On their website, the Sensory Processing Disorder Foundation defines SPD (also known as Sensory Integration Disorder) thus: "A condition that exists when sensory signals don't get organized into appropriate responses."
It goes on to say, "A person with SPD finds it difficult to process and act upon information received through the senses, which creates challenges in performing countless everyday tasks. Motor clumsiness, behavioral problems, anxiety, depression, school failure, and other impacts may result if the disorder is not treated effectively."
Those are not tentative, "we think" statements. They boldly declare the existence of a brain condition called SPD, and they assert its nature.
In the absence of obvious, significant, quantifiable brain deficiency, there is no known way of determining that certain otherwise normal children's brains don't organize sensory data appropriately. Therefore, the above statements from SPDF are completely speculative.
A mother recently told me that her 4-year-old daughter has been diagnosed (at a prominent hospital clinic) with SPD. The primary symptom was complaint of her clothes, especially underwear, not feeling right. They itched. They scratched. They felt funny. Almost every morning for the past two years, tantrums have occurred over getting dressed.
Instead of speculating on why this little girl would find certain clothing/fabrics uncomfortable, I focused on what was actually taking place: The child was refusing to get dressed in the morning.
I told the parents to strip the little girl's room of everything except essential furniture and clothing. She could sleep with her favorite stuffed animals, but they were to be removed in the morning. All of her toys were henceforth kept in a playroom.
When she woke up, she had to stay in her room until she was dressed in whatever she wanted to wear.
Two weeks later, I received the following e-mail from Mom: "The very first morning, (daughter) reminded us to remove her sleep toys, so she could get dressed. She then put on underwear and clothes and came out for breakfast. She has done this with no tantrums or requests for help since we began two weeks ago."
At this writing, it's been five weeks since this little girl complained of her clothes not feeling right.
I report. You decide.