We open our ears to the science of sound and hearing this week with a look at the genetic causes of deafness and how a deaf person's brain decodes sign language. We also hear how auditory illusions can fool you into hearing things that aren't there and meet a sound simulation system that can improve the clarity of railway station announcements and recreate the "cocktail party effect" to help build better hearing aids. Plus, we find out why light makes migraines more painful, how cleaner fish keep each other in check and, in Kitchen Science, Dave swaps Ben's ears around...