Abstract
Differences between right and left handwriting were analysed in twenty right-handed normal subjects. The subjects were asked to write a Japanese character of syllabary in squares of three different sizes (1×1, 5×5, and 15×15cm) on a digitizing tablet using the right and left hands alternately. Writing was done ten times for each size, and a total of 60 writings for each subject were recorded in a computer memory. Twelve indices were defined for each writing so that kinematic and morphocinetic differences between the hands might be revealed. A linear discriminant analysis between writings by the right and left hands showed better discrimination in the smaller than larger writings, that was as accurate as the discrimination by visual evaluation of the character shape. The indices showing fluctuation of the pentip acceleration and of the shape deviation were of special value for the discrimination. Size of daily writing is as small as within 1×1cm. That may lead to proficiency in smaller writing with the right hand reflecting the better discrimination by the discriminant function in this study.
