Grammy reporter had migraine not stroke

A US television reporter who lapsed into gibberish during a live shot outside the Grammys suffered a migraine, her doctors say.

KCBS-TV reporter Serene Branson was doing a stand-up on Sunday outside the Staples Centre where the award show was held when her speech became incoherent.

The station quickly cut away, and she was examined by paramedics and recovered at home.

Branson's incoherence fuelled internet speculation that she suffered an on-air stroke.

But doctors at the University of California where she went to get a brain scan and blood work done ruled it out.

Doctors on Thursday said the kind of migraine Branson suffered can mimic symptoms of a stroke.

"A migraine is not just a headache. It's a complicated brain event," said UCLA neurologist Dr Andrew Charles, who examined Branson.

Most people with migraines don't have any warning.

But about 20 to 30 per cent experience sensations before or during a migraine attack.

The most common sensations include seeing flashes of light or zigzag patterns.

In Branson's case, she felt numbness on the right side of her face that affected her speech, Charles said.

"She was actually having the headache while she was having these other symptoms," he said.

Branson told doctors she's had migraines since a child, but never suffered an episode like this before, Charles said.

Branson, a Los Angeles native and two-time Emmy nominee, worked at the CBS affiliate in Sacramento before joining KCBS.

Prior to that, she was a reporter and anchor at TV stations in Palm Springs and Santa Barbara.

Branson has been medically cleared to resume activities.

"She's totally normal. She's completely back to herself," Charles said.