How is it possible that the same child who cowers in abject terror at the sound of a car alarm or a vacuum cleaner can completely ignore your voice when you're calling her to dinner? Your child may have trouble processing the sounds that come to her through her auditory, or hearing, sense — trouble identifying the source and urgency of a sound, trouble with the way the vibrations from sound make her feel, trouble picking out an important sound from a whole lot of noise.