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Cognitive-Motor Multitasking in Older Adults: A Randomized Controlled Study on the Effects of Individual Differences on Training Success

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Abstract

Background Multitasking is an essential part of our everyday life, but performance declines typically in older age. Many studies have investigated the beneficial effects of cognitive, motor and combined cognitive-motor training on multitasking performance in older adults. Previous work, however, has not regarded interindividual differences in cognitive functioning and motor fitness that may affect training benefits. The current study aims to identify whether different training programs may have differential effects on multitasking performance depending on the initial level of cognitive functioning and motor fitness. Methods We conduct a 12-week single-blinded randomized controlled trial. A total of N = 150 healthy older adults are assigned to either a single cognitive, a single motor, or a simultaneous cognitive-motor training. Participants are trained twice per week for 45 min. A comprehensive test battery assesses cognitive functions, motor and cardiovascular fitness and realistic multitasking during walking and driving in two virtual environments. We evaluate how multitasking performance is related not only to the training program, but also to participants’ initial levels of cognitive functioning and motor fitness. Discussion We expect that multitasking performance in participants with lower initial competence in either one or both domains (motor fitness, cognitive functioning) benefits more from single-task training (cognitive training and/or motor training). In contrast, multitasking performance in participants with higher competence in both domains should benefit more from multitask training (simultaneous cognitive-motor training). The results may help to identify whether tailored training is favorable over standardized one-size-fits all training approaches to improve multitasking in older adults. In addition, our findings will advance the understanding of factors that influence training effects on multitasking. Trial registration DRKS (German Clinical Trials Register), DRKS00022407. Registered 26/08/2020 - Retrospectively registered at https://www.drks.de/drks_web/setLocale_EN.do
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Cognitive-Motor Multitasking in Older Adults: A
Randomized Controlled Study on the Effects of
Individual Differences on Training Success
Melanie Mack
University of Münster
Robert Stojan
University of Münster
Otmar Bock
German Sport University
Claudia Voelcker-Rehage ( claudia.voelcker-rehage@uni-muenster.de )
University of Münster
Research Article
Keywords: adaptive, individualized, dual-tasking, aging, ecological validity, exercise, physical activity,
cognition, cognitive testing, combined cognitive-motor intervention
Posted Date: January 27th, 2022
DOI: https://doi.org/10.21203/rs.3.rs-1250580/v1
License: This work is licensed under a Creative Commons Attribution 4.0 International License. 
Read Full License
Version of Record: A version of this preprint was published at BMC Geriatrics on July 15th, 2022. See the
published version at https://doi.org/10.1186/s12877-022-03201-5.
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Abstract
Background
Multitasking is an essential part of our everyday life, but performance declines typically in older age.
Many studies have investigated the benecial effects of cognitive, motor and combined cognitive-motor
training on multitasking performance in older adults. Previous work, however, has not regarded
interindividual differences in cognitive functioning and motor tness that may affect training benets.
The current study aims to identify whether different training programs may have differential effects on
multitasking performance depending on the initial level of cognitive functioning and motor tness.
Methods
We conduct a 12-week single-blinded randomized controlled trial. A total of
N
= 150 healthy older adults
are assigned to either a single cognitive, a single motor, or a simultaneous cognitive-motor training.
Participants are trained twice per week for 45 min. A comprehensive test battery assesses cognitive
functions, motor and cardiovascular tness and realistic multitasking during walking and driving in two
virtual environments. We evaluate how multitasking performance is related not only to the training
program, but also to participants’ initial levels of cognitive functioning and motor tness.
Discussion
We expect that multitasking performance in participants with lower initial competence in either one or
both domains (motor tness, cognitive functioning) benets more from single-task training (cognitive
training and/or motor training). In contrast, multitasking performance in participants with higher
competence in both domains should benet more from multitask training (simultaneous cognitive-motor
training). The results may help to identify whether tailored training is favorable over standardized one-
size-ts all training approaches to improve multitasking in older adults. In addition, our ndings will
advance the understanding of factors that inuence training effects on multitasking.
Trial registration:
DRKS (German Clinical Trials Register), DRKS00022407. Registered 26/08/2020 - Retrospectively
registered at https://www.drks.de/drks_web/setLocale_EN.do
Background
Multitasking (MT) is an integral part of our daily life. Driving a car while using a mobile phone, or strolling
on the sidewalk while watching shop windows, are often-cited examples of everyday behavior in which
we execute multiple actions concurrently. A large number of studies evaluated how such concurrent
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cognitive-motor actions are scheduled, coordinated and supervised (1). Initial theoretical concepts
proposed an unitary, high-level cognitive mechanism called “supervisory attention system” (2) or “central
executive” (3). This mechanism has later been partitioned into components called “executive functions”
(4, 5), although the existence of distinct and separable executive functions has lately been called into
question (6). It is well established that MT skills deteriorate in older age (e.g., meta-analysis by 7),
particularly when tasks place a high demand on working memory (8) or on visuo-spatial processing (9).
This deterioration has been attributed to an interrelated decay of perceptual, sensorimotor and cognitive
functions in older age (10) which have been shown to differ considerably between individuals (11). We
aim to evaluate training programs which counteract the age-related decay of MT, taken interindividual
variability into account and empowering older persons to pursue an independent lifestyle.
A range of studies with healthy young and older participants indicate that such training programs might
indeed be feasible: extensive practice led to a substantial reduction of MT costs (MTC), i.e., of the relative
performance decrement under MT conditions compared to single-task (ST) conditions. In some cases,
MTC were eliminated completely (review in 1). Transfer of benets to unpracticed tasks has also been
observed, which suggests that training can optimize not only the constituent tasks, but also the executive
processes that supervise MT (12–15).
Numerous experimental studies with older participants evaluated cognitive-motor MT training and its
effects on unpracticed MT scenarios. Here we focus on studies which included specically the transfer of
training to unpracticed cognitive-motor MTs, such as walking on a treadmill while completing a working
memory test. Several systematic reviews summarized the literature in this area, each from a somewhat
different viewpoint (16–22). When the literature covered by those reviews is adjusted by removing (1)
double citations of the same study, (2) studies that didn’t test for transfer to unpracticed cognitive-motor
MTs, (3) studies that didn’t include an adequate control group, and (4) studies of populations with health
problems (frail, balance-impaired, osteoarthritis, osteoporosis), then 25 studies remain. Adding four more
recent studies (23–26) brings the total up to 29.
All 29 studies included cognitive-motor MT in their pre- and posttests, but only 15 of them also included
cognitive-motor MT as a substantial or as the only content of their training regime; we will refer to them
as MT training studies. The other 14 studies trained mainly or exclusively ST (two studies ST cognitive
training and twelve studies ST motor training); we will refer to them as ST training studies. Eleven of the
15 MT training studies and nine of the 14 ST training studies found a statistically signicant reduction of
MTC. In particular, MTC for the motor component decreased after training in seven MT training studies
and in six ST training studies; MTC for the cognitive component decreased after training in six MT
training studies, and in three ST motor training studies (cognitive MTC were not provided in four MT
training and in ve ST training studies). Ten studies compared MT training and ST training (24–33), of
which seven of them found MT training more benecial as ST training (24, 26, 27, 29, 30, 32, 33). Only
two studies compared MT training with xed task priority and MT training with variable task priority; they
found the latter instruction to be more effective (14, 34).
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The heterogenous results on training success in above studies led to a widespread discussion about
possible causes and remedies. In particular, it was proposed that some studies yielded no training
benets because of shortcomings regarding (1) sample size: some studies trained only a small number
of participants such that, even if training benets existed, they were not likely to reach statistical
signicance; (2) training quantity: in some studies, the duration, number and/or frequency of training
sessions was quite low, and those studies therefore possibly suffered from oor effects, i.e., the intensity
threshold for substantial training benets was not reached; (3) training intensity: some studies
implemented less-demanding tasks, and therefore again potentially suffered from oor effects; (4)
training variety: some studies trained only a single combination of tasks, which might not be the best way
to support transfer.
The present work addresses yet another possible shortcoming: participants’ initial competence. Since
interindividual differences in cognitive functioning as well as in motor tness increase with advancing
age (35), it is quite likely that some participants in the above studies had higher cognitive functioning
and/or motor tness, while others had lower cognitive functioning and/or motor tness. It further is
conceivable that older adults with lower cognitive and/or motor competence were probably overstrained
by the complexity of cognitive-motor MT, and therefore beneted little from training. If so, the limited
success in above studies could simply reect a sampling bias: possibly, some studies happened to recruit
a larger portion of participants with lower cognitive functioning and/or motor tness, which could explain
why they didn’t yield signicant training benets.
