Does your child react strongly to noises or smells or textures that other children take in stride? Or does he or she beg for more touch and massage, rocking until he or she is dizzy? This child may be living with a little-known condition called sensory processing disorder (SPD). Kids with SPD may seem unduly sensitive to physical sensations, light, and sound, or they may seek out sensations that might make another child woozy. SPD can make it...