2012. Vol.3, No.5, 379-383
Published Online May 2012 in SciRes (
Copyright © 2012 SciRes. 379
Automatic and Controlled Attentional Processes in Amnestic
Mild Cognitive Impairment: The Use of a Mini-Verbal Test
Jonas Jardim de Paula1, Danielle de Souza Costa1, Edgar Nunes de Moraes2,
Rodrigo Nicolato3, Manuel Sedó4, Leandro Fernandes Malloy-Diniz1,3
1Neuropsychological Investigations Laboratory, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
2Internal Medicine Department, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
3Mental Health Department, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
4Mini-Verbal Tests, Boston, US
Received December 19th, 2011; revised January 20th, 2012; accepted February 23rd, 2012
Recent finding suggests that in Amnestic Mild Cognitive Impairment (MCI) executive functions deficits
may be a frequent clinical finding. Automatic and Controlled attentional processes are related to the allo-
cation of cognitive resources in different stimuli, being important to executive functioning. The present
study aims at assessing the hypothesis of executive dysfunction deficits in MCI patients. Method: forty
five MCI patients and forty five normal aging controls (NC) were assessed with the Five Digits Test (5D),
a Mini-Verbal test version of the Stroop Test. Group comparisons were performed by t tests and the
non-parametric Mann-Whitney test. Results: comparisons indicates significant differences between NC
and MCI in efficiency measures of controlled attentional processes, with moderate effect sizes, but not in
automatic attentional processes or processing speed. Conclusion: the present work shows a selective pat-
tern of impairment in MCI, indicating specific deficits in executive functioning with spared processing
Keywords: Executive Functions; Selective Attention; Five Digit Test; MCI; Attentional Process
Mild Cognitive Impairment (MCI) is an intermediate clinical
condition between normal aging and dementia (Petersen et al.,
2001). MCI patients show deficits in specific cognitive func-
tions, do not fill the criteria for dementia diagnosis and have
none or mild impairment in daily life activities. The impairment
may occur in only one cognitive domain (Amnestic or Non-
Amnestic MCI) or multiple domains (Multiple Domain Amnes-
tic MCI or Multiple Domain Non-Amnestic MCI) (Petersen &
Negash, 2008). Some neuropathological markers (Apostolova
et al., 2006) and cognitive-behavioral patterns are being inves-
tigated as possible predictors for MCI to be converted into de-
mentia (Palmer et al., 2010). One possible cognitive profile
which may play a role in this conversion is the executive func-
tions impairment (Balota et al., 2010).
Executive functions are a group of cognitive processes in-
volving abstraction, inhibition, fluency, set shifting, problem
solving and self-regulation. One of the most consensual defini-
tions of this construct is the one proposed by Lezak, Howieson
and Loring (2005): “capacities that enable a person to engage
successfully in independent, purposive, self-serving behavior”.
In a developmental perspective the executive functions show an
inverted “U” shaped curve (Zelazo, Craik, & Booth, 2004),
associated with the maturation of cortico-subcortical connec-
tions of the Prefrontal Cortex, Basal Ganglia, Thalamus and
Cerebellum (Fuster, 2009). The executive changes across the
lifespan seem to be mediated by a significant slowness in proc-
essing speed and a reduced working memory capacity
(Salthouse & Meinz, 1995). Education is an important factor
for executive performance. Lin and Col. (2007) suggest that the
decline of some components of executive functions such as
attention allocation, planning, and initiation are more related to
the aging process whereas educational level is more prone to
explain the decline of initiation, switching, exibility, and
online updating. Recent research indicated that even in Amnes-
tic MCI (MCI) patients might show executive functions im-
pairment. Kramer and Col. (2007) found significant differences
between MCI and normal aging controls in neuropsychological
tests of executive functioning, like the Stroop Color-Word Test,
the Wisconsing Card Sorting Test, Verbal Fluency and Draw-
ing Fluency. The similar results were shown by Traykov and
Col. (2007) using the Stroop Color Word Test and the Modified
Card Test, but not the Trail Making. These findings indicate
that different aspects of executive functioning may be impaired
in MCI, like cognitive shifting, fluency, planning abilities and
selective attention. Executive impairment may be a frequent
finding in these patients and might play a role in the conversion
into dementia.
