1.2.3.1 Familial hemiplegic migraine (FHM)

A 60-year-old man reports his sixth lifetime attack of this pattern, now well documented over the past two decades. He describes a complete loss of vision in one eye only, distinct from the jagged, shimmering lines that also cross his sight on these occasions, with the two features appearing one after the other rather than together. Shortly after, he develops a dragging weakness in the arm on the same side, on this occasion severe enough that his wife had to steady his cup of tea for him. Everything, he is clear, stays confined to that one side of his body. The whole disturbance builds gradually, spreading over what he estimates as ten minutes rather than coming on abruptly. His late father had documented attacks of an essentially identical kind, including weakness down one side, and had once been assessed and told this matched the recognised specialist pattern.