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  1. Home
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  3. /Clinical trials
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  5. /Healthy volunteers
  6. /N-Back Task

Clinical trials data

N-Back Task in healthy volunteer trials: 51 registered studies

Every registered healthy volunteers study on ClinicalTrials.gov that names the N-Back Task in an outcome measure: how often it is a primary outcome, the tests named with it, how large the studies are and when they measure it.

Registered healthy volunteers studies name it in an outcome measure
51
Name it in a primary outcome, 51%
26 of 51
Of the condition's 656 studies name it, against 5% of all registered studies
8%
Other conditions
Median participants per study
44
By phase
Try the 1-Back TaskTry the 2-Back Task

Tests named in the same studies

The library tests that healthy volunteers studies naming the N-Back Task name most often beside it.
  1. 1

    Eriksen Flanker Task7 studies, 3 as a primary outcome

  2. 2

    Stroop Color-Word Test6 studies, 3 as a primary outcome

  3. 3

    Verbal Learning6 studies, 2 as a primary outcome

  4. 4

    Digit Span Test5 studies, 1 as a primary outcome

  5. 5

    Task Switching Test4 studies, 3 as a primary outcome

  6. 6

    Go/No-Go Task4 studies, 2 as a primary outcome

  7. 7

    Attention Network Test4 studies, 1 as a primary outcome

  8. 8

    Verbal Fluency4 studies, 1 as a primary outcome

  9. 9

    Picture Naming Test3 studies, 2 as a primary outcome

  10. 10

    AX Continuous Performance Test3 studies, 1 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

Studies by start year

Each study counted once. 2026 is partly planned starts.
02000: 0 studies, 0 with a test as a primary outcome20002001: 0 studies, 0 with a test as a primary outcome2002: 0 studies, 0 with a test as a primary outcome2003: 0 studies, 0 with a test as a primary outcome2004: 0 studies, 0 with a test as a primary outcome2005: 0 studies, 0 with a test as a primary outcome20052006: 0 studies, 0 with a test as a primary outcome2007: 0 studies, 0 with a test as a primary outcome2008: 1 studies, 0 with a test as a primary outcome2009: 0 studies, 0 with a test as a primary outcome2010: 1 studies, 1 with a test as a primary outcome20102011: 2 studies, 1 with a test as a primary outcome2012: 1 studies, 0 with a test as a primary outcome2013: 2 studies, 0 with a test as a primary outcome2014: 2 studies, 2 with a test as a primary outcome2015: 0 studies, 0 with a test as a primary outcome20152016: 2 studies, 0 with a test as a primary outcome2017: 2 studies, 0 with a test as a primary outcome2018: 2 studies, 1 with a test as a primary outcome2019: 6 studies, 4 with a test as a primary outcome2020: 2 studies, 0 with a test as a primary outcome20202021: 5 studies, 3 with a test as a primary outcome2022: 1 studies, 1 with a test as a primary outcome2023: 5 studies, 3 with a test as a primary outcome2024: 7 studies, 1 with a test as a primary outcome2025: 5 studies, 5 with a test as a primary outcome20252026: 5 studies, 4 with a test as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

Show as a table
Registered studies by start year
Start yearStudiesA test as a primary outcome
200000
200100
200200
200300
200400
200500
200600
200700
200810
200900
201011
201121
201210
201320
201422
201500
201620
201720
201821
201964
202020
202153
202211
202353
202471
202555
202654

Phases and study sizes

By phase

  • Phase 16 studies, 3 as a primary outcome
  • Phase 1/21 studies, 1 as a primary outcome
  • Phase 22 studies, 0 as a primary outcome
  • Phase 32 studies, 0 as a primary outcome
  • Phase 42 studies, 2 as a primary outcome
  • Not applicable35 studies, 19 as a primary outcome
  • Observational3 studies, 1 as a primary outcome

Participants per study

102050100
  • Not applicable40 median, 27 to 60
Participants per study. The bar spans the middle half of the studies in each phase, the mark is the median, and the axis is logarithmic. Phases with fewer than 10 studies that give a size are left out.
Show as a table
Participants per healthy volunteers study that names the N-Back Task, by phase
PhaseStudies with a sizeMedianMiddle half
Not applicable334027 to 60

When healthy volunteer trials measure it

Half of the primary outcomes that name the N-Back Task are measured within 1 day of the start, and the middle half from the first day to 12 weeks. 24 primary outcomes give a duration.

