BJMB
Brazilian Journal of Motor Behavior
Research Article
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Rodrigueset al.
2020
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Influence of exercise on cognitive processing of older women during dual-task balance:
sixteen case reports
ANA C. M. A. RODRIGUES
1,2,3
| RODOLPHO C. R. TININI
4
| VALESKA GATICA-ROJAS
5
| ALFREDO M. B. DE PAULA
1
|
ANDRE L. S. GUIMARÃES
1
| RENATO S. MONTEIRO-JUNIOR
1,3,6
1
Postgraduate Program of Health Sciences (PPGCS), State University of Montes Claros, Montes Claros/MG, Brazil.
2
Physiotherapy, Faculty Santo Agostinho, Montes Claros/MG, Brazil.
3
Postgraduate Program of Neurology (PPGN), Fluminense Federal University, Niteroi/RJ, Brazil.
4
Institute of Agricultural Sciences, Federal University of Minas Gerais, Av. Universitária 1000, Universitário, Montes Claros/MG, Brazil.
5
Human Motor Control Laboratory, Department of Human Movement Sciences, Faculty of Health Sciences, Interdisciplinary Excellence Research Program on Healthy
Aging (PIEI-ES), Universidad de Talca, Av. Lircay S/N, Talca, Chile.
6
Departament of Physical Education, State University of Montes Claros, Av. Doutor Ruy Braga s/n, Vila Mauricéia, Montes Claros/MG, Brazil.
Correspondence to: Ana Carolina de Mello Alves Rodrigues.Physiotherapy, Faculty Santo Agostinho, Montes Claros/MG, Brazil. Address: Avenida Osmane Barbosa, 937,
Conj. Res. JK – Montes Claros-MG. Telephone: +55 38 992327564.
email: acmarodrigues@gmail.com
https://doi.org/10.20338/bjmb.v14i01.160
HIGHLIGHTS
• Cognitive load impairs quiet postural balance
of older adults during a dual-task.
• There is high mediolateral oscillation of
postural control in a dual-task condition.
• Physical exercise in dual-task improves motor
and cognitive performance.
ABBREVIATIONS
ACSM American College of Sports
Medicine
ADLs activities of daily living
CE closed eyes
CoP Center of pressure
CoPap anteroposterior CoP displacement
CoPml mediolateral CoP displacement
DT dual-task
HRR heart rate reserve
MMSE Mini-Mental State Examination
OE open eyes
SPE subjective perceived exertion
WWB Wii Balance Board
PUBLICATION DATA
Received 31 01 2020
Accepted 27 03 2020
Published 01 04 2020
BACKGROUND: Older adults require special attention during cognitive-motor tasks since automatic postural control
is reduced.
AIM: To analyze the effect of physical exercise on dual-task processing of healthy older women performing
standing balance.
METHOD: Sixteen healthy older women were assessed in a quiet standing position with eyes open/closed (single-
task, EO, and EC) and with a cognitive task (dual-task, DT) using a Wii Balance Board. All individuals performed
training (aerobic, strength, and virtual reality exercises) at moderate effort. Center of pressure (CoP)
anteroposterior and mediolateral displacement were analyzed over time pre- and post-training. The Wilcoxon test
was used to compare pre- and post-training.
RESULTS: Greater variability in CoP was observed pre- compared to post-training. In the DT, there was a
significance decrease in post-training variability compared to pre-training (p<0.01).
CONCLUSION: Physical exercise programs for older adults may contribute to simultaneously improving motor-
cognitive performances, associated with improvement in the divided attention.
KEYWORDS: Motor-cognitive task| Balance | Physical Performance | Older adults
INTRODUCTION
The aging process promotes changes in the brain and sensorimotor system,
resulting in cognitive (e.g. deficits in executive functions and attentional resources) and
postural balance declines
1-3
. Impairments in the integration of these systems influences
performance in activities of daily living (ADLs) due to the relationship of cognitive domains
and motor behavior. Older adults require more attention during automatic tasks (e.g.
standing and walking) because of their reduced ability to perform dual-tasks
3
.
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Simultaneous tasks (e.g. talking while walking) are performed daily. Dual-task is the
term used to define tasks performed concomitantly, such as cognitive-motor tasks
1,3-5
. In
automatic tasks, such as standing, older people with decreased postural control present
greater postural oscillation while performing a cognitive task simultaneously, with impairment
of balance
1,3,4,6
. This indicates that the cognitive task interferes in the motor control
1,3,4,6
.
According to the complexity of cognitive demand the motor control could be impaired.
