Myths about women with epilepsy

When Shawna Hignett woke up one January afternoon in 1995, her husband, John, was sitting on the bed beside her. He thought she had collapsed from the fumes while cleaning the oven and suggested they get some fresh air. Two months later she collapsed again, just after picking up the phone. But this time the then 24-year-old Saskatoon resident was taken to hospital, and doctors confirmed she had epilepsy, a neurological disorder that causes seizures and affects less than one per cent of the Canadian population.

"It was the phone ringing that triggered that second seizure," says Shawna, a mother of three. "In that same year in July it happened again. I was in a tailor shop and his phone rang. It was the exact same phone I had at home, and when his phone rang, I went down."

Dr. Nathalie Jetté, an assistant professor of neurology at the University of Calgary, says Shawna's reaction to the phone ringing is called a reflex seizure. "The seizure can consistently be provoked by an external stimulus or even an internal mental process," she says. But that doesn't explain the cause.

In Shawna's case, doctors aren't sure why she developed epilepsy, which isn't unusual. She didn't suffer from any of the known causes: stroke, head trauma, or brain tumour or infection. In less than one per cent of cases, epilepsy is inherited. "In 50 per cent of cases, we don't find the cause," says Jetté, whose brother has epilepsy.

During a CAT scan, doctors found a small cyst, not even two centimetres wide, in Shawna's right anterior temporal lobe. Her neurologist says there's nothing to indicate the cyst is the cause of her epilepsy. Shawna believes her epileptic seizures are related to hormones. "When the first three seizures occurred, they were during my period," says Shawna. She may be on to something.

Hormonal links
"Most studies done in animals and women show that estrogen tends to increase the risk of seizures, whereas progesterone is protective against seizures," says Jetté. During the menstrual cycle, estrogen increases around the time of ovulation, and some women have noted an increase in seizure frequency at that time. As well, just before and during a period, progesterone decreases, and some women may experience an increase in seizure frequency then. Catamenial epilepsy, in which the seizures are related to the menstrual cycle, affects only about 30 per cent of women with epilepsy. Nevertheless, it's a good idea for every woman with epilepsy to keep a seizure diary, says Jetté. "In this diary, she should keep track of her periods."

Even though female hormones may be one of the causes of seizures, women are not more prone to epilepsy than men. In a study published in the October 2005 issue of The Lancet Neurology, it was found that the incidence of epilepsy was similar in males and females. "The hormones can increase the frequency of the seizures, but are rarely the sole cause of the seizures," says Jetté. More research is necessary to understand the full role of hormones in epilepsy, she says.

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