If participants’ initial competence indeed plays a role, this should be considered when designing new
training regimes. In particular, persons with lower cognitive functioning should rst be given cognitive
training alone, before simultaneous cognitive-motor training is introduced. Similarly, persons with lower
motor tness should start out with motor training alone, and those with lower cognitive functioning and
motor tness should start out with a combination of cognitive training alone and motor training alone.
Only persons with higher cognitive functioning and motor tness should receive simultaneous cognitive-
motor training right away. Such an approach would be in line with the modern concepts of
“individualized”, “personalized” or “tailored” training. According to those concepts, physical (36, 37),
cognitive (38, 39), psychosocial (40) and other forms of interventions should not use off-the-rack
standardized protocols, but rather should be tted to each participant’s initial level of competence. The
purpose of our study is to provide experimental evidence for or against the potential benets of tailored
training on cognitive-motor MT.
Available literature provides some indirect evidence in favor of tailored training. For example, older adults’
reduced motor tness was found to be associated with reduced automation and increased cognitive
control in gait tasks (41). This ts well with the view that in older age, more cognitive resources must be
allocated to the motor system and thus are no longer available for the supervision of MT (42). It has
further been shown that motor training of older adults reduces their need for cognitive control of gait (43).
This could indicate that motor training frees up some of the cognitive resources which older persons
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otherwise would allocate to motor control, such that the freed-up resources then become available for the
supervision of MT.
To acknowledge the interindividual differences and evaluate the role of initial cognitive and motor
competence, we designed an experimental protocol which scrutinizes whether older persons with lower
initial competence in either the cognitive and/or the motor domain benet more from domain-specic ST
training, while those with higher competence in both domains benet more from MT training. If our data
meet these expectations, this would strongly support the use of tailored training regimes for cognitive-
motor MT in older age. The training regimes in our study follow established cognitive and/or motor
training procedures. Training benets on participants’ MT performance are assessed by a MT walking
test and by a MT driving test in a virtual environment. The latter test was designed to mimic the
cognitively demanding behavior in everyday life.
Methods
Study aims
This study aims to investigate whether three different training programs (cognitive, motor, and
simultaneous cognitive-motor training) have differential effects on MT performance, in dependence on
participants’ initial cognitive functioning and motor tness. Specically, we expect that (H1) for
participants with lower cognitive functioning, MT performance benets more from cognitive training than
from motor or simultaneous cognitive-motor training, (H2) for participants with lower motor tness, MT
performance benets more from motor training than from cognitive or simultaneous cognitive-motor
training, and (H3) for participants with higher motor tness and higher cognitive functioning, MT
performance benets more from simultaneous cognitive-motor training than from motor or cognitive
training.
Study design
A single-blind, randomized, controlled intervention with healthy older adults is conducted. Three training
programs (cognitive, motor, and simultaneous cognitive-motor training) are included, as well as pre- and
posttests. All participants complete the same pre- and posttests. An overview of the study design is
presented in Table 1. This study protocol follows the SPIRIT guidelines (44, 45). The trial is retrospectively
registered in the DRKS (German Clinical Trials Register) at 26/082020 with the registration number
DRKS00022407.
Recruitment of participants
This study is conducted at the University of Münster (WWU), and at the Chemnitz University of
Technology (TUC), Germany. Participants are recruited via homepage announcements, by personal
contact, senior college, local sports clubs as well as by advertisements in local newspapers, radio
stations, and yers. Interested participants are screened for eligibility using a standardized telephone
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interview that surveys the predened inclusion and exclusion criteria as described below. All participants
give written consent prior to study enrolment. All participants receive monetary compensation (15 € per
testing day).
Eligibility criteria
Inclusion criteria are: (1) aged between 65 and 75 years (minor exceptions are made for couples for
ethical reasons: < 65 and > 75 years), (2) right-handed, (3) active car driving (e.g., at least once a week
within the last 6 months), (4) ability to walk unassisted without self-reported problems (e.g., diculty to
breath, pain, and cardiac palpitations), and (5) community-dwelling. Exclusion criteria are: (6) BMI > 30,
(7) red-green deciency or red-green-color blindness, (8) orthopedic impairments, (9) perceived health
problems, (10) neurological diseases, (11) cardiovascular disorders, (12) previous heart attack or stroke,
or (13) previous head/brain surgery. All information on inclusion and exclusion criteria is self-reported
during a telephone interview.
Randomization
Each subject is randomly allocated to a training group by assigning a random number between 1 and 3 (1
= motor training, 2 = cognitive training, 3 = simultaneous cognitive-motor training) to each participant
using Microsoft Excel. Couples are allocated to the same training program to ensure that they can train
together by assigning only one number. Participants are informed about their training program after
pretesting.
Anonymization and blinding
Different blinding procedures are applied to avoid performance bias during data collection and training,
and conrmation bias in data analysis and data collection. Staff for data collection and data analysis is
blinded for participants’ training group. Trainers are blinded for participants’ pretest performance and are
not involved in posttesting.
Anonymity is ensured by utilizing only pseudonymized codes (IDs) to document pre- and posttest
performance. For training documentation, only participants’ names are used. For the cognitive training
and the simultaneous cognitive-motor training, trainers additionally possess participant’s login data of
the cognitive training software. For data analysis, names and IDs are assigned by a key-list to which only
the current study coordinators and the principal investigators have access.
Instruments and measurements
Screenings
Cognitive impairment
is screened using the Mini-Mental State Examination (MMSE, 46). The test covers
different cognitive domains, such as attention, arithmetical skills, registration, language, memory, and
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orientation. Cognitive impairment is measured on a 30-point scale (30 = no cognitive impairment) with a
score < 25 indicating mild cognitive impairment (47).
Visual acuity
is screened using the Freiburg Visual Acuity Test (FrACT v 3.9.3, 48;
https://michaelbach.de/fract/). Participants are seated on a chair that is positioned in 3 m distance from
the computer monitor. Eighteen Landolt rings (circles with a small opening in one out of eight possible
directions) are displayed sequentially on a 24” monitor (1920 x 1080). Each Landolt ring opening is
paired with a number from 1 to 8 that are displayed on a DIN A4 paper sheet above the monitor.
Participants are asked to state the number that matches the opening of the Landolt ring. The size of the
circles changes with response success. Both decimal acuity (VAdec) and logarithm of the minimum angle
of resolution (LogMAR) are calculated.
Outcome measures
The assessment battery includes two tests on MT, ve on cognitive functions, four on motor tness, and
a cardiorespiratory tness test. In addition, information about sociodemographic as well as health- and
lifestyle-related parameters are assessed.
Questionnaire Battery
All participants complete a self-administered questionnaire battery, which assesses the following
outcome parameters: personal and sociodemographic information (age, gender, weight, height, etc.),
recent driving behavior, years of education and employment, subjective health, objective health, smoking
behavior, history of falls, fall ecacy, physical activity, social and leisure time activities, use of electronic
devices and computer, subjective hand use, handedness, and personality. The questionnaire battery
comprises validated instruments (partly modied), which are shown in Table 2, and some self-generated
items. Participants are asked to complete the questionnaire battery at home, and to hand them over to the
experimenter on their rst day of testing.
Virtual reality walking test
Hard- and software. This test is performed with the GRAIL system (Gait Real-time Analysis Interactive
Lab, Motekforce Link, Amsterdam, the Netherlands) that comprises a 3D instrumented split-belt treadmill
(0.8 x 1.5 m) with two embedded force plates, a semi cylindrical 240° projection screen (2.4 x 5 m), and a
Vicon MX optical infrared tracking system (Vicon, Oxford, United Kingdom). The participant is secured by
two handrails laterally attached to the treadmill, two laser barriers at the front and back end of the
treadmill, and a safety harness that is attached to the ceiling to prevent participants from falling. In
addition, the experimenter can press a stop button to instantly stop the treadmill in case of emergency.
Four serially-connected RGB projectors project a virtual scenario on the projection screen. A photodiode is
attached to the screen to accurately measure stimulus onsets and to prevent varying projection onsets.
