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  1. Home
  2. /Data
  3. /Clinical trials
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  5. /Depression and bipolar disorder
  6. /Symbol Coding

Clinical trials data

Symbol Coding in depression and bipolar disorder trials: 143 registered studies

Every registered depression and bipolar disorder study on ClinicalTrials.gov that names Symbol Coding 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
143
Name it in a primary outcome, 26%
37 of 143
Of the condition's 1,247 studies name it, against 9% of all registered studies
11%
Other conditions
Median participants per study
90
By phase
Try the Symbol Key GameTry Symbol Coding

Tests named in the same studies

The library tests that depression and bipolar disorder studies naming Symbol Coding name most often beside it.
  1. 1

    Trail Making Test67 studies, 19 as a primary outcome

  2. 2

    Verbal Learning44 studies, 13 as a primary outcome

  3. 3

    Digit Span Test39 studies, 14 as a primary outcome

  4. 4

    Stroop Color-Word Test24 studies, 8 as a primary outcome

  5. 5

    Verbal Fluency24 studies, 7 as a primary outcome

  6. 6

    Choice Reaction Time21 studies, 5 as a primary outcome

  7. 7

    Continuous Performance Test16 studies, 4 as a primary outcome

  8. 8

    Category Fluency12 studies, 6 as a primary outcome

  9. 9

    N-Back Task12 studies, 5 as a primary outcome

  10. 10

    Card Sorting Test (Berg)9 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: 0 studies, 0 with a test as a primary outcome2004: 0 studies, 0 with a test as a primary outcome2005: 1 studies, 1 with a test as a primary outcome20052006: 1 studies, 0 with a test as a primary outcome2007: 2 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: 2 studies, 1 with a test as a primary outcome20102011: 2 studies, 0 with a test as a primary outcome2012: 2 studies, 2 with a test as a primary outcome2013: 1 studies, 0 with a test as a primary outcome2014: 4 studies, 3 with a test as a primary outcome2015: 8 studies, 4 with a test as a primary outcome20152016: 6 studies, 1 with a test as a primary outcome2017: 7 studies, 2 with a test as a primary outcome2018: 8 studies, 3 with a test as a primary outcome2019: 8 studies, 1 with a test as a primary outcome2020: 10 studies, 3 with a test as a primary outcome20202021: 11 studies, 4 with a test as a primary outcome2022: 7 studies, 1 with a test as a primary outcome2023: 20 studies, 2 with a test as a primary outcome2024: 14 studies, 2 with a test as a primary outcome2025: 17 studies, 4 with a test as a primary outcome20252026: 12 studies, 3 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
200511
200610
200720
200800
200900
201021
201120
201222
201310
201443
201584
201661
201772
201883
201981
2020103
2021114
202271
2023202
2024142
2025174
2026123

Phases and study sizes

By phase

  • Early phase 11 studies, 0 as a primary outcome
  • Phase 14 studies, 0 as a primary outcome
  • Phase 1/22 studies, 0 as a primary outcome
  • Phase 227 studies, 6 as a primary outcome
  • Phase 2/31 studies, 1 as a primary outcome
  • Phase 318 studies, 4 as a primary outcome
  • Phase 412 studies, 2 as a primary outcome
  • Not applicable57 studies, 12 as a primary outcome
  • Observational21 studies, 12 as a primary outcome

Participants per study

102050100200500
  • Phase 290 median, 65 to 129
  • Phase 3151 median, 58 to 411
  • Phase 451 median, 41 to 168
  • Not applicable84 median, 50 to 146
  • Observational120 median, 75 to 200
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 Symbol Coding, by phase
PhaseStudies with a sizeMedianMiddle half
Phase 2279065 to 129
Phase 31715158 to 411
Phase 4125141 to 168
Not applicable578450 to 146
Observational2112075 to 200

When depression and bipolar disorder trials measure it

Half of the primary outcomes that name Symbol Coding are measured within 8 weeks of the start, and the middle half from 8 weeks to 4 months. 33 primary outcomes give a duration.

