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  5. /Sleep and sleep disorders
  6. /N-Back Task

Clinical trials data

N-Back Task in sleep trials: 51 registered studies

Every registered sleep and sleep disorders 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 sleep and sleep disorders studies name it in an outcome measure
51
Name it in a primary outcome, 39%
20 of 51
Of the condition's 749 studies name it, against 5% of all registered studies
7%
Other conditions
Median participants per study
56
By phase
Try the 1-Back TaskTry the 2-Back Task

Tests named in the same studies

The library tests that sleep and sleep disorders studies naming the N-Back Task name most often beside it.
  1. 1

    Psychomotor Vigilance Task27 studies, 17 as a primary outcome

  2. 2

    Symbol Coding14 studies, 10 as a primary outcome

  3. 3

    Balloon Risk14 studies, 5 as a primary outcome

  4. 4

    Go/No-Go Task12 studies, 1 as a primary outcome

  5. 5

    Digit Span Test10 studies, 2 as a primary outcome

  6. 6

    Trail Making Test7 studies, 1 as a primary outcome

  7. 7

    Card Sorting Test (Berg)7 studies, 0 as a primary outcome

  8. 8

    Task Switching Test6 studies, 2 as a primary outcome

  9. 9

    Delay Discounting4 studies, 3 as a primary outcome

  10. 10

    Verbal Learning4 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: 1 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: 2 studies, 0 with a test as a primary outcome2009: 0 studies, 0 with a test as a primary outcome2010: 0 studies, 0 with a test as a primary outcome20102011: 1 studies, 1 with a test as a primary outcome2012: 0 studies, 0 with a test as a primary outcome2013: 1 studies, 0 with a test as a primary outcome2014: 1 studies, 0 with a test as a primary outcome2015: 2 studies, 1 with a test as a primary outcome20152016: 2 studies, 2 with a test as a primary outcome2017: 4 studies, 1 with a test as a primary outcome2018: 6 studies, 3 with a test as a primary outcome2019: 4 studies, 2 with a test as a primary outcome2020: 1 studies, 0 with a test as a primary outcome20202021: 5 studies, 3 with a test as a primary outcome2022: 6 studies, 2 with a test as a primary outcome2023: 6 studies, 2 with a test as a primary outcome2024: 3 studies, 1 with a test as a primary outcome2025: 4 studies, 2 with a test as a primary outcome20252026: 2 studies, 0 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
200510
200600
200700
200820
200900
201000
201111
201200
201310
201410
201521
201622
201741
201863
201942
202010
202153
202262
202362
202431
202542
202620

Phases and study sizes

By phase

  • Phase 13 studies, 1 as a primary outcome
  • Phase 22 studies, 1 as a primary outcome
  • Phase 31 studies, 0 as a primary outcome
  • Phase 42 studies, 1 as a primary outcome
  • Not applicable41 studies, 17 as a primary outcome
  • Observational2 studies, 0 as a primary outcome

Participants per study

102050100
  • Not applicable58 median, 35 to 105
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 sleep and sleep disorders study that names the N-Back Task, by phase
PhaseStudies with a sizeMedianMiddle half
Not applicable405835 to 105

When sleep trials measure it

Half of the primary outcomes that name the N-Back Task are measured within 2 weeks of the start, and the middle half from 2 days to 2 weeks. 16 primary outcomes give a duration.

Latest time point of each outcome

  • Within a day6 outcomes, 2 as a primary outcome
  • Up to 4 weeks21 outcomes, 12 as a primary outcome
  • 1 to 3 months8 outcomes, 2 as a primary outcome
  • 3 to 6 months9 outcomes, 0 as a primary outcome
  • 6 to 12 months1 outcomes, 0 as a primary outcome
  • No duration given6 outcomes, 4 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

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

Status, results, interventions and countries

Status

  • Recruiting9 studies, 3 as a primary outcome
  • Completed32 studies, 15 as a primary outcome
  • Stopped early2 studies, 1 as a primary outcome
  • Status unknown8 studies, 1 as a primary outcome

What they test

  • Behavioral21 studies, 6 as a primary outcome
  • Drug12 studies, 3 as a primary outcome
  • Device7 studies, 4 as a primary outcome
  • Dietary supplement3 studies, 1 as a primary outcome
  • Radiation3 studies, 2 as a primary outcome
  • Other9 studies, 4 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 States12 studies, 5 as a primary outcome
  • Hong Kong9 studies, 1 as a primary outcome
  • Singapore6 studies, 5 as a primary outcome
  • Switzerland6 studies, 1 as a primary outcome
  • China4 studies, 0 as a primary outcome
  • France4 studies, 3 as a primary outcome
  • Sweden3 studies, 2 as a primary outcome
  • Canada1 studies, 0 as a primary outcome
  • Germany1 studies, 1 as a primary outcome
  • Taiwan1 studies, 0 as a primary outcome
  • United Kingdom1 studies, 0 as a primary outcome

