ConductCognition

  • Domains

    Tests

    • Processing speed43
    • Attention113
    • Working memory50
    • Executive function143
    • Episodic memory72
    • Response inhibition9
    • Social cognition75
    • Language42

    Most used

    Evidence

    1. Verbal Fluency TestGradeA
    2. Stroop Color-Word TestGradeA
    3. Trail Making TestGradeA
    4. N-Back TaskGradeA
    5. Go/No-Go TaskGradeA
    6. Digit Span TestGradeA
    7. Symbol Coding TestGradeA
    8. Verbal Learning TestGradeA
    REDTry it nowStroop Color-Word Test
    All 547 tests

    Browse by

    • Phone290
    • Tablet323
    • Untimed326
    • Up to 5 minutes69
    • Evidence grade A40

  • First studies

    Grade, length

    • Reaction Time StudyGradeA7 min
    • Pilot ScreeningGradeA15 min
    • Medication StudiesGradeA−26 min
    • Language-Minimized ScreeningGradeA−30 min

    Age groups

    • Older Adult Executive SpeedGradeA20 min
    • School-AgeGradeA−33 min

    Memory

    • At-Home MemoryGradeA26 min
    • Working Memory and LearningGradeA−19 min
    • Associative MemoryGradeB32 min
    • Working Memory CapacityGradeB34 min

    Language and perception

    • LanguageGradeA−33 min
    • Visual PerceptionGradeB27 min
    • Listening and Auditory ProcessingGradeB31 min

    Executive function and attention

    • Executive ControlGradeA18 min
    • Attention and ImpulsivityGradeA−26 min
    • Visual AttentionGradeB27 min
    • Creativity and Flexible ThinkingGradeB30 min
    • Reasoning and SpatialGradeB32 min

    Movement

    • Motor and AttentionGradeA−29 min
    • Motor LearningGradeB34 min

    Behavior, mood and choice

    • Food Choice and Self-ControlGradeA−29 min
    • Sleep and FatigueGradeB23 min
    • Social CognitionGradeB23 min
    • Impulsivity and Substance UseGradeB26 min
    • Emotion and MoodGradeB28 min
    • Decisions and RewardGradeB29 min
    All 26 batteries

    Find one

    Up to 15 minutes2Up to 30 minutes19Phone8
    Test order labBattery gradesHow batteries work

  • Use and evidence

    • Overview
    • Compare all 547 tests
    • Test-retest
    • Reliability and validity
    • Battery grades26
    • Download and cite

    Clinical trials

    • Overview
    • By condition25
    • By test101
    • Trial design benchmark
    • Cognitive outcomes, 2026

    Conditions

    Registered studies

    • Dementia and Alzheimer's1,673
    • Aging, frailty and exercise1,398
    • Depression and bipolar disorder1,247
    • Stroke1,233
    • Substance use and addiction895
    • Parkinson's disease892
    • Cancer760
    All 25 conditions
    16,361Registered studies name a cognitive test in an outcome measure11,688 name a test you can run hereExplore the studies
  • 1

    Build

    • Study design
    • Customize tests
    • Repeat visits
    • Study cost calculator
    2

    Recruit

    • Recruitment setup
    • Prolific
    • Sona Systems
    • CloudResearch Connect
    • Qualtrics
    3

    Run

    • Remote testing
    • Participant devices
    • Phone timing check
    • Offline edition
    4

    Results

    • Automated scoring
    • Test norms
    • Study Quality Monitor
    • Data export
    Platform overview

    Compliance

    • HIPAA-ready testing
    • US clinical research
    • Data Policy
    • Privacy Policy
    • Terms of Use

  • Research areas

    Tests used in each

    • Aging and dementia188
    • Decisions and reward105
    • Child development and education87
    • Language and bilingualism64
    • Social behavior62
    • Psychiatric groups35
    • Training and intervention28
    • Mood, anxiety and trauma25
    • Substance use and impulsivity25
    • Neurological and movement research19
    • Brain injury and concussion14
    • Sleep and fatigue14
    • ADHD11
    • Eating and obesity8
    • Medication and drug trials8

    Research settings

    • Student participant pools
    • Teaching a class
    • Clinical trials
    • US clinical research
    • Sites without internet
    Planning a study?