An ergonomic handheld key switch with a left and a right button and a voice recorder are used to record
participant’s responses.
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The virtual scenario is designed with D-Flow (Motekforce Link, Amsterdam, the Netherlands). The
scenario roughly depicts an industrial-like environment with abstract objects placed laterally to a virtual
walking path (see Figure 1). Motor and cognitive tasks are customized and added to the application (cf.
below). All instructions and all stimuli are presented visually at eye level in a small, rectangular area in the
middle of the projection screen.
Motor and cognitive tasks. Six different tasks with ve trials each are presented in a mixed order. Task
presentation and order is identical for each participant and at pre- and posttest. No given task is
presented more than twice in a row. Every trial lasts 30 s with inter-trial intervals of 3 s to introduce the
next trial (e.g., “Standing only” or “Walking only”, in German language). The scenario lasts 16.5 min in
total.
One baseline task, three STs (one motor, two cognitive), and two cognitive-motor MTs are performed: (1)
Standing task (baseline): Participants stand quietly with both feet on the treadmill while maintaining a
straight direction of view by looking at a xation cross. Posture is assessed via ground reaction forces.
(2) Walking task: Participants walk at 1 m/s while maintaining a straight direction of view by looking at a
xation cross. As the treadmill accelerates and decelerates at 0.2 m/s², transitions between standing and
walking take 5 s. Gait performance is assessed via ground reaction forces. (3) Serial Threes task: The
Serial Threes task is an established measure of updating of working memory (59, 60). Participants stand
quietly on the treadmill and look at a xation cross at the center of the projection screen. At the beginning
of each trial, a three digit-number is displayed for 5 s. Participants are asked to count backwards in steps
of three loudly, and as quickly and accurately as possible. They are instructed to keep their eyes open
during counting, and to stop counting when the next task is displayed on the screen. Participants are
asked to spell out the whole number (e.g., “177” instead of “77”), and not to correct errors (i.e., to continue
counting backwards from a possibly wrong number). Verbal responses (i.e., numbers) are protocolled by
the experimenter, and are additionally recorded using a voice recorder. (4) Color Word Stroop task: The
Stroop task is used to assess inhibitory control (61). In each trial, color-denoting words (i.e., yellow, red,
blue, green) are sequentially presented for 500 ms in a mixed order with ten words per trial. Each stimulus
is followed by a central xation cross for 1800 to 2200 ms, such that mean ISI is 2500 ms. Font and
meaning of color words match on congruent trials (e.g., the word “green in green font), and do not match
on incongruent trials (e.g., the word “green” in blue font). Two response words are presented for 1500 ms
on the projection screen, time locked with stimulus onset. They are displayed in two rectangular areas,
one located to the left below the stimulus word and the other located to the right below the stimulus word.
Both response words are presented in white font; one names the font of the stimulus word, and the other
names one of the three other fonts. Participants have to indicate which of the two response words names
the stimulus font, by depressing either the left or the right button of a handheld key switch. Participants
are instructed to give their responses as fast and as accurately as possible. The design of the Stroop task
is balanced across congruency (50% congruent, 50% incongruent), stimulus font (25% of each font),
stimulus meaning (25% of each meaning), position of correct and false answer boxes (50% left, 50%
right), and frequency of correct and false response words per color (50% correct, 50% false). Reaction
times and correctness of responses are recorded.. (5) Multitask 1: The walking task and Serial Threes
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task are executed concurrently. (6) Multitask 2: The walking task and Stroop task are executed
concurrently. Participants are instructed to not give preference to either one of the concurrently executed
tasks, while responding to cognitive tasks as fast and as accurately as possible. Outcome measures are
the same as described above.
Procedure. Participants familiarize with the treadmill by walking through a virtual forest environment for
about 5 to 10 min, while walking speed increases slowly up to 1 m/s. Familiarization ends when
participants are able to walk securely while focusing their attention on the center of the projection screen.
Physically low demanding tests (including MMSE and DSST), of about 12 to 15 min duration in total, are
scheduled after familiarization to ensure that participants return to a physical resting state. After that,
participants perform a short practice run of about 2 min including a shortened trial of each task in a xed
order.
Virtual reality driving test
Hard- and software. This test follows closely the driving test of Wechsler, Drescher (62), where a
schematic drawing of the setup is provided. The setup consists of a VW Golf seat and three 48” monitors
that are mounted at eye level, covering a visual eld of 195°. A Logitech G27 steering wheel is located
slightly to the left in front of the middle monitor. Gas and brake pedals are placed on the oor in a
position similar to a real car. The car seat and pedals are adjustable to provide a realistic and
comfortable driving position. A conventional numeric keypad is mounted to the right of the steering
wheel, within participants’ easy reach. Numbers from 1 to 6 are visible on the keypad, other characters are
covered by black tape. A regular headset is used for auditory task presentation and to present
characteristic driving noise.
The driving simulation uses commercially available hard- and software (Carnetsoft version 8.0,
Groningen, The Netherlands). Figure 2 shows the setup of the scenario. It displays 25.7 km of a slightly
winding rural road, without intersections or trac lights. The simulated environment pictures a typical
landscape with clouds in a blue sky, mountains, little animal enclosures, grasslands, trees, trac signs,
gas stations, and construction sides. Regular oncoming trac comprises cars and busses. The scenario
does not involve any pedestrians, cyclists, or other road users. Participants drive a VW Golf with
automatic transmission and a simulated dashboard that is presented at the bottom of the middle screen.
Velocity is displayed on a speedometer. The participant's vehicle is continually accompanied by one car
in the rear and another car in front. The lead car is programmed to drive at 70 km/h, and to slow down
slightly if the distance to the participant’s car exceeds 100 m. The rear car is programmed to follow at a
reasonable distance. In case of an accident, the front window shatters and the drivers car is directly
thereafter repositioned between the lead car and the rear car.
Motor and cognitive tasks. Participants perform a driving task and a battery of additional tasks that are
designed to mimic cognitively effortful activities typically performed during driving. On three driving
courses, they perform the driving task alone, the additional tasks alone, or the driving and the additional
tasks concurrently.
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Driving-alone course: participants are instructed to follow the lead car at a regular distance with about 70
km/h, to pay attention to posted speed limits, and to brake when the lead car brakes. Ten braking events
are presented at irregular course locations, that are identical for all participants and at pre- and posttest.
As the lead car approaches a 40 km/h speed limit sign, its brake lights ash up and the car slows down
to 40 km/h within about 7 s. It keeps that velocity for about 6 s, and then accelerates within about 9 s
back to 70 km/h. Lateral car position, car velocity, and distance to the lead car are continuously
assessed. For braking responses, reaction times for gas-off and brake-on reactions are measured.
Cognition-alone course: the participants’ car drives in autopilot mode and responds automatically to
braking maneuvers of the lead car. Two different types of tasks are presented at xed course locations in
a mixed order that is identical for all participants and at pre- and posttest. Both tasks are presented either
visually on the windshield or auditory through headphones. (1) In the typing task, participants are asked
to type a three-digit number with their right hand into the numeric keypad, as quickly and as accurately as
possible. Stimuli presentation lasts about 5 s for visual trials, and about 3 s for auditory trials. (2) In the
reasoning task, participants are asked to verbally provide arguments for or against issues of general
interest, e.g., to state an argument for/against the use of electric vehicles. Each request is presented for
about 5 s visually or 4 s auditory, and cannot be answered adequately by a simple “yes” or “no”. Requests
are limited to 80 characters, and to two lines on the windshield. The experimenter protocols the
participants’ answers. Answers are marked as correct if participants give a valid argument, and are
marked as incorrect if participants give an invalid argument, or if they do not answer at all. The validity of
arguments is agreed-upon among experimenters before the study. Both the typing and the reasoning task
comprise 30 trials, 15 presented auditory and 15 presented visually. The concrete stimuli (three-digit
numbers, reasoning questions) differ between trials, and they also differ between pre- and posttest;
however, they are the same for all participants. Reaction times and correctness of responses are
measured for the typing task, and correctness of answered requests is assessed for the reasoning task
(as reaction time was not assessed).
MT course: participants actively drive and brake for the lead car, and they also respond to typing and
reasoning tasks that are analogous to those on the cognition-alone course. No instructions are given
regarding the preference for driving versus for additional tasks.
