Our paper entitled “Probing ERP correlates of verbal semantic processing in patients with impaired consciousness” about semantic abilities in non-communicating patients is available online in Neuropsychologia or in PDF here.
Reference: Rohaut, B., Faugeras, F., Chausson, N., King, J.-R., Karoui, I. E., Cohen, L., & Naccache, L. Probing ERP correlates of verbal semantic processing in patients with impaired consciousness. Neuropsychologia. 2015 Jan;66:279–92.