Background: Post-stroke cognitive impairment (PSCI) occurs in approximately half of ischemic stroke survivors. Infarct location is a potential determinant of PSCI, but a comprehensive map of strategic infarct locations is lacking. In this large-scale multicenter lesion-symptom mapping study, we aimed to identify infarct locations most strongly predictive of PSCI, and use this information to develop a prediction model. Methods:We harmonized individual patient data from twelve cohorts through the Meta-VCI-Map consortium. Patients with acute symptomatic infarcts on CT/MRI and cognitive assessment <1 year poststroke were eligible. PSCI was defined as impairment in ≥1 cognitive domains on neuropsychological assessment or impairment on the Montreal Cognitive Assessment. Voxel-based lesion-symptom mapping (VLSM) was used to calculate voxel-wise odds ratios for PSCI. For the prediction model, a "location impact score" on a five-point scale was derived from the VLSM results. Combined internal-external validation was performed using leave-one-cohort-out cross-validation for all twelve cohorts. Findings:In our combined sample of 2950 patients (age 67±12 years, 39% female), 44% had PSCI. We achieved almost complete lesion coverage of the brain in our analyses (87%). Infarcts in the left frontotemporal lobes, left thalamus, and right parietal lobe were strongly associated with PSCI (False Discovery Rate corrected q<0•01; voxel-wise odds ratios >20). These strategic regions were mapped onto a three-dimensional brain template to visualize PSCI risk per brain region. The location impact score showed good correspondence between predicted and observed risk across cohorts after adjusting for cohortspecific PSCI occurrence. Interpretation:This study provides the first comprehensive map of strategic infarct locations associated with risk of PSCI. A location impact score was derived from this map that robustly predicted PSCI across cohorts and can be applied by clinicians to identify individual patients at risk of PSCI.

Cerebral small vessel disease (SVD) is an important cause of cognitive impairment. Important MRI manifestations of SVD include white matter hyperintensities (WMH) and lacunes. This narrative review addresses the role of anatomical lesion location in the impact of SVD on cognition, integrating findings from early autopsy studies with emerging findings from recent studies with advanced image analysis techniques. Early autopsy and imaging studies of small case series indicate that single lacunar infarcts in, for example the thalamus, caudate nucleus or internal capsule can cause marked cognitive impairment. However, the findings of such case studies may not be generalizable. Emerging location-based image analysis approaches are now being applied to large cohorts. Recent studies show that WMH burden in strategic white matter tracts, such as the forceps minor or anterior thalamic radiation (ATR), is more relevant in explaining variance in cognitive functioning than global WMH volume. These findings suggest that the future diagnostic work-up of memory clinic patients could potentially be improved by shifting from a global assessment of WMH and lacune burden towards a quantitative assessment of lesion volumes within strategic brain regions. In this review, a summary of currently known strategic regions for SVD-related cognitive impairment is provided, highlighting recent technical developments in SVD research. The potential and challenges of location-based approaches for diagnostic purposes in clinical practice are discussed, along with their potential prognostic and therapeutic applications.

Background and PurposeStudies on the impact of small vessel disease (SVD) on cognition generally focus on white matter hyperintensity (WMH) volume. The extent to which WMH location relates to cognitive performance has received less attention, but is likely to be functionally important. We examined the relation between WMH location and cognition in a memory clinic cohort of patients with sporadic SVD.MethodsA total of 167 patients with SVD were recruited from memory clinics. Assumption-free region of interest-based analyses based on major white matter tracts and voxel-wise analyses were used to determine the association between WMH location and executive functioning, visuomotor speed and memory.ResultsRegion of interest-based analyses showed that WMHs located particularly within the anterior thalamic radiation and forceps minor were inversely associated with both executive functioning and visuomotor speed, independent of total WMH volume. Memory was significantly associated with WMH volume in the forceps minor, independent of total WMH volume. An independent assumption-free voxel-wise analysis identified strategic voxels in these same tracts. Region of interest-based analyses showed that WMH volume within the anterior thalamic radiation explained 6.8% of variance in executive functioning, compared to 3.9% for total WMH volume; WMH volume within the forceps minor explained 4.6% of variance in visuomotor speed and 4.2% of variance in memory, compared to 1.8% and 1.3% respectively for total WMH volume.ConclusionsOur findings identify the anterior thalamic radiation and forceps minor as strategic white matter tracts in which WMHs are most strongly associated with cognitive impairment in memory clinic patients with SVD. WMH volumes in individual tracts explained more variance in cognition than total WMH burden, emphasizing the importance of lesion location when addressing the functional consequences of WMHs.

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