A Systematic Review of Cognitive Outcomes in Angiographically Negative Subarachnoid Haemorrhage

Clinical outcomes, including performance on cognitive assessment, in patients with angiographically negative subarachnoid haemorrhage (anSAH) are often interpreted as benign with a good prognostic trajectory. However, diffuse cognitive deficits have been reported within this patient cohort resulting from anSAH, albeit to a lesser extent when compared to other neurovascular events. We consider cognitive outcomes in relation to anSAH to systematically review reported deficits, with a view to quantify and categorise cognitive impairment in this cohort. Anxiety and depression were also included within this review, provided they were assessed alongside cognitive function. Performance deficits in attention and executive function are commonly reported, with set-shifting and interference tasks most commonly impaired in patients. Non-executive cognitive functions are negatively implicated also. Clinical implications and hypotheses relating to the source of these deficits are discussed. This review was formally registered with PROSPERO (CRD42017075294).