Procedure. One half of the driving-alone course and the complete cognition-alone course are scheduled
on one day, in balanced order. The other half of the driving-alone course and the complete MT course are
scheduled on another day, again in balanced order. The order of days is also balanced. On a separate day
before testing, participants practice the driving-alone course and the cognition-alone course for
approximately 5 min each, but they don’t practice the MT course.
Cognitive functions
A battery of ve tests is used to measure a broad range of different cognitive functions. All tests follow
standardized procedures and instructions. Four tests are computerized, one is a paper and pencil test.
Computerized tests are conducted on a 24” computer screen with a display resolution of 1920 x 1080
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pixel and a screen distance of about 65 cm. Each computerized test takes about 10 min with up to three
practice trials of about 1 to 2 min each. Response feedback in provided after practice trials, but not after
registered trials.
The N-back, Simon and Task switching tests are programmed in E-Prime 2.0 (Psychology Software Tools,
Pittsburgh, PA) with stimuli presented in six blocks with inter-block breaks of 5 s (20 s after block 3). The
maximum response window is 2000 ms. After a response is given or after 2000 ms a central xation
cross is presented for a variable response-stimulus interval between 800 to 1200 ms. All stimuli are black
and presented on a white screen background. Participants respond by depressing the “X” or “M” key on a
German keyboard with their left and right index nger, and they are instructed to respond as fast and as
accurately as possible. Reaction times and correctness of responses are recorded.
Updating
is assessed using the 2-back condition of a visuo-spatial N-back test (63). A black 4x4 grid is
presented continuously. Dots (n = 19 per block) are presented sequentially in the center of different grid
cells for 500 ms. Participants have to memorize the position of the dots and to depress the right key “M”
when the position of the current dot is identical to the position of the second-to-last dot (target). They
have to depress the left key “X” when the current dot appears at a different position as the second-to-last
dot (non-target). In total, 30 targets and 72 non-targets are presented.
Inhibitory control
is assessed using the Simon test (64). A black xation cross is presented continuously
on a white screen. Left- or rightward pointing arrows (n = 32 per block) are displayed sequentially for 500
ms either on the left or right side of the xation cross. For one half of the stimuli the direction and
position of the arrow are congruent (e.g., leftward pointing arrow on the left side), while for the other half
of the stimuli, direction and position are incongruent (e.g., leftward pointing arrow on the right side, n =
96). Participants are instructed to press the left key “X” for leftward pointing arrows and the right key “M”
for rightward pointing arrows.
Shifting
is assessed using a modied visual task switching test (65). Geometrical shapes (n = 17 per
block) are presented sequentially for 1500 ms. The geometrical shapes are either quadratic or circular
and either big or small. Participants are instructed to indicate either the size of the shape (subtask A) or
the form of the shape (subtask B) by pressing either the left key “X” for small or circular shapes or the
right key “M” for big or quadratic shapes. In each block subtasks are presented in the following order:
AABBAABBAABBAABBA. No external cues about subtask order are provided.
Dual-tasking
(DT) is assessed using a dual-tasking test adapted from literature (66) where a manual
tracking task and an auditory discrimination task are performed concurrently. Nine trials with about 45 s
each are presented in three blocks: (a) three trials ST manual tracking (b) three trials ST auditory
discrimination, and (c) three trials DT manual tracking and auditory discrimination with both tasks being
performed simultaneously. The three blocks are presented in a randomized order across participants. In
ST manual tracking trials, a small red target square moves from one side of the screen to the other
following an unpredictable wave-shaped path. Participants are instructed to track the red target with a
small white crosshair cursor that is controlled using a joystick. Only the vertical movement of the cursor
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can be controlled, the horizontal movement is aligned with the target. Participants are instructed to use
the joystick with the right hand to keep the cursor as close as possible to the target. The vertical distance
between cursor and target is continuously measured over the whole trial. In ST auditory discrimination
trials, ten target sounds and 18 to 20 distractor sounds are presented per trial in a random sequence
through headphones: the target sound is a high-pitched tone (1086 Hz), and two low-pitched tones (217
Hz and 652 Hz) are non-target distractor sounds. All sounds are presented for 75 ms with a jittered ISI of
1000 to 1300 ms. Participants are instructed to respond to the high-pitched tone only by depressing the
“F12” key with their left index nger, and to react as fast and as accurately as possible. Reaction times
and correctness of responses are assessed. In the DT manual tracking and auditory discrimination trials,
participants perform both tasks simultaneously. No instructions are given regarding the prioritization of
either one of the tasks. Same outcome measures are recorded as in the ST conditions.
Global cognition
is assessed using the Digit-Symbol-Substitution test (DSST; 67). This test is part of the
Wechsler Adult Intelligence Scale (68) and is performed as paper-and-pencil tests.
Motor tness
A battery of four established motor tests is used to determine different aspects of motor tness (55, 69)
following standardized procedures and instructions. Time is kept using a regular stop watch. Short
practice trials with two to ve repetitions are performed before each test.
Leg strength and endurance
is assessed using the Chair stand test of the senior tness test for older
adults (70). Participants sit on a height-adjustable chair without armrests. Arms are crossed with hands
on opposite shoulders. Participants continuously rise up to a straight standing position and sit down to a
fully seated position with a straight back as often as possible within 30 s. They are asked to keep their
arms crossed and both feet on the oor during the whole test. Correctly executed chair stands are
registered.
Bimanual dexterity
is measured with the Purdue Pegboard test (71, 72). The Pegboard consists of two
rows of 25 small holes from top to bottom. Small metal pins (pegs) are located at the upper left and right
of the board. Participants are instructed to simultaneously pick up a peg from the right side with the right
hand and a peg from the left side with the left hand, to place both pegs into the top empty holes in the left
and right row, and to repeat this procedure as often as possible within 30 s. Three trials are performed.
The number of rows with two correctly placed pegs is assessed for each trial.
Static balance
is assessed using the One-legged stand test with open and closed eyes (73). The test is
performed in the GRAIL (cf. section on virtual reality walking test), but the waistcoat is not used as it
could affect participants' posture. Eight trials are performed in total, the rst four trials with eyes open,
and the second four trials with eyes closed. Each leg is assessed twice, in alternating order. Participants
stand on one leg with the other leg slightly exed while looking straight ahead. The experimenter stands
quietly sideways to the participant, to prevent falls. Participants are instructed to keep their arms at the
side of their body, to not hop with their standing leg, not to put down their lifted feet, not to push the lifted
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leg against the standing leg during balancing, and not to open their eyes during eyes closed trials. Each
trial is self-initiated. Participants are instructed to stand on one leg as long as possible. The experimenter
starts time keeping when the participant lifts one leg, and stops when the participant is violating one of
the above mentioned standards or after 20 s. Standing duration and ground reaction forces are assessed.
Psychomotor speed
is measured using the Feet tapping test (69). Participants sit on a stationary chair
(height adjustable) without armrests, and are asked to move both feet simultaneously back and forth
across a mid-sagittal line on the oor. They are instructed to move both feet as fast as possible, while
ensuring that both soles completely contact the oor at each tap. Two trials of 20 s duration are
performed. The number of correct taps is registered using a hand clicker.
Cardiovascular Fitness
Cardiovascular tness is measured by a spiroergometry (ZAN600 CPET, nSpire Health, Oberthulba,
Germany) on a stationary bicycle (Lode Corival cpet, Groningen, the Netherlands). Participants are asked
to avoid caffeine and alcohol intake for 12 hrs before testing and any vigorous exercise on the day
before. Each measurement is accompanied by a physician or participants are required to bring a medical
clearance certicate based on exercise electrocardiography (ECG) and clinical history. Respiration
(oxygen (VO2) and carbon dioxide consumption (VCO2)) is measured breath-by-breath. Heart rate is
assessed using an integrated digital twelve-lead electrocardiogram (Kiss, GE Healthcare, Munich,
Germany). A Borg’s 6-20 scale (74) is used to assess the rate of perceived exertion (RPE, 6 = “No exertion
at all”, 20 = “Maximal exertion”) every two minutes (74) as indicated by the participant by pointing on the
number from 6 to 20 on an RPE sheet. Blood pressure is monitored via a sphygmomanometer.