Latest time point of each outcome

  • Within a day22 outcomes, 12 as a primary outcome
  • Up to 4 weeks9 outcomes, 4 as a primary outcome
  • 1 to 3 months10 outcomes, 3 as a primary outcome
  • 3 to 6 months4 outcomes, 3 as a primary outcome
  • 6 to 12 months3 outcomes, 2 as a primary outcome
  • No duration given3 outcomes, 2 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

48 of the 51 outcome measures give a duration. A single visit counts as within a day.

Status, results, interventions and countries

Status

  • Recruiting6 studies, 4 as a primary outcome
  • Active, not recruiting1 studies, 1 as a primary outcome
  • Completed34 studies, 18 as a primary outcome
  • Stopped early5 studies, 2 as a primary outcome
  • Status unknown5 studies, 1 as a primary outcome

What they test

  • Behavioral13 studies, 7 as a primary outcome
  • Drug11 studies, 4 as a primary outcome
  • Device12 studies, 9 as a primary outcome
  • Dietary supplement3 studies, 1 as a primary outcome
  • Procedure1 studies, 0 as a primary outcome
  • Diagnostic test1 studies, 0 as a primary outcome
  • Other17 studies, 8 as a primary outcome
  • None given1 studies, 0 as a primary outcome

Intervention types as registered. A study can list several; observational studies often list none.

Where their sites are

  • United States16 studies, 9 as a primary outcome
  • United Kingdom6 studies, 2 as a primary outcome
  • China4 studies, 3 as a primary outcome
  • Türkiye4 studies, 2 as a primary outcome
  • France3 studies, 2 as a primary outcome
  • Germany3 studies, 1 as a primary outcome
  • Hong Kong3 studies, 2 as a primary outcome
  • Switzerland3 studies, 0 as a primary outcome
  • Austria1 studies, 0 as a primary outcome
  • Belgium1 studies, 1 as a primary outcome
  • Czechia1 studies, 1 as a primary outcome
  • Netherlands1 studies, 1 as a primary outcome

16 countries in all. A study with sites in several counts in each; 2 list no site.

Reported results

Completed studies with results posted on ClinicalTrials.gov, a results paper the registry links to the study, or both.

Completed healthy volunteers studies that name the N-Back Task: 12 of 34, 35%

Every completed study with a cognitive outcome: 3,626 of 7,953, 46%

Completed healthy volunteers studies that name the N-Back Task and every completed study, by how they reported results
ResultsCompleted healthy volunteers studies that name the N-Back TaskEvery completed study
Results on ClinicalTrials.gov and a paper0, 0%776, 10%
Results on ClinicalTrials.gov only4, 12%1,139, 14%
A results paper only8, 24%1,711, 22%
Neither22, 65%4,327, 54%

The 51 studies

Filter by phase, sponsor, status, country, intervention, outcome list, size and start year. Each study links to its record on ClinicalTrials.gov.
ConditionHealthy volunteers
TestThe N-Back Task

51 studies match. 26 name the N-Back Task in a primary outcome. Median size 44 participants. Median time to the primary outcome: 1 day.

Loading 51 studies; the filters turn on when they arrive.

By start year
024682000: 0 studies, 0 naming the N-Back Task in a primary outcome20002001: 0 studies, 0 naming the N-Back Task in a primary outcome2002: 0 studies, 0 naming the N-Back Task in a primary outcome2003: 0 studies, 0 naming the N-Back Task in a primary outcome2004: 0 studies, 0 naming the N-Back Task in a primary outcome2005: 0 studies, 0 naming the N-Back Task in a primary outcome20052006: 0 studies, 0 naming the N-Back Task in a primary outcome2007: 0 studies, 0 naming the N-Back Task in a primary outcome2008: 1 studies, 0 naming the N-Back Task in a primary outcome2009: 0 studies, 0 naming the N-Back Task in a primary outcome2010: 1 studies, 1 naming the N-Back Task in a primary outcome20102011: 2 studies, 1 naming the N-Back Task in a primary outcome2012: 1 studies, 0 naming the N-Back Task in a primary outcome2013: 2 studies, 0 naming the N-Back Task in a primary outcome2014: 2 studies, 2 naming the N-Back Task in a primary outcome2015: 0 studies, 0 naming the N-Back Task in a primary outcome20152016: 2 studies, 0 naming the N-Back Task in a primary outcome2017: 2 studies, 0 naming the N-Back Task in a primary outcome2018: 2 studies, 1 naming the N-Back Task in a primary outcome2019: 6 studies, 4 naming the N-Back Task in a primary outcome2020: 2 studies, 0 naming the N-Back Task in a primary outcome20202021: 5 studies, 3 naming the N-Back Task in a primary outcome2022: 1 studies, 1 naming the N-Back Task in a primary outcome2023: 5 studies, 3 naming the N-Back Task in a primary outcome2024: 7 studies, 1 naming the N-Back Task in a primary outcome2025: 5 studies, 5 naming the N-Back Task in a primary outcome20252026: 5 studies, 4 naming the N-Back Task in a primary outcome

