The Impact of Cognitive Reserve on the Neuropsychological Functioning of Hispanic Patients with Minor Neurocognitive Disorder

doi:10.4236/psych.2013.410A004

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Psychology

2013. Vol.4, No.10A, 19-22

Published Online October 2013 in SciRes (http://www.scirp.org/journal/psych) http://dx.doi.org/10.4236/psych.2013.410A004

The Impact of Cognitive Reserve on the Neuropsychological

Functioning of Hispanic Patients with

Minor Neurocognitive Disorder

Jorge A. Herrera Pino1,2, Nora Dieguez1,3, Jose Armas1,2

1Medical Care Consortium, Inc., Miami, USA

2Herbert Wertheim College of Medicine, Florida International University, Miami, USA

3Neurobehavioral Institute of Miami, Coral Gables, Miami, USA

Email: [email protected]

Received August 7th, 2013; revised September 9th, 2013; accepted September 28th, 2013

Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium,

provided the original work is properly cited.

The purpose of this study was to explore the impact of cognitive reserve, on the neuropsychological status

of a sample of otherwise healthy Hispanic patients, who complained of memory difficulties, and thus

were suspected to present minor neurocognitive disorder. To this effect, 100 consecutive cases referred

for neuropsychological evaluation by their primary care physicians comprised the initial sample. Two

groups of 32 patients were formed on the basis of their scores in the Cognitive Reserve Questionnaire

(CRQ) that was administered to all participants. The results obtained by both groups in an eclectic battery of

neuropsychological instruments were compared. The results indicated that the CRQ High Score group had

significantly better performance than the CRQ Low Score group in the tests administered, except those

tapped into memory processes. This was interpreted, to be related to the fact that all of these patients fell

into the category of mild cognitive impairment of the amnestic type, as neither group performed well in

these specific instruments. The findings of this study were interpreted to lend support to the notion that

better cognitive reserve was associated with better cognitive status in the later years of life.

Keywords: Cognitive Reserve; Neuropsychological Evaluation; Mild Neurocognitive Disorder; Mild

Cognitive Impairment

Introduction

The seminal work of Yaakov Stern (2002) opened the doors

to a whole field of scientific endeavor related to the concept of

cognitive reserve. In this regard, this concept has been the focus

of a significant amount of research in recent years (cf. Stern,

2006, 2009; Stern et al., 2003). At the center of the notion of

cognitive reserve is the assumption that there are things people

can do, to better their cognitive health, and to improve the

chances of maintaining an adequate cognitive status throughout

the aging process, or even when assailed by disease that would

otherwise lead to impaired cognition (Vasile, 2013).

Patients who present to their primary care physicians or to

specialists complaining of memory difficulties, have often been

placed within the category of mild cognitive impairment, as per

the original ideas proposed by Petersen (2004), Petersen et al.

(2001), and Petersen et al. (1999). They were even diagnosed

with mild cognitive impairment (MCI) of the amnestic type.

There was also great concern regarding the rate of conversion

of these patients to a full blown dementing disorder of primary

degenerative type, such as Alzheimer’s disease.

However, the term mild cognitive impairment, as such, while

being a useful concept, was never made a diagnosis, even

though some authors referred to it (cf. Albert et al., 2013). Re-

cently, the fifth edition of the Diagnostic and statistical manual

of mental disorders of the American Psychiatric Association

(DSM-5; APA, 2013) includes the diagnosis of minor neuron-

cognitive impairment, within which mild cognitive impairment

has been included. This is the term used throughout this paper

to refer to the participants of this study.

Methodology

Ethical Considerations

This study was approved by the Institutional Review Board

of the Medical Care Consortium, Inc., (MCCI) as an archival,

cross-sectional, quasi-experimental research.

Participants

The participants of this study were 100 consecutive, other-

wise healthy, Hispanic patients seen at the Cognitive Health

Program of MCCI, who were referred by their primary care

physicians for presenting memory complaints. MCCI is a

multi-center organization that provides primary and specialized

medical care in out-patient settings. The initial sample of 100

patients included 62 females and 38 males.

Two samples were derived on the bases of the scores ob-

tained in the Cognitive Reserve Questionnaire (CRQ; Alberca

Serrano, 1998) described below. The 32 patients with the high-

J. A. HERRERA PINO ET AL.

est scores in the CRQ (CRQH) had an average score of 12.75

(sd = 1.98), an average chronological age of 73.02 years (sd =

8.65), and an average of 13.78 years of education (sd = 4.03).

The 32 patients with the lowest scores in the CRQ (CRQL)

obtained an average score of 4.00 (sd = 2.07), they had an av-

erage chronological age of 70.19 years (sd = 7.28), and an av-

erage level of education of 4.63 years (sd = 3.49). As seen in

Table 1, the means of both groups differed significantly in the

scores obtained in the CRQ and in the level of education, but

not in chronological age.

Instruments and Procedures

All participants were administered the CRQ, as well as an

eclectic battery of neuropsychological instruments described

below.

The Cognitive Reserve Questionnaire (CRQ; Alberca Ser-

rano, 1998) was administered in its original version in Spanish.