Participants undergo a ramp protocol. For male participants, the load starts at 20 W and continuously
increases by 20 W/min. For female participants, the load starts at 10 W and increases by 15 W/min. All
participants are instructed to maintain a cycling frequency between 60 to 80 revolutions per minute. Both
protocols are preceded by a 3 min resting period and followed by 5 min cool-down period (1 min initial
load, 4 min no load). Protocols are terminated when participants respiratory exchange ratio (RER =
VCO2/VO2) remains > 1.05 for at least 30 s or exceeds 1.10, in case of volitional fatigue, or occurrence of
physiological risk factors (i.e., blood pressure > 230/115 mmHg, dizziness, HR > about 220-age, cardiac
arrhythmia, or other abnormalities). Each measurement is accompanied by an experienced sport
scientist. Peak oxygen uptake (VO2 peak: VO2 consumption during the maximum load level achieved),
RER, and the maximum load level (i.e., wattage) are analyzed and considered for rating the measurement
validity.
Training
Three different training programs (cognitive, motor, and simultaneous cognitive-motor training) are
conducted over a period of twelve weeks in the facilities of the TUC and the WWU. Two training sessions
are scheduled per week, for a total of 24 training sessions (total training time: 1080 min). Each training
session has a duration of about 60 min, including 15 min for preparation (e.g., changing clothes, warm-
Page 14/29
up, hard- and software preparation). Each training program is conducted as circuit training with three 15
min blocks yielding a training sequence with a total of 72 training blocks. To ensure continuous training
progress, diculty level of the training is continuously adapted to the individual’s performances.
Participants of the motor and the simultaneous cognitive-motor training wear a heart rate monitor during
training to ensure that training intensity does not exceed 60% of VO2-peak, as determined by
spiroergometry at pretesting. Training sessions are supervised by skilled trainers in group settings with a
trainer-participant-ratio of at least 1:3 (motor and simultaneous cognitive-motor training) or at least 1:10
(cognitive training). The trainers provide instructions, help participants to sign into the software
applications, answer questions and protocol participants’ performances. They are onboarded to the
training procedure in a two-day workshop. To improve attendance and contribution, explanations about
the possible benets of the training are provided to the participants. Attendance and drop-outs are
documented. To ensure a total attendance of 24 sessions for each participant, missing training sessions
(e.g., in case of illness) are made up within the total training period of twelve weeks. Apart from training,
participants are asked to continue their regular everyday activities. Table 3 illustrates exemplary training
sessions for each of the three programs.
Cognitive training
Training equipment and exercises. The training program is conducted in a computer-pool with one
separate computer per participant. The exercises are presented on a computer monitor mounted at eye
level in front of the participant. Handheld trackball mice (YUMQUA Y-01, YUMQUA, Shenzhen, China) were
used to control the cursor. This ensures that the same pointing device can also be used for simultaneous
cognitive-motor training (see below). The training program includes 22 different cognitive exercises from
three different software applications NeuroNation (NeuroNation, Berlin, Germany; 15 exercises),
Happyneuron (Scientic Brain Training, Lyon, France; four exercises), and Neuropeak (75 ; three
exercises). Exercises train different cognitive functions, specically inhibitory control, updating, shifting,
MT and action planning which are essential for everyday life functioning. Each of these cognitive
functions is trained to the same extend over the whole training course.
Procedure. Exercises are practiced and explained within the software. In each of the 72 training blocks
one exercise is provided respectively. Over the whole training, the different exercises are performed
several times in a predened order which is similar for all participants. The rst time an exercise is
provided, it is performed at the lowest diculty level and adapts automatically over the course of the
training based on previous scores.
Motor training
Training equipment and exercises. The training program is conducted in a customized exercise room.
Hand movements were not involved in the exercises, to ensure that the same exercises can also be
performed during simultaneous cognitive-motor training (see below). Motor training consists of a oor
program and a walking program. The oor program entails different exercises that train either strength (
n
= 10) or balance (
n
= 17). To vary the diculty level of the exercises, different sport material is used:
Page 15/29
AIREX pad, balance board, balance pad with little nubs (Sissel Balance Fit), balance pad with big nubs
(Sport-Thieme Gymt, Germany), rocker board (easy version, Sport-Thieme Gymt, Germany), rocker
board (dicult version, Sport-Thieme Gymt, Germany). In total, 29 variations of strength exercises and
51 variations of balance exercises are provided. Five different exibility exercises are performed for
recovery between and at the end of the strength and balance exercises: strength exercise (4 min),
exibility exercise (1 min), balance exercise (4 min), exibility exercise (1 min), strength exercise (4 min),
exibility exercise (1min). The walking program is conducted on a curved-belt non-motorized treadmill
(Speedt SpT-1000C, Tobeone, Korea). It comprises nine different walking exercises with varying
diculty. Exercises are changed every 5 min. The extent to which each of the three motor functions
(walking = 435 min strength = 344 min, balance = 172 min is trained over the whole training is the same
for each participant, only the diculty level varies. Exercises were chosen to train a wide range of motor
functions. Aerobic tness was not trained to avoid confounds by induced metabolic changes (76, 77).
Procedure. Exercises are explained by the trainers. Each of the 72 training blocks is assigned to either the
oor program or the walking program in a predetermined order until the last training session is nished:
(1) walking, (2) oor, (3) walking, (4) oor, (5) oor. A oor program block contains two different strength
exercises of 4 min and one balance exercise of 4 min in between. Each of the three exercises is followed
by a recovery period of 1 min in which a exibility exercise is performed. In one walking program block,
three walking exercises are performed for 5 min each. Over the whole training, the different exercises are
provided several times in a predened order which is similar for all participants. The rst time an exercise
is presented, it is performed at the lowest diculty level and adapted over the course of the training
based on trainers valuation (except of the exibility exercises which are used for physical recovery and
don’t change in their diculty level). Criteria for valuation are, e.g., unsteady stand, uncoordinated
movements, tremor, heavy breathing.
Simultaneous cognitive-motor training
This training is conducted in the same customized exercise room as the motor training. Cognitive
exercises are presented on a 48” screen, with one separate screen per participant. Screens are mounted at
eye level in front of the participants, to ensure that the visual angle of the presented exercises remains
comparable to the cognitive training. Participants follow the same procedures as in the motor and
cognitive training programs, but they perform the exercises simultaneously. They perform, for example,
knee lifts concurrently with the N-back exercise. Both motor and cognitive exercises are adapted to the
training progress as described above.
Schedule of activities
The overall schedule of activities is presented in Figure 3. Pretests as well as posttests are administered
on two separate days, with one rest day in between. Each testing day lasts about 2 to 2.5 hrs including
small breaks and instructions. Different predetermined testing sequences are implemented to control for
order effects and other potential confounds: At the beginning of each testing day, cognitive and motor
tests and the visual acuity test are administered in four different orders. After that, participants are tested
Page 16/29
in the driving simulator, with driving courses presented in a counterbalanced order (cf. section on virtual
reality driving test), independently of the tests administered before. The virtual reality driving test is
followed either by the virtual reality walking test or by cardiorespiratory tness assessment, also
independently of the tests administered before. After their second day of pretesting, participants are
informed about their training program. Training starts one week or less after pre-tests and is conducted
for 12 weeks (two times per week, cf. section on training). Posttests are scheduled in the week after the
last training session. For each given participant, posttests are scheduled in the same order as pretests.
Data collection, management and analysis
Data collection and management
Electronic data will be stored on password protected hard drives. Hard drives and hard copy forms will be
stored in locked cabinets to which only the current project staff has access. Databases will only include
pseudonymized ID codes. The key-list that allows to link participant’s names with the ID codes will be
stored separately from the data. Data quality will be promoted by double data entry and plausibility and
range checks.
Statistical analyses
Our main statistical analyses evaluate whether the three training programs have differential effects on
MT performance, in dependence on participants’ initial cognitive functioning and motor tness. We
calculate linear mixed-effect models. Dependent variables are MT performance in the walking and driving
test. The independent variables Training Group (cognitive, motor, simultaneous cognitive-motor) and
Time (pre, post), Initial Cognitive Functioning and Initial Motor Fitness (continuous variables) as well as
potential confounds are added as xed effects.
We expect signicant three-way interactions between Training Group, Time and Initial Cognitive
Functioning (H1), as well as between Training Group, Time and Initial Motor Fitness (H2). We further
expect a signicant four-way interaction between Training Group, Time, Initial Cognitive Functioning and
Initial Motor Fitness (H3). Post-hoc tests evaluate whether indeed MT performance benets most from
cognitive training in persons with lower cognitive functioning, from motor training in persons with lower
motor tness, and from simultaneous cognitive-motor training in persons with higher motor tness and
higher cognitive functioning (cf. study aims).
