Ischemia in Broca Area is Associated with Broca Aphasia More Reliably in Acute Than in Chronic Stroke

Background And Purpose: We aimed to determine if ischemia involving Broca area predicts Broca aphasia more reliably in acute or chronic stroke.

Methods: We included consecutive right-hand-dominant patients with left hemisphere ischemic stroke (<48 hours from onset for acute stroke or >6 months after stroke for chronic stroke). MRI scans were analyzed for ischemic lesions or hypoperfusion in Broca area (Brodmann areas 44 and 45). Patients were scored on the Western Aphasia Battery to classify aphasia syndromes; chi(2) tests were used to identify significant associations.

Results: The presence of infarct involving any part of Broca area and the presence of Broca or global aphasia was much stronger in acute (chi(2)=38.1; df1; P<0.0001) than in chronic stroke (chi(2)=0.54; df1; P=0.46; not significant). The association between infarct or hypoperfusion covering all of Broca area and the presence of Broca or global aphasia was much stronger in acute (chi(2)=35.8; df1; P<0.0001) than in chronic stroke (chi(2)=1.2; df1; p=0.27; not significant). In a subset of 20 patients studied longitudinally, the associations were significant only acutely, not chronically (chi(2)=20; df1; P<0.0001 vs. chi(2)=0; df1; p=1; not significant for ischemia involving part of Broca area, and chi(2)=16.4; df1; P<0.0001 vs chi(2)=3.2; df1; p=0.08; not significant for ischemia covering all of Broca area).

Conclusions: Broca aphasia is more reliably associated with infarct/ hypoperfusion of Broca area in acute stroke. Many chronic stroke patients with damage to part or all of Broca area had neither Broca nor global aphasia. Broca or global aphasia was sometimes present initially in these patients but resolved by 6 months. Our results indicate that the acute aphasia syndrome may allow the clinician to predict the compromised vascular territory, even when structural imaging shows only a small (or no) infarct.