An interventional study of Computer-Based Mental Fatigue Protocol in Mental Fatigue and Muscle Strength Dynamometer, sponsored by Florida Institute for Human and Machine Cognition. Recruiting at 1 site in United States. Open to participants aged 18 Years to 39 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-29.
Sponsored by Florida Institute for Human and Machine Cognition · Not applicable, Interventional, and Basic science
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Among 56 studies in Mental Fatigue with a site in United States — 19 open to participants now, 23 under way, 1 of them phase 3. Mental Fatigue · United States.
Among the 56 studies in Mental Fatigue with a site in United States, this one is the 14th largest by planned enrollment of the 47 interventional ones that give a count, is one of 11 that started in 2026, is one of 36 with no phase, reaches primary completion later than 18 of the 22 other live ones, and was the 54th registered.
175 studies on the registry are indexed under Mental Fatigue; 54 are open to participants now.
Browse Mental Fatigue studies →19 of the 56 studies in Mental Fatigue with a site in United States are open now. Recruiting first, the newest first:
St. Louis University · Sites in United States
Ages 18–50 · Healthy volunteers
University of Alabama at Birmingham · Sites in United States
Ages 18+
Samphire Group, Inc. · Sites in United States
Ages 18–65 · Women only · Healthy volunteers
Washington State University · Sites in United States
Ages 40–60 · Women only · Healthy volunteers
Outliers, Inc. · Sites in United States
Ages 18–55 · Healthy volunteers
A study can be open while its sites in United States have not opened yet or have stopped. Only those recruiting at a site in United States →
Of the 29 Mental Fatigue studies recruiting now, 9 (31%) set no upper age limit and 19 (66%) stop at 75 or younger; 1 takes children under 18; 15 take healthy volunteers.
This study: 18 Years to 39 Years · all sexes · healthy volunteers too.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
56 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 3 · Phase 2 7 · Phase 3 1 · Phase 4 1
First in 2011; this study’s year is marked. 11 started in 2026.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 50 is above the median of 45 across 143 interventional studies indexed under Mental Fatigue.
Median enrollment 35 across the 47 interventional studies, 55 across the 9 observational. Of the 32 that completed or were terminated, 4 (13%) have results posted.
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13 of 56 have an industry lead sponsor. The 10 most frequent:
Florida Institute for Human and Machine Cognition is the lead sponsor of 9 studies on the registry; 6 are open to participants now.
Florida Institute for Human and Machine Cognition has 1 study filed under Mental Fatigue — fewer than ten, so there is no comparison to draw.
12 of the studies in Mental Fatigue with a site in United States that are under way reach primary completion within a year, 0 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT06095297University of Alabama at BirminghamLong COVID Brain Fog: Cognitive Rehabilitation Trial | 2026-12 |
| NCT07525063Duke UniversityPain & Reward Neuromodulation of CNS Circuits | 2026-12 |
| NCT06614309Mayo ClinicNon-invasive Treatment for Long COVID (Post COVID-19 Condition) Brain Fog | 2026-12 |
| NCT07892911Ancestral Supplements, LLCA Study to Evaluate the Effects of a Beef Liver Supplement on Energy, Mood, and Mental Clarity | 2026-12-01 |
| NCT06142253VA Office of Research and DevelopmentWater-based Activity to Enhance Recovery in Long COVID-19 | 2026-12-31 |
Add all 12 to your calendar (.ics) → With an account.
Among the 56 studies in Mental Fatigue with a site in United States, from their registry updates:
This tab as a report to print or save as PDF → With an account.
This study will investigate the acute effects of mental fatigue on lower-extremity muscle strength and limb symmetry in healthy young adults. Participants will complete lower-extremity strength testing before and after a standardized computer-based mental fatigue protocol involving tasks of attention, reaction time, concentration, and working memory. Muscle strength and limb symmetry will be assessed using isokinetic dynamometry, with muscle activity measured using surface electromyography. Participants will also complete subjective measures of mental fatigue, sleepiness, mental effort, and perceived physical exertion. Heart rate will be monitored throughout the study, and brain activity may be assessed during cognitive tasks. The study will determine whether acute mental fatigue is associated with changes in muscle strength, limb symmetry, and neuromuscular performance.
This study will investigate the acute effects of mental fatigue on lower-extremity muscle strength, interlimb symmetry, and neuromuscular performance in healthy young adults. The study will use a within-subject, repeated-measures design in which participants complete lower-extremity strength testing immediately before and after a standardized computer-based mental fatigue protocol. Each participant's pre-fatigue measurements will serve as the baseline comparison for their post-fatigue measurements.
Participants will complete one experimental session lasting up to approximately two hours at the Florida Institute for Human and Machine Cognition (IHMC) Healthspan, Resilience, and Performance Research Complex. Before testing, participants will undergo eligibility screening, provide written informed consent, and complete familiarization with the strength-testing procedures and computer-based cognitive tasks. Following familiarization, participants will complete a standardized rest period of at least five minutes before baseline measurements are collected.
Lower-extremity muscle strength will be assessed using a Biodex isokinetic dynamometer. Participants will perform knee extension and flexion with both lower extremities at three different movement speeds to assess strength across multiple testing conditions. Peak torque will be used as a primary measure of muscle strength. Testing of both limbs will also allow calculation of a Limb Symmetry Index (LSI) to quantify differences in strength between the lower extremities. Participants will rate their perceived physical exertion following each strength assessment.