  • Methods

    • How evidence grades work
    • How test batteries work
    • How test order works
    Methods and questions

    Help

    • FAQ
    • Recruitment guides
    • Compare platforms

    Updates

    • Blog
    • New tests by email
    Latest post10 November 2026What you can do in ConductCognition todayA short tour of ConductCognition as it stands on 10 November. After this, we'll post when something changes how you run a study.Read the post
  • Pricing
Start Free
Log In
Log InStart Free
  1. Home
  2. /Data
  3. /Clinical trials
  4. /Conditions
  5. /Pain and fatigue
  6. /Symbol Coding

Clinical trials data

Symbol Coding in pain and fatigue trials: 82 registered studies

Every registered pain and fatigue 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 pain and fatigue studies name it in an outcome measure
82
Name it in a primary outcome, 21%
17 of 82
Of the condition's 681 studies name it, against 9% of all registered studies
12%
Other conditions
Median participants per study
72
By phase
Try the Symbol Key GameTry Symbol Coding

Tests named in the same studies

The library tests that pain and fatigue studies naming Symbol Coding name most often beside it.
  1. 1

    Verbal Learning22 studies, 2 as a primary outcome

  2. 2

    Trail Making Test13 studies, 4 as a primary outcome

  3. 3

    Stroop Color-Word Test10 studies, 3 as a primary outcome

  4. 4

    Digit Span Test10 studies, 2 as a primary outcome

  5. 5

    Verbal Fluency10 studies, 2 as a primary outcome

  6. 6

    Paced Visual Serial Addition Test9 studies, 4 as a primary outcome

  7. 7

    N-Back Task5 studies, 1 as a primary outcome

  8. 8

    Selective Reminding Task5 studies, 1 as a primary outcome

  9. 9

    Psychomotor Vigilance Task4 studies, 1 as a primary outcome

  10. 10

    Category Fluency3 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: 2 studies, 0 with a test as a primary outcome2003: 0 studies, 0 with a test as a primary outcome2004: 1 studies, 0 with a test as a primary outcome2005: 0 studies, 0 with a test as a primary outcome20052006: 1 studies, 1 with a test as a primary outcome2007: 0 studies, 0 with a test as a primary outcome2008: 2 studies, 1 with a test as a primary outcome2009: 1 studies, 0 with a test as a primary outcome2010: 2 studies, 1 with a test as a primary outcome20102011: 1 studies, 0 with a test as a primary outcome2012: 1 studies, 0 with a test as a primary outcome2013: 6 studies, 0 with a test as a primary outcome2014: 2 studies, 0 with a test as a primary outcome2015: 4 studies, 2 with a test as a primary outcome20152016: 3 studies, 1 with a test as a primary outcome2017: 2 studies, 0 with a test as a primary outcome2018: 2 studies, 2 with a test as a primary outcome2019: 1 studies, 0 with a test as a primary outcome2020: 5 studies, 2 with a test as a primary outcome20202021: 4 studies, 2 with a test as a primary outcome2022: 4 studies, 0 with a test as a primary outcome2023: 10 studies, 0 with a test as a primary outcome2024: 9 studies, 4 with a test as a primary outcome2025: 6 studies, 0 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
200220
200300
200410
200500
200611
200700
200821
200910
201021
201110
201210
201360
201420
201542
201631
201720
201822
201910
202052
202142
202240
2023100
202494
202560
2026121

Phases and study sizes

By phase

  • Phase 12 studies, 0 as a primary outcome
  • Phase 1/22 studies, 0 as a primary outcome
  • Phase 217 studies, 4 as a primary outcome
  • Phase 2/31 studies, 0 as a primary outcome
  • Phase 38 studies, 1 as a primary outcome
  • Phase 43 studies, 1 as a primary outcome
  • Not applicable36 studies, 7 as a primary outcome
  • Observational13 studies, 4 as a primary outcome

Participants per study

102050100
  • Phase 2104 median, 38 to 131
  • Not applicable50 median, 34 to 98
  • Observational89 median, 58 to 126
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 pain and fatigue study that names Symbol Coding, by phase
PhaseStudies with a sizeMedianMiddle half
Phase 21710438 to 131
Not applicable355034 to 98
Observational128958 to 126

When pain and fatigue trials measure it

Half of the primary outcomes that name Symbol Coding are measured within 9 weeks of the start, and the middle half from 5 weeks to 6 months. 15 primary outcomes give a duration.

Latest time point of each outcome

  • Within a day13 outcomes, 2 as a primary outcome
  • Up to 4 weeks18 outcomes, 2 as a primary outcome
  • 1 to 3 months24 outcomes, 5 as a primary outcome
  • 3 to 6 months12 outcomes, 3 as a primary outcome
  • 6 to 12 months7 outcomes, 1 as a primary outcome
  • 1 to 2 years1 outcomes, 1 as a primary outcome
  • Over 2 years1 outcomes, 1 as a primary outcome
  • No duration given6 outcomes, 2 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

76 of the 82 outcome measures give a duration. A single visit counts as within a day.

