Pica is the eating of non-food stuff, like hair, wood, drywall, and is caused by a mineral deficiency. Have their mineral levels tested and supplement accordingly.
Hearing sensitivity is common in ASD. Check bacteria, minerals and yeast first. Consider listening therapies like Auditory Integration Therapy (AIT) and use noise-cancelling headphones or an iPod to drown out the noise. Investigate auditory therapy and noise-blocker headphones.