This week, we talked about motion and how we perceive motion. We learned about a woman who had a deficiency in this perceiving ability. It baffled me. Once again, I can’t imagine living life this way. It’s as if she was using a flip book as she walked through life.
Any avid reader of my blog entries will notice that the most interesting topics to me are conditions where there is a deficiency in “normal” perception. I must qualify that statement; to normalize perception is useless because we know that there is a subjective component to perception. However, I mean to say that conditions that result in atypical sensations are very interesting to me.
But I digress. Let’s go back to talking about patient L.M. She suffered a stroke and lost her ability to perceive motion, a condition called akinetopsia. As we learned in class, motion is its own sensation and is not an extrapolation over time or space. Her other visual systems functioned normally. She could identify objects, see colors, etc. Things like crossing the street scared her, as it should. But relatively medial tasks like filling a cup with water or listening to someone talk were nearly impossible without some type of trouble. She could not see when the water level of a cup move so she did not know when to stop pouring. She would get freaked out by hearing someone talk without seeing their lips move.
Because the condition resulted from her stroke, it means that she had normal visual functioning before her stroke. This also means that she experienced something very different than what she was used to which could cause potential mental disturbance. I know if I suddenly developed this condition, I too would be very scared and freaked out by it. I do not even know how I could cope.
What is very unique about this situation is that all her other senses are intact. Like I mentioned before, her hearing was not disturbed so she could hear things that did not match up with what images she saw in her head. What I wonder is whether or not she could still sense biological motion. If she suffered a stroke and only certain areas of the brain were affected, was the superior temporal sulcus, the area associated with biological motion, affected as well? If not, maybe she could still perceive biological motion. These questions will be left unanswered as she was the only documented case with this condition and she is deceased.
