Unintentional injury is the leading cause of pediatric mortality. One leading cause of unintentional injury is pedestrian injury. Children with developmental disabilities, particularly those with attention-deficit/hyperactivity disorder–combined type (ADHD-C) seem to have increased pedestrian injury risk. This study examined (1) the differences in pedestrian behavior between children with ADHD-C and normally developing comparison children and (2) the mediating factors that might link ADHD-C with pedestrian injury risk.
A total of 78 children aged 7 to 10 years (39 children with ADHD-C diagnoses and 39 age- and gender-matched typically developing children) participated. The main outcome measure was pedestrian behavior, as measured in a semi-immersive, interactive, virtual pedestrian environment. Key pedestrian variables related to different aspects of the crossing process were identified: (1) before the cross (ie, evaluating aspects of the crossing environment); (2) making the cross (ie, deciding to cross and initiating movement); and (3) safety of the cross (ie, safety within the pedestrian environment after the decision to cross was made).
Children with ADHD-C chose riskier pedestrian environments to cross within (F1,72 = 4.83; P < .05). No significant differences emerged in other aspects of the crossing process. Executive function played a mediating role in the relationship between ADHD-C and the safety of the cross.
Children with ADHD-C seem to display appropriate curbside pedestrian behavior but fail to process perceived information adequately to permit crossing safely.
Comments
Pedestrian Injury in Children with ADHD
The study by Stavrinos et al. [1] assessing street-crossing behavior in an "interactive, semi-immersive virtual pedestrian environment" found that children with ADHD, Combined type (ADHD-C) were, compared to normal controls, more likely to cross the street when it was less safe to do so.
Although this study provides objective evidence in a standardized setting of the potential for physical injury associated with ADHD-C, the virtual reality (VR) methodology employed likely underestimates the true risk. Visual traffic images consisted of three video screens in a frontal field of view; there was no attempt to simulate a 360 degree environment or introduce other visual distracters. Likewise, traffic and ambient noise were only presented from the frontal direction. Children with ADHD - by definition - have difficulty with visual and auditory distractions. In this era of multi-channel audio technology with side and rear speakers, it is disappointing that greater effort was not made to better simulate a true street environment with visual and/or auditory distractions coming from multiple directions.
The investigators' observation that children with ADHD-C were more likely to choose riskier pedestrian environments for crossing is consistent with other studies that demonstrate increased risk-taking behavior in this population. [2] However, distortion and/or impairment of time perception may be an alternate explanation. The children with ADHD-C displayed appropriate curbside behavior (e.g., appropriately looked in both directions) but then chose smaller time gaps to cross within and thus had significantly less time to spare upon reaching the end of the crosswalk until the next car crossed. Several studies have shown that children with ADHD-C differ significantly in estimates of elapsed time and reproduction of time duration intervals. [3,4] For this reason, the aberrant pedestrian behavior of children with ADHD-C is likely not just a manifestation of risk-taking behavior but also a consequence of impaired time perception. Regrettably, the authors failed to discuss either risk- taking behavior or time perception as constructs in children with ADHD.
One recent study found that teens with ADHD-C and a co-morbid learning disability (LD) were more likely to engage in risk-taking behavior than teens with ADHD-C but not LD. [5] Another study has likewise suggested that there may be greater time perception impairments in children with co-morbid ADHD-C + LD compared to those with ADHD-C alone. [6] Although 30% or more of children with ADHD-C have a learning disorder, children with LD were excluded from this study. It would be interesting to see if a comorbid ADHD-C + LD cohort would have demonstrated even riskier pedestrian street-crossing behavior -- especially since executive functioning was identified as a mediating variable in this study and is often impaired in children with LD.
Although virtual pedestrian environments provide a useful controlled setting for evaluating high-risk populations and identifying effective interventions, future studies - especially those focused on youth with ADHD -- would likely be strengthened if visual and auditory stimuli in other spatial dimensions were added to further enhance the VR paradigm's ecological validity.
References:
1. Stavrinos D, Biasini F, Fine R, et al. Mediating Factors Associated with Pedestrian Injury in Children with Attention- Deficit/Hyperactivity Disorder. Pediatrics. 2011;128:296-302.
2. Drechsler R, Rizzo P, Steinhausen HC. Decision-making on an explicit risk-taking task in preadolescents with attention- deficit/hyperactivity disorder. J Neural Transm. 2008;115(2):201-9.
3. Meaux JB, Chelonis JJ. Time perception differences in children with and without ADHD. J Pediatr Health Care. 2003;17(2):64-71.
4. Plummer C, Humphrey N. Time perception in children with ADHD: the effects of task modality and duration. Child Neuropsychol. 2009;15(2):147- 62.
5. McNamara J, Vervaeke SL, Willoughby T. Learning disabilities and risk-taking behavior in adolescents: a comparison of those with and without comorbid attention-deficit/hyperactivity disorder. J Learn Disabil. 2008;41(6):561-74.
6. Gooch D, Snowling M, Hulme C. Time perception, phonological skills and executive function in children with dyslexia and/or ADHD symptoms. J Child Psychol Psychiatry. 2011;52(2):195-203.
Conflict of Interest:
None declared