Assessment of handedness using a digitizing tablet: a new method.

The assessment of handedness is of interest in some psychiatric populations, above all in schizophrenic patients, because there may be a relationship between neurodevelopmental, hemispheric damage and psychiatric disease processes (Crow TJ. Schizophrenia Bulletin 1990;16:433-443; Tyler M, Diamond J, Lewis S. Schizophrenia Research 1995;18:37-41). Various methods to assess handedness have been proposed. In order to detect the most precise instrument for the assessment of handedness, two different measures, a questionnaire and a computational procedure for movement analysis, were compared in a group of healthy subjects. The ability of the methods to discriminate not only between the groups of right-handers (n=12) and left-handers (n=23), but also between left-handers trained in school to use the non-dominant right hand ('inconsistent' left-handers; n=11) and those allowed to use their left hand for writing ('consistent' left-handers; n=12) was investigated. For future investigations, our main concern was to determine if one method had superiority over the other. The results revealed that the Edinburgh Handedness Inventory (EHI) distinguishes just as well as the computational method between right-handers and non-right-handers. However, more precise discrimination between the subgroups of 'consistent' and 'inconsistent' left-handers is possible using digitized analysis of hand-motor performance. According to our results handedness should be assessed not only with the EHI, but also with the computer-aided analysis of hand-movements.