Low Speech Connectedness in Alzheimer’s Disease is Associated with Poorer Semantic Memory Performance

Abstract

Connected speech is an everyday activity. We aimed to investigate whether connected speech can differentiate oral narrative production between adults with Alzheimer’s disease (AD; n = 24) and cognitively healthy older adults (n = 48). We used graph attributes analysis to represent connected speech. Participants produced oral narratives and performed semantic, episodic, and working memory tasks. AD patients produced less connected narratives than cognitively healthy older adults. Connectedness was associated with semantic memory in AD and with episodic memory in controls. Word-graphs connectedness represents a practical tool to assess cognitive impairment in AD patients.

Who Does What to Whom? Graph Representations of Action-Predication in Speech Relate to Psychopathological Dimensions of Psychosis

“…The association between psychosis speech and decreased graph size may reflect a similar phenomenon as the decreased semantic density found by Rezaii et al [5]. With regard to measures of connectedness and organization, recent studies have relied on the feature LSCC, the largest strongly connected component, as an absolute and relative quantity with respect to randomly generated graphs [8, 19, 20]. Our findings suggest that additional information can be captured with other non-redundant features describing size, connectedness and organization – for example, we found that diameter and average short path length convey non-redundant information about the expansiveness of the network in addition to number of nodes and edges, network density and average degree can be used along the connectedness measure of LSCC, and z-score analysis of ASPL can be considered as a measure of speech graph organization.…”

Who does what to whom? graph representations of action-predication in speech relate to psychopathological dimensions of psychosis

“…The association between psychosis and decreased speech graph size may reflect a similar phenomenon as the decreased semantic density found by Rezaii et al 5 and decreased idea density reported by Moe et al 19 . With regard to measures of connectedness and organization, recent studies have relied on the LSCC, the largest strongly connected component, as an absolute and relative quantity with respect to randomly generated graphs 8 , 20 , 21 . Our findings suggest that additional information can be captured with other non-redundant features describing size, connectedness, and organization.…”

Graph structure analysis of speech production among second language learners of Spanish and Chinese

“…Long-range recurrences provide a measure of global connectedness. Applying this method to characterize thought disorders, we found that the higher the connectedness, the lower the cognitive decline associated with mental illness, demonstrating that word graph connectedness may predict a diagnosis of schizophrenia ( Mota et al, 2014 , 2017 ; Palaniyappan et al, 2019 ; Morgan et al, 2021 ; Spencer et al, 2021 ), as well as the cognitive decline associated with dementia ( Bertola et al, 2014 ; Malcorra et al, 2021 ). Moreover, studying the typical development of discourse patterns, we found that connectedness develops in association with general intelligence (IQ), theory of mind and verbal memory performance, predicting reading acquisition months in advance ( Mota et al, 2016 , 2020 ).…”

“…The authors showed that short-range recurrences (e.g., the repetitions of the same word associations) decreased during children’s emerging literacy, but increased with advancing age. Conversely, the ability to produce long-range recurrences in a well-connected narrative increased over school years, and maturation is reached only during high school ( Mota et al, 2018 ), but decreased in older adults in typical aging, as well as in dementia ( Malcorra et al, 2021 ).…”