Implicit Reading In Chinese Pure Alexia

BackgroundPure alexia is an acquired reading disorder, characterized by selective reading impairment in premorbidly literate individuals with little or no writing problems, and oral speech and comprehension were relatively preserved. A number of recent studies show that some patients with pure alexia display evidence of implicit access to lexical and semantic information about words which they could not explicitly read. This phenomenon has not been systematically investigated in Chinese patients.ObjectivesWe here investigate a Chinese patient, who met the criteria of pure alexia and had lesions in the left occipito-temporal region and the splenium of the corpus callosum. We aimed to study whether this patient had reading patterns similar to both Chinese and alphabetic alexia in the literature, whether implicit reading can be observed in Chinese pure alexia, and whether this phenomenon can be more easily manifested.MethodsHis explicit and implicit reading was evaluated with various stimuli in a number of tasks, such as, the Aphasia Battery of Chinese (ABC), oral reading and comprehension, homophone matching, word-picture matching, semantic categorization, word-word matching, lexical decision. ResultsWe found that despite his severe impairments in overt reading and definition of any characters, his performance was well above chance in various implicit tasks. With respect to lexical decision, his accuracy was so high that his performance was almost normal.ConclusionsWe have no evidence for the existence of a reading strategy (Radical-by-radical, RBR) comparable to letter-by-letter reading (LBL) in Chinese alexia. There seems to be a causal relationship between tracing-aid reading and writing/copying ability. These reading findings provide unequivocal evidence for the existence of implicit reading in Chinese readers with pure alexia and further suggest the involvement of the right hemisphere.