Language, Ageing, and Cognitive Decline
Humans now live much longer, but many elders are incapacitated for decades by diseases caused by neurodegeneration, such as dementia and Alzheimer’s, resulting in immense economic and psychological burdens at every level of society across the world. We aim to understand the biological bases of such decline, especially in the context of Chinese language and culture, with the aim of detecting the onset of these diseases early enough to design methods of effective intervention.
Project PI: Prof. Wang Shi Yuan, William
Language connects sounds with the world of meanings, and is the defining feature of our species. Formation and retrieval of meanings are traditionally regarded as intact in normal ageing. Recent research has begun to challenge this notion. For example, compared with young subjects, older subjects tend to rely more on the prefrontal cortex in many semantic tasks, including speech comprehension. Resting-state fMRI studies have also revealed robust age-related changes in functional connectivity, most notably an inverted U-shaped trajectory for long-range connections within the frontotemporal and frontoparietal networks.
Intriguingly, the peak of the developmental trajectory appears to coincide with the onset of behavioural decline in semantic ability. However, how these large-scale changes in the brain’s “functional connectome” relate to semantic processing has yet to be elucidated. We are extending our knowledge regarding the age-related neural reorganisation that underlies the changes in semantic ability across the adult lifespan, by clarifying the behavioural and neural consequences of the changing resting-state functional connectivities in the left hemisphere. In parallel, we are investigating how Cantonese tones are perceived differently as people age, and how these tones may be exploited in helping Cantonese elders retain and enhance their memories for words and sentences.
