An embodied approach to language comprehension in probable Alzheimer’s Disease: could perceptuo-motor processing be a key to better understanding?

One of the central tenets of the embodied theory of language comprehension is that the process of understanding prompts the same perceptuo-motor activity involved in actual perception and action. This activity is a component of comprehension that is not memory–dependent and is hypothesized to be intact in Alzheimer’s Disease (AD). Each article in this thesis is aimed at answering the question whether individuals with probable AD, healthy older adults and younger adults show differences in their performance on tests where perceptual and motoric priming take place during language comprehension. The second question each article asks is whether language comprehension in AD can be facilitated by the specific use of this perceptual and motoric priming. Article I examines whether the way individuals with pAD represent verbs spatially matches the way healthy older and younger adults do, and how stable these representations are. It also explores in what way spatial representations may relate to verb comprehension, more specifically, whether representations matching the norms translate into a better quality of verb comprehension. Article II tests the interaction between the verbs’ spatial representations taking place during comprehension and perceptual cues - compatible and incompatible to the representations - in order to investigate whether individuals with pAD show differences in susceptibility to perceptual cues, compared to healthy older and younger participants. The second aim of this article is to explore in what way performance on a word-picture verification task can be affected, with reference to the fact that in previous studies on young participants, both priming and interference have resulted from the interaction of linguistic and perceptual processing. Article III explores the Action Compatibility Effect (ACE) (Glenberg & Kaschak, 2002) with the aim of finding out whether the ACE exists for volunteers with pAD and whether it can facilitate language comprehension. The order of presentation of language and movement is manipulated to establish whether there is a reciprocal relationship between them. This information could be crucial in view of possible applications to individuals with pAD. These articles test, for the first time, the effects of the manipulation of the perceptuo-motor component during language comprehension in individuals with pAD; they are intended as a methodological exploration contributing to a better understanding of the potential of embodiment principles to support language comprehension changes associated with pAD. Embodiment effects need to be studied further with a view to putting them to use in either clinical or real-life applications.