Natural history and medical treatment of cognitive dysfunction after spontaneous subarachnoid haemorrhage: review of current literature with respect to aneurysm treatment.

Aneurysmal subarachnoid haemorrhage (aSAH) has the highest mortality and morbidity among all types of stroke. Unfortunately, cognitive dysfunction remains a major problem to those who survive the acute crisis. Most studies focused on patients after microsurgical clipping, which turned out to be different from the modern patient cohorts. With the widespread introduction of endovascular surgery as the first choice of treatment, there was a hope that post-aSAH cognitive dysfunction could be markedly reduced. However, data showed that post-aSAH cognitive dysfunction remained a major burden to the survivors of our modern patient cohort that returned to the community more than nine months after the initial haemorrhage. There is, therefore, a need to further understand its pathophysiology and natural history, and to develop effective treatment strategy. The results are encouraging and further clinical studies are indicated. Collaborations between cognitive scientists, neurologists and neurosurgeons are essential to advance the understanding of the problem.