Sensory processing (originally called "sensory integration dysfunction" or SID) refers to the way the nervous system receives messages from the senses and turns them into appropriate motor and behavioral responses.
Every day we are exposed to thousands of sensory experiences that come to us through our senses of vision, hearing, touch, movement, smell, taste, and proprioception (our sense of position in space). There are birds chirping, horns honking, air conditioners running, and lights humming. Our clothes have different textures; we get into cars and move forward, stop, start, and turn; and we smell foods, perfumes, and deodorants.
Among all these experiences, most of us are able to tune out the things that are irrelevant to what we are currently engaged in and tune into the things we need in order to be able to navigate and respond to our environment. However, some individuals may react differently. Some find these experiences to be confusing and overwhelming, while others may be unresponsive to these experiences in a way that may be different from most individuals.