11 countries in all. A study with sites in several counts in each; 3 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 sleep and sleep disorders studies that name the N-Back Task: 17 of 32, 53%

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

Completed sleep and sleep disorders studies that name the N-Back Task and every completed study, by how they reported results
ResultsCompleted sleep and sleep disorders studies that name the N-Back TaskEvery completed study
Results on ClinicalTrials.gov and a paper1, 3%776, 10%
Results on ClinicalTrials.gov only2, 6%1,139, 14%
A results paper only14, 44%1,711, 22%
Neither15, 47%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.
ConditionSleep and sleep disorders
TestThe N-Back Task

51 studies match. 20 name the N-Back Task in a primary outcome. Median size 56 participants. Median time to the primary outcome: 2 weeks.

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

By start year
02462000: 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: 1 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: 2 studies, 0 naming the N-Back Task in a primary outcome2009: 0 studies, 0 naming the N-Back Task in a primary outcome2010: 0 studies, 0 naming the N-Back Task in a primary outcome20102011: 1 studies, 1 naming the N-Back Task in a primary outcome2012: 0 studies, 0 naming the N-Back Task in a primary outcome2013: 1 studies, 0 naming the N-Back Task in a primary outcome2014: 1 studies, 0 naming the N-Back Task in a primary outcome2015: 2 studies, 1 naming the N-Back Task in a primary outcome20152016: 2 studies, 2 naming the N-Back Task in a primary outcome2017: 4 studies, 1 naming the N-Back Task in a primary outcome2018: 6 studies, 3 naming the N-Back Task in a primary outcome2019: 4 studies, 2 naming the N-Back Task in a primary outcome2020: 1 studies, 0 naming the N-Back Task in a primary outcome20202021: 5 studies, 3 naming the N-Back Task in a primary outcome2022: 6 studies, 2 naming the N-Back Task in a primary outcome2023: 6 studies, 2 naming the N-Back Task in a primary outcome2024: 3 studies, 1 naming the N-Back Task in a primary outcome2025: 4 studies, 2 naming the N-Back Task in a primary outcome20252026: 2 studies, 0 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
200510
200600
200700
200820
200900
201000
201111
201200
201310
201410
201521
201622
201741
201863
201942
202010
202153
202262
202362
202431
202542
202620

Library tests named most

  • N-Back Task51 studies, 20 as a primary outcome
  • Psychomotor Vigilance Task27 studies, 17 as a primary outcome
  • Symbol Coding14 studies, 10 as a primary outcome
  • Balloon Risk14 studies, 5 as a primary outcome
  • Go/No-Go Task12 studies, 1 as a primary outcome
  • Digit Span Test10 studies, 2 as a primary outcome
  • Trail Making Test7 studies, 1 as a primary outcome
  • Card Sorting Test (Berg)7 studies, 0 as a primary outcome
  • Task Switching Test6 studies, 2 as a primary outcome
  • Delay Discounting4 studies, 3 as a primary outcome

Largest condition groups

  • Sleep and sleep disorders51 studies, 20 as a primary outcome
  • Depression and bipolar disorder5 studies, 3 as a primary outcome
  • Substance use and addiction3 studies, 0 as a primary outcome
  • Anxiety, PTSD and OCD3 studies, 1 as a primary outcome
  • Cardiovascular disease3 studies, 0 as a primary outcome
  • Mild cognitive impairment2 studies, 1 as a primary outcome
  • Healthy volunteers2 studies, 1 as a primary outcome
  • Dementia and Alzheimer's1 study, 0 as a primary outcome
  • Parkinson's disease1 study, 0 as a primary outcome
  • ADHD1 study, 0 as a primary outcome
  • Aging, frailty and exercise1 study, 0 as a primary outcome
  • Obesity and diabetes1 study, 0 as a primary outcome

Phases

Participants

Lead sponsor: industry 5, other 46. Interventional 49, observational 2.