All statistical analyses are performed using SPSS for Windows (IBM Corp., Armonk, NY) and R (78).
Sample size estimate / power calculations
To approximate the required sample size to test our hypotheses, a statistical power analysis was
performed a priori with G*Power 3.0. The following parameters were entered:
= .085 (i.e., a small to
medium-sized effect, 79), alpha = .05, 1-beta = .80, number of tested predictors = 2 (for each hypothesis,
based on dummy coded variables). The estimated required sample size was
N
= 118 to provide a
Page 17/29
sucient power to detect a small to moderate effect. To account for a typical attrition rate of 20% for
comparable training studies we plan to recruit a total of
N
= 150 participants with training group sizes of
n
= 50 participants each.
Monitoring
No data monitoring committee is required because the training is conducted by skilled and trained
instructors who have no interest in a specic outcome of the trainings. Furthermore, participants are
under observation of qualied project staff that intervenes if they notice a negative reaction during the
measurements at pre- and posttest or training.
Discussion
Our study evaluates whether three different training programs (cognitive, motor, and simultaneous
cognitive-motor training) have differential effects on MT performance, in dependence on participants’
initial cognitive functioning and motor tness. In particular, we expect that for participants with lower
cognitive functioning, MT performance benets more from cognitive training than from motor or
simultaneous cognitive-motor training, for participants with lower motor tness, MT performance benets
more from motor training than from cognitive or simultaneous cognitive-motor training, and for
participants with higher motor tness and higher cognitive functioning, MT performance benets more
from simultaneous cognitive-motor training than from motor or cognitive training.
Our ndings will be relevant, both for basic and for applied science. On the basic side, they will contribute
to the long-standing debate whether MT is an emergent property, arising from the interaction of the
constituent tasks (e.g., 80), or rather is a dedicated sensorimotor processing stage (7). Specically, if
training of the constituent tasks is indeed benecial for MT performance, as per our hypotheses H1 and
H2, this would support the emergent-property model. If such a benet cannot be substantiated, this would
rather support the dedicated-stage model.
On the applied side, our ndings will provide experimental evidence for or against the notion that tailored
training is more ecient than off-the-rack standardized training (36–40). If the data are in agreement
with our hypotheses, they would support this notion; otherwise, they would oppose it. More specically,
the outcome of the present study can be used to assign future participants to a training program that
matches best their needs. In particular, we could use each participant’s pretest scores of the initial
cognitive and motor performance to calculate the expected MT performance after cognitive training, after
motor training and after cognitive-motor training. Based on these predictions, each person could then be
referred to the training program that is likely to be most effective for that particular person.
List Of Abbreviations
BMI
Body Mass Index
Page 18/29
DSST
Digit-Symbol-Substitution Test
DT
Dual-tasking /Dual-task
ECG
Exercise Electrocardiogram
FrACT
Freiburg Visual Acuity Test
GRAIL
Gait Real-time Analysis Interactive Lab
ISI
Inter Stimulus Interval
MMSE
Mini-Mental State Examination
MT
Multitasking / Multitask
MTC
Multitasking Costs
RER
Respiratory Exchange Ratio
RPE
Rate of Perceived Exertion
ST
Single-Tasking / Single-Task
TUC
Chemnitz University of Technology
VA
Visual Acuity
VCO2
Volume of Carbon Dioxide
VO2
Volume of Oxygen
WWU
University of Münster
Declarations
Ethics approval and consent to participate
The study was approved by the ethics committee of the Chemnitz University of Technology (registration
number V-280-17-CVR-Multitasking-29062018) is conducted in agreement with the principles of the
Page 19/29
Declaration of Helsinki. Participants are informed about the study goals. Written, informed consent is
obtained from the participants prior to participation, which they can withdraw at any time. All data and
information from the participants are stored securely and is pseudomized by a coded ID number.
Consent for publication
Data will only be published in an anonymized fashion. Personal information about the study participants
will not be published.
Availability of data and materials
The anonymized datasets used and/or analyzed during the current study are available from the
corresponding author on reasonable request.
Competing interests
The authors declare that they have no competing interests.
Funding
The study was funded by the German Research Foundation (DFG) and is part of the DFG Priority Program
SPP 1772 (grant VO 1432/22-1). RS is supported by an ESF (European Social Fund) and SAB
(Development Bank of Saxony) doctoral scholarship (100342331). The funding body doesn’t play any
role in the design of the study, the collection, analysis and interpretation of data and the decision to write
and publish manuscripts. The study protocol has not been peer reviewed by the funding body.
Authors' contributions
OB and CVR are the PIs of the study, conceptualized the study, and received the funding for the project
through an application to the DFG. All authors (MM, RS, OB, VR) made substantial contributions to the
conception and design of the study protocol and the interpretation of expected results of the study. RS
made substantial contribution to the creation of new software used in the study. All authors drafted the
study protocol or substantively revised it and approved the submitted version. All authors agreed both to
be personally accountable for the author's own contributions and to ensure that questions related to the
accuracy or integrity of any part of the study, even ones in which the author was not personally involved,
are appropriately investigated, resolved, and the resolution documented in the literature.
Corresponding author
Correspondence to Claudia Voelcker-Rehage
Acknowledgements
We would like to thank all former members and associates of the project, research group members,
technicians, and student members for their help with hard- and software implementation, data
Page 20/29
acquisition, analysis, training administration and implementation. We also would like to thank all
participants for partaking in the rst data collection phase of this project.
References
1. Koch I, Poljac E, Muller H, Kiesel A. Cognitive structure, exibility, and plasticity in human
multitasking - an integrative review of dual-task and task-switching research. Psychol Bull.
2018;144(6):557–83.
2. Norman DA, Shallice T. Attention to action: wiled and automatic control of behavior. In: Davidson RJ,
Schwartz GE, Shapiro D, editors. Consciousness and self-regulation. Boston, MA: Springer; 1986.
p.1–18.
3. Baddeley A, Logie R, Bressi S, Della Sala S, Spinnler H. Dementia and working memory. Q J Exp
Psychol. 1986;38(4):603–18.
4. Miyake A, Friedman NP, Emerson MJ, Witzki AH, Howerter A, Wager TD. The unity and diversity of
executive functions and their contributions to complex "Frontal Lobe" tasks: a latent variable
analysis. Cogn Psychol. 2000;41(1):49–100.
5. Baddeley A. Exploring the central executive. Q J Exp Psychol. 1996;49(1):5–28.
. Bock O, Haeger M, Voelcker-Rehage C. Structure of executive functions in young and in older persons.
PLoS ONE. 2019;14(5):e0216149.
7. Verhaeghen P, Steitz DW, Sliwinski MJ, Cerella J. Aging and dual-task performance: a meta-analysis.
Psychol Aging. 2003;18(3):443–60.
. Voelcker-Rehage C, Stronge AJ, Alberts JL. Age-related differences in working memory and force
control under dual-task conditions. Aging Neuropsychol Cogn. 2006;13(3-4):366–84.
9. Beurskens R, Bock O. Age-related decits of dual-task walking: a review. Neural Plast.
2012;2012:131608.
10. Li KZ, Lindenberger U. Relations between aging sensory/sensorimotor and cognitive functions.
Neurosci Biobehav Rev. 2002;26(7):777–83.
11. Wollesen B, Voelcker-Rehage C. Differences in cognitive-motor interference in older adults while
walking and performing a visual-verbal Stroop task. Front Aging Neurosci. 2019;10:426.
12. Bherer L, Kramer AF, Peterson MS, Colcombe S, Erickson K, Becic E. Transfer effects in task-set cost
and dual-task cost after dual-task training in older and younger adults: further evidence for cognitive
plasticity in attentional control in late adulthood. Exp Aging Res. 2008;34(3):188–219.
13. Liepelt R, Fischer R, Frensch PA, Schubert T. Practice-related reduction of dual-task costs under
conditions of a manual-pedal response combination. J Cogn Psychol. 2011;23(1):29–44.
14. Kramer AF, Larish JF, Strayer DL. Training for attentional control in dual task settings: a comparison
of young and old adults. J Exp Psychol Appl. 1995;1(1):50.
