Where before we had muddle and mystery, now we have a clear target. This is progress. There are some loose ends. It is unsettling to find that dorsal simultanagnosics can perceive the shape of one object, and spatial relations among parts of one object, but not spatial relations among several objects. Optic aphasia is the prime example.
Patients specifically lack the ability to name visually presented objects.
A sound or touch immediately yields the name. But they can pantomime the use of objects, and sort them by category. None of the models of this syndrome are satisfactory. Surprisingly, there is no part of this model that can be damaged to produce optic aphasia. Given that optic aphasics can gesture appropriately to visual stimuli they cannot name, and correctly sort or match visual stimuli according to semantic attributes, then their impairment cannot lie anywhere in vision, semantics, or the path between the two.