Usually the assessment of executive functions is carried out
with classic neuropsychological tests such as the Stroop
Color-Word Test (Stroop, 1935) and the Trail Making Test
(Reiten, 1955). These measures are adequate for the detection
of executive dysfunction in subjects with dementia and MCI
(Fisher et al., 1990; Koss et al., 1984; Kramer et al., 2007).
Nonetheless, these tasks are greatly influenced by formal edu-
cation and reading abilities (Johnson, Flicker & Lichtenberg,
2006; Lucas et al., 2005). An alternative in these situations is
the Mini-Verbal Tests (MVT) which try to be as independent as
possible from school learning and culturally-acquired routines
of the subjects. In the MVT the verbal content is limited to a
few well-known familiar concepts, shown to the subject as
series of visual images. MVT tasks are ideal for the assessment
of cognitive functions of bilingual, illiterate or very low edu-
cated people, since their results are less biased by other inter-
venient factors (Sedó, 2004).
An important feature of the executive functioning is the se-
lective allocation of attentional resources to specific environ-
mental stimuli. The human attentional system may be divided
into three major components: an alerting/vigilance network
involved in the regulation of arousal and alert tonus; a posterior
attentional network involved in spatial orientation and percep-
tion of sensory stimuli; and an anterior/executive network in-
volved in the detection of events, conscious attentional proc-
essing and executive control of behavior (Lang, 2002). The
posterior network is related to automatic attentional process,
conducting intuitive allocation of attentional resources in spa-
tial information and is also related to the posterior parietal lobe
and its connections with the thalamus and the brainstem,
(Cohen et al., 1998) while the anterior network is related to
controlled attentional process which involves conscious alloca-
tion of rescources, inhibition and a greater involvement of ex-
ecutive control, being associated with the anterior cingulate
cortex and its connections with the prefrontal cortex and the
thalamus (Cohen et al., 1998). Performance in neuropsy-
chological assessment of this process indicates that controlled
attentional process demands more cognitive resources, which
may be seen in the increase of time needed to perform the tasks
(a measure of speed) and higher error rate (a measure of effi-
ciency) (Lucas et al., 2005).
The Five Digit Test (5D), proposed by Sedó (2004) is a
MVT adaptation of the Stroop Color-Word Test. For the test
execution the subject must know only the first five numbers (1 -
5) and their corresponding symbols, which are always shown in
the canonical display. The test measures the continuous verbal
performance at different levels of the attentional network, since
it involves an automatic process (reading numbers and counting
figures) and a controlled process where subjects must inhibit an
automatized routine of processing in favor of a secondary
non-intuitive one (saying the number of digits instead of read-
ing the digit).
The present work aims at assessing the performance of MCI
patients in the 5D task and compare the automatic and con-
trolled processes of selective attention speed and efficiency in
these participants. The tested hypothesis is that MCI patients
show greater impairment in the controlled process than in the
automatic process when compared to normal aging controls
Forty five patients diagnosed with MCI (23 men and 22
women) and forty five NC (21 men and 24 women) were as-
sessed for this study. The NC group was composed by patients'
relatives or community older adults recruited by local an-
nouncements, while the MCI patients were invited after clinical
evaluation in a clinical center specialized in gerontology. The
inclusion criteria for the NC group were total score on the Bra-
zilian version of the Mini-Mental State Exam above the pro-
posed cutoff for education (Brucki et al., 2003), total score on
the fifteen item version of the Yeasavage Geriatric Depression
Scale (Brazilian version) below the cutoff score for depression
(Paradella, Lourenço & Veras, 2005) and no functional im-
pairment assessed by the Lawton-Brody (Lawton & Brody,
1969) and Katz (Katz, Downs, Cash & Grotz, 1970) daily life
activities indexes. The MCI group was diagnosed by a multid-
isciplinary assessment conducted by at least one gerontologist
and one clinical neuropsychologist based on the Petersens and
col. criteria for MCI (2001). Also a semi-structured interview
based on the DSM-IV was conducted by the researchers for
screening other neuropsychiatric conditions. All participants
were assessed in accordance with the Declaration of Helsinki,
and the Research Ethics Committee of the Universidade Federal
de Minas Gerais (334/06) gave written consent and approval.
Participants’ data is shown in Table 1.
