Migraines can be hell at the best of times, and thanks to our hormones more women suffer from them than men (one in four women compared with one in 12 men).
But for Gloucestershire-based Kay Russell, going to bed with a migraine didn't just come with the usual throbbing pain, nausea and sensitivity to light. When Kay had a migraine earlier this year she woke up the next day with slurred speech. Then suddenly, one day she started talking in a French accent - and has done so ever since.
It's a real nightmare for Kay, who's only been to France twice and used to have a typical English accent. People refuse to believe it's really her when she's on the phone, even old friends. Kay also had to quit her job as a sales executive because of it.
Kay, 49, suffers from foreign accent syndrome (FAS), an extremely rare brain condition that has affected just 60 people worldwide since it was first identified in 1941. She has been a migraine sufferer for 20 years.
FAS affects the part of the brain that controls speech and, as in Kay's case, can be triggered by a migraine. According to experts it can last for a few days or, in some cases, can be permanent. There is no known cure, so nobody knows how long Kay will continue to sound French.
Thankfully there are treatments for migraine, including painkillers, anti-inflammatory drugs and oestrogen patches. Taking magnesium and vitamin B2 supplements may also help.
Find out more about migraine triggers and treatments at The Migraine Trust.