What Is Sensory Processing Disorder?

Sensory processing disorder (SPD) is a condition in which a person does not respond normally to sounds, smells, textures, and other stimuli. They may be so sensitive to, say, a movie soundtrack they can't sit in a theatre, or so insensitive to stimuli they go to great lengths to seek it out.

Previously called sensory integration dysfunction, SPD is most common in children (although it can affect adults) and frequently affects people with certain developmental disorders such as autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and obsessive-compulsive disorder (OCD).

Diagnosing SPD can be challenging, as there are no official criteria for the condition, but there is a relatively standard treatment for sensory processing disorder—a type of occupational therapy known as sensory integration therapy.

Symptoms of Sensory Processing Disorder

Children with sensory processing disorder do not respond normally to stimuli that others would not be affected by in one of three ways. They may be over-responsive (also called hyper-responsive) to bright lights; loud, sudden, or sustained sounds (the whirr of a blender, say, or even music); the sensation of scratchy or itchy fabrics such as wool or clothing tags against their skin; and even certain tastes or smells. They may also be unable to tolerate physical contact with other people—for example, the pressure of a hug. Being in a crowd may be unbearable for children with SPD.

Such over-responsivity to outside stimuli can cause a child to have anxiety, trouble engaging in routine activities, and difficulty adapting to new situations. Over-responsive reactions can be mild or so debilitating a child must leave the situation immediately. As a result, it can be hard for children with SPD to engage with other kids.

Other children may have a muted or delayed response to stimuli known as under-responsivity or hypo-responsivity. For example, they may not react to the pain of a scraped knee or the discomfort of extreme cold or heat. The brains of some kids with sensory processing disorder do not adequately process messages from the muscles or joints, impairing their motor skills or posture. They may be labeled as clumsy or klutzy, or regarded as "floppy," apparently needing to prop themselves against a wall while standing, for example.

A third manifestation of SPD is called sensory craving, in which a child feels driven to seek out stimuli. The need to "feel" or experience is so strong they may act out.

Some children with SPD struggle with anxiety and may have other disorders as well, among them:

• Dyspraxia, a coordination disorder that affects the development of fine motor skills. Young children with dyspraxia may be slow to reach milestones such as walking or feeding themselves. As they get older, they may struggle with writing, drawing, and certain physical activities.
• Postural disorder: Poor perception of body position and movement (as described above)
• Sensory discrimination disorder: An inability to detect subtle differences in visual, tactile, auditory, and physical input

Causes

A specific cause of sensory processing disorder has yet to be determined. According to the STAR Institute for Sensory Processing, some research has suggested SPD may be inherited; prenatal or birth complications and certain environmental factors may also play a role.

Other research suggests a possible genetic connection. One study looked at a sample of over 1,000 toddler-aged twins and found that when one twin was hypersensitive to sound and light, there was an increased likelihood the other was as well.

Furthermore, there's research to suggest the brains of people with SPD may be structured and wired differently than those of others. For example, a 2013 study used brain imaging to show structural differences in the posterior white matter of children with SPD that correlates with atypical sensory behavior.

In 2014, another study examined neural connectivity in the white matter of children with SPD and found marked differences in areas of the brain controlling sensory perception and integration.

Diagnosis

Diagnosing SPD can be problematic. Many practitioners regard it as a singular condition and there are even clinics that specifically treat it. At the same time, however, sensory processing disorder is not in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Instead, sensory challenges are listed as a possible symptom of ASD.

That said, the first step toward confirming a child has SPD is observing behaviors that suggest the disorder and seeking a diagnosis. In addition to considering those behaviors a doctor will want to know about a child's developmental history and general health. They may do a physical examination, psychological evaluations, and speech and language testing.

There also are a variety of screening tests for SPD, including the Sensory Integration and Praxis Tests (SIPT) and the Sensory Processing Measure (SPM).

Treatment

The frontline treatment for SPD involves a form of occupational therapy known as sensory integration therapy. This approach includes a "sensory diet" consisting of a daily menu of individualized, supportive sensory strategies and a variety of activities, equipment, and accommodations designed to stimulate and/or desensitize a child, depending on whether they are hyper- or hypo-reactive.

For a child who is hyper-reactive, these might include:

• Dimming the lighting or wearing sunglasses or visor to block overhead fluorescent lighting
• Wearing ear plugs or headphones in noisy environments
• Avoiding strongly scented products (e.g., perfumes, air fresheners, soaps)
• Limiting food options to avoid personal aversions (e.g., intensely spicy, textured, cold, hot)
• Wearing clothing that accommodates personal sensitivities (e.g., tight waistbands and/or scratchy fabric, seams, and tags)
• Brushing, a technique in which a soft-bristled brush is used on the skin to help a child tolerate touch

Kids who are under-reactive or sensation-seeking can benefit from:

• Sensory-stimulating toys (e.g. safe chewies and fidget items)
• Opportunities for rocking, swinging and other sensory-stimulating activities
• Strong tasting and/or textured foods, cold and hot beverages
• Furniture arrangements that reduce chances of bumping into sharp or hard surfaces

Cognitive behavioral therapy may also be effective to help gradually increase tolerance for overwhelming sensory experiences.

A Word From Verywell

Sensory processing disorder can be challenging for children and their parents. Early intervention is ideal, as children can respond well to therapy while they develop physically and psychologically. It is also important to educate family members, teachers, and caregivers on how to help prevent distress in children with SPD, which will allow them to function better in social and school settings. Symptoms of SPD may dissipate or become easier to manage once coping strategies have been successfully integrated into a child's daily life.