What are the signs of affected sensory processing system?
The systems may be hypo or hyper active in processing.
Typically each system will exhibit some prominent behaviors that characterize the working of that system.
Some behaviors that may act as alerts for sensory processing difficulties can be:

Tactile system
Hypoactivity may be presented as :
o Child may crave touch, needs to touch everything and everyone
o is not aware of being touched/bumped unless done with extreme force or intensity
o is not bothered by injuries, like cuts and bruises
o may not be aware that hands or face are dirty or feel his/her nose running
o has difficulty with fine motor tasks such as buttoning, zipping, and fastening clothes
o may be a messy dresser
o has difficulty using scissors, crayons, pencil

Hyperactivity may present as :
o Child becomes fearful, anxious or aggressive with light or unexpected touch
o may overreact to minor cuts, scrapes, and or bug bites
o avoids touching certain textures of material (blankets, rugs, stuffed animals)
o will be distressed by dirty hands and want to wipe or wash them frequently
o distressed about having hair, toenails, or fingernails cut, face, teeth or hair wash
o is a picky eater

Vestibular System

Hyper activity may present as:
o Child avoids/dislikes playground equipment; i.e., swings, ladders, slides, or merry-go-rounds
o prefers sedentary tasks, moves slowly and cautiously
o fearful of activities which require good balance

Underactive system may present as:
o Child in constant motion, can't seem to sit still
o craves fast, spinning, and/or intense movement experiences
o always running, jumping, hopping etc. instead of walking
o clumsy and has a limp, "floppy" body
o frequently slumps, lies down, and/or leans head on hand or arm while working at his/her desk

Proprioceptive system

Underactive system may present as:
o Child seeks out jumping, bumping, and crashing activities
o stomps feet when walking
o frequently falls on floor intentionally
o chews on pencils

Overactive system may present as:
o Child has difficulty regulating pressure when writing/drawing; may be too light to see
o frequent breaking of writing utensil breaks as writing is very hard
o written work is messy and he/she often rips the paper when erasing
o always seems to be breaking objects and toys

Auditory
Overreactive system may present as:
o Child is very easily distracted by sounds not normally noticed by others
o distracted by loud or unexpected sounds
o bothered/distracted by background environmental sounds; i.e., horn of vehicle
Underregistered system may present as:
o Child often does not respond to verbal cues or to name being called
o appears to "make noise for noise's sake"
o loves excessively loud music or TV