In 1956, Botterell classified patients with aneurysms into five grades according to the severity of their condition after bleeding: Grade I: little bleeding, consciousness, no neurological dysfunction. Grade II: little bleeding, consciousness, mild neurological dysfunction, such as actinic nerve palsy and cervical tonicity. Grade IIIa: moderate bleeding, drowsiness or blurred, cervical tonicity, with or without neurological dysfunction. Grade IIIb: moderate or heavy bleeding, with significant neurological dysfunction and progressive worsening. Grade IV: elderly patients with low bleeding volume and mild neurological dysfunction, but with severe vascular disease. Grade V: Dying patients with central nervous system failure or denervation tonic manifestations. The American Aneurysm Collaborative Study Group proposed the following criteria with slight modifications: Grade I: asymptomatic: complete recovery after the last bleeding. Grade II: Mild: clear consciousness with headache and no significant neurological deficits. Grade III: moderate: ① drowsiness, with headache and cervical tonicity, without cerebral hemisphere dysfunction; ② wakefulness, basic recovery after bleeding, with cerebral hemisphere dysfunction remaining. Grade IV: severe: ① confusion, but no important neurological dysfunction; ② drowsiness or unresponsiveness, with cerebral hemisphere dysfunction (such as hemiplegia, aphasia, psychiatric symptoms). Grade V: decortical tonicity with loss of response to stimuli. Grade 0: unruptured aneurysm.