Every year, strokes kill millions of people and leave millions more permanently disabled (page S2). They are terrifying ordeals that usually occur without warning — even though the causes are known (S4 and S12) — and rob people of their independence through impaired speech and movement. Researchers are trying to work out why the blood suddenly stops flowing smoothly to the brain, and how to limit and repair the resulting damage, thereby helping survivors to put their lives back together.

Credit: Nik Spencer

Treating stroke is a race against time: starved of oxygen, the brain cells die in the millions every minute. Doctors are therefore experimenting with mobile units that bring the hospital to the patient, drastically reducing the time it takes to deliver drugs that can limit the damage (S5).

Once a stroke has left its mark, the focus shifts to repair. One promising approach involves the use of hydrogels — polymers that can deliver treatments directly to the injured brain and stimulate and nurture the growth and differentiation of neural stem cells (S6).

Patients face a long road to recovery. But the months or years of physical therapy can be made less gruelling by incorporating the use of robotic helpers and other mechanical devices (S8).

For many people, however, physical recovery is the easy part. Strokes often result in depression, and it is becoming clear that this is not just because they are traumatic life events, but because they actually make the brain more susceptible to mood disorders. A topic of some controversy, therefore, is whether every patient should automatically receive antidepressants (S10).

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