I think it can be hard for neurotypicals to understand what these sensory issues can feel like. Of course, everyone is different and each person has their own particular issues. But I did want to pass along an interesting article on one individual's experiences of sensory challenges. Brian King is a social worker, as well as someone diagnosed with Asperger's as an adult. Check out the third issue of Brian's Spectrumite magazine to learn about what his experience is like. Talk to your kids about their experiences, and try to understand their own particular sensitivities. Maybe the school can be a little more flexible, or some sensory related modifications can be written into the IEP.
Still not sure these sensory issues are real? Just think about biting on foil or scratching fingers down a chalkboard. Can you imagine trying to learn while that's going on?