Latest time point of each outcome

  • Within a day6 outcomes, 2 as a primary outcome
  • Up to 4 weeks33 outcomes, 5 as a primary outcome
  • 1 to 3 months70 outcomes, 16 as a primary outcome
  • 3 to 6 months19 outcomes, 7 as a primary outcome
  • 6 to 12 months8 outcomes, 2 as a primary outcome
  • Over 2 years1 outcomes, 1 as a primary outcome
  • No duration given6 outcomes, 4 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

137 of the 143 outcome measures give a duration. A single visit counts as within a day.

Status, results, interventions and countries

Status

  • Recruiting34 studies, 11 as a primary outcome
  • Not yet recruiting4 studies, 0 as a primary outcome
  • Active, not recruiting6 studies, 2 as a primary outcome
  • Completed62 studies, 20 as a primary outcome
  • Stopped early8 studies, 1 as a primary outcome
  • Status unknown29 studies, 3 as a primary outcome

What they test

  • Behavioral21 studies, 7 as a primary outcome
  • Drug62 studies, 11 as a primary outcome
  • Device36 studies, 6 as a primary outcome
  • Dietary supplement6 studies, 2 as a primary outcome
  • Procedure1 studies, 0 as a primary outcome
  • Diagnostic test2 studies, 1 as a primary outcome
  • Biological2 studies, 1 as a primary outcome
  • Combination product1 studies, 0 as a primary outcome
  • Other17 studies, 5 as a primary outcome
  • None given13 studies, 7 as a primary outcome

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

Where their sites are

  • United States37 studies, 14 as a primary outcome
  • China27 studies, 4 as a primary outcome
  • Canada23 studies, 4 as a primary outcome
  • Germany7 studies, 4 as a primary outcome
  • Spain7 studies, 2 as a primary outcome
  • Denmark6 studies, 1 as a primary outcome
  • France6 studies, 1 as a primary outcome
  • Italy6 studies, 2 as a primary outcome
  • Taiwan6 studies, 2 as a primary outcome
  • United Kingdom6 studies, 1 as a primary outcome
  • Estonia4 studies, 2 as a primary outcome
  • Finland4 studies, 4 as a primary outcome

36 countries in all. A study with sites in several counts in each; 6 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 Symbol Coding: 30 of 62, 48%

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

Completed depression and bipolar disorder studies that name Symbol Coding and every completed study, by how they reported results
ResultsCompleted depression and bipolar disorder studies that name Symbol CodingEvery completed study
Results on ClinicalTrials.gov and a paper9, 15%776, 10%
Results on ClinicalTrials.gov only5, 8%1,139, 14%
A results paper only16, 26%1,711, 22%
Neither32, 52%4,327, 54%

The 143 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
TestSymbol Coding

143 studies match. 37 name Symbol Coding in a primary outcome. Median size 90 participants. Median time to the primary outcome: 8 weeks.

Loading 143 studies; the filters turn on when they arrive.

By start year
051015202000: 0 studies, 0 naming Symbol Coding in a primary outcome20002001: 0 studies, 0 naming Symbol Coding in a primary outcome2002: 0 studies, 0 naming Symbol Coding in a primary outcome2003: 0 studies, 0 naming Symbol Coding in a primary outcome2004: 0 studies, 0 naming Symbol Coding in a primary outcome2005: 1 studies, 1 naming Symbol Coding in a primary outcome20052006: 1 studies, 0 naming Symbol Coding in a primary outcome2007: 2 studies, 0 naming Symbol Coding in a primary outcome2008: 0 studies, 0 naming Symbol Coding in a primary outcome2009: 0 studies, 0 naming Symbol Coding in a primary outcome2010: 2 studies, 1 naming Symbol Coding in a primary outcome20102011: 2 studies, 0 naming Symbol Coding in a primary outcome2012: 2 studies, 2 naming Symbol Coding in a primary outcome2013: 1 studies, 0 naming Symbol Coding in a primary outcome2014: 4 studies, 3 naming Symbol Coding in a primary outcome2015: 8 studies, 4 naming Symbol Coding in a primary outcome20152016: 6 studies, 1 naming Symbol Coding in a primary outcome2017: 7 studies, 2 naming Symbol Coding in a primary outcome2018: 8 studies, 3 naming Symbol Coding in a primary outcome2019: 8 studies, 1 naming Symbol Coding in a primary outcome2020: 10 studies, 3 naming Symbol Coding in a primary outcome20202021: 11 studies, 4 naming Symbol Coding in a primary outcome2022: 7 studies, 1 naming Symbol Coding in a primary outcome2023: 20 studies, 2 naming Symbol Coding in a primary outcome2024: 14 studies, 2 naming Symbol Coding in a primary outcome2025: 17 studies, 4 naming Symbol Coding in a primary outcome20252026: 12 studies, 3 naming Symbol Coding 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
200511
200610
200720
200800
200900
201021
201120
201222
201310
201443
201584
201661
201772
201883
201981
2020103
2021114
202271
2023202
2024142
2025174
2026123