Physical exercise is recommended to preserve physical abilities (such as strength
and balance) and aerobic resistance, as well as to reduce cognitive decline
1,6
. According to
Choi et al.
4
and Delbroek, et al.
1
, older adults with balance disorders and cognitive deficits
show a higher risk of falls, with subsequent diminished physical activity and greater
functional dependence. Thus, since ADLs require the management of simultaneous motor-
cognitive tasks
5
, the exercise program for older adults should provide physical and mental
stimulus, with simultaneous demands to confront the reality of the dual-tasks performed on
a daily basis.
The American College of Sports Medicine (ACSM) recommends aerobic, strength,
endurance, balance, and stretching exercises for older adults to maintain their physical
capabilities. The exercise choice depends on the goal of the intervention. However, it is still
unclear whether the exercise choice influences postural control variability during a motor-
cognitive task. The aim of this study was to analyze the effect of individualized exercise
(exergame, aerobic, and strength training) on standing balance control during a motor-
cognitive task in healthy older women. Our hypothesis was that exercise would improve
postural balance control during a motor-cognitive task in older women.
METHODS
A case reports study following the Consensus-based Clinical Case Reporting
Guideline Development (CARE)
7
.
Participants
Sixteen healthy women older adults from Montes Claros city, Minas Gerais State,
Brazil were recruited through posters displayed near the university and clinics to participate
in a longitudinal research project called “Physical exercise, physical and mental health of
older adults”. As the adherence of women to this project was greater than men, to maintain
homogeneity of the sample, the data of males (n = 4) were not included. The inclusion criteria
were i) women aged ≥60 years of age, ii) preserved communication ability, iii) independent
ambulation, and iv) medical certificate to perform exercise. Participants were excluded if they
presented i) musculoskeletal injury that would make it impossible to practice exercise, ii)
labyrinthitis or other vestibular disorders, iii) use of psychotropic drugs, iv) cognitive
impairment. We used the MMSE to quantify cognitive decline according to educational level,
adopting the cutoff scores of 13 points for illiterate participants, 18 for low-middle school (up
to 8 years), and 26 for highly schooled individuals (over 8 years)
8,9
. The final score is the
sum of the points obtained in each category, totaling 30 points. Data were collected through
a history taken with the older women. All participants were informed about the procedures,
requirements, risks, and benefits of participation before signing a consent form, which was
approved by University’s local ethics committee (n°1.365.041/2015).
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Computerized Posturography and dual-task assessment
The Wii Balance Board (Nintendo®, Kyoto, Japan) platform, with a sampling
frequency of 40 Hz, was used to assess balance from the anteroposterior (CoP
ap
) and
mediolateral (CoP
ml
) CoP displacement
10
for one minute (30 seconds of adaptation to
posture and 30 seconds of signal collection) in a standing position.
A routine program using LabVIEW
®
software, version 8.5 (National Instruments,
Texas, USA) was designed for data acquisition and reading on a computer. Data obtained
were analyzed through specific routines programmed in Matlab
®
(MathWorks Inc., USA),
which was also used for all statistical procedures. A Fourier transform spectral analysis was
performed and all data were filtered using a 3
rd
order Butterworth low-pass filter with a cutoff
frequency of 12 Hz.
The older people stood comfortably on the WBB with their arms at their sides and
feet spread shoulder width apart. Postural balance was analyzed in different tasks performed
sequentially. The individual remained standing with eyes open (EO) and closed (EC),
characterizing a simple motor task. Each test was repeated twice. Subsequently,
participants remained in a standing position with eyes open, simultaneously performing a
cognitive task (subtraction of seven from one hundred, continuously)
11,12
. This setting
characterized the dual-task (DT) paradigm with motor-cognitive demand.
Training Program
After the balance evaluation, the older women performed different training
programs: composed of treadmill aerobic exercise, with intensity maintained between 40-
59% of heart rate reserve (HRR), which is equivalent to a moderate effort
13
; strength
exercises (exercises of upper and lower limbs, prioritizing large muscle groups and requiring
support of body weight), and exergames (exercises with virtual reality). The strength
program consisted of squatting exercises on an unstable surface (with shoulder extension
and elbow flexion in the anteroposterior axis), frontal pulls on the pulley, and shoulders
adduction on the pulley with elbows extended. For exergames, the Nintendo Wii console
(Nintendo
®
, Kyoto, Japan) and Wii Balance Board platform (WBB) (Nintendo
®
, Kyoto, Japan)
were used. The device packages used were: Wii Fit Plus (Rowing Squat, In Line Lunge,
Table Tilt) and Wii Sports Resort (Sword Play Duel, Sword Play Showdown), which consists
of exercises for the upper and lower limbs similar to the strength exercise group. All
packages were from Nintendo
®
(Kyoto, Japan).
