The art of learning encompasses many different methods of relating the material to a student through, visual, audio, hands-on, etc. approaches, and different people have different strengths when it comes to these different approaches, but the MCAT is a test the requires a lot of critical reading.
You may be better when you hear material, but now is the time to maximize your methods for written learning.
Until the MCAT is offered on a MP3 with a provided scantron, my best advice would be to push yourself to strengthen your apparent weakness with written material.