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
NCT07903896Start2026PhaseNot applicableConditionsDepression and bipolar disorder, Sleep and sleep disorders, Anxiety, PTSD and OCDParticipants75Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskSecondary
  • Eriksen Flanker TaskSecondary
NCT07830056Start2025PhasePhase 4ConditionsSleep and sleep disordersParticipants33Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskPrimary1 week
  • Go/No-Go TaskPrimary1 week
  • Psychomotor Vigilance TaskPrimary1 week
  • Task Switching TestPrimary1 week
  • Finger Tapping TaskPrimary1 week
  • Balloon RiskSecondary1 week
NCT07695246Start2026PhaseNot applicableConditionsAging, frailty and exercise, Sleep and sleep disordersParticipants183Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskSecondary6 months
  • Card Sorting Test (Berg)Secondary6 months
  • Psychomotor Vigilance TaskSecondary6 months
  • Stop-Signal TaskSecondary6 months
NCT07085754Start2025PhaseNot applicableConditionsSleep and sleep disordersParticipants60Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskSecondarysame day
NCT07084701Start2025PhaseNot applicableConditionsSleep and sleep disordersParticipants30Lead sponsorOtherStatusRecruitingLibrary tests named
  • Digit Span TestPrimary2 weeks
  • N-Back TaskSecondary2 weeks
  • Psychomotor Vigilance TaskSecondary2 weeks
NCT06824415Start2025PhaseNot applicableConditionsDepression and bipolar disorder, Sleep and sleep disordersParticipants55Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskPrimarysame day
  • Multi-Source Interference TaskPrimarysame day
NCT06307483Start2023PhaseObservationalConditionsSleep and sleep disorders, Cardiovascular diseaseParticipants499Lead sponsorOtherStatusCompletedLibrary tests named
  • Trail Making TestSecondary13 weeks
  • Stroop Color-Word TestSecondary13 weeks
  • N-Back TaskSecondary13 weeks
  • Memory Updating TaskSecondary13 weeks
NCT06286774Start2024PhaseNot applicableConditionsSubstance use and addiction, Sleep and sleep disordersParticipants256Lead sponsorOtherStatusRecruitingLibrary tests named
  • Stroop Color-Word TestSecondary13 weeks
  • N-Back TaskSecondary13 weeks
  • Delay DiscountingSecondary6 months
NCT06260254Start2024PhaseNot applicableConditionsObesity and diabetes, Sleep and sleep disordersParticipants23Lead sponsorOtherStatusCompletedLibrary tests named
  • Symbol CodingSecondary
  • N-Back TaskSecondary
  • Psychomotor Vigilance TaskSecondary
  • Matrix ReasoningSecondary
  • Balloon RiskSecondary
NCT06054243Start2023PhaseNot applicableConditionsSleep and sleep disorders, Anxiety, PTSD and OCDParticipants137Lead sponsorOtherStatusCompletedLibrary tests named
  • Digit Span TestSecondary6 months
  • N-Back TaskSecondary6 months
  • Go/No-Go TaskSecondary6 months
  • Balloon RiskSecondary6 months
NCT05956392Start2023PhaseNot applicableConditionsSleep and sleep disordersParticipants150Lead sponsorOtherStatusRecruitingLibrary tests named
  • Symbol CodingPrimary
  • N-Back TaskPrimary
  • Psychomotor Vigilance TaskPrimary4 weeks
  • Symbol Scan TaskPrimary4 weeks
NCT05790161Start2023PhaseNot applicableConditionsSleep and sleep disordersParticipants54Lead sponsorOtherStatusStatus unknownLibrary tests named
  • N-Back TaskSecondary2 weeks
  • Go/No-Go TaskSecondary2 weeks
NCT05764798Start2022PhasePhase 1ConditionsSleep and sleep disordersParticipants60Lead sponsorOtherStatusStatus unknown

Paper 1Paper 2

Library tests named
  • Stroop Color-Word TestSecondary8 weeks
  • N-Back TaskSecondary8 weeks
  • Go/No-Go TaskSecondary8 weeks
  • Psychomotor Vigilance TaskSecondary8 weeks
  • Go/No-Go Association TaskSecondary8 weeks
NCT05611619Start2023PhaseNot applicableConditionsSleep and sleep disordersParticipants45Lead sponsorOtherStatusCompletedLibrary tests named
  • Symbol CodingPrimary
  • N-Back TaskPrimary
  • Psychomotor Vigilance TaskPrimary
  • Matrix ReasoningPrimary
  • Balloon RiskPrimary
NCT05485415Start2022PhaseNot applicableConditionsSleep and sleep disordersParticipants66Lead sponsorOtherStatusCompletedLibrary tests named
  • N-Back TaskSecondary6 months
  • Psychomotor Vigilance TaskSecondary6 months
NCT05481424Start2022PhaseNot applicableConditionsSleep and sleep disordersParticipants20Lead sponsorOtherStatusCompletedLibrary tests named
  • Symbol CodingSecondary5 weeks
  • N-Back TaskPrimary5 weeks
  • Psychomotor Vigilance TaskPrimary5 weeks
  • Balloon RiskPrimary5 weeks
  • Line Angle MatchingSecondary5 weeks
NCT05409339Start2016PhaseNot applicableConditionsSleep and sleep disordersParticipants20Lead sponsorOtherStatusCompleted

Paper 1Paper 2Paper 3Paper 4Paper 5

Library tests named
  • N-Back TaskPrimary1 week
  • Psychomotor Vigilance TaskPrimary1 week
NCT05372900Start2022PhaseNot applicableConditionsSleep and sleep disordersParticipants43Lead sponsorIndustryStatusCompleted

