Impairment of facial recognition in patients with right cerebral infarcts quantified by computer aided ''morphing''

Objective-To investigate where facial recognition is located anatomically and to establish whether there is a graded transition from unimpaired recognition of faces to complete prosopagnosia after infarctions in the territory of the middle cerebral artery. Methods-A computerised morphing program was developed which shows 30 frames gradually changing from portrait photographs of unfamiliar persons to those of well known persons. With a standardised protocol, 31 patients with right and left sided infarctions in the territory of the middle cerebral artery and an age and sex matched control group were compared by non-parametric tests. Results and conclusion-Facial recognition in patients with right sided lesions was significantly impaired compared with controls and with patients with left sided lesions. A graded impairment in facial recognition in patients with right sided ischaemic infarcts in the territory of the middle cerebral artery seems to exist.