Past research has been inconsistent with regard to the effects of normal aging and sex on strategy use during verbal fluency performance. In the present study, both Troyer et al.'s (1997) and Abwender et al.'s (2001) scoring methods were used to measure switching and clustering strategies in 60 young and 72 older adults, equated on verbal ability. Young adults produced more words overall and switched more often during both phonemic and semantic fluency tasks, but performed similarly to older adults on measures of clustering. Although there were no sex differences in total words produced on either fluency task, males produced larger clusters on both tasks, and females switched more frequently than males on the semantic but not on the phonemic fluency task. Although clustering strategies appear to be relatively age-insensitive, age-related changes in switching strategies resulted in fewer overall words produced by older adults. This study provides evidence of age and sex differences in strategy use during verbal fluency tests, and illustrates the utility of combining Troyer's and Abwender's scoring procedures with in-depth categorization of clustering to understand interactions between age and sex during semantic fluency tasks.

Clustering and switching strategies during phonemic and semantic verbal fluency tasks as defined by Troyer et al. (1997), Abwender et al. (2001), and Lanting et al. (2009) were compared using archival data to determine which scoring procedures best differentiate healthy older adults (n = 26) from individuals with early-stage Alzheimer's disease (AD, n = 26). Total word production showed the largest group difference, especially for semantic fluency. The AD group produced fewer switches when compared to the healthy control group, whereas the groups did not differ in cluster size. The AD group also accessed fewer novel semantic subcategories, presumably due to reduced access to semantic memory storage rather than lower processing speed. Clustering and switching scores on the phonemic task did not add information above total words produced, consistent with previous research indicating these variables are most informative in relation to semantic fluency.

Clustering and switching strategies during phonemic and semantic verbal fluency tasks were investigated in healthy adults (n = 193, 86 males, 20-90 years) in young, middle-aged, young-old, and old-old age groups (Study 1). Older groups produced fewer total words and lower switching scores; males relied more on clustering and females on switching to produce equivalent output. In Study 2, early Alzheimer's disease participants, compared to healthy older adults, (n = 26 per group) produced fewer total words and smaller average clusters. Sex, age, and clinical differences on switching and clustering strategies support a dual processing model of verbal fluency.

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