Abstract W P130: Recovery of "Cortical Deficits" after Thalamic Stroke Related to Changes in Functional Connectivity in Cortex

Abstract

Background: Thalamic stroke can cause various “higher cortical” deficits, including impaired naming after left thalamic stroke and impaired emotional empathy after right thalamic stroke. Impaired naming is also associated with left inferior temporal gyrus (ITG) lesions, and impaired empathy with right ITG lesions. Deficits after thalamic stroke may be due to diaschisis, or dysfunction of cortex due to impaired input from thalamus. Changes in cortical function can be explored using resting state functional connectivity MRI (rsfcMRI). We tested the hypotheses that in patients with acute ischemic stroke restricted to left or right thalamus with naming/empathy impairment but no motor impairment, connectivity between left and right ITG (but not between left and right precentral gyrus; PrG) is (1) significantly different from that of controls within 3 days of stroke, and (2) normalizes over time with recovery of the naming/empathy impairment. Methods: We evaluated 7 patients with ischemic strokes restricted to the thalamus within 3 days of onset and 7 age-matched controls with rsfcMRI, structural and perfusion MRI, and testing of naming and empathy. Three patients had repeat imaging and cognitive testing. Results: Stroke patients showed significantly higher connectivity between left and right ITG at onset compared to controls (z score= 2.21 vs. 1.42; p=0.04), but showed no difference in connectivity between left and right PrG (z score= 1.87 vs. 1.70; p=0.53). Three patients who showed recovery of naming/empathy showed change in homologous connectivity toward more normal values in ITG, but less change (or change toward less normal values) in PrG from Time 1 to Time 2 (see Figure). Conclusion: In patients with thalamic infarcts, recovery of naming or empathy is associated with “normalization” of homologous connectivity in cortical regions thought to be critical for those cortical functions (e.g. ITG), consistent with recovery from diaschisis.