Relation of hand performance and preference in male and female left-handers to familial sinistrality and writing hand.

The relations of hand performance to the degree of left-hand preference, and left- minus right-hand performance were studied in left-handed male and female subjects considering familial sinistrality and writing hand. Hand performance was assessed by a dot-filling test; hand preference was assessed by the Edinburgh Handedness Inventory. It was established that there were fundamental differences in relationships between performance and preference measures to sex, familial sinistrality, and writing hand, which also created different patterns in the relationships between hand performance and the difference in performance between hands.