Sensory processing disorder is a neurological condition in which a child's brain confuses and misinterprets sensory information, resulting in inappropriate or abnormal responses, according to the STAR Center. SPD is categorized into subtypes, such as sensory discrimination disorder, depending on which senses and neurological functions the condition disrupts.
The body has eight sensory systems, explains the STAR Center. The five main systems are visual, olfactory, auditory, gustatory and tactile, which relate to the body’s physical perception of the surrounding environment. The three remaining senses are vestibular, interoception and proprioception, which involve physiological perception and physical orientation, such as hunger, stress, spatial recognition and muscular coordination. SPD interferes with the brain’s ability to coordinate these sensory functions, leading to a wide range of neurological symptoms, including clumsiness, impaired motor skills, overactivity, or extreme sensitivity to sound or touch. Children with SPD often struggle to make accurate distinctions between different types of sounds, smells, textures and other stimuli.
Sensory processing disorder usually accompanies other developmental issues, such as autism, and it can appear in adults as well as children, according to WebMD. An SPD sufferer may be highly sensitive to stimuli or abnormally unresponsive, and reactions vary significantly from person to person. For example, a child who is overly sensitive to sound may vomit after hearing an offensive noise, while another child may feel an urge to hide. A child with low responsiveness may appear disengaged or suffer injuries due to a lack of response to heat or pain.