Surface electromyography (EMG) will be used to record muscle activity from selected muscles of both thighs during strength testing. Participants may also perform maximal voluntary isometric contractions before the primary strength assessment to assist with normalization and interpretation of EMG signals. EMG measurements will be used to examine whether changes in strength following the mental fatigue protocol are accompanied by changes in muscle activity.
Following the baseline strength assessment, participants will complete approximately 30 minutes of standardized computer-based cognitive tasks designed to require sustained attention, concentration, reaction time, working memory, and mental effort and thereby induce acute mental fatigue. Tasks may include a psychomotor vigilance task, an incongruent Stroop task, and an n-back working-memory task. Reaction time and response accuracy may be recorded during the cognitive tasks.
Subjective mental fatigue and sleepiness will be assessed before and after the mental fatigue protocol. Following the cognitive tasks, participants will also rate the mental effort required to complete the tasks. These measures will be used to characterize the subjective response to the mental fatigue protocol and evaluate whether participants experienced increased mental fatigue following the intervention.
Heart rate and cardiac activity may be continuously monitored using a Polar H10 chest sensor during the experimental session to provide additional information regarding physiological responses during the strength-testing and cognitive-task portions of the protocol. Brain electrical activity may also be recorded using noninvasive electroencephalography (EEG) during the cognitive tasks in a subset of participants.
Immediately following completion of the mental fatigue protocol and post-task questionnaires, participants will repeat the same bilateral Biodex strength assessment performed at baseline. Testing procedures, positioning, movement speeds, instructions, and outcome measurements will be kept consistent between the pre- and post-fatigue assessments. Surface EMG will again be recorded during strength testing, and participants will rate their perceived physical exertion.
The primary analyses will compare pre- and post-fatigue measures of lower-extremity muscle strength and limb symmetry to determine whether acute mental fatigue is associated with changes in peak torque or LSI. Additional analyses will examine subjective mental fatigue, sleepiness, mental effort, perceived physical exertion, muscle activity, cognitive-task performance, and physiological responses. The findings will help determine whether acute mental fatigue should be considered when measuring and interpreting lower-extremity strength and limb symmetry in research, rehabilitation, and human performance settings.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will complete baseline lower-extremity muscle strength testing followed by approximately 30 minutes of standardized computer-based cognitive tasks designed to induce acute mental fatigue. Lower-extremity muscle strength testing will then be repeated immediately following the mental fatigue intervention.
Other: Computer-Based Mental Fatigue Protocol
Participants will complete approximately 30 minutes of standardized computer-based cognitive tasks designed to induce acute mental fatigue. The tasks require sustained attention, concentration, reaction time, working memory, and mental effort and may include the Psychomotor Vigilance Task (PVT), incongruent Stroop task, and n-back task. Participants will complete the mental fatigue protocol after baseline strength testing and before the post-intervention strength assessment. Subjective mental fatigue and sleepiness will be assessed before and after the intervention, and perceived mental effort will be assessed following the intervention.
Lower-Extremity Muscle Strength
Lower-extremity muscle strength will be assessed using a Biodex isokinetic dynamometer during bilateral knee extension and flexion at three different movement speeds. Peak torque will be recorded as the primary measure of muscle strength. Changes in peak torque from baseline to immediately following the computer-based mental fatigue intervention will be evaluated.
Time frame: Baseline and immediately following the approximately 30-minute mental fatigue intervention, during a single study visit lasting up to 2 hours.
Lower-Extremity Limb Symmetry
Limb symmetry will be assessed using peak torque measurements obtained from both lower extremities during isokinetic knee extension and flexion testing. A Limb Symmetry Index (LSI) will be calculated to quantify the similarity in muscle strength between the two lower extremities. Changes in LSI from baseline to immediately following the computer-based mental fatigue intervention will be evaluated.
Time frame: Baseline and immediately following the approximately 30-minute mental fatigue intervention, during a single study visit lasting up to 2 hours.
Plan to share: Yes — De-identified individual participant data that underlie the results reported in publications from this study may be made available to other researchers for scientific research purposes. Data will be shared without information that directly identifies participants.
Supporting information: Study protocol
Time frame: Data will be available beginning 12 months and ending 36 months following publication of the primary findings from this study.
Access criteria: De-identified data may be shared with scientific and clinical researchers for research purposes, including individual participant data meta-analyses. Requests for data should be directed to Dr. Nicole Rendos at nrendos@ihmc.org and may be submitted up to 36 months following publication of the primary findings from this study. Researchers requesting access will be required to provide an appropriate scientific rationale for the request and sign a data access agreement before receiving the data.
No publications or documents are linked to this record.
Started Sep 2026 (actual). Primary completion is estimated for Dec 2027, 15 months after the start.
Of 80 non-industry interventional studies with no phase under Mental Fatigue, half reached primary completion within 9 months of starting (the median), counting those still running; a quarter within 3 and three quarters within 23. This study's planned 15 months is above that.
Counting every sponsor, half of 92 studies reached it within 8 months; a quarter within 3 and three quarters within 23.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Florida Institute for Human and Machine Cognition