But even more important, Miranda found something amiss on his EEG, which he said is an indication Beckett could be having seizures that are impossible to see physically.
After more tests were done, including a sleep EEG, it was determined that Beckett almost certainly isn't autistic, Miranda said. He has a version of Landau Kleffner syndrome, a rare brain seizure disorder that can masquerade as autism.
Miranda put Beckett on anti-seizure medicine and the results have been astounding.
"Within a period of 60 days his vocabulary went from maybe two or three words to about 300 words," Miranda said.
To watch Beckett today, you might think he has a bit of trouble speaking, but it's minor. You'd never think he was autistic. He's being mainstreamed in kindergarten, in a school that he attends with his brother.
But that is yet another thing Kavanagh has had to fight for, because the autism label stuck for so long it was hard to remove.
She's also had to battle conventional wisdom in the medical community. Despite the EEG results, other doctors she'd seen in the past told her Beckett's seizures didn't meet the standard criteria for treatment. He wasn't having enough seizures, in other words.
Typically with anti-seizure medicine, the course of treatment is no more than four years. In that amount of time, the seizures usually clear up as the brain is literally retrained to stop seizing.
Many types of anti-seizure medicine are in use for other symptoms, such as bipolar disorder. But there is great debate within the autism medical community about when anti-seizure drugs should be used and about how severe the seizures have to be before they are treated.
Further complicating things, these seizures can often be completely invisible to the naked eye, or mistaken for staring or daydreaming -- symptoms typical of autism.
That was the problem for 8-year-old Justin Senigar. When he was 18 months old, his parents, concerned about his lack of speech, took him to a doctor. They were told he was on the "spectrum" and to focus on speech therapy.
The Senigars never quite believed it. His eyes told them something else. He would close his eyelids for moments at a time. It looked almost as if he was dreaming.
They searched for answers year after year, even taking him to a revered neurologist when he was 4 years old.
"They didn't run tests, they didn't do anything," Justin's mother, Paula Senigar, said.
Until the Senigars found Miranda when Justin was 7, all the response they could get from him was one-word answers or just nods or shakes of his head.
After running tests on Justin and finding from his EEG that there seemed to be fairly significant seizure activity, Miranda prescribed anti-seizure medicine, which made a difference for him immediately.
"Within the first couple of weeks," Todd Senigar said. "We started to see that he was able to maintain focus on … schoolwork.
"We noticed that his language was developing and he was able to be more expressive. And it was exciting for us," Paula added.
The Senigars will never be able to get back the years before Justin was diagnosed. They watch old home videos, remember specific instances when Justin seemed a little off and wish they could have found out something sooner.