The cognitive screening was conducted by the use of the
Mini-Mental State Exam and the Clock Drawing Test. Selective
attention was assessed with the 5D, a MVT test divided into
four successive parts: 1) decoding, 2) retrieving, 3) inhibiting
and 4) shifting, which involve, respectively: reading, Counting,
choosing, and switching a series of stimuli (Figure 1). Each
part of the test is preceded by a training containing 10 items;
after the instructions, the subject has four trials to correctly
respond to the items. If the subject is unable to perform the
training items, the test is interrupted. The items are shown in
pages of 50 items (10 rows of five items) and each of them is
surrounded by a rectangular frame. Previous studies attested its
validity and potential for clinical use (Lang, 2002; Sedó, 2004).
Figure 1.
The five digits test.
Copyright © 2012 SciRes.
Copyright © 2012 SciRes. 381
In the decoding part of the test, the subject is shown a series
of 50 boxes that require automatic reading of the items inside
each box, which are groups of one to five congruous digits (one
1, two 2 s, three 3 s…) that must be read. In the second part,
Retrieving, the subject is shown a series of 50 boxes where one
to five stars must be counted. In the third part—the inhibition
part—digits are shown in incongruous forms (one 4, two 3 s,
five 1 s…) and the person is asked to say the number of digits,
demanding a controlled process of inhibition. In the fourth part
of the test an additional difficulty is shown to the subject:
he/she has to switch from counting to reading in 20% of the
items of the page (the items marked by a much darker frame),
resulting in a series of congruent and incongruent items that
demand a more intense controlled process of inhibition and
The four parts of the 5D measure the “speed” of information
processing (time in seconds) and the “efficiency” of their re-
sponses (number of errors). Considering the processes involved
the test can be divided in automatic attentional processes (De-
coding/Retrieving) and controlled attentional processes (Inhib-
iting/Shifting). An interference score was computed as recom-
mended by the test author (Sedó, 2004) subtracting the reading
time of the inhibiting and shifting components, creating two
new variables: executive-inhibiting and executive-shifting.
Statistical Analysis
Data distribution was assessed by the Kolmogorov-Smirnnov
test. Continuous variables with parametric distribution were
compared by independent samples t tests and effect sizes were
estimated by Cohen’s d. Non parametric data were compared
by the Mann-Whitney U Test and effect sizes estimated by the r
statistic (Z/N). The frequency of gender in the two samples
was compared by a chi-square test. Significance levels were
established at 0.05.
Comparisons between the MCI group and the NC on the 5D
are shown on Table 1. No differences in age and education
were found between the two groups (p > 0.05). No significant
differences on gender frequency were found (p > 0.05). Besides
screening tests, only measures of efficiency in controlled atten-
tional components differed significantly (p < 0.001), with mod-
erate effect sizes. The group differences considering Automatic
and Attentional Processes in terms of “speed” and “efficiency”
are exposed in Figure 2.
This study evaluated the performance of MCI patients in a
MVT version of the Stroop Color-Word Task considering the
automatic and the controlled processes of selective attention.
As expected, controlled attentional process demands more cog-
nitive resources, which is illustrated by the slower times of
execution and loss of efficiency when the two conditions were
compared. This phenomenon however was more prone in MCI
patients when efficiency was considered, but no differences
were found between this group and healthy older adults when
speed was compared. These findings suggest that MCI patients
show a “fast but inaccurate” pattern of performance commonly
found in clinical conditions where executive functions are often
impaired (Kogan, 1971).
These findings are complementary to other studies that sug-
gest that even in MCI executive functions may be impaired. In
the 5D test Moderate Effect Sizes were found when efficiency
Table 1.
Participants description and group comparisons.
