Verbal Fluency Markers of Cognitive Decline in Galician–Spanish Bilingual Older Adults: A Pilot Study

Purpose: As life expectancy increases, cognitive decline becomes an important public health concern. The early detection of cognitive changes is essential for timely treatment. This study examined the performance of Galician–Spanish bilingual older adults on verbal fluency tasks to determine whether measures of total correct words, average number of clusters, average cluster size, and average number of switches could detect varying levels of cognitive decline. Method: Sixty-three bilingual (or multilingual) participants from the SECONDSGALES project (38 controls, 13 with mild cognitive impairment [MCI] and 12 with dementia) aged 65 years and older were evaluated, in their preferred language, across two tasks: animals for semantic fluency (SF), and the letter S for letter fluency (LF). Results: Linear mixed-effects model analyses revealed that cognitively impaired participants produced fewer correct words than controls across both tasks, although the difference was more pronounced on SF than on LF. None of the clustering and switching measures yielded significant results on SF. On LF, cognitively impaired participants showed significantly fewer clusters and significantly fewer switches, and the dementia group showed significantly smaller clusters compared to controls. Estimates across three out of four models suggest a tendency for scores to decline as impairment increases. Conclusions: Our results indicate that the average number of clusters, the average number of switches on LF, and the total number of correct words on both SF and LF seem particularly sensitive to cognitive status. There also seems to be a gradual reduction in verbal fluency performance across these three measures as cognitive decline increases.