Discourse about discourse: what is it and how does it progress in Alzheimer's disease?

Discourse about discourse or a subject's comments about his/her performance during a discourse task can be defined as modalizing discourse (discours modalisateur; [Nespoulous, 1980]; [Nespoulous et al., 1998]). Since it does not convey the expected content of the discourse task (referential discourse), modalizing discourse has often been considered non-informative, and as such, has received little interest. The present study investigated the modalizing aspect of discourse production and its evolution in Alzheimer's disease (AD). Five AD patients produced a picture-induced narrative across five consecutive assessments. Two measures were derived: the modalizing/referential ratio (M/R ratio) and the percentage of repeated ideas. Results revealed that, compared to a group of 27 normal controls matched for age and education, AD patients: (1) obtained higher M/R ratios that tended to diminish as the number of assessments increased, and (2) produced higher percentages of repeated ideas throughout all assessments. These results suggest that modalizing discourse makes up a large proportion of AD patients' discourse and should be included in further studies to accurately describe their discourse behavior. The implications of modalizing discourse on preserved pragmatic abilities and its inclusion in comprehensive management programs of AD patients are discussed.