Ipsilateral Extinction in the Hemineglect Syndrome

Data suggest right-hemisphere dominance for attention. Right-hemisphere lesions reduce attentional capacity that may manifest as neglect or extinction. Attention can be assessed with the Face-Hand Test where touch on the face may extinguish simultaneous touch on the hand. Extinction ipsilateral to unilateral lesions suggests abnormal attention to ipsilateral hemispace. We tested patients with left- and right-hemisphere lesions without neglect and right-hemisphere lesions with neglect with stimuli applied exclusively ipsilateral to lesions. In experiment 1, stimuli were applied in face-hand combinations. In experiment 2, the Face-Hand Test was ranked from 0 (no extinction) to 7 (marked extinction) using progressively greater stimulation. In both experiments, right-hemisphere patients with neglect made significantly more errors than left-hemisphere patients without neglect. These data support models of bidirectional right-hemisphere attentional dominance.