Adaptive reasoning and problem-solving are critical skills that allow for accurate decisions to be made based on varying levels of information. In many situations these decisions must be made and communicated under stressful, time-sensitive conditions. In such contexts, an ability to apply inductive and deductive reasoning to complex, ambiguous, and/or novel problems is critical. The objective of the INSIGHT project is to establish a comprehensive and rigorous brain training protocol to significantly improve adaptive reasoning and problem solving. We will examine a variety of interventions (cognitive training, physical fitness training, physiological stimulation, , and combinations thereof) to assess their ability to improve adaptive reasoning and problem solving abilities. Multimodal interventions are hypothesized to act synergistically to significantly enhance fluid intelligence (Gf) and underlying brain structure and function.
Recent innovations in cognitive neuroscience have advanced understanding of the neurobiological foundations of fluid intelligence (Gf) and adaptive reasoning and problem solving (ARP). Rather than engaging a single brain structure (e.g., prefrontal cortex) or operating at a fixed level of performance throughout adulthood, emerging neuroscience evidence indicates that Gf and ARP are mediated by a distributed neural system whose functions can be significantly enhanced by specific types of interventions, including cognitive training, high-definition transcranial direct-current brain stimulation (HD-tDCS), and physical fitness training. The main objective of the INSIGHT project is to establish and validate a comprehensive and rigorous brain training protocol that incorporates the best available interventions for the enhancement of Gf and ARP. The project was divided into two phases, with the first occurring in February -November 2014 and the second occurring February - December 2015. The two phases were similar in structure and goals/hypotheses, but had several methodological differences in terms of interventions, arms, and outcome measures. This document contains information pertinent to only the 2014 phase, which examined the relative contributions of physical fitness intervention, video-game based training, and high-definition transcranial direct-current brain stimulation (HD-tDCS) to the improvement of Gf/ARP, executive function, working memory, relational memory, physical fitness level, and brain structure/function. Arms/groups completed 1 week of testing to establish baseline measurements of cognitive abilities, physical fitness, and brain structure/function. 16 weeks of various intervention protocols. These protocols could include single or multiple intervention type(s) with varying schedules. Three 70-min training sessions were completed per week, so all arms completed 56 hours of training, total. Following completion of the intervention period was 1 week of post-assessment to measure changes in cognitive abilities, physical fitness, and brain structure/function. Technical Justification for Physical Fitness Intervention: The beneficial effects of physical fitness on cognitive performance and brain health have been documented in many studies. For example, this literature suggests that increased exercise leads to the birth of new neurons in the hippocampus (a key brain region underlying Gf), increased connections among neurons throughout the brain, the development of new vasculature structure, increased production of neurotrophic proteins, enhanced learning and memory, and enhanced executive control including attention and inhibition, working memory, mental flexibility, and action monitoring. In particular, (1) exercise effects are largest for tasks that involve executive control functions for working memory, planning, and problem solving - abilities that are essential for Gf and ARP; and (2) aerobic exercise training, when combined with strength and flexibility training, had a greater positive effect on cognition compared to exercise training programs that included only aerobic components. Such findings provide important justification for the physical activity intervention proposed here. Hence, the proposed fitness intervention employs a combined aerobic/resistance training program to further enhance the benefits of cognitive training on Gf and ARP. Technical Justification for Video Game-Based Training: Training on five cognitive skills - (1) processing speed, (2) attention, (3) working memory, (4) relational memory, and (5) cognitive flexibility - has been shown to provide promising transfer results to Gf and other relevant constructs. This training regime is the basis for the design of the Mind Frontiers software platform. Mind Frontiers includes an integrated suite of mini-games that are designed to train these five core cognitive skills. The mechanics, as abstractions of the cognitive exercises, ensure that the scientific integrity and the training effect of the exercises are preserved, but the exercises are implemented as games with motivational features and adaptive difficulty. Technical justification for HD-tDCS: It has been hypothesized that Gf and ARP are critically dependent on a fronto-parietal brain network, and thus that bilateral, specific stimulation of the frontal cortex with high definition transcranial direct current stimulation (HD-tDCS) would have an excitatory effect on neurons within that network, making them more likely to fire, and thereby enabling faster learning and facilitating transfer to Gf. Technical Justification for Active Control: Change detection and visual search tasks were selected as the active control tasks because previous work had indicated that training low-level perceptual abilities did not transfer to Gf and ARP.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Masking
DOUBLE
Enrollment
521
Mind Frontiers cognitive training software (Aptima Inc.) is a Wild West-themed Android application played on Nexus 10 tablets. This intervention includes 20 70-min sessions (23.33 hrs) completed over 12 weeks: 1/wk weeks 5-8, 2/wk weeks 9-16. The 6 mini-games, played in random order for 10 min each session, are Ante Up (Tower of London, executive functioning); Irrigator (visuospatial reasoning); Pen 'Em Up (dual task switching, executive function); Supply Run (Keep Track, working memory updating); Riding Shotgun (visuospatial working memory); and Sentry Duty (dual n-back, working memory). There is also a meta-game in which players build a town using resources earned from the mini-games, played for 5 min each session.