Library tests named most

  • Symbol Coding143 studies, 37 as a primary outcome
  • Trail Making Test67 studies, 19 as a primary outcome
  • Verbal Learning44 studies, 13 as a primary outcome
  • Digit Span Test39 studies, 14 as a primary outcome
  • Stroop Color-Word Test24 studies, 8 as a primary outcome
  • Verbal Fluency24 studies, 7 as a primary outcome
  • Choice Reaction Time21 studies, 5 as a primary outcome
  • Continuous Performance Test16 studies, 4 as a primary outcome
  • Category Fluency12 studies, 6 as a primary outcome
  • N-Back Task12 studies, 5 as a primary outcome

Largest condition groups

  • Depression and bipolar disorder143 studies, 37 as a primary outcome
  • Anxiety, PTSD and OCD13 studies, 8 as a primary outcome
  • Multiple sclerosis8 studies, 1 as a primary outcome
  • Sleep and sleep disorders8 studies, 4 as a primary outcome
  • Pain and fatigue8 studies, 4 as a primary outcome
  • Aging, frailty and exercise5 studies, 1 as a primary outcome
  • Schizophrenia and psychosis4 studies, 1 as a primary outcome
  • Cardiovascular disease4 studies, 1 as a primary outcome
  • Mild cognitive impairment3 studies, 2 as a primary outcome
  • Parkinson's disease3 studies, 0 as a primary outcome
  • Cancer3 studies, 2 as a primary outcome
  • Dementia and Alzheimer's2 studies, 1 as a primary outcome

Phases

Participants

Lead sponsor: industry 27, other 116. Interventional 122, observational 21.

