Arduino, L. S. 1, 2 , Veronelli, L. 3, 4 , Vallar, G. 3, 5 & Girelli, L. 3
1 Department Of Psychology, LUMSA University, Rome, Italy
2 ISTC-CNR, Rome, Italy
3 Department of Psychology, University of Milano-Bicocca, Milan, Italy
4 Department of Neuro Rehabilitative Sciences, Casa Di Cura Privata del Policlinico, Milan, Italy
5 IRCCS Istituto Auxologico Italiano, Milan, Italy
In radial line bisection tasks, neurologically unimpaired participants (UP) transect the line too far (up) from the body with respect to the objective midpoint of the stimulus, while right-brain damaged patients with unilateral spatial neglect (USN) could do so close (down) to the body (Halligan and Marshall, 1993). In a recent study with UP, Arduino, Previtali and Girelli (2010) reported a “length effect” specific to orthographic stimuli in the bisection of horizontal strings, with a leftward bias for long stimuli, and a rightward bias for short ones. In the present study, nine USN patients and matched healthy controls were asked to bisect radial words (5-10 letters) and comparable lines. A directional bias closer the body in USN patients with respect to controls was found. Furthermore, both patients and controls bisected differently words and lines, with a “length effect”, i.e., a bias toward the body for short stimuli, limited to words. This pattern of results mimics what reported by Arduino et al. (2010) in lateral bisection: visuo-perceptual and linguistic features of the stimulus modulate the participants’ performance in lateral and radial bisection.