Charlie was in a serious car accident in which several bones were broken. He appeared fine (besides the obvious injuries), and never lost consciousness. However, three days later he suffered a fat embolism (probably because of his fractures). This embolism occluded his posterior cerebral arteries, and initially resulted in cortical blindness. A week later, his vision had returned, but several other visual deficits remained. Among these he could not attend to more than one object at a time, and he was unable to track objects with his eyes (indicating ocular apraxia and ataxia).
As part of developing a rehabilitation protocol, Charlie underwent an intense neuropsychological evaluation 12 months after the occlusion. Something that his evaluators noticed right away was that, although he showed no verbal deficits and was oriented to time and place, he did not once establish eye contact during the course of the examination. He also continued to be unable to follow objects with his eyes when instructed or reach for target objects (he kept missing). Also, when Charlie was asked to pour a glass of water, he missed the mark entirely, pouring water all over the table and floor.
When asked to describe complex objects, all he could do was list specific details; he didn’t seem able to talk about the whole, integrated object. When shown a circle and asked to point to the middle, Charlie was unable to do so. Also, when shown two objects overlapping each other (such as a hand partially covering a face), he could only recognize one or the other, but never both.
Here are some further results of his evaluation:
| Test | Administration | Charlie’s Performance |
|---|---|---|
| Wechsler Adult Intelligence Scale-Revised (WAIS-R) | The WAIS is a series of subtests intended to assess verbal abilities (such as Information, Comprehension, Arithmetic, etc.) and non-verbal abilities (such as Picture Completion, Picture Arrangement). | Above average verbal score. |
| Rey-Osterreith Complex Figure Test | Requires a patient to copy a complex figure while it is still in front of them, and then to reproduce it from memory after a delay. | Unable to copy most of the figures, either immediately or from memory. |
| Real object naming, visual | Patient was shown 7 real objects, and asked to identify them. | Charlie could name all 7 real objects, but could not name line drawings of the same objects. |
Questions
- What condition or conditions (there may be more than one possibility) are being described in this case?
- What brain area or area(s) may be involved? Be sure to consider which visual stream is involved. Is there a specific hemisphere that is affected? How do you know?
- How should these brain areas function normally? What could be causing this dysfunction?
- What do the assessments and their results tell you about this person’s abilities and condition?
Remember to document your sources!
Originally published at http://www.sciencecases.org/mini_perception/6charlie.asp
Copyright © 1999–2009 by the National Center for Case Study Teaching in Science. Please see our usage guidelines, which outline our policy concerning permissible reproduction of this work.
