Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT03894241 |
| Other study ID # |
CONICYT/FONDECYT 2016/11160703 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
August 1, 2017 |
| Est. completion date |
October 31, 2019 |
Study information
| Verified date |
November 2023 |
| Source |
Pontificia Universidad Catolica de Valparaiso |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Education and health are crucial topics for public policies as both largely determine the
future wellbeing of the society. Currently, several studies recognize that physical activity
(PA) benefits brain health in children. However, most of these studies have not been carried
out in developing countries or lack the transference into the education field.
The Cogni-Action Project is a crossover-randomized trial. The aim of the study is to
determinate the acute effects of three different training sessions consisting in (i)
"Moderate-Intensity Continuous Training" (MICT), (ii) "Cooperative High-Intensity Interval
Training" (C-HIIT), and (iii) sedentary activity on spontaneous brain activity and
neuroelectric indices of cognitive performance during a working memory and a reading task, as
measured by electroencephalography (EEG) and eye-tracker. In an energy expenditure
counterbalanced fashion, 32 adolescents will randomly undergo each training session , two
weeks apart.
The main strength of this project is that, to our knowledge, this is the first study
analysing the potential influence of PA, sedentarism, and physical fitness on brain structure
and function, cognitive performance, and academic achievement in Latin-America and,
specifically, in Chile which has been catalogued with an important sociocultural gap. For
this purpose, this study will use advanced technologies in neuroimaging (MRI),
electrophysiology EEG, and eye-tracking , as well as objective and quality measurements of
several physical and cognitive health outcomes.
Description:
Regarding the study (i.e., crossover-randomized trial), children will be randomized to each
protocol session, participating in all of them with two-weeks apart . Thus, they will assist
to our gym to perform one of the three protocol and subsequently they will be move to a
laboratory where they will undergo EEG and eye-tracking measurements during resting state
condition and during two different cognitive tasks More details can be found in following
sections.
The design of the project will consist of a counterbalanced cross-over trial where the
participants will perform, on different days, three different PA training protocols in a
random order. Each child will visit our laboratory three times, every two weeks to ensure a
"wash-out" period with the purpose of mitigating the PA effect from each protocol.
Participants will assist to the three different sessions at the same weekday (e.g., Monday)
and at the same daytime to avoid differences in preceding school activities or circadian
rhythms. Participants will undergo a "Sedentary condition" (SC), sitting and watching a
documentary on TV as has been used previously, and two different PA protocols consisting in
"Moderate-Intensity Continuous Training" (MICT), i.e., continuous outdoor walking, and
"Cooperative High-Intensity Interval Training" (C-HIIT), composed of a circuit training with
a partner (physical education teacher). These three protocols have been chosen in view of
what corresponds to types of activities usually performed in schools. Thus, SC mimics the
time spent during any academic lesson (i.e. mathematics or language lessons); MICT represents
the typical activity in a PE class; and C-HIIT has been selected since it is postulated as an
exercise protocol that could possibly be implemented in the PE class. The three protocols are
designed so that energy expenditure is equivalent between them, to eliminate differences in
the energy expenditure as a possible confounding factor. The energy expenditure calculation
protocol is detailed on supplementary material.
After each PA protocol, the participants will undergo EEG and eye-tracking measurements as
follows: 1st, resting state spontaneous brain activity will be assessed during 3 min with EEG
only, and subsequently, eye-tracking will be registered in parallel with EEG while
participants perform the cognitive tasks (a working memory task and a reading task). The
measurements will start between 20 to 25 minutes after the end of each condition. In this
way, we will emulate a school recess in the Chilean context, before the start of the next
subject. All measures will be carried out in the "Laboratorio Lenguaje & Cognición ELV",
which belongs to the Literature and Language Sciences Institute of the Pontificia Universidad
Católica de Valparaíso. To avoid subjective influence of evaluator, when the participants go
to the laboratory, the evaluator will be blinded according to which PA protocol participants
performed.
Neuroelectric and eye-tracker measurements EEG measurement: A B-Alert X24 device for EEG
(Advanced Brain Monitoring, California, United States) will be used, which consists of 24
active electrodes that minimize the noise of electrical devices outside the biological
processes of interest, ensuring good signal quality. Two channels will be used to register
electrooculographic activity, to better discriminate between true electroencephalographic and
electrooculographic activity associated with eye movement and blinking. Recordings will be
done at a sampling rate of 256 values per second, with a band-pass filter between 0.1 - 100
Hz, and a notch filter of 50 Hz to eliminate the noise of the surrounding alternating current
in the room. It should be noted that this equipment is wireless, which makes it more
convenient and faster to mount on participants. For this study the investigators will focus
on the channels Fz, Cz, CPz, Pz, POz, Oz, O1 and O2.
Eye-tracker: A Tobii Pro TX300 (Tobii, Stockholm, Sweden) will be used to track eye movements
directly through a light sensitive camera near the infrared spectrum. This equipment studies
the visuomotor characteristics during the process of reading and the trajectories of the look
around each word. In addition, it will serve to define the exact moments at which these words
are read and thus be able to synchronize the EEG record to calculate an average signal (N400)
that reflects the brain's processing of language. The same device records raw values of pupil
size (diameter), saving all data with a sampling rate of 300 Hz.
