Effect of Right Hemispheric Aphasia on 1-Year Outcomes in Acute Ischemic Stroke Patients

Aphasia is usually associated with left hemispheric stroke, but may also occur after right hemispheric ischemic stroke. The long-term prognostic significance of right hemispheric aphasia is not well defined.

We pooled patients with baseline aphasia from the Albumin in Acute Ischemic Stroke (ALIAS I and II) trials and classified them by hemispheric involvement (left vs. right) at enrollment. The primary outcome was functional independence (modified Rankin Scale [mRS] 0-2) at 1 year. The secondary outcome was utility-weighted mRS (UW-mRS) at 1 year. A sensitivity analysis examined excellent outcome (mRS 0-1) using the same multivariable logistic regression model. Multivariable models adjusted for age, baseline National Institutes of Health Stroke Scale (NIHSS) score strata, treatment group, right versus left hemispheric involvement, IV recombinant tissue plasminogen activator (tPA) administration, baseline aphasia severity, and neglect.

We analyzed 584 acute ischemic stroke patients (mean age 67.54 ± 13.67 SD, 51.5% were men) with aphasia; 503 patients had left hemispheric aphasia, and 81 had right hemispheric aphasia. The proportion of patients who were functionally independent at 1 year was significantly lower in patients with right hemispheric aphasia than in those with left-hemispheric aphasia (22% versus 37%, p = 0.017). In the adjusted analysis, patients with right hemispheric aphasia had significantly lower odds of 1-year functional independence (OR 0.48, 95% CI 0.24-0.93; p = 0.034) after adjustment for potential confounders. Patients with right hemispheric aphasia had a non-significantly lower 1-year UW-mRS score (β = -0.11, 95% CI -0.23 to 0.01; p = 0.071). In the sensitivity analysis using the stricter mRS 0-1 threshold, right hemispheric aphasia showed a consistent but non-significant trend toward lower odds of excellent recovery (OR 0.59, 95% CI 0.27-1.21; p = 0.20). In the longitudinal ordinal analysis across all follow-up time points, there was no significant difference in overall mRS trajectory between groups (OR 1.27, 95% CI 0.28-5.85; p = 0.756). The hemisphere effect on functional independence persisted after adjustment for handedness (OR 0.48, p = 0.034).

Among acute ischemic stroke patients presenting with aphasia, right hemispheric involvement was associated with approximately 50% lower adjusted odds of 1-year functional independence, despite milder baseline aphasia severity, suggesting that non-language right hemisphere syndromes rather than the language deficit itself may drive this adverse prognosis.