However, some common sensations can be so overwhelming for some children that everyday activities are affected.
Some experts claim it disrupts the lives of an estimated one in 20 children, but the debate is raging: Is it a separate condition, or a symptom of something else?
For Jack Sundstrom, what seemed like normal child's play would have been too much not long ago.
"He lived much of his first 5 years of life with his hands over his head," said Zoe Sundstrom.
Zoe Sundstrom says as a baby, Jack startled too easily.
He loved to eat, but never reacted to his food. At night, he would bang his head. He didn't like loud noises or too much bright light.
Was this ADHD, or even autism?
Sundstrom says Jack didn't really fit the diagnosis for either.
Eventually, she was told he had SPD, or sensory processing disorder.
Jack struggles with information that comes in through his senses, such as sight, sound and touch.
"Whenever I'm over stimulated, I cover my ears," said patient Jack Sundstrom.
A door slamming or a tap on the shoulder might cause a child with a sensory problem to act out, or not react at all.
Think of it as a neurological traffic jam that prevents certain parts of the brain from receiving sensory information correctly.
Researchers say the result can be clumsiness, behavioral problems, anxiety, depression, school failure and more -- but this is no clear-cut disorder.
"More often than not, when I see a child with that level of significant sensory issues, there are other issues going on as well," said Dr. Louis Kraus, child psychiatrist at Rush University Medical Center.
Kraus says the symptoms of SPD are similar to those seen in other conditions, and that is where the debate comes in.
Does SPD need its own label, or is it just part of something else?
Currently, SPD is not listed in the influential Diagnostic and Statistical Manual produced by the American Psychiatric Association.
Kraus worries that parents may shop around for this diagnosis because it seems less severe than autism or ADHD.
"The concern that I have is that for those kids with more significant issues, that their actual diagnoses are being missed in lieu of SPD," said Kraus.
Whether SPD is diagnosed alone or along with something else, the most common treatment is occupational therapy.
Therapists guide the child through fun activities structured to activate or calm the senses.
In one, Jack wears a weighted blanket to help him concentrate while writing.
Deborah Michael of North Shore Pediatric Therapy says the goal is to teach the child how to respond appropriately to sensations.
"We want to get them to internalize strategies and get to know how to get their bodies and brains just right," said Michael.
Some experts are still looking for proof that the therapy works.
Zoe Sundstrom says it's making a difference for Jack.
"He knows what to do when he is over-stimulated; he knows what to do when he is in a weird environment that is really uncomfortable," said Sundstrom.
A group of parents and therapists is now lobbying to get SPD included in the next edition of the official psychiatric manual.
Also, researchers at the University of North Carolina at Chapel Hill are involved in a federally-funded study looking at sensory problems in children with autism.
Click here for some sensory research in children at the University of North Carolina-Chapel Hill
North Shore Pediatric Therapy, Inc.
Phone: (877) 486-4140
Fax: (847) 486-4145
Dr. Louis Kraus
Rush Univ. Med. Ctr.
Autism Resource Ctr.