Association between Striatal Brain Iron Deposition, Microbleeds and Cognition 1 Year After a Minor Ischaemic Stroke

Brain iron deposits (IDs) are inversely associated with cognitive function in community-dwelling older people, but their association with cognition after ischemic stroke, and whether that differs from microbleeds, is unknown. We quantified basal ganglia IDs (BGID) and microbleeds (BMBs) semi-automatically on brain magnetic resonance images from patients with minor stroke (NIHSS < 7), at presentation and 12 months after stroke. We administered the National Adult Reading Test (NART, estimates premorbid or peak adult cognition) and the Revised Addenbrooke’s Cognitive Examination (ACE-R; current cognition) at 1 and 12 months after stroke. We adjusted analyses for baseline cognition, age, gender, white matter hyperintensity (WMH) volume and vascular risk factors. In 200 patients, mean age 65 years, striatal IDs and BMBs volumes did not change over the 12 months. Baseline BGID volumes correlated positively with NART scores at both times (ρ = 0.19, p < 0.01). Baseline and follow-up BGID volumes correlated positively with age (ρ = 0.248, p < 0.001 and ρ = 0.271, p < 0.001 respectively), but only baseline (and not follow-up) BMB volume correlated with age (ρ = 0.129, p < 0.05). Both smoking and baseline WMH burden predicted verbal fluency and visuospatial abilities scores (B = −1.13, p < 0.02 and B = −0.22, p = 0.001 respectively) at 12 months after stroke. BGIDs and BMBs are associated differently with cognition post-stroke; studies of imaging and post-stroke cognition should adjust for premorbid cognition. The positive correlation of BGID with NART may reflect the lower premorbid cognition in patients with stroke at younger vs older ages.


Baseline Sample Stroke subtype, arterial territory and cerebral hemisphere affected
Supplementary  Figure S2.2. Bar Graphs of each of the old stroke lesion clusters per hemisphere/site in the presence or absence of microbleeds (i.e. BMB vs. No BMB) at baseline and 1 year after the index stroke. MCA_noBMB: no. of patients that did not have microbleeds with 1-7 old stroke cortical lesion clusters in the Middle Cerebral Artery (MCA) territory; MCA_BMB: no. of patients that had at least 1 microbleed with 1-7 old stroke cortical lesion clusters in the MCA territory; ACA_noBMB: no. of patients that did not have microbleeds with 1-7 old stroke cortical lesion clusters in the Anterior Cerebral Artery (ACA) territory; ACA_BMB: no. of patients that had at least 1 microbleed with 1-7 old stroke cortical lesion clusters in the ACA territory. Following the same format: PCA_noBMB and PCA_BMB refers to similar information but for the Posterior Cerebral Artery territory, BZ_noBMB and BZ_BMB refers to similar information for the Border Zones (i.e. watershed regions), Cer/BS_noBMB and Cer/BS_BMB refers to similar information for the cerebellum and brain stem, Lac_noBMB and Lac_BMB refers to similar information but for lacunar stroke lesions in the subcortical regions, optical radiations and pons, RH and LH groups similar information in the Right and Left Hemispheres.

ACE-R 1-year follow-up (ACER_2tp) examined with respect to the first wave of cognitive testing (ACER_1tp)
There are no valid cases for ACER_2tp when ACER_1tp = 59.000.

ACE-R attention and orientation 1-year follow-up (Orientation_2tp) examined with respect to the first wave of cognitive testing (Orientation_1tp)
Orientation_2tp is constant when Orientation_1tp = 12.00.

Case Processing Summary
Orientation_1tp

ACE-R memory 1-year follow-up (Memory_2tp) examined with respect to the first wave of cognitive testing (Memory_1tp)
There are no valid cases for Memory_2tp when Memory_1tp = 8.000.

ACE-R verbal fluency 1-year follow-up (Fluency_2tp) examined with respect to the first wave of cognitive testing (Fluency_1tp)
There are no valid cases for Fluency_2tp when Fluency_1tp = 2.000.

ACE-R language 1-year follow-up (Language_2tp) examined with respect to the first wave of cognitive testing (Language_1tp)
Language_2tp is constant when Language_1tp = 19.00.

ACE-R visuospatial ability 1-year follow-up (Visuospatial_2tp) examined with respect to the first wave of cognitive testing (Visuospatial_1tp)
Visuospatial_2tp is constant when Visuospatial_1tp = 8.00.
There are no valid cases for Visuospatial_2tp when Visuospatial_1tp = 11.000.

NART 1-year follow-up (NART_2tp) examined with respect to the first wave of cognitive testing (NART_1tp)
There are no valid cases for NART_2tp when NART_1tp = 7.000.