| Summary: | 博士 === 國立臺灣師範大學 === 特殊教育研究所 === 88 === This study (with three sub-studies) examined the issue based on traditional and contemporary perspectives of handedness development. They are "a reliability and validity study of the handedness inventory (mainly focusing on construct validity)", "handedness development: a comparison of cerebral palsied and typically developed children", and "the effects of object position and size on manual asymmetries in cerebral palsied and typically developed children".
In sub-study I, the handedness inventory was developed. The inventory demonstrated satisfactory surface validity, test-retest reliability, internal consistency (Cronbach α), and parent-child agreement. Content validity was established by the use of expert panel and construct validity was studied by using two-stage exploratory factor analysis and one-stage confirmatory factor analysis with 385, 728, and 744 subjects (ages ranging from 4- to 12-years) respectively. Two factors were identified finally: sequenced/complex tasks (factor 1) and non-sequenced/simple tasks (factor 2).
In sub-study II, 101 data from cerebral palsies and 801 typical children with ages from 4- to 12-years were analyzed. The higher laterality quotient and the frequency of right handedness were found on factor I activities than on factor II activities for both groups. The results indicated significant effects for different tasks in manual preference. Cerebral palsies'' laterality quotient and frequency of right handedness were significantly lower than typical children; the association between early brain injuries and atypical lateral preference was strong. Four and five-old-years are more non-right handed and lower scored than other groups in typical children. It was also noted that there was no difference in handedness performance among other 7 groups from 6- to 12-old-years. The year in the senior class of kindergartens (6-year-old) was the most critical period in the process of establishing stable hand preference; social stress was important to substantiate this phenomenon.
In sub-study III, an experimental study of handedness based on contemporary view was conducted to examine the size and position effects on the use of non-preferred hand in 32 cerebral palsies and 26 typical children. The subjects were asked to execute upper extremity movements 18 times; they pushed balls forward into a box. Two kinds of different ball size (volleyball and baseball) with three different positions (contralateral, middle and ipsilateral sides relative to the non-preferred hand) were experienced by each subject (2×3 = 6 different pushing situations) ; six situations were repeated 3 times (6×3 = 18). Results of two-way ANOVA (2×3) suggested that no interaction existed between position and size effects in both groups. However, the differences in object position did influence the use of non-preferred hand and the object size did not demonstrate the same effect in cerebral palsies and typical children. Context effects, especially the position effect, can be manipulated as a therapeutic and educational strategy to facilitate the use of impaired hand for the children with cerebral palsy.
In summaries, the handedness inventory demonstrated good reliability and validity and included two factors. Task property, brain damage, and social stress might influence manual asymmetries. Context variables including task property and object position can be analyzed and utilized to help the children with motor deficiency.
|
|---|
