JOURNAL OF CLINICAL AND EXPERIMENTAL NEUROPSYCHOLOGY
2007, 29 (2), 187–197
© 2006 Psychology Press, an imprint of the Taylor & Francis Group, an informa business
http://www.psypress.com/jcen DOI: 10.1080/13803390600629775
NCEN
Verbal learning and memory deficits in
Mild Cognitive Impairment
MCI - Memory Deficits
F. Ribeiro,
1,2
M. Guerreiro,
1,2
and A. De Mendonça
1,3
1
Dementia Clinics, Institute of Molecular Medicine and Faculty of Medicine of Lisbon, Lisbon,
Portugal
2
Laboratory of Language, Institute of Molecular Medicine and Faculty of Medicine of Lisbon,
Lisbon, Portugal
3
Neurology Department and Laboratory of Neurosciences, Institute of Molecular Medicine and
Faculty of Medicine of Lisbon, Lisbon, Portugal
Criteria for amnestic MCI rely on the use of delayed recall tasks to establish the presence of memory impairment.
This study applied the California Verbal Learning Test to detail memory performance in MCI patients (n = 70), as
compared to control subjects (n = 92) and AD patients (n = 21). Learning across the 5 trials was different among
the 3 groups. Learning strategy was also different, the MCI group showing less semantic clustering than the con-
trol group. However, both MCI patients and controls could benefit from semantic cueing. This study showed that
beyond consolidation deficits, MCI patients have marked difficulties in acquisition and recall strategies.
INTRODUCTION
Memory complaints are common in aged people.
Some of these aged people experience changes severe
enough to bring them to the medical doctor, who
nowadays commonly establishes the diagnosis of
Mild Cognitive Impairment (MCI) (de Mendonça,
Guerreiro, Ribeiro, Mendes, & Garcia, 2004). MCI
patients typically present with memory complaints of
unknown etiology and perform below the norms for
age and education on neuropsychological memory
tests. Nevertheless they have a relatively normal gen-
eral cognitive function, maintain their activities of
daily living and are not demented (Petersen et al.,
1999). Mild Cognitive Impairment, particularly the
amnestic type (Petersen et al., 2001a), appears to rep-
resent a transition between normal aging and early
dementia, since in clinical settings patients with MCI
show rates of conversion to dementia, usually Alzhe-
imer’s disease (AD), of about 12% per year (Petersen
et al., 1999). Criteria for amnestic MCI make use of
scores in delayed recall of episodic memory tasks to
establish the presence of memory impairment (Win-
blad et al., 2004; see Arnaiz & Almkvist, 2003 for a
review on memory deficits in MCI and AD). How-
ever, poor delayed recall can reflect deficits in distinct
memory processes: encoding, consolidation and ret-
rieval. The contribution of these processes to the
observed deficit is still unclear (Arnaiz & Almkvist,
2003). Deficits in semantic memory were also found in
MCI as in AD patients (Dudas, Claghe, Thompson,
Graham, & Hodges, 2005). Furthermore, recent work
has called attention to the relevance of examining
memory deficits in areas other than declarative mem-
ory, by using verbal and nonverbal priming tests
(Perri et al., 2005). Impairments in other cognitive
domains, such as orientation, attention, executive
functions and visuospatial abilities, may also be found
in patients with MCI (Grundman et al., 2004; Ribeiro,
Guerreiro, & de Mendonça, in press). Detailed know-
ledge of the memory processes disturbed in MCI
should contribute to the understanding of the patho-
physiology of MCI, and help to delineate future reha-
bilitation interventions in these patients.
In order to characterize the MCI memory profile
under the present study, a well known test of verbal
Address correspondence to Filipa Ribeiro, Laboratory of Language, Faculty of Medicine of Lisbon, Av. Prof. Egas Moniz, 1649-028
Lisbon, Portugal (E-mail: piparibeiro@mail.telepac.pt).