Like the spinning blue circle on a computer screen when something stops working - that's how Karen Fisher describes the imminent arrival of a migraine.
"It's like my brain just stops working ... it's like it's buffering,'' Ms Fisher says.
"I don't have an aura, I just get vertigo, I do get a headache as well, I get increased light sensitivity, increased sound sensitivity."
Vertigo and nausea-inducing vestibular migraines frequently leave Ms Fisher, 59, bedridden and contributed to her decision to retire from her nursing career earlier than she had previously planned.
The migraines caused Ms Fisher and her husband to cut short an overseas holiday last year.
"I had episodes on the plane, got taken off at Singapore Airport, all very dramatic,'' she says.
After suffering from vertigo and nausea more than a decade ago, Ms Fisher was initially diagnosed with Meniere's disease and placed on a low-salt diet.
When her symptoms worsened a few years later, Ms Fisher was determined to get to the bottom of things and saw a series of specialists. It was only in 2025 that she was diagnosed with migraines and she is still battling to get the condition under control.
About 3.9 million Australians suffer from migraines, according to data published by the Australian Institute of Health and Welfare. Females are more than twice as likely as males to suffer from the condition.
North Canberra Hospital Neurology and Stroke Department director Dr Ronak Patel says the exact cause of migraines is unknown. But it involves pain-processing issues in the brain and is driven by peptides known as neuropeptides.
In addition to helping patients identify and avoid migraine triggers, several prescription medications can reduce the frequency of attacks and symptoms.
For patients who don't respond well to the most commonly prescribed preventer medications, a new range of medications known as CGRP inhibitors have become available over the past decade. Another alternative is botulinum toxin (Botox) injections.
Studies have found that CGRP inhibitors and Botox injections can reduce migraine episodes by 50 per cent in some patients.
"Quite often patients ask if there is a head to head comparison between the Botox and these medications and there is no clinical evidence to compare those,'' Dr Patel says.
"What I often say is that migraine is very individualised. If you do not respond to botulinum toxin injection you may try CGRP and there are patients in clinical practice who do not respond very well to CGRP but have a very good response to botulinum toxin."
Having unsuccessfully tried a series of preventer medications, in recent weeks Ms Fisher began receiving Botox injections. She is optimistic, having been told by other patients in a Facebook support group that the injections have helped them.
"The other week, I saw a woman who posted that she was on her fourth round of Botox and it had started working, She'd been sick for years and it was just like a ray of sunshine and a rainbow over my day,'' Ms Fisher said.
When she is well enough, Ms Fisher volunteers at a hospital and aged care homes by visiting patients with her sheepdog, Rufus. If her symptoms improve, she may even return to some paid nursing work.
Her advice other migraine sufferers is not to leave symptoms untreated.
"Get on the waitlist as early as you can,'' she says.
"If you don't get success, go to somebody else and don't just put up with it. You have to give each treatment time [to see if it works], but keep trying."