2026 is partly planned starts.

Show as a table
Matching studies by start year
Start yearStudiesAs a primary outcome
200000
200100
200200
200300
200400
200500
200600
200700
200810
200900
201011
201121
201210
201320
201422
201500
201620
201720
201821
201964
202020
202153
202211
202353
202471
202555
202654

Library tests named most

  • N-Back Task51 studies, 26 as a primary outcome
  • Eriksen Flanker Task7 studies, 3 as a primary outcome
  • Stroop Color-Word Test6 studies, 3 as a primary outcome
  • Verbal Learning6 studies, 2 as a primary outcome
  • Digit Span Test5 studies, 1 as a primary outcome
  • Task Switching Test4 studies, 3 as a primary outcome
  • Go/No-Go Task4 studies, 2 as a primary outcome
  • Attention Network Test4 studies, 1 as a primary outcome
  • Verbal Fluency4 studies, 1 as a primary outcome
  • Picture Naming Test3 studies, 2 as a primary outcome

Conditions

  • Healthy volunteers51 studies, 26 as a primary outcome
  • Aging, frailty and exercise6 studies, 5 as a primary outcome
  • Mild cognitive impairment4 studies, 1 as a primary outcome
  • Sleep and sleep disorders2 studies, 1 as a primary outcome
  • Dementia and Alzheimer's1 study, 0 as a primary outcome
  • Brain injury and concussion1 study, 0 as a primary outcome
  • Schizophrenia and psychosis1 study, 1 as a primary outcome

Phases

Participants

Lead sponsor: industry 5, other 46. Interventional 48, observational 3.

As a primary outcomeSecondary or other outcomeThe N-Back Task

The studies, newest registration first

Each number opens the study's record on ClinicalTrials.gov.

Registered studies that match the filters, newest registration first, with the library tests each one names and the outcome list that names them.
StudyStartPhaseConditionsParticipantsLead sponsorStatusLibrary tests named, with the latest time point
NCT07837661Start2026PhaseNot applicableConditionsHealthy volunteersParticipants22Lead sponsorOtherStatusCompletedLibrary tests named
  • N-Back TaskPrimarysame day
NCT07831499Start2026PhasePhase 4ConditionsHealthy volunteersParticipants40Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskPrimary12 weeks
NCT07759648Start2025PhaseObservationalConditionsHealthy volunteersParticipants47Lead sponsorOtherStatusCompletedLibrary tests named
  • N-Back TaskPrimarysame day
NCT07650006Start2026PhaseNot applicableConditionsHealthy volunteersParticipants30Lead sponsorOtherStatusCompletedLibrary tests named
  • Stroop Color-Word TestSecondary12 weeks
  • Digit Span TestSecondary12 weeks
  • N-Back TaskSecondary12 weeks
NCT07546916Start2026PhaseNot applicableConditionsHealthy volunteersParticipants40Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskPrimary2 days
  • Eriksen Flanker TaskPrimary2 days
NCT07443189Start2021PhaseNot applicableConditionsHealthy volunteers, Aging, frailty and exerciseParticipants233Lead sponsorOtherStatusCompleted

