cognitive mechanism that causes deficits in executive functions is not the same mechanism that causes repetitive behaviors. Repetitive behaviors may be the result of a much more complex malfunction. The neural pathways involved in repetitive behaviors may be a more primal circuit and cannot be overridden by strong EF skills. Thus, having higher EF skills may not correlate to less repetitive behaviors.

15 Cohen, 15 Overall, this study may not have found a correlation between HTKS and RBS-R scores, but it did succeed for the first time in showing a statistical difference in HTKS scores for children with autism compared to that of TD children. Future research should further analyze the relationship between the scores, particularly in children with autism because of the fact that typically developing children tend not to score significantly on the RBS-R. A much larger sample size is needed to fully determine if there is a relationship. The implications of there being a relationship between the scores are very useful. If it is found that increased executive functioning leads to less repetitive behaviors for children with autism, then therapies can be geared towards improving the child's executive functioning to indirectly limit their repetitive behaviors. There lies the potential to vastly improve the child's as well the child's caretakers quality of life.

16 Cohen, 16 References Croen, Lisa, Judith Grether, Jenny Hoogstrate, and Steve Selvin. "The Changing Prevalence of Autism in California." Journal of Autism and Developmental Disorders 32.3 (22): Howlin, Patricia, Susan Goode, Jane Hutton, and Michael Rutter. "Adult Outcome for Children with Autism." Journal of Child Psychology and Psychiatry J Child Psychol & Psychiat 45.2 (24): Kidwell, Katherine. "Trees and Traffic: Restorative Environments and Children's Executive Functioning." (212). Lam, Kristen S. L., and Michael G. Aman. "The Repetitive Behavior Scale-Revised: Independent Validation in Individuals with Autism Spectrum Disorders." Journal of Autism and Developmental Disorders 37.5 (26): Lan, Xuezhao, Cristine H. Legare, Claire Cameron Ponitz, Su Li, and Frederick J. Morrison. "Investigating the Links between the Subcomponents of Executive Function and Academic Achievement: A Cross-cultural Analysis of Chinese and American Preschoolers." Journal of Experimental Child Psychology 8 (211): Mandell, D. S. "Factors Associated With Age of Diagnosis Among Children With Autism Spectrum Disorders." Pediatrics (25): Ponitz, Claire Cameron, Megan M. Mcclelland, J. S. Matthews, and Frederick J. Morrison. "A Structured Observation of Behavioral Self-regulation and Its Contribution to Kindergarten Outcomes." Developmental Psychology 45 (29):