Structural brain correlates of verbal and nonverbal fluency measures in Alzheimer's disease

This study examined the relationships between regional brain volumes and se mantic, phonological, and nonverbal fluency in 32 participants with Alzheim er's disease (AD). Object but not animal semantic fluency correlated with f rontal and temporal gray matter volumes. Phonological fluency was not signi ficantly associated with any brain volume examined. Nonverbal fluency was s electively associated with bilateral frontal gray matter volumes. Hippocamp al volumes, although markedly reduced in these patients, were not related t o any of the fluency measures. Results lend evidence to the importance of t he frontal lobes in the directed generation of nonverbal and verbal exempla rs by AD patients. Furthermore, both left- and right-hemisphere regions con tribute to the generation of verbal and nonverbal exemplars.