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    16,361Registered studies name a cognitive test in an outcome measure11,688 name a test you can run hereExplore the studies
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  1. Home
  2. /Data
  3. /Clinical trials
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  5. /Depression and bipolar disorder
  6. /N-Back Task

Clinical trials data

N-Back Task in depression and bipolar disorder trials: 79 registered studies

Every registered depression and bipolar disorder 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 depression and bipolar disorder studies name it in an outcome measure
79
Name it in a primary outcome, 35%
28 of 79
Of the condition's 1,247 studies name it, against 5% of all registered studies
6%
Other conditions
Median participants per study
68
By phase
Try the 1-Back TaskTry the 2-Back Task

Tests named in the same studies

The library tests that depression and bipolar disorder studies naming the N-Back Task name most often beside it.
  1. 1

    Trail Making Test19 studies, 6 as a primary outcome

  2. 2

    Verbal Fluency13 studies, 5 as a primary outcome

  3. 3

    Symbol Coding12 studies, 5 as a primary outcome

  4. 4

    Go/No-Go Task12 studies, 2 as a primary outcome

  5. 5

    Choice Reaction Time11 studies, 3 as a primary outcome

  6. 6

    Digit Span Test11 studies, 3 as a primary outcome

  7. 7

    Stroop Color-Word Test11 studies, 3 as a primary outcome

  8. 8

    Verbal Learning8 studies, 3 as a primary outcome

  9. 9

    Card Sorting Test (Berg)8 studies, 1 as a primary outcome

  10. 10

    Continuous Performance Test7 studies, 4 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: 1 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: 0 studies, 0 with a test as a primary outcome2009: 0 studies, 0 with a test as a primary outcome2010: 1 studies, 0 with a test as a primary outcome20102011: 0 studies, 0 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: 3 studies, 3 with a test as a primary outcome2015: 2 studies, 2 with a test as a primary outcome20152016: 4 studies, 2 with a test as a primary outcome2017: 5 studies, 3 with a test as a primary outcome2018: 6 studies, 2 with a test as a primary outcome2019: 2 studies, 0 with a test as a primary outcome2020: 7 studies, 3 with a test as a primary outcome20202021: 9 studies, 4 with a test as a primary outcome2022: 5 studies, 2 with a test as a primary outcome2023: 11 studies, 2 with a test as a primary outcome2024: 3 studies, 1 with a test as a primary outcome2025: 7 studies, 3 with a test as a primary outcome20252026: 12 studies, 1 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
200310
200400
200500
200600
200700
200800
200900
201010
201100
201200
201310
201433
201522
201642
201753
201862
201920
202073
202194
202252
2023112
202431
202573
2026121

Phases and study sizes

By phase

  • Phase 13 studies, 0 as a primary outcome
  • Phase 28 studies, 4 as a primary outcome
  • Phase 2/32 studies, 1 as a primary outcome
  • Phase 31 studies, 0 as a primary outcome
  • Phase 43 studies, 0 as a primary outcome
  • Not applicable53 studies, 16 as a primary outcome
  • Observational9 studies, 7 as a primary outcome

Participants per study

102050100
  • Not applicable76 median, 50 to 111
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 depression and bipolar disorder study that names the N-Back Task, by phase
PhaseStudies with a sizeMedianMiddle half
Not applicable527650 to 111

When depression and bipolar disorder trials measure it

Half of the primary outcomes that name the N-Back Task are measured within 4 weeks of the start, and the middle half from 6 days to 9 weeks. 28 primary outcomes give a duration.

Latest time point of each outcome

  • Within a day12 outcomes, 6 as a primary outcome
  • Up to 4 weeks27 outcomes, 9 as a primary outcome
  • 1 to 3 months22 outcomes, 9 as a primary outcome
  • 3 to 6 months9 outcomes, 2 as a primary outcome
  • 6 to 12 months2 outcomes, 1 as a primary outcome
  • Over 2 years1 outcomes, 1 as a primary outcome
  • No duration given6 outcomes, 0 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

73 of the 79 outcome measures give a duration. A single visit counts as within a day.

