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Studies of word production in patients with Alzheimer's disease have identified the age of acquisition of words as an important predictor of retention or loss, with early acquired words remaining accessible for longer than later acquired words. If, as proposed by current theories, effects of age of acquisition reflect the involvement of semantic representations in task performance, then some aspects of word recognition in patients with Alzheimer's disease should also be better for early than later acquired words. We employed a version of the lexical decision task which we term the lexical selection task. This required participants to indicate which of four items on a page was a real word (the three "foils" being orthographically plausible nonwords). Twenty-two patients with probable Alzheimer's disease were compared with an equal number of matched controls. The controls made few errors on the test, demonstrating that the controls were cognitively intact, and that the words were familiar to participants of their age and level of education. The Alzheimer patients were impaired overall, and recognized fewer late than early acquired words correctly. Performance of the Alzheimer patients on the lexical selection task correlated significantly with their scores on the mini mental state examination. Word recognition becomes impaired as Alzheimer's disease progresses, at which point effects of age of acquisition can be observed on the accuracy of performance. (Contains 1 figure and 2 tables.)

Split fovea theory proposes that when the eyes are fixated within a written word, visual information about the letters falling to the left of fixation is projected initially to the right cerebral hemisphere while visual information about the letters falling to the right of fixation is projected to the left cerebral hemisphere. The two parts of the word must be re-united before the word can be recognised. Bilateral projection theory proposes instead that visual information is projected simultaneously to both hemispheres provided that it falls within the fovea (defined as the central 2-3 degrees). On this more traditional account, no interhemispheric transfer would be required in order to read a word presented within the fovea. We review the evidence in support of split fovea theory and consider some of the objections that have been raised. We argue that a split fovea affects the reading of words at fixation, something that must be recognised and accounted for by cognitive, computational and neural models of reading. (Contains 5 figures.)

We explain once again the distinction between the "split fovea theory" and the "bilateral projection theory", and consider the implications of the two theories for understanding the processing of centrally fixated words and faces.