Status, results, interventions and countries

Status

  • Recruiting17 studies, 2 as a primary outcome
  • Not yet recruiting8 studies, 1 as a primary outcome
  • Active, not recruiting3 studies, 1 as a primary outcome
  • Completed42 studies, 12 as a primary outcome
  • Stopped early4 studies, 0 as a primary outcome
  • Status unknown8 studies, 1 as a primary outcome

What they test

  • Behavioral14 studies, 1 as a primary outcome
  • Drug33 studies, 6 as a primary outcome
  • Device15 studies, 2 as a primary outcome
  • Dietary supplement2 studies, 1 as a primary outcome
  • Diagnostic test3 studies, 1 as a primary outcome
  • Other18 studies, 3 as a primary outcome
  • None given8 studies, 3 as a primary outcome

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

Where their sites are

  • United States27 studies, 3 as a primary outcome
  • Türkiye7 studies, 2 as a primary outcome
  • Denmark6 studies, 3 as a primary outcome
  • Spain6 studies, 2 as a primary outcome
  • Germany5 studies, 1 as a primary outcome
  • Switzerland5 studies, 0 as a primary outcome
  • France4 studies, 1 as a primary outcome
  • United Kingdom4 studies, 0 as a primary outcome
  • Canada3 studies, 1 as a primary outcome
  • Czechia3 studies, 1 as a primary outcome
  • Italy3 studies, 1 as a primary outcome
  • Norway3 studies, 0 as a primary outcome

28 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 pain and fatigue studies that name Symbol Coding: 23 of 42, 55%

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

Completed pain and fatigue studies that name Symbol Coding and every completed study, by how they reported results
ResultsCompleted pain and fatigue studies that name Symbol CodingEvery completed study
Results on ClinicalTrials.gov and a paper9, 21%776, 10%
Results on ClinicalTrials.gov only8, 19%1,139, 14%
A results paper only6, 14%1,711, 22%
Neither19, 45%4,327, 54%

The 82 studies

Filter by phase, sponsor, status, country, intervention, outcome list, size and start year. Each study links to its record on ClinicalTrials.gov.
ConditionPain and fatigue
TestSymbol Coding

82 studies match. 17 name Symbol Coding in a primary outcome. Median size 72 participants. Median time to the primary outcome: 9 weeks.

Loading 82 studies; the filters turn on when they arrive.

By start year
0510152000: 0 studies, 0 naming Symbol Coding in a primary outcome20002001: 0 studies, 0 naming Symbol Coding in a primary outcome2002: 2 studies, 0 naming Symbol Coding in a primary outcome2003: 0 studies, 0 naming Symbol Coding in a primary outcome2004: 1 studies, 0 naming Symbol Coding in a primary outcome2005: 0 studies, 0 naming Symbol Coding in a primary outcome20052006: 1 studies, 1 naming Symbol Coding in a primary outcome2007: 0 studies, 0 naming Symbol Coding in a primary outcome2008: 2 studies, 1 naming Symbol Coding in a primary outcome2009: 1 studies, 0 naming Symbol Coding in a primary outcome2010: 2 studies, 1 naming Symbol Coding in a primary outcome20102011: 1 studies, 0 naming Symbol Coding in a primary outcome2012: 1 studies, 0 naming Symbol Coding in a primary outcome2013: 6 studies, 0 naming Symbol Coding in a primary outcome2014: 2 studies, 0 naming Symbol Coding in a primary outcome2015: 4 studies, 2 naming Symbol Coding in a primary outcome20152016: 3 studies, 1 naming Symbol Coding in a primary outcome2017: 2 studies, 0 naming Symbol Coding in a primary outcome2018: 2 studies, 2 naming Symbol Coding in a primary outcome2019: 1 studies, 0 naming Symbol Coding in a primary outcome2020: 5 studies, 2 naming Symbol Coding in a primary outcome20202021: 4 studies, 2 naming Symbol Coding in a primary outcome2022: 4 studies, 0 naming Symbol Coding in a primary outcome2023: 10 studies, 0 naming Symbol Coding in a primary outcome2024: 9 studies, 4 naming Symbol Coding in a primary outcome2025: 6 studies, 0 naming Symbol Coding in a primary outcome20252026: 12 studies, 1 naming Symbol Coding in a primary outcome

2026 is partly planned starts. Not shown: 1 planned to start after 2026.