As a primary outcomeSecondary or other outcomeSymbol Coding

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
NCT07879924Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants60Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Symbol CodingSecondary1 week
  • Choice Reaction TimeSecondary1 week
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
NCT07757997Start2026PhaseObservationalConditionsDepression and bipolar disorderParticipants143Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestOther outcome8 weeks
  • Symbol CodingOther outcome8 weeks
  • Choice Reaction TimeOther outcome8 weeks
NCT07633626Start2026PhaseObservationalConditionsDepression and bipolar disorder, CancerParticipants24Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestPrimary12 weeks
  • Verbal LearningPrimary12 weeks
  • Verbal FluencyPrimary12 weeks
  • Digit Span TestPrimary12 weeks
  • Symbol CodingPrimary12 weeks
  • Symbol Scan TaskPrimary12 weeks
NCT07611773Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants270Lead sponsorIndustryStatusRecruitingLibrary tests named
  • Verbal LearningSecondary10 weeks
  • Symbol CodingSecondary10 weeks
NCT07523048Start2025PhasePhase 2ConditionsDepression and bipolar disorderParticipants30Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondary2 weeks
  • Symbol CodingSecondary2 weeks
  • Symbol Scan TaskSecondary2 weeks
  • Implicit Association Test (IAT)Secondary2 weeks
  • Effort for Rewards TaskPrimary2 weeks
  • Effort Discounting TaskSecondary2 weeks
NCT07508215Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants120Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondary8 weeks
  • Stroop Color-Word TestSecondary8 weeks
  • Verbal LearningSecondary8 weeks
  • Symbol CodingPrimary8 weeks
NCT07504120Start2025PhaseNot applicableConditionsMultiple sclerosis, Depression and bipolar disorder, Aging, frailty and exercise, Pain and fatigueParticipants50Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningSecondary16 weeks
  • Symbol CodingSecondary16 weeks
NCT07474974Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants44Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningSecondary9 weeks
  • Symbol CodingSecondary9 weeks
  • Contrast Sensitivity TestSecondary9 weeks
NCT07462013Start2025PhaseNot applicableConditionsDepression and bipolar disorderParticipants120Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestPrimary6 months
  • Digit Span TestPrimary6 months
  • Symbol CodingPrimary6 months
  • Card Sorting Test (Berg)Primary6 months
NCT07376018Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants60Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningSecondary12 weeks
  • Symbol CodingSecondary12 weeks
  • Dimensional Change Card SortSecondary12 weeks
  • Size Order Memory TestSecondary12 weeks
  • Pattern and Letter ComparisonSecondary12 weeks
  • Picture Order Memory TestSecondary12 weeks
NCT07350226Start2025PhaseNot applicableConditionsDepression and bipolar disorderParticipants86Lead sponsorOtherStatusActive, not recruitingLibrary tests named
  • Trail Making TestPrimary8 weeks
  • Stroop Color-Word TestPrimary8 weeks
  • Verbal LearningPrimary8 weeks
  • Verbal FluencySecondary8 weeks
  • Digit Span TestPrimary8 weeks
  • Symbol CodingPrimary8 weeks
  • Category FluencyPrimary8 weeks
  • Picture Naming TestPrimary8 weeks
  • Task Switching TestSecondary8 weeks
  • Clock Drawing TaskPrimary8 weeks
  • Complex Figure Copy and RecallSecondary8 weeks
NCT07309302Start2025PhaseNot applicableConditionsDepression and bipolar disorder, Anxiety, PTSD and OCDParticipants64Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestPrimary5 months
  • Stroop Color-Word TestPrimary5 months
  • Verbal LearningPrimary5 months
  • Verbal FluencyPrimary5 months
  • Symbol CodingPrimary5 months
  • Continuous Performance TestPrimary5 months
  • Category FluencyPrimary5 months
  • Eriksen Flanker TaskPrimary5 months
  • Balloon RiskPrimary5 months
  • Emotional Stroop TaskPrimary5 months
  • Visual Search TestPrimary5 months
  • Serial Naming TaskPrimary5 months
NCT07274917Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants9Lead sponsorOtherStatusCompletedLibrary tests named
  • Symbol CodingSecondary12 weeks
NCT07273604Start2015PhaseNot applicableConditionsMultiple sclerosis, Depression and bipolar disorder, Anxiety, PTSD and OCD, Pain and fatigueParticipants148Lead sponsorOtherStatusCompletedLibrary tests named
  • Verbal FluencyPrimary12 weeks
  • Symbol CodingPrimary12 weeks
  • Category FluencyPrimary12 weeks
  • Paced Visual Serial Addition TestPrimary12 weeks
  • Selective Reminding TaskPrimary12 weeks
NCT07263022Start2026PhasePhase 3ConditionsSchizophrenia and psychosis, Depression and bipolar disorderParticipants24Lead sponsorOtherStatusRecruitingLibrary tests named
  • Symbol CodingPrimarysame day
  • Matrix ReasoningPrimarysame day
  • AX Continuous Performance TestPrimary1 week
  • Word Pair LearningPrimarysame day
  • Four-Armed BanditPrimary1 week
NCT07262008Start2026PhasePhase 3ConditionsDepression and bipolar disorderParticipants120Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Symbol CodingSecondary12 weeks
NCT07253038Start2025PhaseObservationalConditionsDepression and bipolar disorder, Huntington's diseaseParticipants40Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal FluencySecondarysame day
  • Symbol CodingSecondarysame day
NCT07204314Start2025PhasePhase 3ConditionsDepression and bipolar disorderParticipants180Lead sponsorIndustryStatusRecruitingLibrary tests named
  • Symbol CodingSecondary14 weeks
NCT07186023Start2025PhaseNot applicableConditionsDepression and bipolar disorderParticipants124Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal FluencySecondary4 weeks
  • Digit Span TestSecondary4 weeks
  • Symbol CodingSecondary4 weeks
NCT07168447Start2025PhaseObservationalConditionsDepression and bipolar disorder, Anxiety, PTSD and OCD, Pain and fatigueParticipants85Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Digit Span TestSecondary1 week
  • Symbol CodingSecondary1 week
NCT07143838Start2026PhaseNot applicableConditionsDepression and bipolar disorderParticipants12Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondary3 weeks
  • Symbol CodingSecondary3 weeks
  • Choice Reaction TimeSecondary3 weeks
NCT07009223Start2025PhaseNot applicableConditionsDepression and bipolar disorder, Aging, frailty and exerciseParticipants120Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestPrimary6 months
  • Symbol CodingPrimary6 months
  • Card Sorting Test (Berg)Primary6 months
  • Task Switching TestPrimary6 months
NCT06901687Start2025PhasePhase 2ConditionsMultiple sclerosis, Depression and bipolar disorderParticipants170Lead sponsorOtherStatusRecruitingLibrary tests named
  • Symbol CodingSecondary8 weeks
NCT06870968Start2025PhaseNot applicableConditionsMultiple sclerosis, Depression and bipolar disorderParticipants40Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Symbol CodingOther outcome5 months
  • Eriksen Flanker TaskOther outcome5 months
  • Dimensional Change Card SortOther outcome5 months