This instrument yields a total score of 25 and includes assess-

ment of the following dimensions:

 Level of education

 Highest level of education of one of the parents

 Additional training or courses taken

 Occupation or profession

 Formal musical training or education

 Languages spoken at a conversational level

 Reading activity

 Intellectual games or pastime

In addition to the CRQ, all participants were administered an

eclectic battery of neuropsychological instruments based on a

process oriented, evidence based paradigm. The instruments

included in this battery were the written (SDW); and oral (SDO)

administrations of the Symbol Digit Modalities Test (Smith,

1973, 1982, 2002), the Controlled Oral Word Association Test

(COW; Lezak, Howieson, & Loring, 2004; Spreen & Strauss,

1998), the Boston Naming Test (BNT; Kaplan, Goodglass, &

Weintraub, 1983, 1996), the administrations RAI (recall of the

list in the first trial), RAV (recall of the list in the fifth trial),

and RAD (recall of the list with a 20 minute delay) of the Rey

Auditory Verbal Learning Test (Schmidt, 1996), the copy

(ROC) and delayed (30 minute) (ROM) administrations of the

Rey Osterrieth Complex Figure Test (Rey, 2003; Meyers &

Meyers, 1995), and the Revised Benton Visual Retention Test

(BVR; Benton, 1974, 2002; Sivan, 1992). All neuropsycho-

logical tests were administered in Spanish, as this was the pre-

ferred language of all participants.

Data Analysis

Differences between the mean values obtained, by the two

Table 1.

Demographic data by group.

Groups by CRQ score

CRQLS N = 32CRQHS N = 32 Student t

CRQ 4.00 (2.07) 12.75 (1.98) −17.224*

Age 70.19 (7.28) 73.03 (8.65) −1.422

Education (years) 4.62 (3.49) 13.781 (4.030) −9.705*

CRQLS = Cognitive Reserve Questionnaire Low Scoring, CRQHS = Cognitive

Reserve Questionnaire High Scoring, ( ) standard deviation, *p ≤ 0.000.

groups of patients with high and low scores in the CRQ in the

different measures included in this study, were analyzed by

means of the Student-t statistical procedure.

Results

As noted above, Table 1 includes the differences between

both groups of participants in the variables of scores in the

CRQ, chronological age, and level of education. Table 2 shows

the mean values obtained by both groups in the different in-

struments included in the neuropsychological battery adminis-

tered to all participants.

An inspection of this table reveals that the mean score ob-

tained by the CRQ High Scoring (CRQHS) group in the written

administration of the Symbol Digit Modalities Test (SDW) was

26.59 (sd = 9.70), while the corresponding value obtained by

the CRQ Low Scoring (CRQLS) group was 12.78 (sd = 9.05).

The difference between these two means was found to be sig-

nificant at the level of p < 0.000, Relative to the oral admini-

stration of this instrument (SDO), the mean score obtained by

the CRQHS group was 29.68 (sd = 10.92), whereas the CRQLS

group obtained a mean value of 15.25 (sd = 10.31). Once again,

the difference between the means of both groups was found to

be significant at the level of p < 0.000.

The results obtained by both groups in the Controlled Oral

Word Association Test (COW) are as follows. The CRQHS

group obtained a mean value of 24.65 (sd = 8.61). The CRQLS

group obtained a mean score of 15.68 (sd = 7.68). The differ-

ence between these two means is statistically significant at the

level of p < 0.000.

A 30 item version of the Boston Naming Test (BNT; Saxton

et al., 2000) was used as part of the neuropsychological test

battery administered to all the participants of this study. The

Table 2.

Means and standard deviations in neuropsychological tests by group.

Groups by CRQ score

NP Tests

CRQLS N = 32 CRQHS N = 32 Student t

SDO 15.25 (10.31) 29.68 (10.920 −5.436*

SDW 12.78 (9.05) 26.59 (9.70) −5.887*

COW 15.68 (7.68) 24.65 (8.61) −4.393*

BNT 16.87 (3.94) 22.68 (4.27) −5.654*

RAI 3.71 (1.08) 4.28 (1.44) −1.763

RAV 6.00 (2.40) 7.87 (2.12) −3.304**

RAD 4.40 (2.48) 5.87 (2.70) −2.259***

ROC 22.01 (7.40) 30.23 (4.44) −5.383*

ROM 6.29 (3.35) 10.71 (5.40) −3.933*

BVR 2.12 (1.56) 3.75 (1.79) −3.863*

NP Tests = Neuropsychological Tests, CRQLS= Cognitive Reserve Questionnaire

Low Scoring, CRQHS = Cognitive Reserve Questionnaire High Scoring, SDO =

Symbol Digit Modalities Oral, SDW = Symbol Digit Modalities Written, COW =

Controlled Oral Word Association, BNT = Boston Naming Test, RAI = Rey

Auditory Verbal Learning (I), RAV= Rey Auditory Verbal Learning (V), RAD =

Rey Auditory Verbal Learning (D), ROC= Rey Osterrieth Complex Figure Copy,

ROM = Rey Osterrieth Complex Figure Memory, BVR = Benton Visual Reten-

tion, ( ) standard deviation, *p ≤ 0.000, **p ≤ 0.002, ***p ≤ 0.027.

