(LOS ANGELES) -- A doctor who treated Serene Branson, the CBS Los Angeles reporter whose garbled live report from Sunday's Grammy awards had many wondering if she suffered a stroke on the air, said a complex migraine was to blame.
"Her description of the events is really entirely typical of complex migraine," said Dr. Andrew Charles, director of the Headache Research and Treatment Program in the UCLA Department of Neurology, who saw Branson Thursday morning.
A symptom of migraine aura is "dysphasic language dysfunction," in which people know what they want to say but they can't get the words out. This is similar to aphasia, which can signal a stroke or a tumor.
"Imaging studies ruled out other kinds of problems like a stroke or primary brain event," Charles said.
Like a stroke, a complex migraine can disturb blood flow in the brain. But the main event in a migraine is "a storm of brain activity" that causes "waves of change in brain function" that spread across the brain, Charles said.
"There are dramatic changes in blood flow, but in the case of migraine, the changes don't reach the point where they actually damage the brain," Charles said. "There are no residual effects."
The video of the episode was to some upsetting to watch, as Branson's speech suddenly became slurred and incomprehensible. She appeared increasingly aware that something was wrong during the broadcast.
Branson was examined shortly after the incident by paramedics on location. Her vital signs were normal and she was not hospitalized.
Copyright 2011 ABC News Radio