Development of executive functions over a two-year period in youth with High-Functioning Autism or ADHD Per Normann Andersen1, Erik Winther Skogli2, Kjell Tore Hovik3, & Merete Øie4, 5 Lillehammer University College, Norway. 2Innlandet Hospital Trust, Division Habilitation and Rehabilitation, Norway. 3Innlandet Hospital Trust, Division Mental Health Care, Norway. 4 Department of Psychology, University of Oslo, Norway. 5 Innlandet Hospital Trust, Research department
1
INTRODUCTION
MATERIALS AND METHODS
•• Executive functions (EF) underlie complex cognitive processes influencing school and social functioning. Despite executive dysfunction being considered a core deficit in young people with High-Functioning Autism (HFA ) and Attention-Deficit Hyperactivity Disorder (ADHD; Rommelse, Geurts, Franke, Buitelaar, & Hartmann, 2011), many with these disorders perform normal on EF tests. Based on this we wanted to examine how many participants within each group displayed EF difficulties over time.
•• Thirty-four children with HFA, 75 children with ADHD and 50 healthy control (HC) children were assessed with EF tests at baseline and after two years (see Andersen, Skogli, Hovik, Egeland, & Øie 2015 ). Demographic Characteristics Baseline (T1) Variable
AIMS •• The first aim of the study was to investigate the development of EF in children and adolescents with HFA or ADHD over a two-year period. •• The second aim was to investigate the clinical impact of EF impairment and the percentagewise distribution of performance levels by the clinical groups on various measures of EF.
Follow-up (T2)
HFA
ADHD
HC
HFA
ADHD
HC
(n=34)
(n=75)
(n=45)
(n=34)
(n=75)
(n=45)
Sex (m/f)
28/6
39/36
29/16
28/6
39/36
29/16
Age
11.6 (2.0)
11.6 (2.0)
11.4 (1.5)
13,8 (2.0)
13.6 (2.1)
13.5 (1.4)
FSIQ
99.9 (17.4)
95.5 (13.9)
104.5 (13.1)
98.5 (16.9)
95.2 (14.7)
106.5 (12.7)
Table 1. Demographic characteristics , means and standard deviations by group
Figure 1: Percentagewise distribution on EF scaled scores (SS) at baseline
Figure 2: Percentagewise distribution on EF scaled scores (SS) at follow-up
SS >14 SS 11 - 13 SS 7 -10 SS 4 - 6
29,6
28,3
33,2
SS 1 - 3
ADHD: Attention-deficit/hyperactivity disorder; HFA: High-Functioning Autism. Mean for normative data equals SS 10, 1 SD equals SS 3; Higher score = better result
RESULTS •• Consistent with earlier research, both clinical groups had significant EF deficits compared to HC children at baseline and at follow-up. •• Children with HFA displayed more EF difficulties both at baseline and at follow-up compared with the children with ADHD or the HC children. •• At follow-up, 75% (64% at T1) of the children with HFA continued to show working memory (WM) deficits compared to age norm, while only 34% (47,1% at T1) of the children with ADHD had a similar level of WM deficit.
DISCUSSION AND CONCLUSIONS •• Despite a maturation in EF over two years, EF deficits in children with HFA or ADHD seem to persist into adolescence. References Andersen, P. N., Skogli, E. W., Hovik, K. T., Egeland, J., & Øie, M. (2015). Associations Among Symptoms of Autism, Symptoms of Depression and Executive Functions in Children with High-Functioning Autism: A 2 Year Follow-Up Study. Journal of Autism and Developmental Disorders, 45(8), 2497-2507. doi:10.1007/s10803-015-2415-8 Rommelse, N. N. J., Geurts, H. M., Franke, B., Buitelaar, J. K., & Hartman, C. A. (2011). A review on cognitive and brain endophenotypes that may be common in autism spectrum disorder and attention-deficit/hyperactivity disorder and facilitate the search for pleiotropic genes. Neuroscience & Biobehavioral Reviews, 35(6), 1363-1396. doi:10.1016/j.neubiorev.2011.02.015
•• Our findings indicate that children with HFA display more severe EF impairment at baseline and follow-up compared with children with ADHD. •• Heterogeneity in EF is large, with fairly 60 % of the children with ADHD and 40% of the HFA participants scoring within or above the normal range on EF tests. •• As the children in the current study were followed for only two years, it is uncertain whether the difficulties seen in EF tasks in the clinical groups are the result of a developmental delay that will gradually mature, or represent a more stable endophenotype. •• This study emphasizes the importance of doing individual assessments of EF in children with HFA or ADHD to detect strengths and difficulties. Contact: Per Normann Andersen, Lillehammer University College,
[email protected] Acknowledgements The project has received financial support from Innlandet Hospital Trust (grant number 150186) and the Regional Resource Center for Autism, ADHD, Tourette syndrome and Narcolepsy, Oslo University Hospital (grant number 150182).
