Now that computer-based tools are available, the ability to draw is not as important as a good sense of design. You don't have to be an amazing artist in order to be a graphic designer, but you do have to be able to make basic sketches and drawings on paper. Your sketches and drawings should be able to convey your ideas to someone else, most likely your boss or a client. If you feel uncomfortable with your drawing skills, find some tutorials on drawing and sketching. Don't worry or get frustrated, since the more you practice, the more you will get comfortable and gain confidence.
A neurologist is a medical doctor who specializes in treating diseases that affect the human nervous system.