Based on high intensity cardiovascular resistance training (HICRT), this intervention includes a combination of aerobic and strength training. Sessions are conducted in a group of ≤20 participants per class, with ≤5 participants per trainer. This intervention includes 28 70-min sessions (32.67 hrs) completed over 16 weeks: 3/wk weeks 1-4, 2/wk weeks 5-8, 1/wk weeks 9-16. At the first and last session, participants complete the Army Physical Readiness Test. All other sessions consist of: Warm-up; Walk/Run; 2 HICRT circuits with 3 sets of 3-4 exercises; 1-2 min jump rope and 4-min power series between HICRT segments; Drills \& Skills; and Cool-down/stretch.
The active control condition consists of 2 tasks (change detection and visual search) with 3 variants each. This intervention includes 48 70-min sessions (56 hrs) completed over 16 weeks: 3/wk. The 6 tasks are played in random order for 10 min each session.
Active HD-tDCS is administered during the first 30 minutes of each Mind Frontiers session. Therefore, the schedule is 20 30-min sessions (10 hrs) completed over 12 weeks: 1/wk weeks 5-8, 2/wk weeks 9-16. The HD-tDCS devices are Soterix Medical 2x2 models, using 4 electrodes (2 anodal and 2 cathodal). Electrodes are held in place with custom, 3D-printed electrode holders inserted into EEG caps, using EEG gel. Participants receive 2.0 mA current for 30 min, split over the 2 anodal electrodes, each drawing ≤1.0 mA. Stimulation is ramped up and ramped down over 30 sec at the beginning and end of the 30-min stimulation period.
Sham HD-tDCS is administered during the first 30 minutes of each Mind Frontiers session. Therefore, the schedule is 20 30-min sessions (10 hrs) completed over 12 weeks: 1/wk weeks 5-8, 2/wk weeks 9-16. The HD-tDCS devices are Soterix Medical 2x2 models, using 4 electrodes (2 anodal and 2 cathodal). Electrodes are held in place with custom, 3D-printed electrode holders inserted into EEG caps, using EEG gel. Participants do not receive sustained stimulation; it is ramped up and ramped down over 30 sec at the beginning and end of the 30-min stimulation period to elicit the sensation of simulation and make the sham condition more convincing.
Mind Frontiers cognitive training software (Aptima Inc.) is a Wild West-themed Android application played on Nexus 10 tablets. This intervention includes 20 70-min sessions (23.33 hrs) completed over 12 weeks: 1/wk weeks 5-8, 2/wk weeks 9-16. The 6 mini-games, played in random order for 10 min each session, are Ante Up (Tower of London, executive functioning); Irrigator (visuospatial reasoning); Pen 'Em Up (dual task switching, executive function); Supply Run (Keep Track, working memory updating); Riding Shotgun (visuospatial working memory); and Sentry Duty (dual n-back, working memory). There is also a meta-game in which players build a town using resources earned from the mini-games, played for 5 min each session.
