Imagine half of your world disappearing before your eyes in a split second. You wait for it to come back, but it never does. Everything you see is cut in half! I recently met a man that experienced this odd and rare brain condition.
This senior-aged man arrived in our practice in a wheelchair saying that he couldn’t see to his left. He had recently suffered a stroke in the right half of his brain and had lost complete function of his left arm and leg. After some testing, we discovered that indeed the entire left side of his vision was gone due to the stroke. This made sense since the right brain receives left side vision information.
However, I wasn’t expecting what he said next, “I have to turn my plate around to see the food on the other side.” You see, if just the left side of his vision is missing all he’d have to do is look a little more to his left to see the other side of the plate. I diagnosed him with hemispatial neglect (AKA left side neglect). He’s only aware of the right side of objects!
Patients with this condition will eat only the food on the right side of their plate, notice only the right side of a picture, and only draw the right side of a clock. This is an actual drawing from a hemispatial neglect patient. Some severe cases have even demonstrated the amazing ability to flip the neglect in their mind’s eye. For example, after being shown an upside-down picture of a face, the patient will mentally flip the picture right-side up and neglect the left side of the face!
We learn a lot about brain function by studying the devastating, but fascinating effects of brain damage. From neglect patients we’ve discovered that the right side of the brain is responsible for spatial interpretation. The eyes collect data about our environment, but the brain interprets and organizes it.