15. Boot WR, Basak C, Erickson KI, Neider M, Simons DJ, Fabiani M, et al. Transfer of skill engendered by
complex task training under conditions of variable priority. Acta Psychol. 2010;135(3):349–57.
Page 21/29
1. Pichierri G, Wolf P, Murer K, de Bruin ED. Cognitive and cognitive-motor interventions affecting
physical functioning: a systematic review. BMC Geriatr. 2011;11(1):29.
17. Wollesen B, Voelcker-Rehage C. Training effects on motor-cognitive dual-task performance in older
adults. Eur Rev Aging Phys Act. 2014;11(1):5–24.
1. Agmon M, Belza B, Nguyen HQ, Logsdon RG, Kelly VE. A systematic review of interventions
conducted in clinical or community settings to improve dual-task postural control in older adults. Clin
Interv Aging. 2014;9:477–92.
19. Plummer P, Zukowski LA, Giuliani C, Hall AM, Zurakowski D. Effects of physical exercise interventions
on gait-related dual-task interference in older adults: a systematic review and meta-analysis.
Gerontology. 2015;62(1):94–117.
20. Levin O, Netz Y, Ziv G. The benecial effects of different types of exercise interventions on motor and
cognitive functions in older age: a systematic review. Eur Rev Aging Phys Act. 2017;14:20.
21. Wang R-Y, Wang Y-L, Cheng F-Y, Chao Y-H, Chen C-L, Yang Y-R. Effects of combined exercise on gait
variability in community-dwelling older adults. Age. 2015;37(3):40.
22. Wang X, Pi Y, Chen P, Liu Y, Wang R, Chan C. Cognitive motor interference for preventing falls in older
adults: a systematic review and meta-analysis of randomised controlled trials. Age Ageing.
2015;44(2):205–12.
23. Fraser SA, Li KZ, Berryman N, Desjardins-Crepeau L, Lussier M, Vadaga K, et al. Does combined
physical and cognitive training improve dual-task balance and gait outcomes in sedentary older
adults? Front Hum Neurosci. 2017;10:688.
24. Wollesen B, Mattes K, Schulz S, Bischoff LL, Seydell L, Bell JW, et al. Effects of dual-task
management and resistance training on gait performance in older individuals: a randomized
controlled trial. Front Aging Neurosci. 2017;9:415.
25. Ansai JH, de Andrade LP, de Souza Buto MS, de Vassimon Barroso V, Farche ACS, Rossi PG, et al.
Effects of the addition of a dual task to a supervised physical exercise program on older adults’
cognitive performance. J Aging Phys Act. 2017;25(2):234–9.
2. Raichlen DA, Bharadwaj PK, Nguyen LA, Franchetti MK, Zigman EK, Solorio AR, et al. Effects of
simultaneous cognitive and aerobic exercise training on dual-task walking performance in healthy
older adults: results from a pilot randomized controlled trial. BMC Geriatr. 2020;20(1):83.
27. Hiyamizu M, Morioka S, Shomoto K, Shimada T. Effects of dual task balance training on dual task
performance in elderly people: a randomized controlled trial. Clin Rehabil. 2012;26(1):58–67.
2. Plummer-D'Amato P, Cohen Z, Daee NA, Lawson SE, Lizotte MR, Padilla A. Effects of once weekly
dualtask training in older adults: a pilot randomized controlled trial. Geriatr Gerontol Int.
2012;12(4):622–9.
29. Yamada M, Aoyama T, Tanaka B, Nagai K, Ichihashi N. Seated stepping exercise in a dual-task
condition improves ambulatory function with a secondary task: a randomized controlled trial. Aging
Clin and Exp Res. 2011;23(5):386–92.
Page 22/29
30. Theill N, Schumacher V, Adelsberger R, Martin M, Jäncke L. Effects of simultaneously performed
cognitive and physical training in older adults. BMC Neurosci. 2013;14(1):103.
31. Falbo S, Condello G, Capranica L, Forte R, Pesce C. Effects of physical-cognitive dual task training on
executive function and gait performance in older adults: a randomized controlled trial. Biomed Res
Int. 2016;5812092.
32. Uemura K, Yamada M, Nagai K, Tateuchi H, Mori S, Tanaka B, et al. Effects of dual-task switch
exercise on gait and gait initiation performance in older adults: preliminary results of a randomized
controlled trial. Arch Gerontol Geriatr. 2012;54(2):e167-e71.
33. You JH, Shetty A, Jones T, Shields K, Belay Y, Brown D. Effects of dual-task cognitive-gait intervention
on memory and gait dynamics in older adults with a history of falls: a preliminary investigation.
NeuroRehabilitation. 2009;24(2):193–8.
34. Silsupadol P, Siu K-C, Shumway-Cook A, Woollacott MH. Training of balance under single-and dual-
task conditions in older adults with balance impairment. Phys Ther. 2006;86(2):269–81.
35. Park DC, Reuter-Lorenz P. The adaptive brain: aging and neurocognitive scaffolding. Annu Rev Clin
Psychol. 2009;60:173–96.
3. Hobbs N, Godfrey A, Lara J, Errington L, Meyer TD, Rochester L, et al. Are behavioral interventions
effective in increasing physical activity at 12 to 36 months in adults aged 55 to 70 years? A
systematic review and meta-analysis. BMC Med. 2013;11(1):1–12.
37. Gabriel BM, Zierath JR. The limits of exercise physiology: from performance to health. Cell Metab.
2017;25(5):1000–11.
3. Zokaei N, MacKellar C, Cepukaityte G, Patai EZ, Nobre AC. Cognitive training in the elderly:
bottlenecks and new avenues. J Cogn Neurosci. 2017;29(9):1473–82.
39. Irazoki E, Contreras-Somoza LM, Toribio-Guzman JM, Jenaro-Rio C, van der Roest H, Franco-Martin
MA. Technologies for cognitive training and cognitive rehabilitation for people with mild cognitive
impairment and dementia. A systematic review. Front Psychol. 2020;11:648.
40. Testad I, Corbett A, Aarsland D, Lexow KO, Fossey J, Woods B, et al. The value of personalized
psychosocial interventions to address behavioral and psychological symptoms in people with
dementia living in care home settings: a systematic review. Int Psychogeriatr. 2014;26(7):1083–98.
41. Godde B, Voelcker-Rehage C. More automation and less cognitive control of imagined walking
movements in high- versus low-t older adults. Front Aging Neurosci. 2010;2.
42. Craik FI, Byrd M. Aging and cognitive decits: the role of attentional ressources. In: Craik FI, Trehub S,
editors. Aging and cognitive processes. Boston: Springer; 1982. p.191–211.
43. Godde B, Voelcker-Rehage C. Cognitive resources necessary for motor control in older adults are
reduced by walking and coordination training. Front Hum Neurosci. 2017;11:156.
44. Chan A-W, Tetzlaff JM, Altman DG, Laupacis A, Gøtzsche PC, Krleža-Jerić K, et al. SPIRIT 2013
statement: dening standard protocol items for clinical trials. Ann Intern Med. 2013;158(3):200–7.
Page 23/29
45. Chan A-W, Tetzlaff JM, Gøtzsche PC, Altman DG, Mann H, Berlin JA, et al. SPIRIT 2013 explanation
and elaboration: guidance for protocols of clinical trials. BMJ. 2013;346.
4. Folstein MF, Folstein SE, McHugh PR. “Mini-mental state: a practical method for grading the
cognitive state of patients for the clinician. J Psychiatr Res. 1975;12(3):189–98.
47. Creavin ST, Wisniewski S, Noel-Storr AH, Trevelyan CM, Hampton T, Rayment D, et al. MiniMental
State Examination (MMSE) for the detection of dementia in clinically unevaluated people aged 65
and over in community and primary care populations. Cochrane Database Syst Rev. 2016(1).
4. Bach M. The Freiburg Visual Acuity Test - automatic measurement of visual acuity. Optom Vis Sci.
1996;73(1):49–53.
49. Mossey JM, Shapiro E. Self-rated health: a predictor of mortality among the elderly. Am J Public
Health. 1982;72(8):800–8.
50. Hultsch DF, Hertzog C, Small BJ, Dixon RA. Use it or lose it: engaged lifestyle as a buffer of cognitive
decline in aging? Psychol Aging. 1999;14(2):245–63.
51. Renner B, Schwarzer R. Risk and health behaviors. Documentation of the scales of the research
project:“Risk Appraisal Consequences in Korea” RACK. International University Bremen and Freie
Universität Berlin. 2005.
