simultanagnosia

[sī′məl-tăn′ăg-nōzhə]
n.
  1. Inability to recognize multiple elements in a simultaneously displayed visual presentation; the ability to appreciate elements of a scene but not the display as a whole.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.