Hand skill and hand-eye preference in relation to verbal ability in healthy adult male and female right-handers.

Verbal as well as non-verbal performances were investigated in relation to both hand skill assessed by finger-tapping performances and hand-eye preference in 83 healthy adult right-handers, most of them students. The primary objective of this study was to show better finger-tapping performances in right-handed participants with best verbal IQ values. We found that it was not the non-verbal but the verbal abilities that were related to finger-tapping performances. This was proven, especially as to the left-hand taps. Faster left-hand taps in participants with higher verbal IQ values may be due to a closer cooperation of right-hemispheric regions in information processing and an intimate relationship between language and finger-motor functions. Secondary objectives assessed by explorative data analyses included gender differences and hand-eye preference. While in the females left-hand taps correlated somewhat more with verbal IQ values, in the males this effect was seen in selected variables of the right-hand taps. Moreover, laterality assessed in finger-tapping performances may not be in accordance with laterality found in the handedness questionnaire. In addition to this, congruent hand-eye dominance was found to be slightly more prevalent in participants with best verbal IQ values. However, these findings will have to be confirmed in further experiments.