Forming New Orthographic Representations in Alzheimer’s Disease and Mild Cognitive Impairment

Abstract

When we read the same word several times, we end up forming an orthographic representation of it that allows us to read it in a fluid way. Several investigations were aimed at how healthy people, children or dyslexic adults learn new words, but little is known on how this process works on patients with neurodegenerative diseases, for example Alzheimer’s disease (AD) and mild cognitive impairment (MCI). Hence, the aim of this project was to analyze the formation of new orthographic representations in these people. For that purpose, eight words of a very low frequency were selected, half of them short and half of them long, and were presented six times to the participants, 4 of them in a narrative context. The learning process was measured according to the elimination of the length effect that indicates the crossing from a sublexical reading to a lexical one. The results showed the disappearance of the length effect in the control group, as well as a reduction in RTs in MCI participants and AD patients, without a disappearance of length effect in these groups. All this indicates that learning was consolidated in the control group, whereas in the MCI and the AD group it cannot be said that a new representation has formed.