Sensory Processing Disorder: "is a condition that exists when sensory signals don't get organized into appropriate responses. Pioneering occupational therapist and neuroscientist A. Jean Ayres, PhD, likened SPD to a neurological "traffic jam" that prevents certain parts of the brain from receiving the information needed to interpret sensory information correctly. A person with SPD finds it difficult to process and act upon information received through the senses, which creates challenges in performing countless everyday tasks. Motor clumsiness, behavioral problems, anxiety, depression, school failure, and other impacts may result if the disorder is not treated effectively.
One study (Ahn, Miller, Milberger, McIntosh, 2004) shows that at least 1 in 20 children’s daily lives is affected by SPD. Another research study by the Sensory Processing Disorder Scientific Work Group (Ben-Sasson, Carter, Briggs-Gowen, 2009) suggests that 1 in every 6 children experiences sensory symptoms that may be significant enough to affect aspects of everyday life functions. Symptoms of Sensory Processing Disorder, like those of most disorders, occur within a broad spectrum of severity. While most of us have occasional difficulties processing sensory information, for children and adults with SPD, these difficulties are chronic, and they disrupt everyday life." (http://www.sinetwork.org/about-sensory-processing-disorder.html)
Auditory Processing Disorder: "Auditory processing disorder (APD), also known as central auditory processing disorder (CAPD), is a complex problem affecting about 5% of school-aged children. These kids can't process the information they hear in the same way as others because their ears and brain don't fully coordinate. Something adversely affects the way the brain recognizes and interprets sounds, most notably the sounds composing speech.
Kids with APD often do not recognize subtle differences between sounds in words, even when the sounds are loud and clear enough to be heard. These kinds of problems usually occur in background noise, which is a natural listening environment. So kids with APD have the basic difficulty of understanding any speech signal presented under less than optimal conditions." (http://kidshealth.org/parent/medical/ears/central_auditory.html)
Visual-motor integration: Eye hand coordination
Modulation Related to body position and Movement: do they turn head to look at you or full body.
Vestibular processing: The vestibular system detects movement and gravitational pull, and it provides information regarding the position of our head in space and acceleration and deceleration of movement. It is the first sensory system to fully develop in utero and is located in the inner ear. The vestibular system has strong neurological connections in the brain and is a major organizer of varied sensory input. This system is considered the most influential sensory system and has tremendous impact on one’s ability to function daily. Directly or indirectly, the vestibular system influences nearly everything we do. It is the unifying system in our brain that modifies and coordinates information received from other systems, and it functions like a traffic cop, telling each sensation where and when it should go or stop. (http://nspt4kids.com/health-topics-conditions/vestibular-processing/) Basically this is why he moves all the time ie rocking.