Status, results, interventions and countries

Status

  • Recruiting21 studies, 6 as a primary outcome
  • Not yet recruiting4 studies, 0 as a primary outcome
  • Active, not recruiting2 studies, 2 as a primary outcome
  • Completed36 studies, 17 as a primary outcome
  • Stopped early4 studies, 1 as a primary outcome
  • Status unknown12 studies, 2 as a primary outcome

What they test

  • Behavioral17 studies, 7 as a primary outcome
  • Drug18 studies, 4 as a primary outcome
  • Device24 studies, 8 as a primary outcome
  • Dietary supplement5 studies, 1 as a primary outcome
  • Procedure3 studies, 0 as a primary outcome
  • Biological2 studies, 1 as a primary outcome
  • Combination product2 studies, 0 as a primary outcome
  • Other14 studies, 6 as a primary outcome
  • None given5 studies, 4 as a primary outcome

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

Where their sites are

  • United States22 studies, 12 as a primary outcome
  • Canada10 studies, 6 as a primary outcome
  • China10 studies, 1 as a primary outcome
  • United Kingdom10 studies, 2 as a primary outcome
  • Germany5 studies, 3 as a primary outcome
  • Hong Kong4 studies, 1 as a primary outcome
  • Netherlands3 studies, 0 as a primary outcome
  • Denmark2 studies, 0 as a primary outcome
  • Norway2 studies, 0 as a primary outcome
  • Switzerland2 studies, 2 as a primary outcome
  • Taiwan2 studies, 0 as a primary outcome
  • Belgium1 studies, 0 as a primary outcome

17 countries in all. A study with sites in several counts in each; 1 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 depression and bipolar disorder studies that name the N-Back Task: 19 of 36, 53%

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

Completed depression and bipolar disorder studies that name the N-Back Task and every completed study, by how they reported results
ResultsCompleted depression and bipolar disorder studies that name the N-Back TaskEvery completed study
Results on ClinicalTrials.gov and a paper4, 11%776, 10%
Results on ClinicalTrials.gov only4, 11%1,139, 14%
A results paper only11, 31%1,711, 22%
Neither17, 47%4,327, 54%

The 79 studies

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

79 studies match. 28 name the N-Back Task in a primary outcome. Median size 68 participants. Median time to the primary outcome: 4 weeks.

Loading 79 studies; the filters turn on when they arrive.

By start year
0510152000: 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: 1 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: 0 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, 0 naming the N-Back Task in a primary outcome20102011: 0 studies, 0 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: 3 studies, 3 naming the N-Back Task in a primary outcome2015: 2 studies, 2 naming the N-Back Task in a primary outcome20152016: 4 studies, 2 naming the N-Back Task in a primary outcome2017: 5 studies, 3 naming the N-Back Task in a primary outcome2018: 6 studies, 2 naming the N-Back Task in a primary outcome2019: 2 studies, 0 naming the N-Back Task in a primary outcome2020: 7 studies, 3 naming the N-Back Task in a primary outcome20202021: 9 studies, 4 naming the N-Back Task in a primary outcome2022: 5 studies, 2 naming the N-Back Task in a primary outcome2023: 11 studies, 2 naming the N-Back Task in a primary outcome2024: 3 studies, 1 naming the N-Back Task in a primary outcome2025: 7 studies, 3 naming the N-Back Task in a primary outcome20252026: 12 studies, 1 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
200310
200400
200500
200600
200700
200800
200900
201010
201100
201200
201310
201433
201522
201642
201753
201862
201920
202073
202194
202252
2023112
202431
202573
2026121

Library tests named most

  • N-Back Task79 studies, 28 as a primary outcome
  • Trail Making Test19 studies, 6 as a primary outcome
  • Verbal Fluency13 studies, 5 as a primary outcome
  • Symbol Coding12 studies, 5 as a primary outcome
  • Go/No-Go Task12 studies, 2 as a primary outcome
  • Choice Reaction Time11 studies, 3 as a primary outcome
  • Digit Span Test11 studies, 3 as a primary outcome
  • Stroop Color-Word Test11 studies, 3 as a primary outcome
  • Verbal Learning8 studies, 3 as a primary outcome
  • Card Sorting Test (Berg)8 studies, 1 as a primary outcome

Conditions

  • Depression and bipolar disorder79 studies, 28 as a primary outcome
  • Anxiety, PTSD and OCD12 studies, 6 as a primary outcome
  • Sleep and sleep disorders5 studies, 3 as a primary outcome
  • Schizophrenia and psychosis3 studies, 2 as a primary outcome
  • Aging, frailty and exercise3 studies, 1 as a primary outcome
  • Substance use and addiction3 studies, 3 as a primary outcome
  • ADHD2 studies, 1 as a primary outcome
  • Dementia and Alzheimer's1 study, 1 as a primary outcome
  • Mild cognitive impairment1 study, 1 as a primary outcome
  • Brain injury and concussion1 study, 1 as a primary outcome

Phases

Participants

Lead sponsor: industry 7, other 72. Interventional 70, observational 9.

