The current study examines whether the Homophone Meaning Generation Test (HMGT; Warrington, 2000) is correlated with the phonemic and/or the semantic fluency tests and compares its association with the number of switches and clusters and the mean cluster size of these two tasks. One hundred healthy Hebrew speakers (18–35 years of age; mean = 24.9) generated meanings for 24 homophones and provided words beginning in three different letters, as well as words belonging to three semantic categories. Results show that the HMGT score correlated significantly and similarly with the total score of both the phonemic and the semantic fluency tests. There was a significant correlation between the HMGT and the number of phonemic switches and clusters, but not between the HMGT and the mean phonemic cluster size. The HMGT correlated with the number of semantic switches and clusters, as well as with the mean semantic cluster size. The findings suggest that the relationship between these tests is mediated by a shared executive component, attesting to the HMGT's utility in tapping into mechanisms of shifting and mental flexibility. (JINS, 2007, 13, 424–432.)

Sex differences in executive speech tasks, favoring women, have been noted in behavioral studies and functional imaging studies. In the present study, the clustering and switching components of semantic and phonemic verbal fluency tests were examined in 40 healthy men and 40 healthy women. Possible sex differences in the influence of cognitive factors such as speed of information processing, word knowledge, and/or verbal long-term memory on these verbal fluency factors were also assessed. The results showed that women switched more often between categories in the phonemic fluency test, whereas men showed a trend toward a larger cluster size leading to a smaller total number of words generated. Additionally, higher performance on the Digit Symbol test was associated with better performance on the semantic and phonemic verbal fluency test in men, whereas in women, better memory performance was associated with better performance on these verbal fluency tests. Our data indicate that men and women are using different processing strategies for phonemic verbal fluency tests to optimize verbal fluency task performance. In the current study, women adopted a more successful strategy of balancing clustering and switching in the phonemic fluency task. (JINS, 2006, 12, 502–509.)

Amnestic mild cognitive impairment (aMCI) represents a high-risk factor for Alzheimer's disease (AD) and is characterized by a selective decline in episodic memory. Although by definition aMCI is not associated with impaired verbal fluency performance, we examined relative differences between fluency tasks because AD is characterized by poorer semantic than phonemic fluency. Phonemic and semantic fluency trials were administered to 46 healthy controls, 33 patients with aMCI, and 33 patients with AD. Results revealed a progressive advantage (controls > aMCI > AD) in semantic, relative to phonemic fluency. Difference scores between tasks distinguished each group from the others with medium to large effect sizes (d) ranging from 0.49 to 1.07. Semantic fluency relies more on semantic associations between category exemplars than does phonemic fluency. This aMCI fluency pattern reflects degradation of semantic networks demonstrating that initial neuropathology may extend beyond known early changes in hippocampal regions. (JINS, 2006, 12, 570–574.)The data were collected in accordance with the guidelines of the Helsinki Declaration and approved by the Research Ethics and Scientific Review Committee of Baycrest Centre. This is an original submission. Portions of these data were presented at the annual meeting of the International Neuropsychological Society, February 2005, St. Louis, Missouri. There is no conflict of interest.