Brain Tumor?

       Conservative columnist Robert Novak has been getting a lot of bad news lately--last week he pummelled a pedestrian with his car.  This week, he ended being diagnosed with a brain tumor.  Whether you like (Karl Rove), hate (Valerie Plame), or don't know the man, that's sad news. 

     Novak got a lot of blowback because when he hit the pedestrian while driving his black Corvette, he just kept a right on goin'.  In fact, it took a biker to stop him down the road before he claimed he had any idea what happened.  Yeah right.  Except...medical science could actually prove him right. That is, his ignorance in nearly cutting down an innocent may have been a symptom of his yet undiagnosed brain tumor. 

    People who develop brain tumors often have their visual system affected.  That's because the neurons that help us see actually travserse the brain from the back of your head (occipital lobe, where the visual cortex is located) all the way to your eyeballs.  Here's a picture for you:

 Tumors can grow anywhere, but because of the extensiveness of the visual system, they often affect it.  And a common visual problem is called a hemianopsia.  In this condition, you lose half of your visual field.  Need another picture? 

This is called right hemianopsia because of the loss of things on that side. 

 The weird and sad thing is that people with hemianopsia often don't realize they have it, and they go right along doing their thing until...BAM! 

Such may have been the case with Novak.  Apparently, he was taking a right turn when he hit the pedestrian, who had the right of way, as he stepped into the crosswalk.  A person with a hemianopsia could have done if he or she had visual loss on the same side as the bystander. 

All of this is theory--I have no idea where Novak's tumor is or what kind it is (benign or malignant).  But as I said, it could explain why Novak drove an entire block