ABSTRACT
Introduction Different findings from studies of functional brain asymmetry in humans have highlighted
a variety of possible causes for this phenomenon.1'5 The most investigated characteristic of lateralized asymmetry is handedness. Although the reported percentage of left-, or right-handed individuals differs from study to study, this could be due to methodological differences between these studies, such as the questionnaires used, the tasks performed, or the action(s) observed.6'8 Furthermore, handedness may be affected by a number of social and native factors as well as severity of climatic-geographic conditions under which a subject lives.9 Examination of a variety of asymmetrical sensorimotor characteristics-leading hand, foot, eye and earalso can result in alternative interpretations o f the obtained data. While some authors deny the existence o f people with absolute left characteristics (the preference of left side for the use of the hand, foot, eye and ear),10 others report a high proportion of such individuals in some geographical regions.11