University of Illinois at Urbana-Champaign
Urbana, Illinois, United States
Change in Bochum Matrices Test
BOMAT is a non-verbal, one-dimensional neuropsychological test of Gf. The test consists of a series of 5x3 matrices of patternswith each matrix missing one field. The participant selects one of six possible answers that complete the matrix. The problems range from simple to complex and are all in black-and-white. Participants complete a 15-min practice and have 45 min to complete as many problems as they can (29 total).
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Letter Sets
This test is a measure of Gf. For each problem of the Letter Sets task, the participant is shown 5 sets of letters, with 4 letters in each set. Four of the sets of letters follow a rule, while the fifth set of letters is different from the rest. With the exception of sounds of the sets of letters, shapes of the letters, or potential word formation of the letters, the participant must determine which rule applies to 4 of the letter sets and indicate the 1 letter set that doesn't fit. Participants have 7 minutes to complete as many problems as they can (15 total), with each problem getting progressively more difficult.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Number Series
This test is a measure of Gf. Participants are shown a series of arithmetic number series and need to select the next number in the series from 5 possible answers at the bottom of the screen. The participant is given 5 practice problems at the beginning of instruction, and must complete as many problems as possible in 5 min (10 total).
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Rotation Span
This is a test of working memory. Participants must remember a series of arrows presented (16 possible arrows varying in length and direction), while maintaining accuracy on an interleaved letter rotation task (determining if a letter is facing the correct direction after rotation).
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Symmetry Span
This is a test of working memory. Participants must remember a series of blocks presented (from a 4x4 grid) while maintaining accuracy on an interleaved symmetry judgment task.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Reading Span
This is a test of working memory. Participants must remember a series of words presented (18 possible 4-letter words) while maintaining accuracy on an interleaved task where they judge sensible or nonsensical sentences.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Garavan
The Garavan task is a serial attention task that measures executive function, specifically task-switching ability. Participants are presented with a series of large and small squares, 10 series/trial in total. Subjects must keep a mental count of how many large and small squares have been presented. For each square, the participant rapidly updates this mental count and then presses the spacebar to see the next square. At the end of the sequence (length is random), a response screen appears and participants report their final count of large and small squares. On a given trial, 11-15 updates are made. Dependent measures are response time for consecutive trials of the same type (no-switch RT) and response time for consecutive trials that differ (switch RT). A cost RT metric can be computed by taking the difference between Switch and No-Switch RT as a measure of set shifting.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Stroop
The Stroop task is a measure of executive function, specifically inhibition. In this task, subjects are asked to indicate the color of each word stimulus. The stimulus may be congruent (the word meaning and text color match), or incongruent (the word meaning and text color differ).