Page 1 of 6

Questions, answered from the data

How many depression and bipolar disorder trials use Symbol Coding?

143 registered depression and bipolar disorder studies on ClinicalTrials.gov name it in an outcome measure, 37 of them in a primary outcome: 11% of the condition's 1,247 studies with a cognitive outcome, against 9% of all of them. It is the 5th most named test in depression and bipolar disorder trials.

Which tests do depression and bipolar disorder trials use with Symbol Coding?

The Trail Making Test (67 studies), Verbal Learning (44 studies) and the Digit Span Test (39 studies).

How many participants do phase 2 depression and bipolar disorder trials that use Symbol Coding enroll?

Half of the phase 2 studies that name it enroll 90 participants or fewer, and the middle half enroll 65 to 129. 27 of them give a size.

When do depression and bipolar disorder trials measure Symbol Coding?

Half of the primary outcomes that name Symbol Coding are measured within 8 weeks of the start, and the middle half from 8 weeks to 4 months. 33 primary outcomes give a duration.

How many completed depression and bipolar disorder trials that use Symbol Coding have reported results?

30 of the 62 completed studies that name it, 48%, have reported results: 14 posted them on ClinicalTrials.gov, 25 have a results paper linked to the registry record, and 9 did both. The other 32 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.

More on Symbol Coding and depression and bipolar disorder

  • Every cognitive test in depression and bipolar disorder trials: 1,247 studies
  • Symbol Coding in all clinical trials: 1,457 studies

Symbol Coding in other conditions

  • Multiple sclerosis375
  • Dementia and Alzheimer's117
  • Aging, frailty and exercise116
  • Sleep and sleep disorders89
  • Mild cognitive impairment84
  • Pain and fatigue82
  • Stroke61
  • Substance use and addiction60
  • Obesity and diabetes59
  • Cancer58
  • Healthy volunteers56

Other tests in depression and bipolar disorder trials

  • Trail Making Test204
  • Verbal Learning178
  • Verbal Fluency154
  • Digit Span Test143
  • Stroop Color-Word Test138
  • Go/No-Go Task79
  • N-Back 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 Symbol Key Game and Symbol Coding as one test family, so this page counts their studies together.

Run Symbol Coding 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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