Dual task performance by patients with left or right speech dominance as determined by carotid amytal tests.

Patients who had their speech dominance determined by carotid Amytal testing were evaluated with a dual task procedure consisting of reading and finger tapping. As expected, the asymmetry of interference between tasks varied with speech dominance. Patients with left hemisphere speech tended to show greater interference in the right hand whereas patients with right hemisphere speech showed greater interference in the left hand. Since the right hemisphere dominant patients were also right-handed, the results suggest that interference effects are more closely linked to speech than to motor dominance.