Connected Speech, Aging and Neurodegeneration

My research examines how typical aging and neurodegenerative conditions affect different dimensions of connected speech. A central conclusion emerging from this work is that similar observable behaviours can reflect very different cognitive mechanisms. A pause, for example, may indicate word-retrieval difficulty, episodic-memory search, discourse planning, or an adaptive attempt to preserve the quality of the message. Disfluencies are therefore sensitive to cognitive change, but are rarely specific markers of a single underlying impairment. 

Beyond disfluencies, I examine lexical-semantic and macrolinguistic measures that can be quantified more systematically across speakers and tasks. By comparing these different types of markers and relating them to cognitive and clinical profiles, my work evaluates the potential of connected speech as a diagnostic and prognostic tool in neurodegenerative conditions.

My current work adopts a more functional perspective on connected-speech changes. Rather than considering every deviation from the target as an error, I examine whether and how it allows speakers to preserve informativeness. This “good-enough” approach aims to characterize the different solutions available when the most precise response cannot be produced and to determine which linguistic, cognitive, acoustic, and gestural resources support successful adaptation.

In a chapter on language in Alzheimer’s disease, we argue that language changes should be assessed not only in terms of impairment, but also in terms of their consequences for the informativeness and effectiveness of communication. In a study led by A. Römkens, we investigated how healthy older adults manage word-retrieval difficulties in connected speech, showing that they may trade lexical accuracy for fluency by producing a less precise response rather than interrupting or abandoning their utterance.

On-going project: In a current collaborative project (Sarah Maso, PhD candidate; Dr. Lola Danet, Prof.  Jérémie Pariente, Dr. Hélène Cochet), we examine how people with primary progressive aphasia maintain informative communication despite progressive language impairment. The project moves beyond naming accuracy to investigate the multiple verbal and non-verbal resources through which speakers compensate for linguistic difficulties.

A complementary part of my research examines how the brain maintains language performance despite aging or neurodegeneration. Using structural and resting-state functional MRI, this work has investigated changes in connectivity within the language network and between language and domain-general control networks. These studies suggest that aging and early Alzheimer’s disease cannot be understood solely in terms of neural deterioration. Increased connectivity within and beyond the language network may support preserved performance or reflect compensatory reorganization.

• Rafiq, M., Jucla, M., Guerrier, L., Péran, P., Pariente, J., & Pistono, A. (2022). Language functional connectivity across the lifespan: Disentangling the effects of typical aging and Alzheimer’s disease. Frontiers in Aging Neuroscience, 14, 959405.
• Pistono, A., Senoussi, M., Guerrier, L., Rafiq, M., Gimeno, M., Péran, P., Jucla, M., & Pariente, J. (2021). Language network connectivity increases in prodromal Alzheimer’s disease. Journal of Alzheimer’s Disease, 82(1), 447–460.
• Pistono, A., Guerrier, L., Péran, P., Rafiq, M., Gimeno, M., Bézy, C., Pariente, J., & Jucla, M. (2021). Increased functional connectivity supports language performance in healthy aging despite gray matter loss. Neurobiology of Aging, 98, 52–62.