52. Cwikel JG, Fried AV, Biderman A, Galinsky D. Validation of a fall-risk screening test, the Elderly Fall
Screening Test (EFST), for community-dwelling elderly. Disabil Rehabil. 1998;20(5):161–7.
53. Dias N, Kempen GI, Todd C, Beyer N, Freiberger E, Piot-Ziegler C, et al. Die deutsche Version der Falls
Ecacy Scale-International Version (FES-I). Z Gerontol Geriatr. 2006;39(4):297–300.
54. Baecke J, Burema J, Frijters J. A short questionnaire for the measurement of habitual physical
activity in epidemiological studies. Am J Clin Nutr. 1982;36(5):936–42.
55. Niemann C, Godde B, Voelcker-Rehage C. Senior dance experience, cognitive performance, and brain
volume in older women. Neural Plast. 2016;2016.
5. Vieluf S, Mahmoodi J, Godde B, Reuter E-M, Voelcker-Rehage C. The inuence of age and work-
related expertise on ne motor control. GeroPsych. 2012;25(4):199–206.
57. Oldeld RC. The assessment and analysis of handedness: the Edinburgh inventory.
Neuropsychologia. 1971;9(1):97–113.
5. Rammstedt B, Danner D. Die Facettenstruktur des Big Five Inventory (BFI). Diag. 2016.
59. Bristow T, Jih C-S, Slabich A, Gunn J. Standardization and adult norms for the sequential subtracting
tasks of serial 3’s and 7’s. Appl Neuropsychol Adult. 2016;23(5):372–8.
0. Ruesch J. Intellectual impairment in head injuries. Am J Psychiatry. 1944;100(4):480–96.
1. Stroop JR. Studies of interference in serial verbal reactions. J Exp Psychol. 1935;18(6):643–62.
2. Wechsler K, Drescher U, Janouch C, Haeger M, Voelcker-Rehage C, Bock O. Multitasking during
simulated car driving: a comparison of young and older persons. Front Psychol. 2018;9(910).
3. Kirchner WK. Age differences in short-term retention of rapidly changing information. J Exp Psychol.
1958;55(4):352.
Page 24/29
4. Simon JR, Rudell AP. Auditory SR compatibility: the effect of an irrelevant cue on information
processing. J Appl Psychol. 1967;51(3):300.
5. Jersild A. Mental set and shift. Archives of psychology, whole no. 89. J Exp Psychol. 1927;49:29–50.
. Künzell S, Sießmeir D, Ewolds H. Validation of the continuous tracking paradigm for studying implicit
motor learning. Exp Psychol. 2016;63(6):318.
7. Jaeger J. Digit Symbol Substitution Test: the case for sensitivity over specicity in
neuropsychological testing. J Clin Psychopharmacol. 2018;38(5):513–9.
. Wechsler D. The measurement of adult intelligence. Baltimore, MD: Williams & Wilkins Co.; 1939.
9. Voelcker-Rehage C, Godde B, Staudinger UM. Physical and motor tness are both related to cognition
in old age. Eur J Neurosci. 2010;31(1):167–76.
70. Rikli RE, Jones CJ. Development and validation of a functional tness test for community-residing
older adults. J Aging Phys Act. 1999;7(2):129–61.
71. Tin J. Purdue Pegboard examiner manual. Chicago IL: Science Research Associates; 1968.
72. Tin J, Asher EJ. The Purdue Pegboard: norms and studies of reliability and validity. J Appl Psychol.
1948;32(3):234.
73. Ekdahl C, Jarnlo GB, Andersson SI. Standing balance in healthy subjects. Evaluation of a quantitative
test battery on a force platform. Scand J Rehabil Med. 1989;21(4):187.
74. BORG GAV. Psychophysical bases of perceived exertion. Med Sci Sports Exerc. 1982;14(5):377–81.
75. Lussier M, Saillant K, Vrinceanu T, Hudon C, Bherer L. Normative data for a tablet-based dual-task
assessment in healthy older adults. Arch Clin Neuropsychol. 2020.
7. Kleinloog JP, Mensink RP, Ivanov D, Adam JJ, Uludağ K, Joris PJ. Aerobic exercise training improves
cerebral blood ow and executive function: a randomized, controlled cross-over trial in sedentary
older men. Front Aging Neurosci. 2019;11:333.
77. Sonntag WE, Eckman DM, Ingraham J, Riddle DR. Regulation of cerebrovascular aging. In: Riddle DR,
editor. Brain aging: models, methods, and mechanisms. Boca Raton: Taylor & Francis; 2007.
7. R Core Team. R: A language and environment for statistical computing. Vienna, Austria: R
Foundation for Statistical Computing; 2020.
79. Cohen J. Statistical power analysis for the behavioral sciences: Routledge; 1988.
0. McDowd J, Craik F. Effects of aging and task diculty on divided attention performance. J Exp
Psychol Hum Percept Perform. 1988;14(2):267–80.
Tables
Table 1 is available in the Supplemental Files section.
Table 2
Instruments used for the questionnaire battery
Page 25/29
Outcome measure Instrument
Subjective health Self-rated health(49)
Objective health Diseases and use of medication(50)
Smoking behavior Tobacco consumption(51)
History of falls Elderly Fall Screening Test(52)
Falls ecacy Falls Ecacy Scale(53)
Physical activity Baecke Inventory(54)
Social and leisure time activities Participation in everyday activities(55)
Subjective hand use Frequency of hand use in different daily activities(56)
Handedness Edinburgh Handedness Inventory(57)
Personality Big Five Inventory (58)
Table 3
Exemplary training session of the cognitive, motor, and simultaneous cognitive-motor training
Page 26/29
Time
(min) Cognitive training Motor training Simultaneous cognitive-motor
training
0-15 Preparation Preparation Preparation
15-
30 NeuroNation
Colorado (inhibitory
control; dl 3)
Treadmill training
Walking at an individually
chosen pace (dl 1)
Stop and start walking
again (dl 2)        
Short and long steps
alternating (dl 3)
NeuroNation + treadmill training
Colorado (dl 1) + walking at an
individually chosen pace (dl 1)
Colorado (dl 1) + stop and start
walking again (dl 2)
Colorado (dl 1) + short and long steps
alternating (dl 3)
30-
45 NeuroNation
Drehuss (updating;
dl 2)
Floor training
Get up from a chair
(strength; dl 2, balance
board)
Hip circles (exibility; dl 1)
Semi tandem stand
(balance; dl 1, AIREX pad)
Knee lifts and external hip
rotation (exibility, dl 2)
Calf lifts (strength; dl 1,
AIREX pad)
Leg swinging sideward
(exibility, dl 3)
NeuroNation + oor training
Drehuss (dl 2) + get up from a chair
(dl 0, oor)
Drehuss (dl 2) + hip circles (dl 1)
Drehuss (dl 2) + semi tandem stand
(dl 1, AIREX pad)
Drehuss (dl 2) + knee lifts and
external hip rotation (dl 2)       
Drehuss (dl 2) + calf lifts (dl 1,
AIREX pad)
Drehuss (dl 2) + leg swinging
sideward (dl 3)
45-
60 NeuroNation
Doppelmerker
(updating, inhibitory
control; dl 4)
Treadmill training
Narrow and wide steps
alternating (dl 4)
Changing speed every 30 s
(dl 5)
Walking and lifting one
knee sideways every 5th
step (dl 6)
NeuroNation + treadmill training
Doppelmerker (dl 1) + narrow and
wide steps alternating (dl 4)
Doppelmerker, (dl 1) + changing
speed every 30 s, (dl 5)
Doppelmerker, (dl 1) + walking and
lifting one knee sideways every 5th
step (dl 6)
Note. NeuroNation: name of the software application; Colorado, Drehuss, Doppelmerker: exercises within
NeuroNation; dl = diculty level.
Figures
Page 27/29
Figure 1
Gait Real Time Analysis Interactive Lab (GRAIL), customized MT scenario.
Page 28/29
Figure 2
Carnet Soft Driving Simulator, customized MT scenario.
Page 29/29
Figure 3
Schedule of activities. BMI = Body Mass Index; DSST = Digit Symbol Substitution Test; FrACT = Freiburg
Visual Acuity Test; MMSE = Mini Mental State Examination
Supplementary Files
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