The tactile system includes nerves under the skin’s surface that send information to the brain. This information includes light touch, pain, temperature, and pressure. These play an important role in perceiving the environment as well as protective reactions for survival.
Dysfunction in the tactile system can be seen in withdrawing when being touched, refusing to eat certain ‘textured’ foods and/or to wear certain types of clothing, complaining about having one’s hair or face washed, avoiding getting one’s hands dirty (i.e., glue, sand, mud, finger-paint), and using one’s finger tips rather than whole hands to manipulate objects. A dysfunctional tactile system may lead to a misperception of touch and/or pain (hyper- or hyposensitive) and may lead to self-imposed isolation, general irritability, distractibility, and hyperactivity.
Tactile defensiveness is a condition in which an individual is extremely sensitive to light touch. Theoretically, when the tactile system is immature and working improperly, abnormal neural signals are sent to the cortex in the brain which can interfere with other brain processes. This, in turn, causes the brain to be overly stimulated and may lead to excessive brain activity, which can neither be turned off nor organized. This type of over-stimulation in the brain can make it difficult for an individual to organize one’s behaviour and concentrate and may lead to a negative emotional response to touch sensations.