Dual-task performance in right- and left-handed adults: A finger-tapping and foot-tapping study

The dual-task paradigm has been used extensively to study laterality with c oncurrent verbalization interfering with right finger-tapping in right hand ers, Only a few studies have used this paradigm to study interference patte rns in left handers and have found inconsistent results. The dual-task para digm has not been used to study interference effects with concurrent verbal ization and foot-tapping. The objective e of this study was to use this par adigm to assess whether verbal interference produces different effects on f inger- and foot-tapping rate for right handers as compared to left handers. 12 right-handed and 12 left-handed men were studied, each with uncrossed h and and foot dominance, i.e., all individuals were either right handed and right footed or left handed and left footed, Subjects performed finger- and foot-tapping tasks with and without verbal interference. A significant rel ationship was found between handedness and finger and foot-tapping rate; in dividuals with a stronger right-hand preference tended to tap at a higher I ate on tile right side and vice-versa. Analogous relationships were not fo und when participants were tapping and speaking concurrently. With verbal i nterference, both right and left handers had a significant asymmetric effec t with a decremental response in right finger-tapping rate and a facilitati ve effect on left finger-tapping rate. In contrast, there was a bilateral d ecremental response in foot-tapping with verbal interference in both right and left handers. The implications of these findings are discussed with ref erence to cerebral laterality of language systems and to the differential o rganization and integration oi the motor representations of the hand and th e foot.