Abstract
Background:
Cognitive changes have been described in subacute TIA/minor stroke (TIA/MIS), but the temporal profile is unknown. We tested the hypothesis that TIA/MIS patients experience transient cognitive impairment, and that this can be predicted by Diffusion-Weighted Imaging (DWI) lesion volume.
Methods:
Acute TIA/MIS stroke (NIH stroke scale score ≤3) patients with no history of cognitive impairment were prospectively recruited within 72 h of onset. Patients underwent Montreal Cognitive Assessment (MoCA), Mini-Mental Status Examination (MMSE) and MRI, including DWI and Fluid-Attenuated Inverse Recovery (FLAIR) sequences, at baseline, days 7 and 30. DWI lesion and FLAIR chronic white matter hyperintensity (WMH) volumes were measured planimetrically.
Results:
Fifty patients (mean age 68 ±15.1 years) were imaged at a median (IQR) of 26.5 (28.5) h after onset. Cognitive impairment (scores ≤26) was detected more frequently with MoCA (31/50, 62%) than MMSE (13/50, 26%, p=0.009). Acute ischemic lesions (DWI) were present in 33 (66%) patients. Mean DWI volume at baseline was 4.5 ± 11.1ml. Patients with DWI lesions (22/33, 67%) had similar impairment rates as those without (9/17, 53%; p=0.34). Linear regression indicated no relationship between acute DWI lesion volume (log transformed) and baseline MoCA scores (β=0.028, 95% CI [-2.09, 2.44]). Impaired patients had larger WMH volumes (13.6 ± 21.9 ml) than unaffected patients (2.6 ± 3.2 ml, p=0.01). Log transformed WMH volumes were inversely predictive of baseline MoCA scores (β=-0.54, 95% CI [-7.84, -2.28]). Median MoCA scores improved over time (27(5) at day 7 and 28(5) at day 30). Patients with baseline impairment and an increase of ≥2 points on MoCA by day 30 were defined as reverters (N=20). DWI lesion frequency was similar in reverters and those with persisting impairment (75% vs 64%, p= 0.50), as was DWI (6.9 ±14.3 ml vs 1.2 ±1.9 ml; p= 0.113) and WMH lesion volume (17.0 ± 26.2 ml vs 8.1 ± 8.1 ml; p= 0.18).
Conclusions:
Most TIA/MIS patients have evidence of temporary acute cognitive impairment when assessed with MoCA. Deficits are correlated with chronic WMH, suggesting an unmasking of subclinical cognitive impairment. Temporary cognitive deficits should be considered in the management of TIA/MIS patients.