Paper

Library tests named
  • Digit Span TestPrimary6 months
  • N-Back TaskPrimary6 months
  • Continuous Performance TestPrimary6 months
  • Picture Naming TestPrimary6 months
  • Eriksen Flanker TaskPrimary6 months
  • Task Switching TestPrimary6 months
  • AX Continuous Performance TestWording unclear
  • Attention Network TestPrimary6 months
  • Posner CueingPrimary6 months
NCT07211269Start2025PhaseNot applicableConditionsHealthy volunteersParticipants40Lead sponsorOtherStatusRecruitingLibrary tests named
  • Stroop Color-Word TestPrimarysame day
  • N-Back TaskPrimarysame day
  • Go/No-Go TaskPrimarysame day
  • Task Switching TestPrimarysame day
NCT07140536Start2025PhaseNot applicableConditionsHealthy volunteersParticipants16Lead sponsorOtherStatusCompletedLibrary tests named
  • N-Back TaskPrimary
  • Task Switching TestSecondary
NCT07010666Start2025PhaseNot applicableConditionsHealthy volunteersParticipants18Lead sponsorOtherStatusCompletedLibrary tests named
  • Verbal LearningPrimarysame day
  • N-Back TaskPrimarysame day
  • Go/No-Go TaskPrimarysame day
NCT06976879Start2024PhaseObservationalConditionsHealthy volunteersParticipants60Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskSecondary
  • Eriksen Flanker TaskSecondary
  • Sustained Attention to ResponseSecondary
NCT06621550Start2024PhaseNot applicableConditionsHealthy volunteersParticipants70Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Trail Making TestSecondary3 days
  • Stroop Color-Word TestPrimary3 days
  • N-Back TaskSecondary3 days
  • Card Sorting Test (Berg)Secondary3 days
  • Eriksen Flanker TaskSecondary3 days
NCT06491264Start2026PhaseNot applicableConditionsHealthy volunteers, Aging, frailty and exerciseParticipantsNot givenLead sponsorOtherStatusStopped earlyLibrary tests named
  • N-Back TaskPrimary12 months
NCT06402916Start2024PhaseNot applicableConditionsHealthy volunteersParticipants60Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Verbal LearningSecondarysame day
  • N-Back TaskSecondarysame day
  • Attention Network TestSecondarysame day
NCT06374732Start2024PhaseNot applicableConditionsHealthy volunteersParticipants369Lead sponsorOtherStatusCompleted

Paper

Library tests named
  • N-Back TaskSecondary9 weeks
  • Eriksen Flanker TaskSecondary9 weeks
NCT06299280Start2024PhaseNot applicableConditionsHealthy volunteersParticipants108Lead sponsorOtherStatusCompletedLibrary tests named
  • N-Back TaskPrimarysame day
NCT06258941Start2025PhasePhase 1/2ConditionsHealthy volunteersParticipants352Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskPrimary2 weeks
  • Eriksen Flanker TaskPrimary2 weeks
NCT06245538Start2024PhaseNot applicableConditionsHealthy volunteersParticipants24Lead sponsorOtherStatusCompletedLibrary tests named
  • N-Back TaskSecondarysame day
NCT06014281Start2023PhaseNot applicableConditionsHealthy volunteersParticipants300Lead sponsorOtherStatusActive, not recruitingLibrary tests named
  • Stroop Color-Word TestPrimary16 weeks
  • N-Back TaskPrimary16 weeks
NCT05974605Start2022PhaseNot applicableConditionsHealthy volunteers, Aging, frailty and exerciseParticipants16Lead sponsorOtherStatusCompletedLibrary tests named
  • Verbal LearningPrimary10 weeks
  • Symbol CodingPrimary10 weeks
  • N-Back TaskPrimary10 weeks
  • Task Switching TestPrimary10 weeks
  • Short Story RecallPrimary10 weeks
  • Matrix ReasoningPrimary10 weeks
  • Size Order Memory TestPrimary10 weeks
  • Picture Order Memory TestPrimary10 weeks
  • Mnemonic Similarity TaskPrimary10 weeks
NCT05890014Start2023PhaseNot applicableConditionsHealthy volunteersParticipants60Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Verbal LearningSecondary4 days
  • N-Back TaskSecondary4 days
  • Attention Network TestSecondary4 days
NCT05878119Start2023PhasePhase 2ConditionsHealthy volunteersParticipants124Lead sponsorIndustryStatusCompletedLibrary tests named
  • Stroop Color-Word TestSecondary10 weeks
  • N-Back TaskSecondary10 weeks
  • Continuous Performance TestSecondary10 weeks
  • Psychomotor Vigilance TaskSecondary10 weeks
  • AX Continuous Performance TestWording unclear
NCT05797636Start2023PhaseNot applicableConditionsHealthy volunteersParticipants30Lead sponsorOtherStatusCompletedLibrary tests named
  • N-Back TaskPrimary
  • Effort Discounting TaskPrimarysame day
NCT05774223Start2023PhaseNot applicableConditionsHealthy volunteersParticipants31Lead sponsorOtherStatusCompletedLibrary tests named
  • N-Back TaskPrimary13 weeks
NCT05595434Start2024PhaseNot applicableConditionsHealthy volunteersParticipants40Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskSecondarysame day
NCT05230212Start2021PhaseNot applicableConditionsHealthy volunteersParticipants31Lead sponsorOtherStatusCompleted

