Is your child an especially picky eater? Does your son or daughter get upset about the clothes you pick out for him or her? Parents may assume the child is acting out, but it may be actually be a sign of an underlying issue.

Sensory processing disorder, or SPD, is a complex brain condition where nervous system sensory signals don’t get organized into appropriate responses, according to the SPD Foundation.

One study found that SPD affected 1 in 20 children’s daily life while other research suggested that 1 in 6 children experiences sensory symptoms that may be significant enough to impact everyday life functions.

A person with the disorder can find it challenging to process information received through the senses and may react atypically. This in turn can affect the way an individual takes on routine tasks and may manifest in clumsiness, behavioral problems, anxiety and issues at school, which is why it is important to seek treatment.

“We may see difficulty with outbursts, emotional regulation and misbehaving; difficulty learning or paying attention; or delays in developmental milestones,” said Brianne Kurcsak, an occupational therapist at Novant Health Rehabilitation Center. “Parents may wonder why their kids don’t like the texture of sand or are picky about their clothes or foods they eat.”

Individuals with SPD can experience it through one sense or through multiple senses. Some people may over-respond to a sensation and find clothing, touch, light or sound to be unbearable. Another individual with SPD may under-respond and show little reaction to stimulation, even when it causes pain.

Children who exhibit an appetite for a sensation and act as if they are in perpetual overdrive are often misdiagnosed as having attention-deficit/hyperactivity disorder (ADHD), according to the SPD Foundation. Healthcare professionals may not always recognize these sensory issues.

“Sometimes a pediatrician will evaluate a child and tell parents that he’s a typical boy and he’ll grow out of it without addressing the integration issue,” Kurcsak said. “Even if the child does learn to tolerate the beach, he or she may never learn to integrate the smell, the touch or the sound, potentially creating additional sensory issues in the future.” While a cause is still unknown, SPD occurs more often in people who have attention-deficit/hyperactivity disorder, autism, anxiety disorders or fragile X syndrome. It’s also thought to be inherited. In a recent study , researchers for the first time identified a biological difference in the brain structures of children with the disorder.

Kurcsak said patients are usually referred to her through a pediatrician or when parents realize something is just not right with the child either because of behavioral issues or a developmental delay.

“Treatment is very personalized and can range from as short as four to six weeks to a few months or longer,” Kurscak said. “The dangers are parents who try to treat SPD on their own or kids who simply aren’t treated. People may think their child has grown out of an issue. They may learn to tolerate something, but if the senses aren’t properly integrated it can cause problems later.”

Children who reach adulthood without treatment for the condition can experience difficulty with routine functions at work and even with close relationships. Many will struggle and feel socially isolated and depressed.

Kurscak recommends that parents look for behavioral patterns in their children and seek out an occupational therapist with extensive sensory training. “If you think something isn’t quite right, push for an answer and request a comprehensive evaluation. Treatment can sometimes be more effective, less intense and shorter in duration if addressed early on,” she said.