A fascinating case of foreign accent syndrome recently cropped up in southwestern Ontario, says a new report published by researchers at McMaster University.

The rare syndrome affects people who have had a stroke, causing them to speak in a different accent than the one they had before the stroke. It usually occurs after a stroke damages the areas of the left hemisphere of the brain related to speech production, such as Broca's area, pre-motor and motor areas and the basal ganglia.

Broca's area is a section of the brain found in the frontal lobe that's connected to speech, while the basal ganglia is responsible for movement.

Rosemary Dore, 50, of Windsor, Ont., had a left-sided stroke that left her with an accent similar to the Canadian East Coast accent, though she had formerly had a southern Ontario accent. Dore had lived in southern Ontario all of her life and only travelled to Florida on vacation. She had never been to the East Coast nor did she have any family members with East Coast accents.

"Everybody, even the doctors … they [thought] I was from Newfoundland, because I have an accent," Dore told CBC News. "But I didn't, because I come from Windsor, Ont."

Her case is the first of its kind reported in Canada, the McMaster researchers said, and one of fewer than 20 cases reported worldwide.

"The folks at Hamilton General realized that they had this really unusual case on their hands — a woman with foreign accent syndrome," said Karin Humphreys, a co-author of the study. "So they called us up here at McMaster University, and we dropped everything and ran to see if we could take some tape recordings of Rosemary.

Researchers gave Dore a CT scan, which revealed various changes in the brain consistent with an ischemic stroke. One month after the stroke, she was tested and found to have 100 per cent speech intelligibility.

Her new accent went unnoticed for some time by medical professionals, who thought she was from out east. Even Dore didn't realize her accent had changed.

Linguistic analyses of Dore's speech were conducted during three interviews with researchers at one-week intervals, starting at about four weeks post-stroke. During the interviews, she was asked to read passages from various texts and talk to her husband. Independent, linguistics trained listeners analyzed the tapes and transcripts of her speech patterns.

In the case of Dore, her accent was found to be a modification of an East Coast accent.

The researchers believe that in the case of foreign accent syndrome, individual brain changes can lead to speech disparities. "In her case, what seems to be in common with a bunch of other patients is this basal ganglia damage - this area that's involved in motor planning," said Humphreys.

"It is not necessarily a 'generic foreign accent' that results," the study says. "Instead, the specific phonological changes that occur may be unique to each individual, reflecting differences in damage within the motor speech network.

"These changes can give rise to specific-sounding accents, including ones like a regional dialect change, rather than a complete foreign accent."

The case study is in the July issue of the Canadian Journal of Neurological Sciences.