Effects of visual search vs. auditory tasks on postural control in children with autism spectrum disorder Amir Hossein Memari a, *, Parisa Ghanouni b , Monir Shayestehfar b , Vahid Ziaee c , Pouria Moshayedi d a Sports Medicine Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran b Rehabilitation Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran c Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran d Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, USA 1. Introduction Autism spectrum disorders (ASD) are a group of child onset neurodevelopmental disabilities which approximately affect 1 in 88 children [1]. The diagnosis of ASD requires impairments in three domains of sociability, language, and behaviors; however, there are other clinical presentations which should be taken into account. Children with ASD usually experience a few problems in fine and gross motor skills such as motor clumsiness, lack of coordination and motor planning which involve the performance of gait and posture [2,3]. Recent studies showed that children with ASD are more posturally instable in the bipedal stance than their typically developing (TD) peers [4–6]. Impairments in brain structures and cognitive functions as well as sensorimotor integrations, may be associated with their higher postural instability [7]. Research indicates that motor impairments similar to abnormal reactions to sensory stimuli [7,8], and cognitive deficits [9] are the most common early symptoms in children with ASD. Thus it is suggest that motor assessment is needed as part of the early clinical assessment in ASD [2]. In most real life situations, postural control is usually accompanied by at least one posture unrelated task (e.g., visual or auditory manipulations) [10]. Indeed maintaining postural control needs to allocate sufficient attention resources to motor, cognitive or sensory stimuli from the context [10,11]. To investigate cognitive mechanisms underlying postural control, a concurrent cognitive task during postural examination (i.e., dual task) is frequently used. When two tasks are involved, there is every likelihood that the attention will be divided between the two [10,12]. Investigating participants in several conditions of different attentional demand (e.g., digit reversal or counting backward by 3 s); Pellecchia showed that postural sway scores would increase when attentional demands of the cognitive task were more challenging [13]. However further study using a memory task in 20 healthy individuals revealed that increased cognitive load of the task would decrease postural sway variability independent of sensory manipulations [14]. Further- more, Vuillerme et al. discussed that distraction from a motor task such as locomotion (using a dual cognitive task) resulted in more Gait & Posture 39 (2014) 229–234 A R T I C L E I N F O Article history: Received 29 December 2012 Received in revised form 27 June 2013 Accepted 10 July 2013 Keywords: Autism spectrum disorder Auditory task Children Postural control Visual task A B S T R A C T Recent research in motor control shows the interactive role of cognitive factors in postural control. However, there is little understanding in how children with autism spectrum disorder (ASD) develop their postural behaviors. This study compares the interference of visual or auditory tasks on postural control in children with ASD. We examined 19 children with ASD (10–15 years old) and also 28 age- matched typically developing (TD) children. They were asked to perform two tasks during postural control: (1) a visual searching task (2) an auditory digit span task. Postural performances were measured with a force platform. Results showed that children with ASD indicated higher postural sway scores in visual task vs. auditory task; as root mean square (p = 0.04), mean velocity (p = 0.01) and sway area (p = 0.02) but TD children scores remained unchanged. Children with ASD also showed significantly higher sway scores than TD children in all parameters. We conclude that in addition to primary differences in patterns of postural control of children with ASD compared to TD children, visual and auditory tasks may differently influence the postural control in this population. ß 2013 Elsevier B.V. All rights reserved. * Corresponding author at: Sports Medicine Research Center, Neuroscience Institute, Tehran University of Medical Sciences, No 7, Al-e-Ahmad Highway, P.O. Box 14395-578, Tehran, Iran. Tel.: +98 21 88630227/8; fax: +98 21 88003539. E-mail addresses: amirmemari@farabi.tums.ac.ir, sportpsych@tums.ac.ir (A.H. Memari). Contents lists available at ScienceDirect Gait & Posture jo u rn al h om ep age: ww w.els evier.c o m/lo c ate/g aitp os t 0966-6362/$ – see front matter ß 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.gaitpost.2013.07.012