The relationship between ischaemic brain lesions and cognitive outcome after aneurysmal subarachnoid haemorrhage

BACKGROUND: Cerebral ischaemia is thought to be an important determinant of cognitive outcome after aneurysmal subarachnoid haemorrhage (aSAH), but the exact relationship is unclear. We studied the effect of ischaemic brain lesions during clinical course on cognitive outcome 2 months after aSAH. METHODS: We studied 74 consecutive patients admitted to the University Medical Center Utrecht who had MRI post-coiling (3–21 days post-aSAH) and neuropsychological examination at 2 months. An ischaemic lesion was defined as hyperintensity on T2-FLAIR and DWI images. We measured both cognitive complaints (subjective) and cognitive functioning (objective). The relationship between ischaemic brain lesions and cognitive outcome was analysed by logistic regression analyses. RESULTS: In 40 of 74 patients (54%), 152 ischaemic lesions were found. The median number of lesions per patient was 2 (1–37) and the median total lesion volume was 0.2 (0–17.4) mL. No difference was found between the group with and the group without ischaemic lesions with respect to the frequency of cognitive complaints. In the group with ischaemic lesions, significantly more patients (55%) showed poor cognitive functioning compared to the group without ischaemic lesions (26%) (OR 3.4, 95% CI 1.3–9.1). We found no relationship between the number and volume of the ischaemic lesions and cognitive functioning. CONCLUSIONS: Ischaemic brain lesions detected on MRI during clinical course after aSAH is a marker for poor cognitive functioning 2 months after aSAH, irrespective of the number or volume of the ischaemic lesions. Network or connectivity studies are needed to better understand the relationship between location of the ischaemic brain lesions and cognitive functioning.