Is Isolated Aphasia Associated with Atrial Fibrillation? A Prospective Study

BACKGROUND: A cardioembolic source, usually atrial fibrillation (AF), is detected in 14-30% of strokes. If AF is found, anticoagulation therapy provides a substantial decrease of the risk of recurrent cerebrovascular ischemic events. AF is often paroxysmal, and extensive diagnostic procedures may be necessary to detect it in patients. Considering cost-effectiveness and patient burden, however, not every suspected patient can be thoroughly screened. Therefore, the identification of risk factors for AF may be helpful. Previous studies have identified isolated aphasia as a risk factor for AF as the cause of the stroke. These studies, however, were performed with small population samples, in a retrospective setting or focused on a specific subtype of aphasia. The aim of this observational study is to prospectively evaluate whether there is a relation between isolated aphasia and AF as the cause of cerebrovascular ischemia. METHODS: All patients admitted to the Atrium Medical Centre, Heerlen, the Netherlands, with cerebrovascular ischemia or transient ischemic attack in the period of August 2009 to March 2010 or October 2013 to January 2014 were included. The patients were evaluated by a neurologist and admitted to the Brain Care Unit for 24-48 h. Medical history, physical examination and diagnostic results were entered in a database. A diagnosis of isolated aphasia was assigned at admission using the National Institutes of Health Stroke Scale (NIHSS). Presence of AF was determined using a 12-lead electrocardiogram (ECG) on admission and continuous ECG monitoring for 1-2 days. During admission, aphasia tests were done, notably the ScreeLing Test and the Boston Naming Test. Data were analyzed using Pearson's χ(2) test, Fisher's exact test, the Mann-Whitney U test and univariate and multivariate logistic regression analyses. RESULTS: A total of 347 patients were included, of which 115 (33.1%) met the criteria for aphasia, with 26 (7.5%) meeting the criteria for isolated aphasia. Of all patients, 90 had a history of AF (66.7%) or AF was found during hospitalization (33.3%). Patients with AF, in contrast to those without, tended to present more often with any type of aphasia (41.1 vs. 30.4%) and isolated aphasia (10.0 vs. 6.6%), but these differences were not significant. A significant relation was found between global aphasia and AF (p = 0.011). Patients with AF scored significantly lower on the ScreeLing Test alone and on both aphasia tests together (p = 0.034). A history of transient ischemic attack significantly increased the risk for isolated aphasia (OR 2.66, 95% CI 1.09-6.47). CONCLUSIONS: A statistically significant relation between isolated aphasia and AF could not be established in this study. However, our results showed a tendency towards significance. Further studies, in which rhythm is observed for a longer period of time, may be required to confirm this hypothesis.