Autistic spectrum disorder (ASD) is a neurodevelopmental disorder that impairs social skills, delays language development, and results in repetitive behaviors and restricted interests which impede academic and social involvement.1
ASD now afflicts one out of every 150 children and one in 94 boys in the United States.2
Scientific evidence has shown that ASD is based on neurophysiological abnormalities, although it continues to be diagnosed on the basis of observable behaviors.3
Central to the diagnosis of the disorder is extreme social isolation and repetitive, even obsessive, attempts to preserve sameness (eg, lining up objects), and to self-stimulate (eg, spinning).1
Above and beyond the limitations caused by deficits in social communication, repetitive behaviors pose an extra barrier to social interaction and community integration.5
Researchers and clinicians have focused on developing effective interventions for decreasing the frequency and severity of problematic stereotypic behaviors, and treatment is often complex, ranging from psychopharmacologic interventions to time-intensive behavior management schedules.6
A prominent theory to explain repetitive behaviors in ASD is that they are a symptom of executive dysfunction.4
Lopez and colleagues7
investigated the relationship between performance on executive function tests and presence of repetitive behaviors in adults with autism spectrum disorder. They found that the presence of repetitive behaviors is strongly correlated with a tendency to perseverate, which supports the theory that these behaviors are a symptom of executive dysfunction. Individuals with ASD were also found to have significant planning deficits. The theory is that the autistic individual is experiencing executive dysfunction, leaving him or her unable to produce, plan, and manage behaviors in the normal manner.4
This inability to control behavior is a possible explanation for the restricted and repetitive nature of the behaviors; the source of executive dysfunction in individuals with ASD may be abnormal frontal lobe development and functioning.7
Physical exercise has shown promise for decreasing repetitive behaviors in autistic children,8
and physical exercise has been shown to improve cognitive function, especially executive function, in normative individuals.10
The neurophysiological mechanisms by which cognitive functions may be improved by exercise are only partially understood and include immediate and direct improvement in cerebral blood flow, as well as longer term benefits to cerebrovasculature, both of which lead to improved delivery of oxygen and nutrients, as well as removal of byproducts.11
In addition, research continues to explore the longer term consequences of exercise for brain health and cognitive function by examining biomarkers indicative of neurotrophic growth, such as brain-derived neurotrophic growth factor, and also via neuroimaging which has suggested neurogenesis, given enlarged structures in the brain after exercise, such as the anterior cingulate cortex, which could impact executive function.13
It is possible that an improvement in executive control functions in those with ASD could work together with direct benefits of physical exercise and may indicate a mechanism behind increased control of repetitive behaviors. Early observational research demonstrated that five children with autism exhibited a decrease in self-stimulatory behaviors in the classroom, following bouts of exercise during gym and recess, but no decrease was seen after a television-watching control condition.15
Kern and colleagues16
examined the influence of antecedent jogging, ball-playing, and academic responding on self-stimulation in seven children with autism; only the jogging intervention consistently decreased self-stimulatory behavior in the post-intervention observation period. Powers and colleagues17
found a similar effect of just 10 minutes of roller skating as the antecedent condition in a single case observation of an autistic boy. Preliminary evidence was compelling, causing some to call for prescription of exercise as treatment for repetitive behaviors.18
Similarly, Rosenthal and Mitchell19
found that, among five children with ASD, self-stimulatory behaviors in the classroom decreased after 20 minutes of jogging compared with no precondition. It has been suggested that the decrease in self-stimulatory behaviors might be the result of fatigue; however, this theory has been criticized because studies have shown that physical activity not only decreases repetitive behaviors, but also has positive effects on attention and academic responding of children with autism.17
These studies suggest that the incorporation of routine breaks for physical exercise throughout the school day for children with ASD could decrease problematic behaviors. However, in each of these studies, the samples were small, even a single case study, and many lacked a control group or comparison condition. Furthermore, effects were only evaluated during the brief period immediately following exercise, thus additional research is needed.
Some studies have also examined the potential impact of longer term exercise for ASD. Pan20
used a within-subjects crossover design for 16 children with ASD and found improved social skills after 10 weeks of group aquatic exercise. However, in another study after 14 weeks of aquatic exercise in seven children with ASD and five controls there were no significant differences found between the two groups, most likely due to limited power, although the pilot study did demonstrate feasibility. 21
Additionally, in these studies, exercise interventions and repeated socialization opportunities were confounded; future research could refine the design to clarify key factors.
While research on the benefits of physical exercise is encouraging, it may also be possible to derive cognitive benefits from videogame play. Research has demonstrated that under some conditions, videogames serving as computerized mental exercise, can improve cognitive functions in the normative population, but the generalizability of these benefits to everyday functions is debated.22
More widely applicable benefits have been noted for such computer training interventions in persons with schizophrenia, a disorder which shares some similar cognitive and behavior challenges with ASD.23
Videogames and virtual reality exergames (eg, Wii) are widely utilized by youth today and specifically, are often attractive to children with pervasive developmental disorders such as ASD; while there are drawbacks to too much or certain types of videogame play, there are also a number of potential benefits in ASD.25
For example, there is growing research literature demonstrating the benefits of virtual reality computer programs for improving social skills in ASD.27
The focus herein is on the use of virtual reality-enhanced exercise for impacting repetitive behaviors and cognitive function, specifically executive function, which could add to the control of repetitive behaviors.
Research on virtual reality exergames has been increasing in part given the rise in childhood obesity, and the potential for exergames to increase physical activity since game play is controlled by the physical movements of the player.28
The popularity and physical activity potential of exergames such as Wii (eg, bowling and tennis) or Dance Dance Revolution (DDR) has led some school districts to incorporate exergames into their physical education curricula. 29
The games provide an alternate means of physical activity that may increase exercise participation with the aim of improved fitness. It has been shown that exergames can increase energy expenditure in normative children,30
and can also elicit fitness gains in persons with developmental disabilities. 31
Mhurchu and colleagues32
conducted a 12-week study using the EyeToy and found that exergaming led children to play fewer videogames overall and engage in more physical activity per week. Yin and Graham33
explored components of DDR, such as music and fun game-like features that may facilitate increased exercise effort through distraction from the discomforts of exercise. Leininger and colleauges34
found a higher rating of enjoyment after exergaming using DDR than after traditional treadmill walking. These studies suggest that exergaming can increase exercise behavior, and thus could become a valuable alternative to traditional modes of exercise. Since compliance with exercise can be challenging at any age, but especially among clinical populations such as ASD,18
exergaming holds particular promise as an exercise intervention given the research noted above on increased motivation, enjoyment, and energy expenditure. However, no prior research has explored the behavioral or cognitive effects of exergaming for persons with autism.
The purpose of the current research is to assess the effects of an acute bout of exergaming on the repetitive behaviors and cognitive performance of children with autism. Previous research suggests that vigorous, aerobic activity decreases repetitive behaviors in the short-term. Literature also suggests that exercise and videogames independently improve performance on tasks assessing executive functioning. Thus, merging exercise and videogaming may have beneficial effects on multiple aspects of dysfunction in children with autism. The current investigation moves away from the case study methodology employed in previous studies,15
and uses a larger sample across two pilot studies, with some control in a mixed within and between subjects design. We hypothesized that the combination of physical and mental exercise in an exergame would yield behavioral and cognitive benefit. In two pilot studies we explored the potential behavioral and cognitive benefits of a single bout of exergaming. We hypothesized that for youth with ASD, a single bout of exergaming would yield decreased repetitive behaviors and increased executive function, compared with a control condition.