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The XIII conference of the European Society of Cognitive Psychology
Granada, Spain - September 2003
WORKING MEMORY UPDATING
IN ELDERLY WITH MILD COGNITIVE IMPAIRMENT
Annapaola Prestia 1, Nadia Gamboz 1, Maria Luisa Onor 2,
Eugenio Aguglia 2 and Carlo Semenza 1
1
2 Department
Department of Psychology
of Technological, Morphological and Clinical Sciences
University of Trieste, Italy
MILD COGNITIVE IMPAIRMENT
 Mild Cognitive Impairment (MCI) is a supposedly transitional
stage between normal aging and dementia (see Peterson, Doody et
al. 2001, and Bischkopf, Busse & Angermeyer, 2002, for a recent
review of the current diagnostic criteria of the preclinical phase of
AD).
 The amnesic mild cognitive impairment (aMCI; Peterson, Doody
et al. 2001), encompassing many of the current diagnostic criteria
for MCI, is characterised by a selective and isolated impairment of
episodic memory.
 Elderly with aMCI show verbal episodic memory performances
equivalent to those of patients affected by mild AD, while their
other cognitive functions and the ability to deal with daily living
activities are preserved (Collie & Maruff, 2000)
IS aMCI A RELIABLE PREDICTOR OF DEMENTIA ?
 The prognostic value of aMCI is still under debate. Many factors
contribute in making it difficult understand weather aMCI
represents a preclinical stage of
AD or weather it is an
independent nosografic entity (Bischkopf, et al., 2002):
not all cases of aMCI convert to dementia (12 % of cases per year)
there aren’t at present validated early markers able to identify the
elderly with aMCI more at risk to develop AD
neuropsicological (large screening batteries), radiological
(hippocampal atrophy) and biological (tau protein, A-42)
markers are under investigation.
 It is reasonable to argue that combining neuropsicological
radiological and biological measures and monitoring longitudinally
the rate of change would undeniably be more informative on the
outcome of aMCI than any of these measures alone.
 Such a diagnostic procedure is, however, still out of reach for a
clinicians who is mainly concerned with individual early diagnosis
of AD.
 It is therefore necessary to emphasise also the search for tools
accessible to clinicians that can detect AD in its early stages.
AIMS OF THE PRESENT INVESTIGATION
 To assess whether inefficient working memory updating represents
a cognitive marker of MCI, in addition to verbal episodic memory
deficit
 To assess whether inefficient working memory updating is a
reliable predictor of incipient AD
WHY WORKING MEMORY UPDATING ?
 Current evidences suggest that executive functioning, subserved
by frontal lobes, is the first non-memory domain to be impaired in
AD, and that the deficits initially involve the operations the
require the manipulation of information (Perry & Hodges, 1999)
 Recent investigations indicated that the updating of verbal
working memory is mediated by the prefrontal regions (Clark,
Egan, McFarlane, Morris et al., 2000)
METHOD
Participants
Age
Education
Verbal IQ
MMSE
Young Adults
25.4
17.2
114.2
30
N = 20
Old Adults
(2.7)
(2.5)
(6.5)
(0.0)
65.1
13.2
110.6
27.5
N = 20
(3.8)
(4.8)
(7.1)
(0.58)
aMCI Patients
73.5
10.5
107.2
27.2
N = 20
(5.8)
(4.8)
(8.0)
(1.5)
Material
Neuropsychological Memory Screening:
Words list free recall task, immediate and delayed prose recall task, backward
and forward version of the verbal digit span task
Working Memory Updating:
Running Memory Task, Working memory updating task
Running Memory Task
(adapted from Morris & Jones, 1990)
Twelve stings of consonants of different lengths. The strings consisted of four,
six and eight consonants, displayed on the computer screen for 2 seconds. At
the end of each string participants were asked to repeat serially the last four
items.
Ex. L G Q P H S T D
Working memory updating task
(adapted from Palladino, Cornoldi,
De Beni & Pazzaglia, 2001)
Twelve lists, 10 words long, matched for word familiarity and word length. Each
list consisted of measurable instances from two semantic category. The words
were displayed on the computer screen for 2 seconds. Variables manipulated
within participants: Working memory load (n.of targets to recall): 2 or 4;
Processing load (n. of updates): 1 or 2. At the end of each list participants were
asked to repeat serially the last or the last two smaller items from each category.
Ex. (4 targets - 2 updates)
ELBOW FINGER MOUSE FROG CHEST NOSE GIRAFFE HORSE FOREHEAD DONKEY
RESULTS
Free Recall
Prose Memory
Immediate
Delayed
Digit Span
Forward
Backward
Running Memory
WM Updating
Young Adults Old Adults Young vs. Old aMCI Patients Old vs. aMCI
t-test
t-test
67
50
.0001
39
.02
(11.3)
(13.5)
(14.7)
70
(13)
62
(14)
.05
40
(22)
.001
70
(13)
60
(15)
.05
35
(23)
.001
7.2
(1.1)
6.0
(1.4)
.005
5.9
(1.0)
n.s
5.9
(0.9)
87
(10.7)
4.5
(1.0)
82
(10.8)
.005
4.3
(1.4)
69
(11.9)
n.s.
94.0
(9.9)
87.9
(15.6)
.0005
n.s.
73.2
(23.1)
.002
.0001
Standard Deviation Units
Old Adults
12 MONTH FOLLOW UP
Working
M emory
Running
Updating * M emory *
Free Recall
Prose
M emory
Imm.
Prose
M emory
Del.
0,00
-1,00
-2,00
-3,00
* W > 6, p < .02
7 aMCI  Mild to moderate AD
9 aMCI Depression
2 aMCI  Stable MCI
2 aMCI Dementia other than AD