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
NCT07873060Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants80Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskSecondary2 weeks
  • Card Sorting Test (Berg)Secondary2 weeks
  • Balloon RiskSecondary2 weeks
  • Spatial N-Back TaskSecondary2 weeks
NCT07848477Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants60Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningPrimary2 weeks
  • Digit Span TestSecondary2 weeks
  • Symbol CodingSecondary2 weeks
  • N-Back TaskSecondary2 weeks
  • Go/No-Go TaskSecondary2 weeks
  • Paired Associate LearningSecondary2 weeks
  • Probabilistic Reversal LearningSecondary2 weeks
  • Mnemonic Similarity TaskSecondary2 weeks
  • Affective Go/No-GoSecondary2 weeks
  • Grid Pattern Span TaskSecondary2 weeks
NCT07667530Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants76Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • N-Back TaskSecondary16 weeks
  • Task Switching TestSecondary16 weeks
NCT07641244Start2026PhaseNot applicableConditionsDepression and bipolar disorder, Anxiety, PTSD and OCDParticipants500Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskPrimary5 years
  • Monetary Incentive DelayPrimary5 years
NCT07619092Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants145Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondary1 week
  • Verbal FluencyPrimary1 week
  • N-Back TaskSecondary1 week
  • Spatial N-Back TaskSecondary1 week
NCT07590999Start2025PhaseNot applicableConditionsDepression and bipolar disorderParticipants106Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningSecondary9 weeks
  • Digit Span TestSecondary9 weeks
  • N-Back TaskSecondary9 weeks
  • Go/No-Go TaskSecondary9 weeks
  • Probabilistic Reversal LearningSecondary9 weeks
  • Affective Go/No-GoSecondary9 weeks
NCT07528157Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants80Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • N-Back TaskSecondary7 weeks
  • Multi-Source Interference TaskSecondary7 weeks
NCT07510646Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants40Lead sponsorIndustryStatusNot yet recruitingLibrary tests named
  • N-Back TaskSecondary6 weeks
NCT07477470Start2026PhaseNot applicableConditionsDepression and bipolar disorder, Anxiety, PTSD and OCDParticipants120Lead sponsorIndustryStatusRecruitingLibrary tests named
  • N-Back TaskSecondary12 weeks
  • Go/No-Go TaskSecondary12 weeks
  • Task Switching TestSecondary12 weeks
  • Attention Network TestSecondary12 weeks
  • Affective Go/No-GoSecondary12 weeks
NCT07437833Start2026PhaseNot applicableConditionsDepression and bipolar disorder, ADHDParticipants1Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskSecondary
NCT07402356Start2025PhaseObservationalConditionsDementia and Alzheimer's, Mild cognitive impairment, Depression and bipolar disorderParticipants140Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondary6 months
  • Verbal LearningSecondary6 months
  • Verbal FluencySecondary6 months
  • N-Back TaskPrimarysame day
  • Category FluencySecondary6 months
  • Picture Naming TestSecondary6 months
NCT07319143Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants90Lead sponsorOtherStatusRecruitingLibrary tests named
  • Stroop Color-Word TestSecondary15 weeks
  • N-Back TaskSecondary15 weeks
  • Monetary Incentive DelaySecondary15 weeks
NCT07201909Start2025PhaseNot applicableConditionsDepression and bipolar disorder, Anxiety, PTSD and OCDParticipants156Lead sponsorIndustryStatusRecruitingLibrary tests named
  • N-Back TaskSecondary12 weeks
  • Go/No-Go TaskSecondary12 weeks
  • Task Switching TestSecondary12 weeks
  • Attention Network TestSecondary12 weeks
  • Emotional Stroop TaskSecondary12 weeks
  • Affective Go/No-GoSecondary12 weeks
NCT07022171Start2025PhaseNot applicableConditionsDepression and bipolar disorderParticipants86Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondary6 weeks
  • N-Back TaskSecondary6 weeks
  • Tower PlanningSecondary6 weeks
NCT06972368Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants60Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskSecondary1 week
  • Go/No-Go TaskSecondary1 week
NCT06824415Start2025PhaseNot applicableConditionsDepression and bipolar disorder, Sleep and sleep disordersParticipants55Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskPrimarysame day
  • Multi-Source Interference TaskPrimarysame day
NCT06813313Start2025PhaseNot applicableConditionsDepression and bipolar disorderParticipants108Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Trail Making TestSecondary5 days
  • Stroop Color-Word TestSecondary5 days
  • Verbal FluencySecondary5 days
  • Digit Span TestSecondary5 days
  • N-Back TaskSecondary5 days
  • Go/No-Go TaskSecondary5 days
  • Card Sorting Test (Berg)Secondary5 days
NCT06751784Start2025PhasePhase 2ConditionsDepression and bipolar disorderParticipants38Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal FluencySecondary1 week
  • Digit Span TestSecondary1 week
  • N-Back TaskPrimary1 week
  • Tower PlanningSecondary1 week
  • Intra/Extra Dimensional Set ShiftSecondary1 week
NCT06534684Start2024PhaseNot applicableConditionsDepression and bipolar disorderParticipants50Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskSecondary2 weeks
NCT06372834Start2023PhaseNot applicableConditionsDepression and bipolar disorderParticipants100Lead sponsorOtherStatusCompletedLibrary tests named
  • Trail Making TestSecondary2 weeks
  • Stroop Color-Word TestSecondary2 weeks
  • Verbal FluencySecondary2 weeks
  • Symbol CodingSecondary2 weeks
  • N-Back TaskSecondary2 weeks
  • Card Sorting Test (Berg)Secondary2 weeks
NCT06346353Start2024PhaseObservationalConditionsDepression and bipolar disorder, Substance use and addiction, Anxiety, PTSD and OCDParticipants756Lead sponsorOtherStatusCompletedLibrary tests named
  • N-Back TaskPrimarysame day
  • Stop-Signal TaskPrimarysame day
NCT06299787Start2022PhaseNot applicableConditionsDepression and bipolar disorder, Substance use and addictionParticipants40Lead sponsorOtherStatusStatus unknownLibrary tests named
  • N-Back TaskPrimary4 weeks
  • Eriksen Flanker TaskPrimary4 weeks
NCT06266715Start2024PhaseNot applicableConditionsDepression and bipolar disorderParticipants120Lead sponsorOtherStatusRecruitingLibrary tests named
  • N-Back TaskSecondary5 months
  • Psychomotor Vigilance TaskSecondary5 months
  • Attention Network TestSecondary5 months
  • Monetary Incentive DelaySecondary4 weeks
NCT06121206Start2023PhaseNot applicableConditionsDepression and bipolar disorderParticipants190Lead sponsorOtherStatusCompleted