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Keep Track
The Keep Track task measures executive function, specifically updating items held in short-term memory. In the task, a series of word stimuli are presented, each belonging to a category. Subjects must remember only the last item presented from each category.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Immediate and Delayed Free Recall - Words
This is a relational memory task. Participants are shown a sequence of 12 words (all 4-letter nouns/verbs), 750 ms for each word. Afterwards, the participant has 30 sec to enter as many words as they can remember from the trial. They do 1 practice trial, followed by 5 test trials. Approximately 20-30 min later, participants are given 90 sec to recall as many words as they can from all 5 previous trials.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Immediate and Delayed Free Recall - Pictures
This is a relational memory task. Participants are shown a sequence of 12 images (all objects, no "action" images), 750 ms for each image. Afterwards, the participant has 30 sec to enter words to describe as many images as they recall from the trial (1 word/image). Each image has multiple words that could be accepted as a correct response (i.e., if shown an image of a chimpanzee, answers "chimpanzee" and "monkey" would both be acceptable). They do 1 practice trial of this task, followed by 5 test trials. Approximately 20-30 minutes later, the participant is given 90 sec to recall as many images as they can from all the previous trials.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Paired Associates
This is a relational memory task. In Paired Associates, a list of 6 unrelated word pairs are presented. At recall, only the first word from each pair is presented. Subjects must enter the second word in the pair. This procedure is repeated with a second list of 6 word pairs. Approximately 20-30 minutes later, the first words from all 12 word pairs are presented. Subjects must enter the second words from each pair.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in VO2 Max (relative, percentile)
Aerobic fitness, defined as maximal oxygen consumption (VO2 max), is assessed using an indirect computerized calorimetry system during a modified Balke treadmill test. During the test, participants' heart rates are monitored using a Polar heart rate monitor, and ratings of perceived exertion are assessed every 2 min. During the test, speed remains constant while incline increases 2-3% every 2 min. Average O2 consumption and respiratory exchange ratio are sampled every 15 sec using a mouthpiece. Relative VO2 max is reported relative to body weight, calculated as ml O2/kg/min. Maximum effort is defined using at least 2 of the following: (1) age-defined maximum heart rate norms (HR \> 85% of predicted max HR), (2) respiratory exchange ratio (CO2/O2) \>1.1, (3) subjective rate of perceived exertion \>17 (of 20), and (4) leveling of VO2 despite increasing aerobic demand. VO2 max percentile is also be reported based on age norms.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Body Mass Index
BMI is calculated from measures of height and weight
Time frame: 2 administrations: within 2 weeks before beginning and after finishing the 16-week intervention period
Change in brain structure
High-resolution structural MRI scan of brain anatomy using MPRAGE sequence, acquired in sagittal orientation (resolution: 0.9 mm, 192 slices, TR 1900 ms, TE 2.32 ms).
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in BOLD signal at rest
Using functional MRI to measure blood-oxygen-level-dependent signal while the subject is at rest and not performing a task
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in BOLD signal during task
Functional MRI that measures brain activity (based on hemodynamic response and blood-oxygenation-level dependent signal) during an experimental task.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Object Location Task performance
Completed during fMRI scanning. In the task, an image with 4 objects is presented on a grid of 9 possible locations. Participants are instructed to memorize the spatial locations of all 4 objects and mentally rotate the grid 90⁰. Participants are then presented with a probe image containing the same 4 objects rotated 90⁰. Participants must indicate whether or not any of the objects changed location in the rotated probe image. There are three possible responses: either all objects match; 1 object moves to a new location; or 2 objects swap locations. This task is a measure of relational memory.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in 3-back Task performance
Completed during fMRI scanning. Participants are presented with a continuous stream of stimuli (either faces or words), and for every stimulus, the participant must indicate (yes/no) whether or not the current stimulus is the same as the one presented three trials back. This task is a measure of working memory.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Diffusion of Water in the brain
Diffusion tensor imaging (DTI) is a magnetic resonance imaging method that is sensitive to the diffusion of water molecules. Diffusion of water in the brain depends on the tissue type, structural architecture, and presence/absence of barriers within imaging voxels. Using this raw imaging information, diffusion-based properties can be estimated including: 1. fractional anisotropy (FA), which is a measure of whether or not the 3-dimensional diffusion is largely directional (e.g., within an axon; thus, anisotropic diffusion), or if the diffusion is equal in all directions (e.g., within CSF; thus isotropic diffusion); 2. radial diffusivity (RD), which is a measure of how diffusion in the plane transverse to the principal direction of diffusion (i.e., within a cross-section of an axon, rather than down the length of an axon).
