There were other symptoms that were probably related to her migraines which, at the time, she had no way of connecting to them. She was easily motion sick. On the plane the summer they flew to England, for instance. She did not actually throw up in the family car but often felt woozy, especially if she tried to read. Rachel and Allison read. They teased her. They complained about not wanting to sit next to her in the car in case she threw up — where’s the barf bag? — but they both had to because neither of them was prepared to give up her window seat. So Claire, the youngest, stuck in the middle, her feet straddling the hump on the floor, was forced to contemplate the unreachable landscape, visible through the front windscreen and over her sisters’ shoulders. She took some small revenge by insisting that either Rachel or Allison keep her window open, no matter how cold it was, otherwise she would throw up on them.

There was a fear that onvercame her, linked to a sensation of being slightly out of control, as though her body were not altogether hers or the line between the world out there and her in here was very thin.

At night sometimes, as Claire lay in her bedroom beside solid, comforting Allison, her body began shrinking. She thought of it as the elevator feeling: shrinking was like falling down an elevator shaft, being both the one falling and the one who watched herself fall, whole but diminishing in scale. Other nights she grew. Her limbs swelled. If she concentrated all her attention on her right hand, it kept growing: its proportions remained the same, it simply expanded. She could not move. She had no warning which nights the distortions were going to happen. Whether she would be dropped into a deep well or lifted into the sky. Disappear or balloon to fill the world.

She didn’t talk about it. She assumed this happened to everyone (Rachel, Allison), and that because the experience was common, no one spoke of it.

Nor did it seem unusual to desire to measure things, trying to keep the world’s wildness at bay. So much sensation — from the whirr of crickets to the whoosh of cars accelerating between stop signs on Rathburn Road, the sometimes bewildering facial expressions of other people, the pressure of others’ gazes and skin, the hard plastic curves of a beloved toy figurine lost when it fell through her fingers into a sewer grate, the assault of the penny arcade machines beside an English beach, the overblown sweetness of honey — and so little means of blocking anything out.

One winter afternoon, aged eight, Claire made her way towards her parents’ bedroom where the pale curtains were often left half-closed. In this room, she was alone, unobserved. She was not thinking in any plotted way about what she was doing. Her mother, and Rachel, and Allison were down the hall and around the corner, a right-hand turn into the kitchen. Claire peeled off her socks. The radiator beneath the window was sheathed in an aura of heat. She pressed her right foot against it. Her skin and muscle flinched. She persisted. She counted to ten, pulled her foot back, and examined the pink flush growing on her sole. The stinging swelled and receded. No other sensation existed while she did this. Then she tried the same with her left foot.

She began to slip away to her parents’ bedroom regularly, in the later afternoon, when she was least likely to be missed, while her mother was preparing supper and her sisters bickering over homework at the dining-room table, her father still away at the school where he taught math. Always at the same radiator, beside the rocking chair over which Sylvia hung her worn shirts and pantyhose, faintly sweet with the odour of her feet and shoes. Beneath the radiator’s eight pleats, dust gathered amidst the pale blue stubble of the broadloom. Cold air billowed through an open slit of window. Claire did not close the door. She folded her knees, pressed both feet to the hot metal, and started counting. Each time there came a point when she could no longer hold her feet in place, her arches contracting even as she bit her tongue and urged herself to go longer. She did not cry. The pain was worse, far worse, when she pulled her feet away. It bowled her over. She bit her hand to counteract it. But the pain was hers, no one’s but hers. She controlled when it started and when it ended, and this produced a satisfaction so deep it became exhilaration. She began to use her wristwatch to time herself — three minutes and forty-four seconds, forty-five, forty-six. Her feet so piercingly tender afterwards it was hard to walk. One step, two steps, three. Once she held her feet so long that she burned them enough to blister. Did she make a sound that time? Someone in the doorway. Her mother in the doorway, bounding across the room, yanking her by the wrist, What the heck do you think you’re doing?