Clustering and switching patterns in semantic verbal fluency among Chinese older adults: associations with cognitive function and dementia screening

Verbal fluency tasks can aid in the early detection of dementia, although the underlying cognitive mechanisms, particularly in Mandarin-speaking populations, remain underexplored. Prior studies often emphasize number of words generated, overlooking more complex components such as clustering and switching and their associations with cognitive functions like memory and orientation. To address this gap, we employed Tongyici Cilin, a comprehensive Mandarin synonym knowledge base, to quantify clustering and switching in large-scale verbal fluency data. Our results show that measures such as number of words generated, and switching frequency are generally associated with memory and orientation, especially among middle-aged and older Mandarin speakers with lower education levels. People with dementia exhibited significant reductions in number of words generated, switching frequency and cluster size, reflecting impaired lexical organization and reduced cognitive flexibility. Similar but milder deficits were observed in the MCI group, suggesting that disruptions in word generation and switching emerge in early cognitive decline and worsen with disease progression. These findings underscore the value of analysing clustering and switching in the verbal fluency task in capturing distinct cognitive processes affected by dementia, thus enhancing early detection and monitoring.