Tydskrif vir Geesteswetenskappe
versão On-line ISSN 2224-7912
VAN WYK, Yolanda; PIENAAR, Anita E. e COETZEE, Dané. The effect of intervention on ocular motor control functions and visual-motor integration status of 6- to 8-year old learners with ADHD. Tydskr. geesteswet. [online]. 2012, vol.52, n.4, pp. 660-677. ISSN 2224-7912.
The American Psychiatric Association's (APA) (2000) Diagnostic and Statistical Manual IV (DSM-IV) describes attention-deficit hyperactivity disorder (ADHD) as a persistent pattern of attention deficit or hyperactivity that accrues more often as the typically expected behaviour of an individual's development level and age. Mercugliano (1999) describes ADHD as levels of attention deficit, with or without impulsive and over-active behaviour that is not within the accepted norms of each age group, where the behaviour occurs in different settings and causes problems with functional adapting. The worldwide incidence of ADHD is reported to be between 3% and 7% (Elia et al. 1999; APA 2000). A high percentage of learners with learning problems (25%-80%) also exhibits symptoms of ADHD, which is a possible indication that one problem can lead to the other and vice versa (Cantwell & Baker 1991; Smith 2001). Studies show that learners with ADHD experienced ocular motor control delays as well as problems with their motor development (George et al. 2005; Papavasiliou et al. 2007). If visual problems are experienced because of ineffective ocular motor control functions, problems can also be expected with binocular fusion, visual tracking, ocular alignment, convergence-divergence, fixation, posture, reading habits and visual awareness, which usually go hand in hand with academic-, gross motor- and sport relatedproblems (Auxter et al. 1993; Desrochers 1999; Cheatum & Hammond 2000). Improving visual problems related to misalignment of the eyes, are often approached using binocular vision exercises. Auxter et al. (1993) define binocular exercises as a practice and learning process to help improve visual perception and/or coordination of the two eyes for more effective binocular fusion. Vision therapy can further be described as an individualised intervention that is designed to improve the binocular system, ocular motor control (convergence, divergence, accommodation, visual tracking, ocular lining and fixation), visual processing, visual-motor skills and/or perceptual-cognitive deviations (Orfield et al. 2001; Barrett 2009). However, the essence of vision therapy is to improve eye muscle function. Mahone et al. (2009) found that learners with ADHD experienced significant delays in regards to ocular motor inhibiting and readiness (saccadic latency and adaptability). Mahone et al. (2009) further indicate that girls with ADHD experience more problems with saccadic latency than boys with ADHD. Barrett (2009) indicated that it must first be established what the visual problems are that are directly related to learners with ADHD before strategies can be constructed for successful remediation. This researcher also states that the current available literature still does not provide enough answers in this respect (Barrett 2009). Literature shows that few studies have been done about the effects a visual-motor program (where visual and motor skills are combined as a strategy) will have on the improvement of ocular motor control and visual-motor integration problems of learners identified with ADHD, thus currently leaving this field with unanswered questions in this regard. The aim of this study was to determine what effect a 9-week ocular motor intervention programme will have on the ocular motor control and visual-motor integration status of 6 to 8-year old learners with ADHD. A pre-test-post-test research design based on availability was used during this study where 47 learners (25 boys and 22 girls) with a mean age of 6.95 years (sd=0.69) took part. The participants were divided into three groups: a group with ADHD (n=20) that underwent the visual-motor based intervention and who were then compared to a control group consisting of learners with ADHD (n=10) and a control group without ADHD (n=17). The intervention group took part in a 9-week (3x/week for 45 minutes) visual-motor based intervention (where approximately 5 minutes of each lesson were spent per learner on individual ocular motor control activities). The Sensory Input Systems Screening Test and Quick Neurological Screening Test II (QNST-II) were used to determine the ocular motor control status (fixation; visual pursuit; ocular alignment and convergence-divergence), while the Beery-Buktenica Developmental Test of Visual-Motor Integration Test-4 was used to determine the visual-motor integration, visual perception and motor coordination status. The Disruptive Behaviour Scale (Bester 2006) (control list for ADHD) was used to identifiy learners with ADHD. Learners were divided into classes according to deviations that were found in their ocular motor control (class 1 - no deviations, class 2 - moderate deviations and class 3 - serious deviations). The results were analysed by using cross tabulation. These results showed movement of participants within the classes in all three groups, which indicated both improvement and deterioration. Slight improvements with regard to serious problems in visual tracking (horisontal and vertical) and convergence-divergence were found in the intervention group which was different from what were seen in the other groups. The intervention effect on visual-motor integration, visual perception and motor coordination was further analysed by dependent t-testing, while a co-variance of analysis (ANCOVA) (corrected for pre-test differences) was used to determine the adjusted mean post-test difference values. These results show that the control group without ADHD obtained the best values before and after the intervention with regards to visual-motor integration. These results were expected seeing that the group without ADHD should not have problems with any of the various functions that were assessed during this study, while maturation during the time of the intervention could also have contributed to further improvements. Significant improvements (d=0.38) in comparison to the control group with ADHD (Group 2) were however found in the motor coordination of the intervention group (Group 1), from which it can be concluded that the intervention program had a positive effect on the improvement of these specific skills. A possible explanation for this improvement in motor coordination is that the intervention program focused on the improvement of visual-motor components and the bigger part of the program consisted of activities to improve gross motor skills, which could have contributed to bigger improvements in motor coordination. It can be concluded that vision therapy has possibilities for the improvement of ocular motor problems among ADHD children, which might contribute to improved visual-motor integration, visual perception and motor coordination of such learners. The results ofthis study should however be substantiated by further investigations of the findings of the investigation.
Palavras-chave : ADHD; okulêre motoriese beheer; oogspiere; visueel-motoriese integrasie; visuele persepsie; motoriese koördinasie; intervensie; fiksasie; visuele navolging; okulêre belyning; konvergensie-divergensie; ADHD; ocular motor control; eye muscles; visual-motor integration; visual perception; motor coordination; intervention; fixation; visual pursuit; ocular alignment; convergence-divergence.