Reviewing Katie's Sensory Issues

So, as I read through the chapter on the day in the life of a sensory over-responsive kid (LaTanya) in Lucy Jane Miller's excellent book, Sensational Kids, I recalled/learned/summarized these facts/observations about Katie:

Specifically, the type of problem Kate most struggles with is Sensory Modulation Disorder (SMD), which "makes it hard for her to match the intensity of her responses to the intensity of the sensations she feel".  Her system "cannot filter sensations in a way that would allow her to come up with an appropriate response" so when she is "alerted" to a sensation, her brain goes immediately to fight/flight/freeze mode.

Miller writes, "Parents of children with sensory over-responsivity tell me that they feel they're constantly tiptoeing through a minefield- always braced for the next event that will trigger a crisis", and that is precisely my experience.  

Also, "A typically developing child gets a sensory message such as the big bang of a slamming door, figures out the cause, and lets it go.  In children with sensory problems, this ability to let go of past messages sometimes appears to be impaired, leading to a 'backlog' of sensation that accumulates until it overwhelms the  child's coping skills" and "It is believed that the cumulative effect of undisposed sensory messages is what causes children with SPD to eventually fall apart over triggering events that are minor".   What if the reason Kate loses it when another kid calls her a name is a whole morning's worth of sensory alerts she hasn't been able to let go of?  

Miller goes on to describe how "LaTanya" is alerted by the overwhelming fumes of the school bus, the typical noisiness of an elementary school bus, and the inadvertent touching and jostling by other kids that happens on the bus.  Not to mention the sensation of the motion of the bus and its frequent stops and starts, and unexpected, loud traffic noises outside, such as sirens and honking horns.  Little wonder if she prefers to sit in the front seat to minimize some of these, and have visual cues to warn her of upcoming sensations. But sadly, in the example, the other kids won't always let her sit where she's most comfortable, and she is often reduced to tears.  "If LaTanya needed a wheelchair or had another physical limitation that made it hard for her to function on the bus, accommodations like an assigned seat would have been made for her long ago. However, because her handicap is invisible, accommodations are made on a spot basis and only after she falls apart, which just confirms everyone's opinion that this is a kid with big problems."  (my emphasis)

What if Katie is experiencing these same things, and arriving at school already so overstimulated that her system can't calm down enough to focus on the tasks at hand?  How much of what looks like ADHD behavior is actually her inability to take anything more in or process the information in the right part of the brain because she is so consumed with sensory overload?