engleski

Usefulness of drawing and writing test with both hands in subjective and objective determination of dominant hemisphere

Brain lateralization is common term used to describe dominance of one brain hemisphere over another for specific function. Right hand dominance in writing is in correlation with development of communicative gesticulation and afterwards with the development of speech in same hemisphere. Nonetheless, part of cognitive functions included in drawing function might have origin in opponent hemisphere. We were interested to find out weather the performance of function common to be processed in one hemisphere would be more precise than the performance of the function processed by both hemispheres while using non dominant hand. We assumed that some people perform both functions with same accuracy and that they are not aware of their own capability in using the other hand. Participants were asked to write two words and draw a particular object – vase with flowers. The sample comprised 1546 children from 19 primary and 8 high schools in Osijek area, from which 1030 primary school children from 1st till 4th grade and 516 high school children from 3rd and 4th grade. 815 girls and 731 boys were included in the research. A leaflet consisting of two parts was used in the research. The first part was a questionnaire consisted of 10 questions for subjective analysis of commonness of using right hand or leg. The second part consisted of a drawing and writing test done with both hands. After we validated the drawing and writing test, children were put into three groups: right-handers, left-handers and ambidextrous. The frequency of answers on commonness of using right hand/leg and our categorization of children based on hand dominance were tested with Chi-square test. In our sample are 1384 (89, 5%) right-handers, 120 (7, 8%) left-handers and 42 (2, 7%) ambidextrous. Among primary school children there are 915 (88, 8%) right-handers, 77 (7, 5%) left-handers and 38 (3, 7%) ambidextrous. Among high school children there are 469 (90, 9%) right-handers, 43 (8, 3%) left-handers and 4 (0, 8%) ambidextrous. Subjective understanding of hand preference is the same as shown in security test for same hand in all questions but those about sport activities such as ball throwing, hitting the ball with the foot, following the rhythm of the music by foot, which are considered to be done automatically. Subjective understanding compared to drawing and writing test deviated in case of ambidextrous who consider themselves right-handers. The fact that the number of ambidextrous is greater in primary schools than in high schools brings us to conclusion that training of the right hand decreases the ability of using both hands equally for both tested functions.

handedness; writing; drawing; lateralization

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