A question from one of my commenters is worth a post of it's own because I've asked the same thing.
"How did they determine she is not autistic? We had our daughter's brain MRI done a few weeks ago and it came back normal. No brain damage or injury. I was shocked!!"
First, I'll address the MRI part of the question. Sissy and Jie Jie's brain MRI also showed normal brain structure except for a slight thinning of the corpus colosum in Sissy's brain.
"MRI can be used to diagnose disorders that cause changes in the brain such as bleeding, alterations in brain tissue or structure such as brain swelling and infiltrative disorders such as inflammation or brain tumors.
MRI can be used to diagnose stroke, which occurs when blood flow to the brain stops. Two major types of strokes are ischemic, caused by a lack of oxygen reaching brain tissue due to artery narrowing or blockage, and hemorrhagic, caused by a broken vein or artery. MRI is especially useful in diagnosing ischemic strokes, because they are more subtle and need the higher resolution to view them. Magnetic resonance imaging with angiography, or MRA, can be useful in diagnosing brain aneurysms, weak areas of arteries that bulge out like balloons and can cause strokes or other complications. MRI does not reveal fresh blood as well as computed tomography, or CT, scans do, and often both are used to diagnose hemorrhagic strokes.
MRI scans are often used to help diagnose abnormalities in the brain, such as birth defects, developmental deformities, damage caused by medical procedures, or cerebral palsy, and these scans can reveal either large or very minute brain changes. MRI scans can also be used to diagnose the effects of a traumatic brain injury, or TBI, on brain tissue. MRI can pick up subtle changes caused by the injury, such as very tiny areas of damage or bleeding.
MRI can be useful in diagnosing brain cysts and tumors, especially very small ones or those that are in areas that other imaging techniques like CT scan cannot visualize well. Sometimes a special dye may be injected into the brain before the MRI to help view differences in the adjacent areas of brain tissue.
MRI is superior to other forms of imaging for diagnosing certain brain infections or conditions that result in inflammation of the blood vessels called vasculitis. MRI also can reveal brain abscesses, collections of pus in the brain due to infection or injury. MRI is very important in the diagnosis of multiple sclerosis and can detect the condition in up to 95 percent of the people who have it because of its ability to detect subtle changes in brain tissue. MRI can be quite useful in helping diagnosing hormonal disorders that affect the brain, such as pituitary problems or Cushing syndrome."
An MRI cannot diagnose mental illness or, as in Jie Jie's case, intellectual disability caused by genetic conditions. MRI doesn't show why any of my three older daughters are intellectually disabled. In Jie Jie's case, changes in her genes make her cells unable to do the job they were supposed to do or cause them not to work at all. No one knows the cause of Sissy's or Blossom's disabilities.
As for austism, there are many, many symptoms and characteristics of autism and Sissy had a ton of them, but she didn't have the main ones. In order to be diagnosed with autism, she needed to exhibit at least two of the following: an obsession with something that she couldn't control, OCD such as lining things up a certain way and tantrums if someone interfered, repetitive muscle movements such as hand flapping, echolalia (repeating the same words or sounds several times in a row - the frequency of repetition is key here because Sissy repeats things a lot, but not like a person with autism apparently does), and not knowing they are doing something and not being able to stop it, like escaping/wandering/eloping, they just won't have an awareness of it, won't plan it, etc...
Sissy has ALL BUT ONE of the social symptoms of autism, and many of the developmental symptoms such as speech impairment, she even repeats things and has OCD tendencies, but they aren't to the extreme that a person with autism tends to do them, therefore, the doctors concluded she didn't have autism. The hardest thing to hear was that "she has insight" into her escaping. I heard the word insight and thought the doctor was crazy, because Sissy isn't insightful about anything at all, but in a clinical sense, insight means awareness. She is aware that she is escaping and she even plans it, she even says she knows it's wrong and dangerous. The big question, though, is how much is she repeating what everyone has said to her about it, hence her saying, "I know it's dangerous. I know it's wrong." But, one cannot dismiss the fact that she does plan it and a person with autism who wanders (the terms for someone who leaves safety without awareness) cannot plan it.
All this said, however, there is something else that I learned. Boys have autism more than girls and girls are often misdiagnosed for years and years and years because their symptoms present differently than boys.
Like many other conditions, autism shares symptoms with other conditions. For example, let's look at vomiting. We vomit for many reasons - flu, food poisoning, pregnancy, over eating, motion sickness, etc. Same with headaches, there are many reasons from being dehydrated to having a brain tumor. Sissy's autism-like symptoms are being chalked up to her developmental delays. Remember, developmental delay means that something didn't develop. Will a newborn baby's brain show a defect just because certain centers of the brain haven't developed yet? No, just like Sissy's brain didn't show a defect where her brain failed to develop. Science just can't see certain things and the brain is still a huge mystery.