1.2.3.1 Familial hemiplegic migraine (FHM)

A 38-year-old woman reports her fourth episode of this nature, which occurred during her shift on the factory floor. Colleagues noticed her stop mid-task; she later described jagged, shimmering lines across her right visual field, quickly followed by a heavy, dragging weakness down the right arm and leg that left her unable to lift a crate. She noted these as bright, positive visual phenomena rather than any dark or missing patches, and everything remained on the right side throughout. At the same time she found she could barely get her words out and had to gesture to a colleague for help. A severe, pounding headache came on within about fifteen minutes of the visual disturbance starting. Her cousin, she says, has suffered near-identical attacks with weakness down one side, and this was formally assessed and found to meet the recognised specialist criteria.