Patients with Alzheimer's disease (AD) were asked to name pictures and
perform a multiple-choice word-picture matching task with verbs and n
ouns. AD patients were significantly more impaired with verbs than nou
ns for both naming and word-picture matching, and their patterns of se
mantic naming errors differed for verbs and nouns. One subgroup of AD
patients was compromised on both naming and word-picture matching cons
istent with a semantic memory deficit. Naming was worse for verbs than
for nouns in these patients, and they produced significantly fewer hi
erarchically related semantic substitutions for verbs than for nouns.
Other AD patients without semantic memory difficulty did not demonstra
te these form class-sensitive patterns. The investigators hypothesize
that form class-specific effects in AD patients' naming are due in par
t to differences in processing verbs and nouns in semantic memory.