Mean (SD) Median Mean (SD)Median
t/U p d/r
Age (Years)1 73.97 (6.59) 75.00 73.87 (6.59)74.00 0.06 0.953 -
Education (Years)1 4.30 (2.26) 4.00 4.70 (3.01) 4.00 –0.58 0.563 -
Mini-Mental State Exam1 26.70 (2.35) 27.00 23.99 (1.89)24.00 4.915 0.001 1.27
Clock Drawing Test2 3.89 (1.46) 4.20 2.46 (1.47) 2.38 213.50 0.001 –0.530
Decoding (Time)1 33.03 (15.58) 27.00 40.43 (12.97)41.00 –1.19 0.239 -
Decoding (Errors)2 0.03 (0.18) 0.00 0.10 (0.40) 0.00 434.50 0.544 -
Retrieving (Time)1 37.90 (14.71) 34.00 41.57 (13.97) 41.00 –0.990 0.326 -
Retrieving (Errors)2 0.23 (0.77) 0.00 0.20 (0.61) 0.00 448.50 0.966 -
Inhibiting (Time)1 63.63 (20.40) 61.00 73.97 (38.39) 65.00 –1.30 0.200 -
Inhibiting (Errors)2 1.80 (1.67) 1.00 5.37 (5.05) 5.00 238.00 0.001 –0.473
Shifting (Time)1 92.40 (23.73) 90.00 104.80 (37.05)99.28 –154 0.129 -
Shifting (Errors)2 4.07 (3.33) 3.50 9.98 (6.91) 7.00 205.50 0.001 –0.538
Executive Inhibition1 29.30 (21.86) 26.00 33.80 (30.83)27.00 –0.65 0.517 -
Executive Shifting1 57.77 (20.44) 57.00 65.54 (32.36)54.28 –1.11 0.271 -
1Parametric Distribution, independent samples t tests and Cohen’s d used; 2Non-Parametric Distribution, Mann-Whitney U Test and r used; NC: Normal
Conrols; MCI: Amnestic Mild Cognitive Impairment.
Figure 2.
Relationship between Speed, Efficiency, Group and Attentional Process. MCI: Amnestic Mild Cognitive Impairment, CI: Confidence
Interval 95%.
in controlled attentional process of these patients was compared
to efficiency in the control group, indicating deficits in inhibi-
tion and cognitive shifting. However no differences were found
in the time required to complete the tasks, suggesting no proc-
essing speed impairments in this population. Even in the “pur-
est” executive indexes of interference (executive-inhibition and
executive-shifting) related to speed of performance no differ-
ence was found. As pointed by Salthouse and Meinz (1995)
even the interference scores of stroop-like tasks are largely
influenced by processing speed and may not reflect executive
impairment. The dissociation of performance between the speed
and efficiency components of controlled attentional process has
an important meaning for clinical practice and must be consid-
ered in the perspective shown above, where a maintenance of
speed and lack of accuracy may indicate a more specific im-
pairment of executive functioning.
In terms of anatomical correlates the controlled attentional
process is associated with the anterior attentional network, con-
sisted of the anterior cingulate cortex and its connections to the
thalamus and the prefrontal cortex. Some authors like Nagata et
al. (2009) argue that executive impairments in controlled atten-
tional tasks might be secondary to histopathological changes in
medial temporal lobe regions, a common feature of Alz-
heimer’s Disease Dementia and MCI (Apostolova et al., 2006).
The disruption of neuronal networks associated with these re-
gions may secondarily affect other cognitive functions. The
proximity and density of neuronal connections between these
regions and the anterior cingulated cortex may be a risk factor
for controlled attentional process impairment in these patients.
Balota and Col. (2010) report that the errors on incongruent
trials were the best predictor of those who convert, differently
from those who do not, to Alzheimer disease dementia over a
14-year period. The results of the current study, aligned with
other findings, suggest that the association of medial temporal
lobe atrophy, controlled attentional process and MCI conver-
sion to dementia should be better investigated by other re-
The use of MVT tasks in low educated subjects proves it is
useful for clinical and research purposes. Other 5D studies in-
dicate good construct and criterion validity for patients of dif-
ferent ages and educational-cultural backgrounds (Sedó & De-
Cristoforo, 2001; Hsieh & Tori, 2007) and the 5D Test seems
ideal for the population assessed in this study. Drawbacks in
instruments like the chromatic (Lezak, Howieson, & Loring,
2005) and linguistic (Cox et al., 1997) properties of traditional
neuropsychological tests like the Stroop Color-word Test have
limited their uses in contexts where difficulties with color per-
ception, reading problems, and language disorders are present.
This is just the recurrent profile of the elderly in Brazil, where
illiteracy reaches 26% (IBGE, 2009). MVT tests in these con-
texts appear to be an appropriate choice for the assessment of
processing speed and executive functions.
The present study has important limitations. First, although it
is well characterized, the sample size is small, limiting the gen-
eralization of the findings. Also, as no other measures of execu-
tive functioning were used in the assessment of these patients
for the research, it is difficult to argue about the construct
specificity of the efficiency impairment as an indicator of a
more generalized executive dysfunction. However, the present
finding indicates a more specific pattern of executive impair-
ment in MCI patients where efficiency may be selectively im-
paired despite speed preservation. The 5D also shows good
evidences of clinical validity for the studied population.
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