LINE BISECTION WITH A HEAD MOUNTED POINTING DEVICE - AN INVESTIGATIONOF THE ROLE OF RIGHT-HAND USE AND BILATERAL HEMISPHERE ACTIVATION IN LEFT NEGLECT

Left hand use in left hemispace has been shown to reduce left neglect. Right hand use can theoretically increase neglect by right spatial cu eing and left hemisphere activation. The aim of the present study was to investigate the role of right hand use and right hemisphere activat ion in left neglect by dissociating hemisphere activation From the hem ispace in which the motor response is made. Twelve neglect patients pe rformed line bisection by two means: with their right hand and with a lamp mounted centrally on the forehead ('miner's lamp'). Lamp use indu ces left and right hemisphere activation without hemispace involvement . Bisection with the lamp and the hand were done with right, left and neutral cues. No difference was found in bisection performance between lamp and right hand use, and no interaction between lamp/hand use and cueing. This indicates that right hand use per se does not influence neglect in line bisection. It is suggested that the apparent lack of r ight hemisphere activation with lamp use is due to the widespread righ t-sided lesion of the typical neglect patient. (C) 1997 Elsevier Scien ce Ltd.