Thalamic aphasia after stroke is associated with left anterior lesion location

Background Aphasic symptoms are typically associated with lesions of the left fronto-temporal cortex. Interestingly, aphasic symptoms have also been described in patients with thalamic strokes in anterior, paramedian or posterolateral location. So far, systematic analyses are missing. Methods We conducted a retrospective analysis of consecutive patients admitted to our tertiary stroke care center between January 2016 and July 2017 with image-based (MRI) proven ischemic stroke. We evaluated stroke lesion location, using 3-T MRI, and presence of aphasic symptoms. Results Out of 1064 patients, 104 (9.8%) presented with a thalamic stroke, 52 of which (4.9%) had an isolated lesion in the thalamus (ILT). In patients with ILT, 6/52 had aphasic symptoms. Aphasic symptoms after ILT were only present in patients with left anterior lesion location (n = 6, 100% left anterior vs. 0% other thalamic location, p < 0.001). Conclusions Aphasic symptoms in thalamic stroke are strongly associated with left anterior lesion location. In thalamocortical language networks, specifically the nuclei in the left anterior thalamus could play an important role in integration of left cortical information with disconnection leading to aphasic symptoms.