A lateralized comparison of handedness and object proximity.

Abstract

This study was motivated by the emerging hypothesis that right-handers are more strongly lateralized and perform better on various aspects of functional asymmetry than do left-handers. Right-and left-handers •were observed for hand selection responses to a unimanual task of reaching for a small cube in positions of right-and left hemispace, prompting hemispheric decision-making related to hand dominance and attentional (visuospatial) stimuli. As predicted, left-handers did not respond with their preferred limb as consistently across positions as did right-handers. Additional inspection of the task suggests that being less lateralized may not be a disadvantage in this context, and that environmental influence may play a significant role in hand selection for a particular motor event.Resume Cette etude avait pour but de verifier une nouvelle hypothese voulant que les droitiers soient plus fortement lateralises et reussissent mieux que les gauchers dans differents aspects de l'asymetrie fonctionnelle. Nous avons observe la preference manuelle de droitiers et de gauchers au cours d'un test unimanuel ou ils devaient atteindre un petit cube, qui, place soit a droite, soit a gauche, sollicitait la prise de decision reliee a. la dominance manuelle et aux stimuli attentionnels (visuospatiaux). Comme prevu, les gauchers n'ont pas repondu aussi regulierement que les droitiers en fonction de leur region frontale dominante. Un examen supplementaire du test suggere que, dans ce contexte, etre moins lateralise ne constitue pas necessairement un desavantage, et que l'incidence de l'environnement peut jouer un role important dans la preference manuelle pour un element moteur precis.

Arm Selection Behavior of Stroke Patients in Reaching: a Preliminary Study

“…Regardless of the affected side, these participants tended to use their dominant righthands to reach for a target in the right field of the workspace and up to a target position of −10° past the body midline (0°) in the contralateral hemispace. This arm selection pattern is similar to the findings of previous studies of healthy adults, in that arm selection changed to the non-dominant left hand at a target position of −10° in the contralateral hemispace of the workspace 7,9,20) . Thus, Pattern A can be called as a "normal-like" arm selection.…”

“…A setting used to investigate the issue of limb selection is one in which a patient has to reach an object placed on a wide-ranging workspace [7][8][9][10][11] . Gabbard and colleagues explored this issue, and found that generally a limb transition from the dominant arm to the non-dominant arm among right-handers occurred around 20° past the body midline in the contralateral hemispace 7,9) . Similar findings were found for children and left-handers 8,12) .…”

Which Factors Affect Hand Selection in Adults? Combined Effects of Ocular Dominance, Task Demand and Object Location

“…Hence, hemispheric bias means that using the ipsilateral hand for reaching can limit biomechanical constraint effects bearing on the movement. In other words, using the contralateral hand for doing such actions requires longer trajectory and body midline crossing, which leads to action efficiency reduction (Gabbard et al, 1997). Recently, some studies suggest other various factors that affect limb selection.…”

“…They use their preferred hand in reaching to most objects in their peripheral environment. Therefore, it was concluded that repetition and frequency of reaching with the preferred hand occurs much more frequently than reaching with the non-preferred hand (Gabbard et al, 2003;Gabbard et al, 1997;Pryde et al, 2000;Doyen et al, 2008). According to the kinesthetic perspective, performing actions on each side of body with the ipsilateral hand is defined as hemispheric bias or kinesthetic proficiency.…”

“…For example, studies performed on adults imply that doing actions in contralateral hemispace reduces probability of using preferred hand considerably , while most subjects prefer the use non-preferred hand for doing and ipsilateral action. According to Gabbard et al(1997) and Gabbard et al (2003), motor dominance (hand dominance) is the first determining factor in selection of hand in the ipsilateral hemispace. Nevertheless, attentional information related to object location can influence limb selection in the contralateral hemispace.…”