Paper 1Paper 2

Library tests named
  • N-Back TaskPrimarysame day
  • Choice Reaction TimePrimarysame day
  • Rapid Visual Information ProcessingPrimarysame day
  • Delayed Recall ModulePrimarysame day

Page 1 of 3

Questions, answered from the data

How many healthy volunteer trials use the N-Back Task?

51 registered healthy volunteers studies on ClinicalTrials.gov name it in an outcome measure, 26 of them in a primary outcome: 8% of the condition's 656 studies with a cognitive outcome, against 5% of all of them. It is the 6th most named test in healthy volunteer trials.

Which tests do healthy volunteer trials use with the N-Back Task?

The Eriksen Flanker Task (7 studies), the Stroop Color-Word Test (6 studies) and Verbal Learning (6 studies).

When do healthy volunteer trials measure the N-Back Task?

Half of the primary outcomes that name the N-Back Task are measured within 1 day of the start, and the middle half from the first day to 12 weeks. 24 primary outcomes give a duration.

How many completed healthy volunteer trials that use the N-Back Task have reported results?

12 of the 34 completed studies that name it, 35%, have reported results: 4 posted them on ClinicalTrials.gov, 8 have a results paper linked to the registry record, and 0 did both. The other 22 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.

More on the N-Back Task and healthy volunteers

  • Every cognitive test in healthy volunteer trials: 656 studies
  • The N-Back Task in all clinical trials: 790 studies

The N-Back Task in other conditions

  • Depression and bipolar disorder79
  • Aging, frailty and exercise68
  • Substance use and addiction68
  • Schizophrenia and psychosis66
  • Sleep and sleep disorders51

Other tests in healthy volunteer trials

  • Stroop Color-Word Test98
  • Trail Making Test68
  • Digit Span Test64
  • Symbol Coding56
  • Verbal Learning56

How the studies are counted

For each test family, the census runs ClinicalTrials.gov's own outcome search for the family's names and reads every study first posted by the day the family was counted. These studies were read on 10 November 2026. A study counts once on a page, however many tests it names. Counts for a test cover every version of the task under any of its names, so a page can count studies that used a commercial version.

The census adds two things to each record and changes nothing in it: which outcome list names the test (primary, then secondary, then other), and the condition groups, matched on the study's condition names and MeSH terms. A study can fall in several groups; one whose only condition is cognitive impairment or decline falls in “Cognitive impairment and decline”. Studies that name only instruments outside the library count in every total and share but are not listed.

A second read on 10 November 2026 added each study's overall status, whether results are posted, its intervention types, the countries of its sites and the time frame of the outcome that names each test. A time frame counts by the latest time point it names: “Baseline, 12 and 24 weeks” is 24 weeks, a single visit is within a day, and one that names no duration, such as “end of treatment”, is left out of the timings.

A third read on 10 November 2026 added the papers the registry links to each study: those its sponsor lists as reporting results, and those PubMed links to it through the study's NCT number. A study has a results paper when one of them came out in or after the month of its primary completion and PubMed does not class it as a protocol, review or comment. A paper that never gives the NCT number is not linked, so some studies counted as reporting neither did publish.

Source: ClinicalTrials.gov, a database of the U.S. National Library of Medicine, which does not endorse these pages. Every study line is in the data release 2.1.0, and the explorer's own file is clinical-trials-studies.json.

The census counts 1-Back Task and 2-Back Task as one test family, so this page counts their studies together.

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