Head turning versus manual pointing to auditory targets in normal subjects and in subjects with right parietal damage

Head turning and manual pointing to auditory targets have been studied in normal subjects and in subjects with right parietal damage. Important differences were found between these two types of movement. (1) In brain-damaged subjects, audiospatial manual pointing deficit patterns and audiospatial head turning deficit patterns were dissociated. Moreover, head turning deficits tended to appear peripherally in both auditory hemifields, while manual pointing deficits tended to appear unilaterally in the left hemifield. (2) In normal subjects, at all tested eccentricities in both hemifields, head turning performances showed a characteristic undershooting of auditory targets when compared to manual pointing. Results are discussed in terms of differences between the processes underlying audio-motor tasks that involve the head and tasks that involve the hands.