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in single-voxel magnetic resonance spectroscopy (MRS)
Technique to measure cell metabolites within a single super voxel of the brain (20 mm3), such as N-acetyl aspartate (NAA)
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Cerebral Blood Flow
During magnetic resonance imaging scans, using the arterial spin labeling technique to acquire multi-slice cerebral blood flow maps
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Saliva-based Genetic Biomarkers
Saliva collected from passive drooling, to be analyzed for biomarkers related to fluid intelligence
Time frame: One administration, within a week after finishing the 16-week intervention
Height
Height measured to calculate BMI estimate
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Weight
Weight measured to calculate BMI estimate
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Demographics Questionnaire
Questionnaire that requests age, birth date, sex, race/ethnicity, occupation.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Big Five Inventory (BFI) Questionnaire
Personality assessment with five dimensions: openness, conscientiousness, extraversion, agreeableness, and neuroticism
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Grit Scale Questionniare
This questionnaire assesses the personality trait of grit, a characteristic associated with passion and adherence to long-term goals, along with strong motivation to achieve goals despite potential obstacles.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Pittsburgh Sleep Quality Index (PSQI)
The PSQI assesses sleep habits on eight dimensions over the past month with 11 open-ended and multiple choice questions. Relevant dimensions include sleep duration, disturbance, latency, day dysfunction, efficiency, quality, use of medications to sleep, and an overall binary score of sleep habits.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Godin-Shepard Leisure Time Physical Activity Questionnaire
This survey asks about level of physical activity during leisure time in the past month, from which longer-term exercise habits can be extrapolated. By collecting height, weight, and resting heart rate with this measure, a VO2 max estimation can be reliably calculated.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in UCLA Loneliness Scale
This survey asks about the frequency (never, rarely, sometimes, often) of 20 statements regarding feelings of loneliness and social connection.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Need for Cognition
This survey asks 45 Likert-type questions regarding the value an individual places upon cognition in daily life.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Change in Implicit Theories of Intelligence Survey (ITIS)
The ITIS asks 8 Likert-type questions regarding personal beliefs about the relative fixedness/malleability of intelligence.
Time frame: 2 administrations: within a week before beginning and after finishing the 16-week intervention period
Physical Activity Enjoyment Scale
The Physical Activity Enjoyment Scale (PACES) measures individuals' enjoyment with their current activity level.
Time frame: Administered once, within a week after finishing the 16-week intervention period
Post-Experiment Survey
This survey was customized for each arm to assess: participant feedback on the various interventions they experienced; strategies developed and used in cognitive training and active control training; expectancy effects of video game-training, physical fitness training, and mindfulness meditation training; and the contribution of external (outside-study) physical activity/exercise and video game play.
Time frame: Administered once, within 2 weeks after finishing the 16-week intervention period
Preference for and Tolerance of the Intensity of Exercise Questionnaire (PRETIE-Q)
The Preference and Tolerance of the Intensity of Exercise Questionnaire (PRETIE-Q) measures individuals' preferences for physical activity type and duration. For instance, does one prefer high-intensity activity for a brief period of time, or low-intensity activity for a longer duration? How does one respond to physical challenge and exhaustion?
Time frame: Two administrations: within a week before beginning and after finishing the 16-week intervention period
Game Feedback - Mind Frontiers
Game feedback surveys were developed in-house and administered to evaluate participant responses to cognitive training. These surveys were administered at Sessions 1, 24, and 48 for the 48-session intervention, or at Sessions 1 and 20 for the 20-session intervention. These surveys evaluated enjoyment, engagement, motivation, demand, and frustration with each mini-game.
Time frame: Administered at Sessions 1, 20 (or 24), and 48 of the Mind Frontiers intervention
Game Feedback - Active Control
Game feedback surveys were developed in-house and administered to evaluate participant responses to active control training. These surveys evaluated enjoyment, engagement, motivation, demand, and frustration with each task.
Time frame: Administered at Sessions 1, 24, and 48 of Active Control intervention
Army Physical Readiness Test (APRT)
The APRT is five exercises: (1) 60-yard shuttle run, (2) standing long jump, (3) one-minute of rowers, (4) one-minute of push-ups, and (5) a 1.5 mile run
Time frame: Administered at Session 1 and Session 28 of the fitness intervention
Heart rate
Participants' heart rates were monitored using Polar heart rate monitor E600 during all sessions of the fitness intervention
Time frame: Data collected continuously during at all 28 fitness intervention sessions
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