For all exercises that made up training program, the intensity was monitored with a
subjective perceived exertion (SPE) between 05-06 points (moderate intensity), from 0 to 10
points according to the American College of Sports
13
. The training program lasted 3 months,
with sessions twice a week, and a session duration of 30 to 45 minutes
14
.
Balance performance was reassessed immediately after the intervention period.
Data Analysis
Displacement of the center of pressure data in CoP
ap
and CoP
ml
directions, at pre-
training and post-training in the DT, EO, and EC conditions was analyzed.
Statistical Analysis
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Data normality was tested using the Lilliefors test. As non-normal distribution was
observed, non-parametric tests were performed. The Wilcoxon test was used to compare
pre and post-training values of CoP
ml
and CoP
ap
in the DT, EO, and EC conditions. The
effect of dual-task on standing is described in percentage of dual-task interference,
calculated according to Rochester et al.
15
. All variables were analyzed at a significance level
of p <0.05.
RESULTS
The present study initially proposed different exercise programs, exergames (n=6),
strength (n=5), and aerobic (n=6). However, when we analyzed the effect of dual-task on
CoP, similar behavior was observed between the different exercise programs, so we decided
to analyze the results as a single group.
The evaluated participants were 66 ± 7 years, with the following physical
characteristics: body mass 62 ± 9.57 Kg, height 1.55 ± 0.05 m, and body mass index 25.81
± 2,35 Kg/m².
The CoP
ap
and CoP
ml
curves in the DT, EO, and EC conditions are shown in figures
1 and 2, respectively. Figure 1 presents the reduced CoP
ml
variability in the EO (standard
deviation: pre = 0.05; post = 0.04), EC (standard deviation: pre = 0.06; post = 0.05), and DT
conditions (standard deviation: pre = 0.12, post = 0.05). Figure 2 shows that COP
ap
variability reduced in EO (standard deviation: pre = 0.23; post = 0.19) and DT conditions
(standard deviation: pre = 0.27, post = 0.22). Greater variability of the center of pressure
displacement was observed in the pre-training condition compared to the post-training
moment, except in the CoP
ap
in the EC condition, where post training values were higher
than pre-training (standard deviation: pre = 0.21; post = 0.23). In the DT condition there was
lower post-training variability compared to pre-training, especially after the first 05 seconds
(which represents the instant of time when the examiner says the numbers to calculate).
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Figure 1. Median curves of variability (standard deviation, SD) of the center of pressure displacement in the
mediolateral direction (CoP ml) of 16 older women. A) eyes open, B) eyes closed, and C) dual-task. The red
and blue curves represent the CoP variability over time (pre- and post-training data, respectively).
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Figure 2. Median curves of variability (standard deviation, SD) of the center of pressure displacement in the
anteroposterior direction (CoP ap) of 16 older women. A) eyes open, B) eyes closed, and C) dual-task. The
red and blue curves represent the CoP variability over time (pre- and post-training data, respectively).
Table 1 presents the median values of CoP
ap
and CoP
ml
variability in the different
tasks, where significant differences can be observed between the pre- and post-training
period. CoP
ml
decreased post-training in all conditions evaluated, whereas CoP
ap
increased
in DT and EC, and decreased only in EO.
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DISCUSSION
The lower variability in mediolateral displacement when the participants were
exposed to a dual-task condition was the most important finding of this study. Posture control
in the vertical position occurs from ankle (CoP
ap
) and hip (CoP
ml
) range of motion
16
.
Rodrigues et al.
17
observed that in older adults, cognitive load during dual-task impairs
balance, mainly in the mediolateral direction, with an increase in CoP oscillation in the
mediolateral direction.
Studies describe
18,19
that permanent balance ability in older adults may be related
to the regular pattern of CoP variability. Yamagata et al.
19
suggest that maintaining stability
in the frontal plane is relatively easier due to the larger support base during the position.
While healthy young adults control postural balance in the sagittal plane during DT
20
, older
adults maintain postural control in the frontal plane during the DT condition. In the present
study, before the training, the participants demonstrated greater mediolateral oscillation
(CoP
ml
) and lower anteroposterior oscillation (CoP
ap
), indicating the use of the hip as a
main strategy for balance control. However, after physical training, the participants
presented lower variability in CoP
ml
and greater variability in CoP
ap
during EO and DT.
These findings show that physical training could promote changes in the postural control
strategy, with greater use of the ankle to the detriment of hip utilization. This demonstrates
that the participants who performed 24 sessions of differentiated exercises presented similar
control of body stability to that observed in young adults.
