M.A. / The study aims to determine whether statistically significant differences exist between boys with attention deficit hyperactivity disorder (ADHD) and boys without ADHD with regard to hemispheric language lateralization and the laterality of various modalities (handedness, eyedness and footedness). According to the literature, a possible connection exists between abnormal lateralization patterns and various developmental disorders (Corballis, 1983; Geschwind & Behan, 1982; Hiscock, 1988, McFarland, 1981; Turkewitz, 1988). Lateralization in the current study refers to hemispheric language specialisation, hand dominance, foot dominance and eye dominance. In most people these functions are lateralized to the one side of the body by the age of seven (Kalat, 1995; Kolb & Whishaw, 1996). They typically manifest a dominant left hemisphere for language and a right-sided dominance for handedness, footedness and eyedness. The result is a dominant left hemisphere, due to the left side of the brain controlling the right side of the body. Some children however manifest insufficient or poor lateralization of these functions. For purposes of this study, it would imply that the functions of language specialisation, handedness, footedness and eyedness are not all lateralized to one side of the body. A possible connection between this poor or insufficient lateralization and ADHD might exist. According to the DSM IV (1997) the essential feature of ADHD is a persistent pattern of inattention and/or hyperactivity/impulsivity that is more frequent and severe than is typically observed in individuals at a comparable level of development. Some of these symptoms causing impairment must have been present before age seven, although many individuals are only diagnosed after the symptoms have been present for a number of years. Impairment resulting from the symptoms should be present in at least two settings, for example, at school and at home. Clear evidence must exist of interference with developmentally appropriate social, academic, or occupational functioning. An empirical study was conducted in order to compare the hemispheric language specialisation, handedness, eyedness and footedness of the various subjects. The subjects consisted of 20 ADHD boys (8 -12 years) who met the criteria of the DSM IV and 20 Non-ADHD boys (8-12 years) without any learning problems. Various interference variables were controlled in the selection of the subjects (see section 5.2.3) Kimura's dichotic listening technique was used to measure hemispheric language specialisation and the Harris-test for Lateral Dominance was used to measure handedness, eyedness and footedness. Wilks's lambda, Pearson's chi-quadrant and Student's t-tests were used during statistical analysis of data. Results indicated statistically significant differences between ADHD boys and non-ADHD boys with regard to hemispheric language specialisation, handedness and footedness. Overall, the results indicated that the ADHD boys are not as strongly lateralized as the non-ADHD boys. The non-ADHD boys showed a stronger left hemispheric language specialisation, right hand dominance and right foot dominance. No statistical differences were recorded with regard to eyedness. The current study provides possible theoretical support for the theory that a connection exists between poor or insufficient lateralization patterns and children with ADHD. However, the study only focused on white boys between the ages of 8-12 years. Further studies involving different age groups, cultures and gender are recommended.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:14685 |
| Date | 14 November 2008 |
| Source Sets | South African National ETD Portal |
| Detected Language | English |
| Type | Thesis |
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