Results indicated significant differences between aMCI patients and healthy
controls in almost all memory tasks, except the digit span task.

Results also indicated that variance across aMCI patients’ performances in the
updating tasks was twice as large as that of the elderly control group, and
larger than variance across performances in episodic memory tasks.

Follow up analysis indicated that those aMCI patients who developed AD after
12 month from the first assessment had significantly worst performances,
compared to healthy controls, that the aMCI patients who had depression in
the working memory updating task and running memory task, while
performances in the episodic memory tasks were equivalent

Four of the 5 aMCI patients who initially showed the worst performances in
the updating task, compared to healthy controls, developed AD
DISCUSSION
While conventional neuropsychological test contribute to diagnose
aMCI by detecting and quantifying an episodic memory
impairment, working memory updating abilities may promptly
identify those aMCI patients who are more at risk to convert to
dementia, as indicated by their more pronounced impairment of
updating processes.
What next …….
More investigations on carefully selected groups of aMCI are
necessary to validate the predictive value to conversion to AD of
working memory updating tasks.
It is recommendable collect normative data on healthy old adults.
REFERENCES
Clark, R. Egan, G., McFarlane, A., Morris, P., Weber, D., Sonkkilla, C., J.,Marcina, and TochonDanguy, H. (2000). Updating working memory for words: A PET activation study. Human Brain
Mapping, 9, 42-54.
Collie A. and Maruff P. (2000). The neuropsychology of preclinical Alzheimer’s disease and mild
cognitive impairment. Neuroscience and Biobehavioral Reviews, 24, 365-374.
Palladino P., Cornoldi C., De Beni R., and Pazzaglia F. (2001). Working memory and updating
processes in reading comprehension. Memory & Cognition, 29, 344-354.
Morris N., Jones D.M. (1990). Memory updating in working memory: The role of the central
executive. British Journal of Psychology, 81, 111-121.
Perry, R. and Hodges, J. (1999). Atten tion and executive deficits in Alzheimer’s disease. A critical
review. Brain, 122, 383-404.
Bischkopf, J., Busse, A., and Angermeyer, M. (2002). Mild cognitive impairment-a review of
prevalence, incidence and outcome according to current approaches. Acta Psychiatrica Scandinavica,
106, 403-414.
Petersen R.C., Doody R., Kurz A., Mohs r.C., Morris J.C., Rabins P.V., Ritchie K. Rossor M., Thal L.,
Winbald B. (2001). Current concepts in mild cognitive impairment. Archives of Neurology, 58, 198592.