Cognitive tasks during neuroelectric and eye-tracker measurements Working memory task. A
N-back task will be run through E-Prime 2.0 software synchronized with the
electroencephalographic recording system and the eye-tracker, to measure neuroelectric
activity and pupil size diameter time-locked to the presentation of each stimulus (targets
and non-targets). The protocol is very similar to the one previously explained for the 0-back
and 2-back conditions during fMRI assessment. The main difference of the present task with
respect to the fMRI's N-back task is that children must press in the keyboard the number "1"
when they detect a target stimulus or the number "2" for non-targets. This type of task
generates an EEG potential related to cognitive processing, characterized by a positive
deflection that peaks roughly around 300 ms (P300), which has been widely studied in various
types of tasks that require conscious attention, in any perceptual modality. In other words,
it is a potential related to events that are consciously perceived, which does not depend on
the stimulated perceptual path, but rather on the need to reallocate cognitive resources and
develop appropriate responses according to the ever-changing context. To isolate the EEG
patterns of P300 in working memory, the investigators will subtract to the result of a 2-back
task, the one of a 0-back. The P300 event-related potential is expected to emerge especially
in the average EEG signal time-locked to the onset of detected targets stimuli. Artifacts
such as electrooculographic signals will be subtracted from the data with an algorithm
implemented in EEGLAB, an EEG analysis toolbox running in MATLAB (Mathworks®). Manual
rejection of single trials will be considered based on visual inspection of artifacts in
data.
Reading task. Language processing will be assessed by a reading comprehension task where
short paragraphs will be presented to be read normally. The eye-tracking technique will be
employed to record eye position, movement and pupil diameter, simultaneous to the EEG record.
Participants will seat in front of a monitor, at approximately 60 cm, placing their chin on
an ergonomic stand piece, which helps to decrease head movements and improves eye-tracker
signal precision. The reading task will be presented with the latest version of Tobii Pro
Lab. After calibrating the system, each child is given a brief contextualization of the
topic, before they start to read, knowing that later they will be asked seven comprehension
questions with varying degrees of complexity. The participants must indicate the correct
answer among three alternatives. It should be noted that three literary texts will be used,
presented in a random fashion (1 per exercise condition). These texts will have the same
difficulty, the same distribution of areas of interest, similar amount of words, and will be
previously validated by a panel of experts. The reading of each word is expected to generate
an EEG negative potential with latency close to 400 ms (N400). The amplitude, topographic
distribution and latency of this potential are electrophysiological neuromarkers of
linguistic ability in general, and the ability to construct meaning from words. The
eye-tracker will be used to study the ocular trajectory during reading and establish the
moments when words are read. EEG and eye-tracking will be registered simultaneously to record
eye movements related to reading, giving measures such as reading speed, fixation durations,
number of fixations, among others), and to measure eye fixation related EEG potentials
associated with cognitive load while reading words. The reader should note that this
potential coincides experimentally with the N400, so they may represent different brain
processes superimposed, or be essentially the reflection of the same mechanism.
Primary outcomes in crossover acute counterbalanced study Resting state spontaneous brain
activity. After the exercise protocol and before the cognitive tasks, spontaneous brain
activity will be measured with EEG while children rest in a seated position, in order to
measure the peak frequency and reactivity of the alpha wave. The dynamics of the alpha peak
frequency (between 7 and 13 Hz) during a 3 minutes period will be calculated by means of a
Hilbert transform. Then, an average value and trend of the alpha peak frequency will be
calculated. It has been postulated that the higher the alpha peak frequency, the greater
general cognitive capacity and processing speed are. The investigators focus on alpha waves
because this brainwave has traditionally associated with different theories of attention and
conscious perception. The frequency of the alpha wave has been discovered to increase after a
session of cognitive tasks. Additionally, the power and frequency of alpha brainwaves prior
to cognitive evaluation have been correlated to performance. If PA exerts a positive effect
over cognitive performance, a single session of PA should also cause an increase in alpha
peak frequency. In fact, this was found by Gutmann et al. in two consecutive studies.
However, a statistical relation between PA-induced increments in alpha peak frequency and
cognitive performance is missing.
Working memory performance: Hits, misses, omissions, and accuracy will be calculated for
targets and non-targets of the n-back task, as well as response latency.
Reading comprehension: Seven questions with varying degree of comprehension complexity will
be given after the texts are read. For every question there will be four alternatives to
choose as the correct answer.
Cognitive load: The investigators group several measures on this category because all of them
have been related with the concept of cognitive load. The first two come from the EEG, and
the other two from the eye-tracker.
P300: The P300 event-related potential associated with the different type of stimulus in the
n-back (target and non-target) will be quantified according to amplitude and latency of the
peak.
N400: This linguistics-related event-related potential also will be described according to
latency and amplitude. Because it will be synchronized with the eye fixation on words during
the reading task, it is conceptually a type of fixation-related potential.
Rapid pupil size variations: Pupil reacts to cognitive requirements and it has been
associated with increases in cognitive load during various tasks including working memory and
reading. The amount of high frequency variations in pupil diameter is estimated by a novel
Index of Cognitive Activity, which increases with cognitive load. This measure can be
represented as a continuous variable in time thanks to the high sampling rate of the
eye-tracker. The Index of Cognitive Activity will be measured during the n-back and reading
tasks.
Word Fixation times: The length of visual fixations also has been associated with the
processing time that the brain dedicates to elaborate a cognitive interpretation of
perception. Average and standard deviation of fixations around words will be calculated for
the reading task.
