Laura Case Study

Neng Gao

A00374935

Module 7: Case Study

Case 2—Laura

What condition or conditions (there may be more than one possibility) are being described in this case?

In the case 2, Laura has faced two types of visual difficulties. First, her world has become colorless. Everything she sees is the gray. She could not image things in color. This is the color agnosia. Secondly, Laura could not determine whether the cup is full when she pour the tea. Also, Laura has a dysfunction of radial movement detection. She thinks the moving car have stopped. This is a movement agnosia.

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?

All Laura’s visual difficulties are caused by the brain damage of “bilateral posterior vascular abnormality”, so, the damage happens on the both of right and left posterior hemisphere. Then, Laura has the color agnosia. According to the textbook, “cortical color blindness, or cerebral achromatopsia, occurs when people have lesions between V1 and the fusiform face area (Garrett, 2011)”. The eft-hemisphere area V4 also be damaged.  Those V1 and V5 both in the ventral streams which used to perceive the color. For the movement agnosia, it always happens in the V5/MT area. This area in the dorsal streams which identify objects visually (Garrett, 2011).

How should these brain areas function normally? What could be causing this dysfunction?

In normally, the area V5/MT in the brain is the place to integrate the information that our sense organs collected. “The MT, in middle temporal area also helps direct reaching movements and eye movements when tracking objects (Garrett, 2011)”. It also has the ability to detect radial movement. When we close to something, the MT will tell people that we are moving together. The area V1 and V4’s main function is perceiving the different color. Cells in V1 are wavelength coded and cells in V4 are color coded (Garrett, 2011). Those areas’ damage causes Laura’s two dysfunctions. The color agnosia will make people lose the ability to perceive colors. The movement agnosia causes the problem to identify objects visually when people walk away from something or close for them.

What do the assessments and their results tell you about this person’s abilities and condition?

The case shows that Laura's reading or writing abilities do not have any effect. She just has color agnosia. Her world is only with gray color. Maybe, Laura has a little problem in radial movement detection, although she could identify objects and complex movements well.

References:

Garrett, B. (2011). Brain & Behavior: An introduction to biological psychology. Vision and Visual Perception. SAGE Publications, Inc.

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