The frequency and severity of persisting neuropsychological deficits after aneurysmal subarachnoid haemorrhage and associated surgical repair of the aneurysm are all too well known.1 What is less clear is the relative contribution of the initial bleed, widely assumed to be the most salient component in determination of cognitive outcome, versus factors associated with surgical and perioperative management. The Johns Hopkins group (this issue, pp 608–615) have evaluated cognitive outcome after surgical repair of ruptured (n=27) and unruptured (n=20) aneurysms in an attempt at partialling out the contribution of the subarachnoid haemorrhage from the appropriate neurosurgical intervention.2 Albeit in a relatively small series, patients with both ruptured and unruptured aneurysms performed, as a group, significantly below published norms on many neuropsychological tests postoperatively. Significant differences between preoperative and postoperative performance emerged in the unruptured aneurysm group on word fluency, verbal recall, and attentional/executive tasks. Performance of patients with ruptured aneurysms was in fact only significantly below that of patients with unruptured aneurysms on a few tests (verbal and visual memory).

The ISUIA study has reported that overall morbidity and mortality rates associated with surgical repair of unruptured intracranial aneurysms are higher than those reported previously.3 A considerable, albeit short term, negative impact on functional health and quality of life has also been identified after treatment of unruptured aneurysms.4 Prospective necropsy and angiographic studies indicate that between 3.6% and 6% of the population harbour an intracranial aneurysm.5 If the morbidity and mortality of elective surgical clipping of asymptomatic unruptured aneurysms are higher than we previously thought, then there are important implications for future clinical management and questions about the need (or not) for more accurate and complex non-invasive screening in concert with determination of parameters of risk.

As in surgical management of acoustic neuromas where hearing preservation has virtually replaced mortality, serious morbidity, and even facial nerve preservation, as a major outcome, enhanced surgical management of intracerebral aneurysms now requires more sensitive less physically based outcomes. The key challenge for applied neuropsychology over the next few years has to be to crystallise outclinically relevant cognitive measures which are comprehensible to our neurosurgical and neuroradiological colleagues and which allow more sensitive audit of interventions and refinement of current practice. In addition the roles of transcranial Doppler documented clinically significant vasospasm, nimodipine, hydrocephalus, and timing of surgery, still evade elucidation.

Interfacing with optimal surgical management of ruptured and unruptured aneurysms is the current revolution in Guglielmi coiling, which has been gathering momentum since the early 1990s. The International Subarachnoid Aneurysm Trial (ISAT)5 is a prospectively randomised controlled clinical trial funded by the United Kingdom Medical Resarch Council, the Canadian Medical Research Council, and the United Kingdom Stroke Association. It aims to compare the safety and efficacy of endovascular treatment of ruptured intracranial aneurysms with conventional neurosurgical clipping in those cases where there is equipoise. A substudy of the main trial is evaluating cognitive outcome in both groups at 1 year follow up in 7 United Kingdom centres, aiming to recruit 150–200 patients in each group. As the largest consecutive series in the neuropsychological outcome of aneurysmal subarachnoid haemorrhage to date this may help with some of the unanswered questions. We may not be able to do anything about the initial bleed, but manipulation of surgical management (hypothermia, temporary clipping, timing of surgery) and maximising the potential of less invasive endovascular techniques are open to us.