Collateral status is an indicator of a favorable outcome in stroke. Leptomeningeal collaterals provide alternative routes for brain perfusion following an arterial occlusion or flow-limiting stenosis. Using a large cohort of ischemic stroke patients, we examined the relative contribution of various demographic, laboratory, and clinical variables in explaining variability in collateral status.

Patients with acute ischemic stroke in the anterior circulation were enrolled in a multi-center hospital-based observational study. Intracranial occlusions and collateral status were identified and graded using multiphase computed tomography angiography. Based on the percentage of affected territory filled by collateral supply, collaterals were graded as either poor (0–49%), good (50–99%), or optimal (100%). Between-group differences in demographic, laboratory, and clinical factors were explored using ordinal regression models. Further, we explored the contribution of measured variables in explaining variance in collateral status.

386 patients with collateral status classified as poor (n = 64), good (n = 125), and optimal (n = 197) were included. Median time from symptom onset to CT was 120 (IQR: 78–246) minutes. In final multivariable model, male sex (OR 1.9, 95% CIs [1.2, 2.9], p = 0.005) and leukocytosis (OR 1.1, 95% CIs [1.1, 1.2], p = 0.001) were associated with poor collaterals. Measured variables only explained 44.8–53.0% of the observed between-patient variance in collaterals.

Male sex and leukocytosis are associated with poorer collaterals. Nearly half of the variance in collateral flow remains unexplained and could be in part due to genetic differences.

The Montreal Cognitive Assessment (MoCA) is a commonly used cognitive outcome in stroke trials. However, it may be insufficiently sensitive to detect impairment in high-functioning stroke survivors. The National Institutes of Health (NIH) Toolbox Cognition Battery (NIHTB-CB), a 30-min comprehensive tablet-based cognitive assessment, may be a better choice to characterize cognitive issues in this cohort.

We compared MoCA and NIHTB-CB performance in young stroke survivors (18–55 years) with excellent functional outcomes (modified Rankin Scale 0–1) reporting subjective cognitive complaints to that of age-matched healthy controls. We recruited 53 stroke survivors and 53 controls. We performed a sensitivity analysis in those participants with normal MoCA scores (≥26).

Median MoCA scores were not significantly different between stroke survivors (27.0 vs. 28.0) and healthy controls. Mean T scores for NIHTB-CB fluid (44.9 vs. 54.2), crystallized (53.8 vs. 60.0), and total cognition (49.1 vs. 58.4) components were significantly lower in stroke survivors compared to healthy controls (p < 0.001 for all). In participants scoring within normal range (≥26) on the MoCA, NIHTB-CB scores for all components remained significantly lower in stroke survivors.

In young stroke survivors with excellent functional outcomes and subjective cognitive complaints, the NIHTB-CB, but not the MoCA, was able to detect differences in cognitive performance between stroke survivors and healthy controls. The NIHTB-CB may be a suitable outcome measure for cognition in clinical trials examining higher-functioning young stroke survivors.

To evaluate an abbreviated NIH Toolbox Cognition Battery (NIHTB-CB) protocol that can be administered remotely without any in-person assessments, and explore the agreement between prorated scores from the abbreviated protocol and standard scores from the full protocol.

Participant-level age-corrected NIHTB-CB data were extracted from six studies in individuals with a history of stroke, mild traumatic brain injury (mTBI), treatment-resistant psychosis, and healthy controls, with testing administered under standard conditions. Prorated fluid and total cognition scores were estimated using regression equations that excluded the three fluid cognition NIHTB-CB instruments which cannot be administered remotely. Paired t tests and intraclass correlations (ICCs) were used to compare the standard and prorated scores.

Data were available for 245 participants. For fluid cognition, overall prorated scores were higher than standard scores (mean difference = +4.5, SD = 14.3; p < 0.001; ICC = 0.86). For total cognition, overall prorated scores were higher than standard scores (mean difference = +2.7, SD = 8.3; p < 0.001; ICC = 0.88). These differences were significant in the stroke and mTBI groups, but not in the healthy control or psychosis groups.

Prorated scores from an abbreviated NIHTB-CB protocol are not a valid replacement for the scores from the standard protocol. Alternative approaches to administering the full protocol, or corrections to scoring of the abbreviated protocol, require further study and validation.