Her recent remarkable change began more than two months ago after Allyson and her parents, Jaime and Aaron Semler, and her grandparents flew to Massachusetts.
There, on March 28, at Children's Hospital Boston, doctors performed a procedure to bypass the blocked arteries in Allyson's brain, which in time will restore blood flow to her brain. The surgery was done by Dr. Michael Scott, one of only a few doctors in the nation who specialize in such operations.
Three incisions were made to Allyson's head - one on each side of her head for the actual surgery and one more on the left side to insert a probe to measure brain activity for research purposes, Semler said.
As the doctor warned, Allyson's face was swollen and her eyes were swollen shut for more than two days after the surgery. But by the third day, most of the swelling had subsided.
Allyson was released from Children's Hospital on April 1 and returned home two days later - in time to celebrate her first birthday April 9 with family and friends. It also gave the family time for final preparations for her parents' wedding on May 6.
Allyson's mother stayed in their East Ridge Drive townhome with the little girl for a month following the surgery, watching for signs of seizures.
Thankfully, there have been none.
Indeed, since the surgery, Jaime Semler said, Allyson is able to focus much better and is reaching normal developmental milestones, something that was impossible prior to surgery.
"She's doing great. She's advanced more than anybody thought," Aaron Semler said.
At the end of this summer, Allyson will be seen by a neurologist at Children's Hospital National Medical Center in Washington, D.C., and have an MRI to see the extent to which the surgery was successful.
And, next March, the family will take Allyson back to Children's Hospital Boston so Dr. Scott can examine her to see how she is doing.
Jaime Semler said the doctor has been "amazing," calling or e-mailing them weekly.
"Words can't express how good you feel about him," Semler said. "We told him he had hands of gold."
Allyson's family is also grateful for the support of the community. As the medical bills start to come in, the financial support has been a help.
Semler said the bills are "pretty steep, but I wouldn't change it."
Among those helping to support the family is the Maugansville Ruritan, which holds an auction every year to raise funds to help others. This year's auction benefitted Allyson's family, raising $13,400 - the highest amount ever, said Marty Lumm, secretary of the Maugansville Ruritan.
An account was also set up at Hagerstown Trust with the more than $7,800 in contributions from the public.
Other fundraisers include one organized by Annie Woods, a resident of Francis Murphy Apartments, where Jaime Semler's grandparents live. Residents raised $200, donating whatever they could, whether it was pocket change or more.
In addition, the Hagerstown Elks Lodge has made two donations totaling $850 to help with medical bills.