ACTIGRAPHIC EVALUATION OF HANDEDNESS

The utility of an objective evaluation of motor activity, actigraphy, was examined in the evaluation of handedness. Hand preference was asse ssed in a homogenous group of 190 young volunteers using the Edinburgh Inventory (EI). The EI distribution obtained in the population studie d was comparable with distributions cited in the literature. Simultane ous actigraphic recordings from both wrists were made in 58 of these s ubjects for 20 h, starting at 1000 h, using an epoch length of 4 s. Ca re was taken to include comparable numbers of right- and left-handers (based on EI score) in this subgroup. Two actigraphic parameters were defined. One of these, the Activity Index (AI[x]), is a measure of the difference in total motor activity between right and left wrist. The other, Movement Index (MI(y)[x]) is a measure of the difference in mov ement pattern, AI[x] showed a moderate but significant correlation wit h EI (r = 0.36, P < 0.005). The correlation between MI(y)[x] and EI wa s high (r = 0.65, P < 0.0001). Rebinning of the data into 60 s epochs decreased the degree of linear correlation between MI(y)[x] and EI. We conclude, in contrast to a previous study, that actigraphy can be use d to discriminate between dominant and non-dominant hands; that the di fference in movement pattern between right and left hand is larger tha n the difference in total motor activity; and that epoch lengths short er than the conventional 60 s are more sensitive for this kind of disc rimination.