[Motor assymetry].

Abstract

Although the study of handedness and its association with hemispheric specialisation represents the prevailing focus of motor dominance research, recent inquiry into footedness and other motoric asymmetries has stimulated several interesting propositions. The present review show the variability of assessing motoric asymmetries. Asymmetry in hand use takes two forms: differential hand preference and differential dexterity between the hands. Motoric asymmetries are strongest and most manifest for handedness (hand preference, performance and dexterity), descending through footedness and other less known asymmetries (tonguedness, chewing preference). Handedness is the most easily observed expression of cerebral lateralization. The alpha and omega of relating handedness to other neuropsychological variables or indices of lateral specialization lies in the classification of handedness. A vast range of testing techniques have been used to assess handedness. Writing hand and self-report are two of the most popular techniques. Other preference measures include observation of how people use tools and questionnaires. Performance tests assess speed and accuracy in tasks stressing manipulative dexterity. Although questionnaires are generally thought to be reliable and valid instruments, there is a disagreement as to the nature, the number and weighting of the items to be included. The least stable results will be obtained if a categorization into "right-handers" and "non-right-handers" is made on the basis of exclusive "right" answers. Slightly more stable is a classification that is based on "right-handers", "mixed preference handers" and "left-hander" based on extreme choices in either direction and intermediate choices. We present shortly a possible inventory assessing motoric asymmetries.