A physical exercise program with dual-task training seems to have effects on the
balance of older adults. Li et al.
6
, evaluated single-support standing balance with eyes open
and closed, which involved standing on the dominant leg for 10 s/trial. The authors found
significant effects of decreased CoP variability post-training. The results are similar to the
findings in our study, although we assessed double-support standing balance. In a
systematic review, Wollesen & Voelcker-Rehage
3
investigated the benefit of dual-task
training for healthy older adults with regard to the training program and task conditions. The
authors found that exercises in dual-task improved standing balance in dual-task conditions
and this could be achieved with specific and general exercises.
The change in strategy promoted by training in postural balance control is important
in relation to the incidence of falls and fractures in older adults, as it reveals improvement in
motor performance due to postural adjustments
1,4
. Another important aspect regarding falls
Table 1 - Median of variability of displacement of the pressure center in the anteroposterior (CoP ap) and mediolateral (CoP ml) under
different pre and post-training conditions from the Wilcoxon analysis.
CoP ap
CoP ml
Pre
Post
p-value
Pre
Post
p-value
DT
0.04
0.26
p<0.01
0.16
0.03
p<0.01
EO
0.29
0.09
p<0.01
0.11
0.02
p<0.01
EC
0.20
0.31
p<0.01
0.09
0.06
p<0.01
Note: DT – dual-task; EO – open eyes; EC – closed eyes; p-value – significant difference between pre and post-training (p<0.05).
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is the impairment in neural processing of older adults, which decreases executive function
and attentional resources
1,2
.
Decreased variability of CoP
ml
may be related to improvement in neural processing
promoted by the varied exercise program in dual-task. Performance in the secondary task
(cognitive task) was not recorded, since speech can interfere in the assessment of balance,
so only a mental calculation task was given. In pre-training, the older women presented
greater variability in center of pressure displacement in the dual-task condition, possibly
because they required more attention and motor planning to maintain balance. At post-
training, lower variability was observed in the dual-task condition, suggesting lower neural
competition between cognitive or motor tasks with the exercise program. The post-training
dual-task cost did not differ from pre-training, however, an improvement was observed in the
motor strategy for balance control of participants, which represents a lesser shift of attention
to the cognitive task.
This relationship between cognition and balance is important for the development
of evaluation and treatment strategies related to aging
1,4
. We speculate that due to the
effects of exercise on the brain
21
, the reduction in mediolateral variability could be related to
greater motor synchrony managed by the bilateral motor cortices, which would result in
better bilateral side-by-side postural control. However, as this was not investigated in the
present study, this is only a hypothetical suggestion.
According to the present study it is suggested that physical exercise (24 sessions
of 30-45 min) performed twice a week can improve dual-task cognitive processing. However,
some limitations of this study should be highlighted: 1) the small sample size; 2) absence of
a control group or different exercise groups.
CONCLUSION
Physical exercise programs for older women may simultaneously contribute to
improving both motor and cognitive performance. The reduction in mediolateral
displacement (CoP
ml
) variability in postural control and potential improvement in the divided
attention may positively influence improvement in motor and cognitive performances.
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ACKNOWLEDGEMENTS
We thank the following funding agencies: Coordenação de Aperfeiçoamento de
Pessoal de Nível Superior (Capes), Conselho Nacional de Desenvolvimento Científico e
Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do Estado de Minas Gerais
(FAPEMIG).
Citation: Rodrigues ACMA, Tinini RCR, Gatica-Rojas V, De Paula AMB, Guimarães ALS, Monteiro-Junior
RS.Influence of exercise on cognitive processing of older woman during dual-task balance: sixteen case reports.
BJMB. 2020: 14(1): 14-23.
Editors: Dr Fabio Augusto Barbieri - São Paulo State University (UNESP), Bauru, SP, Brazil; Dr José Angelo Barela -
São Paulo State University (UNESP), Rio Claro, SP, Brazil; Dr Natalia Madalena Rinaldi - Federal University of
Espírito Santo (UFES), Vitória, ES, Brazil.
Copyright:© 2020 Rodrigues, Tinini, Gatica-Rojas, De Paula, Guimarães and Monteiro-Junior and BJMB. This is an
open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives
4.0 International License which permits unrestricted use, distribution, and reproduction in any medium, provided the
original author and source are credited.
Funding: This study was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes),
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) and Fundação de Amparo à Pesquisa do
Estado de Minas Gerais (FAPEMIG).
Competing interests: The authors have declared that no competing interests exist.
DOI:!https://doi.org/10.20338/bjmb.v14i01.160
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