Associations between stroke severity, aphasia severity, lesion location, and lesion size in acute stroke, and aphasia severity one year post stroke

Abstract

Background The aim of the present study was to investigate the associations stroke severity, aphasia severity, lesion location and lesion size in acute stroke, and aphasia severity in the subacute and chronic stages post stroke. We hypothesized that initial stroke severity and aphasia severity were associated with the patient’s aphasia severity in the subacute and chronic stages of stroke. We expected to find that lesions within the left frontotemporal regions of the brain were associated with aphasia severity post-stroke.

Methods Thirty-three patients with aphasia were included in the study. They were assessed with a standardized aphasia test at admission to the hospital (T1), after 3 months (T2) and finally after 12 months (T3). Stroke severity, initial physical impairment, and initial functional independence were also assessed at T1. Diffusion-weighted magnetic resonance imaging was performed as clinical-routine at admission. Voxel-based lesion symptom mapping and a region of interest analysis (ROI) was performed to analyze MRI-findings.

Results & Outcomes Initial lesion size and aphasia severity were associated with aphasia severity at T2. Initial stroke severity, aphasia severity, and lesion size were not associated with aphasia severity at T3, but the patients’ aphasia severity at T2 predicted aphasia severity at T3. Lesion analysis showed that lesions within the left postcentral gyrus and the left inferior parietal gyrus were significantly associated with aphasia severity at T3. The ROI-analysis did not yield any significant regions of interest to explain the total variance of the patients’ change in scores on the aphasia test from T1 to T3.

Conclusion Lesions within the postcentral gyrus and the inferior parietal gyrus are associated with aphasia severity at T3. Lesion size in the acute stages of stroke is associated with aphasia severity at T1 and T2, but not T3. However, neither initial aphasia severity nor stroke severity was associated with aphasia severity at T3. Aphasia severity in T2 is however strongly associated with aphasia severity in T3.