J. A. HERRERA PINO ET AL.

mean score obtained by the CRQHS group in the BNT was

22.68 (sd = 4.27), while the corresponding value obtained by

the CRQLS group was 16.87 (sd = 3.94). The difference be-

tween these means was found to be statistically significant at

the level of p < 0.000.

The mean score obtained by the CRQHS group in the first

administration of the list of words of the Rey Auditory Verbal

Learning Test (RAI) was 4.28 (sd = 1.44), while the mean score

for the CRQLS group was 3.71 (sd = 1.08). The difference

between these two means was not found to be statistically sig-

nificant (p = 0.083). In the fifth administration of the list of

words of this instrument (RAV), the mean score value for the

CRQHS group was 7.86 (sd = 2.12) and for the CRQLS group

the mean score was 6.00 (sd = 2.40). This difference in mean

values was found to be significant at the level of p = 0.002.

The mean score obtained by the CRQHS group in the de-

layed (20 minutes) administration of the list of words of the

Rey Auditory Verbal Learning Test (RAD) was 5.87 (sd =

2.70), with a corresponding mean value of 4.40 (sd = 2.48) for

the CRQLS group. The difference between these means was

found to be statistically significant at the level of p = 0.027.

Relative to the Rey Osterrieth Complex Figure Test, the

findings were as follows. The CRQHS group obtained a mean

score of 30.23 (sd = 4.44) in the copy administration (ROC).

The CRQLS group obtained an average score of 22.01 (sd =

7.40). The difference between these means was found to be

highly significant (p < 0.000). In the delayed (30 minutes) re-

call administration of this instrument (ROM), the CRQHS

group obtained a mean value of 10.71 (sd = 5.40), and the

CRQLS group obtained a mean value of 6.29 (sd = 3.35). Once

more, the difference between these two means was found to be

highly significant (p < 0.000).

In the Revised Benton Visual Retention Test (BVR), the

CRQHS group obtained an average score of 3.75 (sd = 1.79).

The corresponding value for the CRQLS group was 2.12 (sd +

1.56). The difference between these two means was also found

to be highly significant (p < 0.000).

Discussion

It is evident, on the bases of the results described above, that

the level of cognitive reserve attained by the participants in this

study has a significant and measurable impact on their neuro-

cognitive status, as measured by an eclectic battery of neuro-

psychological instruments. This impact was seen clearly on the

attentional and incidental memory abilities measured by the

written and oral administrations of the Symbol Digit Test. The

results obtained in this study also revealed the impact of cogni-

tive reserve on the verbal fluency and word finding abilities

measured by the Controlled Oral Word Association Test.

The level of cognitive reserve was also noted to have an im-

pact on the naming function of language, as measured by the

Boston Naming Test. In addition to this, the level of cognitive

reserve was also found to have an impact on the visual con-

structional praxis abilities measured by the copy administration

of the Rey Osterrieth Complex Figure Test, as well as the inci-

dental memory functions assessed by the delayed memory ad-

ministration of this instrument.

On the other hand, the impact of the level of cognitive re-

serve, as measured by the CRQ did have a clear impact on tasks

in which memory was an important function. The results of the

recall of the initial presentation of the supra-span list of words

(RAI) of the Rey Auditory Verbal Learning Test did not differ

significantly between the two groups of patients.

Even though the mean values obtained by both groups in the

fifth administration of the word list (RAV) and the delayed

administration (RAD) showed statistical significance, the actual

values differed by less than two (2) points. It is very difficult to

make clinical decisions on the bases of such a narrow margin of

difference. The same may be said of the visual memory func-

tions assessed by the Revised Benton Visual Retention Test

(BVR).

The interpretation of these findings brings out the ever pre-

sent concern of the difference between statistical significance

and clinical significance. Whereas these results show statistical

significance, once again, it is very difficult to translate them

into the clinical setting.

It should be noted that both groups did not perform well in

measures related to memory processes. One possible explana-

tion is the fact that these patients can be characterized as pre-

senting what has been described as mild cognitive impairment

of the amnestic type (now referred to as minor neurocognitive

disorder), as they were referred to the Cognitive Health Pro-

gram of MCCI, by their primary care physicians, for having

reported to them memory difficulties to begin with..

Conclusion and Recommendations

The findings of this study clearly support the initial premise

that there are things that can be done throughout the life cycle,

to improve overall cognitive functioning in the later years of

life. It is important to note that the sample included in this study

is a referred sample, that is, patients referred for neuropsy-

chological evaluation due to memory complaints. In this regard,

it would be important to explore the impact of cognitive reserve

on neuropsychological status of healthy, non-referred individu-

als, as well. It would also be important to replicate this study

with patients that have begun to show symptoms of probable

Alzheimer’s disease.

The knowledge gained through this research can help in the

development of life long strategies to improve or increase cog-

nitive reserve. It can also point the way to the need for devel-

oping and implementing neurobehavioral interventions to

lessen the impact of the aging process or the presence of medi-

cal conditions that may accelerate cognitive decline and result

in functional impairments.

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