Paper

Library tests named
  • Trail Making TestPrimary8 weeks
  • Verbal LearningPrimary8 weeks
  • Verbal FluencyPrimary8 weeks
  • Digit Span TestOther outcome8 weeks
  • N-Back TaskSecondary8 weeks
  • Card Sorting Test (Berg)Other outcome8 weeks
  • Tower PlanningSecondary8 weeks
  • Rapid Visual Information ProcessingPrimary8 weeks
  • Emoji Emotion RecognitionOther outcome8 weeks
  • Letter-Number Sequencing TaskPrimary8 weeks
  • One-Touch Tower PlanningSecondary8 weeks
  • Spatial N-Back TaskSecondary8 weeks

Page 1 of 4

Questions, answered from the data

How many depression and bipolar disorder trials use the N-Back Task?

79 registered depression and bipolar disorder studies on ClinicalTrials.gov name it in an outcome measure, 28 of them in a primary outcome: 6% of the condition's 1,247 studies with a cognitive outcome, against 5% of all of them. It is the 8th most named test in depression and bipolar disorder trials.

Which tests do depression and bipolar disorder trials use with the N-Back Task?

The Trail Making Test (19 studies), Verbal Fluency (13 studies) and Symbol Coding (12 studies).

When do depression and bipolar disorder trials measure the N-Back Task?

Half of the primary outcomes that name the N-Back Task are measured within 4 weeks of the start, and the middle half from 6 days to 9 weeks. 28 primary outcomes give a duration.

How many completed depression and bipolar disorder trials that use the N-Back Task have reported results?

19 of the 36 completed studies that name it, 53%, have reported results: 8 posted them on ClinicalTrials.gov, 15 have a results paper linked to the registry record, and 4 did both. The other 17 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.

More on the N-Back Task and depression and bipolar disorder

  • Every cognitive test in depression and bipolar disorder trials: 1,247 studies
  • The N-Back Task in all clinical trials: 790 studies

The N-Back Task in other conditions

  • Aging, frailty and exercise68
  • Substance use and addiction68
  • Schizophrenia and psychosis66
  • Healthy volunteers51
  • Sleep and sleep disorders51

Other tests in depression and bipolar disorder trials

  • Trail Making Test204
  • Verbal Learning178
  • Verbal Fluency154
  • Digit Span Test143
  • Symbol Coding143
  • Stroop Color-Word Test138
  • Go/No-Go Task79
  • Continuous Performance Test73
  • Card Sorting Test (Berg)65

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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