The "Altitudinal Anton's syndrome": coexistence of anosognosia, blindsight and left inattention.

We describe a 69-year-old patient with superior altitudinal hemianopia who contentiously denied having any visual impairment after stroke in the lower banks of both calcarine fissures. Although the patient did not produce intentional responses to visual stimuli in the blind fields, he showed reduced reaction times to stimuli presented in the inferior visual fields when they were primed by identical stimuli in the superior blind fields. Furthermore he showed left extinction to the double stimulation and delayed reaction times for left unprimed stimuli in the inferior fields. Based on these findings we discuss the possibility that blindsight and right hemisphere damage might be both necessary conditions for denying bilateral blindness.