Sometimes it will happen to Leyla when she's at a meeting or a dinner, and she'll just fall off her chair. Other times, it will happen on a busy street. Most worryingly, it can happen in a tube station or at the top of a flight of stairs.
Periodically, Leyla's world turns upside down. Not metaphorically, but literally. It's as if her internal cameraman has flipped, inverting the scenery. The chronologies of space and time get scrambled. In the film of her day, the narrative becomes a bewildering montage. Without falling unconscious, she falls down.
On occasions, the episodes can be protracted, with Leyla embarking on what she calls her "Alice in Wonderland" interludes. Like the time she got out of a train at Liverpool Street station and couldn't find the taxi rank. She knows it took two hours, but the order of events remains unclear. She recalls a woman declaring, "I'm a doctor", and trying to remove her clothes; a man in plain clothes announcing, "I'm a policeman", and marching her around the concourse; another woman with a little girl, pointing at her and saying, "Look, that's what happens when you get drunk!"
Over the past 13 years Leyla, a professional playwright, has had three separate MRI scans, and once spent an entire week at the Institute of Neurology in London with 25 electrodes on her head to test for anything that might establish epilepsy, narcolepsy or cataplexy - conditions that, in one way or another, make people fall over. But nothing precise has been identified, and the nearest Leyla has come to a diagnosis is the suggestion that she is suffering from a rare migraine condition stemming from the basilar artery. If she does get basilar migraines, however, she does not get the accompanying headaches. She experiences only the nauseating inversions of what may or may not be a migraine "aura".
It began with a bout of flu in Cambridge, when she was 18. Leyla's parents had escaped Iran in the 1970s, where her father had been a political activist. Born in 1975, she was at first surrounded by dissidents from the period of the Shah's rule. After 1979, the small Iranian community in London swelled as more fled the regime of Ayatollah Khomeini. For Leyla, home life had been warm and happy, surrounded by a close, mutually supportive, mostly leftwing Iranian network. Though her parents were atheists, Leyla - for reasons she didn't quite understand - held on to a quiet, intense Muslim faith.
At university in a quintessentially English town, she says, she felt "other" for the first time. She broke up with her pious London boyfriend after he'd made it clear that her commitment to him, and to Islam, was inadequate. She relished undergraduate arguments about God, sparring with other students as they tried to talk her out of her belief. She'd chosen Cambridge because Sylvia Plath had gone there. She read English literature, wrote plays and felt herself coming alive.
Leyla has little doubt that the origins of her condition were physical - a bad flu, leading, perhaps, to an inner ear problem with odd neurological effects. At first she saw ear, nose and throat specialists, but nothing helped, and by the end of her time at Cambridge she was falling over routinely, sometimes concussing herself. Other, more psychological factors, seemed to be at play. In her darker moods, she used to wonder if she was being struck down by God. Then it occurred to her that to give meaning to arbitrary events is a classic trick of religious unreason. Being struck down several times a day was absurd, she decided, and her faith withered accordingly.
In Oliver Sacks's 1970 book Migraine, he made a distinction between the "periodic" element of a migraine, which implies a neurological mechanism at work, and the "circumstantial" aspect, in which the migraine aura may reveal what he called the whole "cosmography" of a person. "A migraine patient is not just complaining of a recurrent dysfunction," Sacks wrote, "he is telling us, if we will listen, the story of his life."
Leyla's falls are too mysterious to know where their causes lie on the spectrum from migraine to epilepsy - if that is where they lie at all. But she now suspects that her condition may have worked its way into her system. Where once her faith had a "centring" effect, her condition now keeps her off-kilter. "And, yes," she adds, "a lot of expressions I use to describe it are the kind of things a refugee might say - bewilderment, not knowing where things are, doubting identity, crossover, betrayal. I wonder if I'd had a clearer sense of my own identity, if I wasn't moving between worlds, I'd have got over it more quickly. Every time it happens, it feels as if the world has gone, and I'm inventing it all over again."
· Names and details have been changed.