Paper

Library tests named
  • N-Back TaskSecondary11 weeks
  • Go/No-Go TaskSecondary11 weeks
  • Psychomotor Vigilance TaskSecondary11 weeks
  • Delayed Recall ModuleSecondary11 weeks
NCT05319262Start2022PhaseNot applicableConditionsSleep and sleep disordersParticipants12Lead sponsorOtherStatusCompleted

Paper

Library tests named
  • Symbol CodingPrimary
  • N-Back TaskPrimary
  • Psychomotor Vigilance TaskPrimary
  • Matrix ReasoningPrimary
  • Balloon RiskPrimary
NCT05270369Start2022PhaseNot applicableConditionsSleep and sleep disordersParticipants159Lead sponsorOtherStatusCompletedLibrary tests named
  • Trail Making TestSecondary12 months
  • Verbal FluencySecondary1 week
  • Digit Span TestSecondary12 months
  • N-Back TaskSecondary12 months
  • Go/No-Go TaskSecondary12 months
  • Category FluencySecondary1 week
  • Card Sorting Test (Berg)Secondary12 months
  • Task Switching TestSecondary12 months
  • Dot-Probe TaskSecondary12 months
  • Implicit Association Test (IAT)Secondary12 months
  • Balloon RiskSecondary12 months
  • Emotion Regulation TaskSecondary1 week
NCT05260801Start2024PhaseNot applicableConditionsSleep and sleep disordersParticipantsNot givenLead sponsorOtherStatusStopped earlyLibrary tests named
  • Symbol CodingSecondary5 weeks
  • N-Back TaskPrimary5 weeks
  • Psychomotor Vigilance TaskPrimary5 weeks
  • Balloon RiskPrimary5 weeks
  • Line Angle MatchingSecondary5 weeks
NCT05232383Start2021PhaseNot applicableConditionsSleep and sleep disordersParticipants96Lead sponsorOtherStatusCompletedLibrary tests named
  • N-Back TaskPrimary2 days
  • Psychomotor Vigilance TaskPrimary2 days
  • Paced Visual Serial Addition TestPrimary2 days
NCT05050812Start2021PhaseNot applicableConditionsMild cognitive impairment, Sleep and sleep disorders, Pain and fatigueParticipants8Lead sponsorOtherStatusStatus unknownLibrary tests named
  • N-Back TaskPrimarysame day
  • Choice Reaction TimePrimarysame day
  • Simple Reaction TimePrimarysame day
NCT04975360Start2019PhaseNot applicableConditionsSleep and sleep disordersParticipants32Lead sponsorOtherStatusCompleted

Paper

Library tests named
  • N-Back TaskSecondary1 day
  • Psychomotor Vigilance TaskSecondary1 day
NCT04736017Start2021PhaseNot applicableConditionsMild cognitive impairment, Parkinson's disease, Sleep and sleep disordersParticipants48Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Trail Making TestSecondary2 weeks
  • Stroop Color-Word TestSecondary2 weeks
  • Verbal LearningPrimary2 weeks
  • Verbal FluencySecondary2 weeks
  • N-Back TaskSecondary2 weeks
  • Go/No-Go TaskSecondary2 weeks
  • Psychomotor Vigilance TaskSecondary2 weeks
  • Sustained Attention to ResponseSecondary2 weeks

Page 1 of 3

Questions, answered from the data

How many sleep trials use the N-Back Task?

51 registered sleep and sleep disorders studies on ClinicalTrials.gov name it in an outcome measure, 20 of them in a primary outcome: 7% of the condition's 749 studies with a cognitive outcome, against 5% of all of them. It is the 8th most named test in sleep trials.

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

The Psychomotor Vigilance Task (27 studies), Symbol Coding (14 studies) and Balloon Risk (14 studies).

When do sleep trials measure the N-Back Task?

Half of the primary outcomes that name the N-Back Task are measured within 2 weeks of the start, and the middle half from 2 days to 2 weeks. 16 primary outcomes give a duration.

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

17 of the 32 completed studies that name it, 53%, have reported results: 3 posted them on ClinicalTrials.gov, 15 have a results paper linked to the registry record, and 1 did both. The other 15 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.

More on the N-Back Task and sleep and sleep disorders

  • Every cognitive test in sleep trials: 749 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
  • Healthy volunteers51

Other tests in sleep trials

  • Psychomotor Vigilance Task237
  • Stroop Color-Word Test89
  • Symbol Coding89
  • Trail Making Test85
  • Verbal Learning66
  • Digit Span Test63
  • Verbal Fluency58

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.

Run the N-Back Task in your trial

Choose tests with a record in registered trials, and run them in a browser at every site, on the same version each visit.

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