Sensorimotor performance asymmetries predict hand selection

Abstract

Handedness is most often measured by questionnaires that assess an individual’s preference for using a particular hand to perform a variety of tasks. While such assessments have proved reliable, they do not address the underlying neurobehavioral processes that give rise to the choice of which hand to use. Recent research has indicated that handedness associated with hemispheric specializations for different aspects of sensorimotor performance. We now hypothesize that an individual’s choice of which hand to use for a given task should result from an interaction between these underlying neurobehavioral asymmetries with task conditions. We test this hypothesis by manipulating two factors in targeted reaching movements: 1) Region of workspace and 2) visual feedback conditions. The first manipulation modified the geometric and dynamic requirements of the task for each arm, whereas the second modified the sensorimotor performance asymmetries, an effect predicted by previous literature. We expected that arm choice would be reflected by an interaction between these factors. Our results indicated that removing visual feedback improved the relative performance of the non-dominant arm and increased the choice to use this arm for targets near midline, an effect that was enhanced for targets requiring larger movement amplitudes. We explain these findings in the context of the dynamic dominance hypothesis of handedness and discuss their implications for the link between hemispheric asymmetries in neural control and hand preference.

Contralesional Arm Preference Depends on Hemisphere of Damage and Target Location in Unilateral Stroke Patients

“…However, the percentage of reaches into the contralateral hemispace with the dominant right arm were not as high as that observed for young adults in several previous studies 24,25 , even those with the same array of targets as we presented in our current study 6 . This difference in reaching pattern between young 6 and older adults (current study) could be attributed to the reported reduction in motor performance and motor transfer asymmetries with aging 26,27 . Consistent with this idea, neuroimaging studies have shown that, as people age, there is a considerable reduction of hemispheric asymmetry 28 .…”

“…The rationale for this is that reaches that cross midline require more energy 22 , although some have also attributed the tendency to the greater demands of intrahemispheric visual-motor processing 23 . However, even in healthy adults this reaching pattern appears to be asymmetric, with the dominant arm making slightly more reaches into the contralateral hemispace 6,21,24 . In the current study, our findings for healthy aged matched control subjects are generally in agreement with these previous studies.…”

“…We also quantified the offset of the RF Midline from the body's midline at each row of targets. This RF Midline offset was computed as a percentage of the distance from the midline of the body and the extreme left or right target at each row 6 .…”

“…For example, in a recent study, we showed that healthy young adults presented with targets throughout the reachable workspace most often chose the ipsilateral arm to reach toward a target on the same side of the workspace. However, the dominant arm was chosen more frequently for targets near midline 6,7 . Thus, workspace location of the target appears to play a significant role in arm selection.…”

Handedness can be explained by a serial hybrid control scheme

“…Handedness has also been described as an asymmetry in the time and/or accuracy associated with fine motor tasks (Annett et al 1979; Carson 1993; Carson et al 1990; Sainburg, 2005; Sainburg and Kalakanis, 2000). We have recently linked these two manifestations of handedness: We showed that hand preference changes for reaching to different locations in space can reverse, depending on which hand has the accuracy advantage (Przbyla et al, 2013). Thus, when reaching to a large number of targets across the workspace, certain locations show dominant arm advantages when subjects have visual feedback and nondominant arm advantages when reaching without visual feedback.…”