Show as a table
Matching studies by start year
Start yearStudiesAs a primary outcome
200000
200100
200220
200300
200410
200500
200611
200700
200821
200910
201021
201110
201210
201360
201420
201542
201631
201720
201822
201910
202052
202142
202240
2023100
202494
202560
2026121

Library tests named most

  • Symbol Coding82 studies, 17 as a primary outcome
  • Verbal Learning22 studies, 2 as a primary outcome
  • Trail Making Test13 studies, 4 as a primary outcome
  • Stroop Color-Word Test10 studies, 3 as a primary outcome
  • Digit Span Test10 studies, 2 as a primary outcome
  • Verbal Fluency10 studies, 2 as a primary outcome
  • Paced Visual Serial Addition Test9 studies, 4 as a primary outcome
  • N-Back Task5 studies, 1 as a primary outcome
  • Selective Reminding Task5 studies, 1 as a primary outcome
  • Psychomotor Vigilance Task4 studies, 1 as a primary outcome

Largest condition groups

  • Pain and fatigue82 studies, 17 as a primary outcome
  • Multiple sclerosis35 studies, 7 as a primary outcome
  • Sleep and sleep disorders10 studies, 6 as a primary outcome
  • Anxiety, PTSD and OCD9 studies, 4 as a primary outcome
  • Depression and bipolar disorder8 studies, 4 as a primary outcome
  • COVID-19 and long COVID7 studies, 2 as a primary outcome
  • Delirium, surgery and intensive care5 studies, 0 as a primary outcome
  • Substance use and addiction4 studies, 1 as a primary outcome
  • Stroke2 studies, 0 as a primary outcome
  • Brain injury and concussion2 studies, 1 as a primary outcome
  • Cancer2 studies, 2 as a primary outcome
  • Aging, frailty and exercise2 studies, 0 as a primary outcome

Phases

Participants

Lead sponsor: industry 11, other 71. Interventional 69, observational 13.

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
NCT07898722Start2025PhaseNot applicableConditionsAnxiety, PTSD and OCD, Pain and fatigueParticipants40Lead sponsorOtherStatusCompletedLibrary tests named
  • Symbol CodingSecondary
NCT07852156Start2026PhaseNot applicableConditionsMultiple sclerosis, Pain and fatigueParticipants42Lead sponsorOtherStatusRecruitingLibrary tests named
  • Symbol CodingSecondary2 weeks
NCT07842302Start2026PhaseNot applicableConditionsMultiple sclerosis, Pain and fatigueParticipants80Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Trail Making TestSecondary6 months
  • Stroop Color-Word TestSecondary6 months
  • Verbal FluencySecondary6 months
  • Symbol CodingPrimary6 months
  • Paced Visual Serial Addition TestSecondary6 months
  • Selective Reminding TaskSecondary6 months
NCT07786987Start2026PhaseObservationalConditionsMultiple sclerosis, Pain and fatigueParticipants50Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Symbol CodingSecondarysame day
NCT07783074Start2026PhaseObservationalConditionsMultiple sclerosis, Healthy volunteers, COVID-19 and long COVID, Pain and fatigueParticipants122Lead sponsorOtherStatusRecruitingLibrary tests named
  • Symbol CodingSecondary9 weeks
  • Finger Tapping TaskPrimary9 weeks
NCT07766213Start2026PhaseObservationalConditionsMultiple sclerosis, Pain and fatigueParticipants60Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningSecondarysame day
  • Symbol CodingSecondarysame day
NCT07724834Start2026PhasePhase 2ConditionsCOVID-19 and long COVID, Pain and fatigueParticipants38Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Symbol CodingSecondary9 months
NCT07680738Start2023PhaseNot applicableConditionsMultiple sclerosis, Pain and fatigueParticipants38Lead sponsorOtherStatusCompletedLibrary tests named
  • Verbal LearningSecondary4 weeks
  • Symbol CodingSecondary4 weeks
NCT07666958Start2026PhaseNot applicableConditionsMultiple sclerosis, Pain and fatigueParticipants45Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Symbol CodingSecondary9 weeks
NCT07565688Start2027PhaseNot applicableConditionsPain and fatigueParticipants45Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Symbol CodingSecondary6 weeks
NCT07555379Start2026PhaseNot applicableConditionsMultiple sclerosis, Sleep and sleep disorders, Pain and fatigueParticipants40Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Symbol CodingSecondary4 weeks
NCT07504120Start2025PhaseNot applicableConditionsMultiple sclerosis, Depression and bipolar disorder, Aging, frailty and exercise, Pain and fatigueParticipants50Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningSecondary16 weeks
  • Symbol CodingSecondary16 weeks
NCT07426991Start2024PhaseObservationalConditionsMultiple sclerosis, Sleep and sleep disorders, Pain and fatigueParticipants837Lead sponsorOtherStatusRecruitingLibrary tests named
  • Symbol CodingPrimary18 months
NCT07409753Start2025PhasePhase 2ConditionsPain and fatigueParticipants60Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningOther outcomesame day
  • Digit Span TestOther outcomesame day
  • Symbol CodingOther outcomesame day
NCT07393672Start2026PhasePhase 2ConditionsAnxiety, PTSD and OCD, Pain and fatigueParticipants104Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondary13 weeks
  • Stroop Color-Word TestSecondary13 weeks
  • Verbal LearningSecondary13 weeks
  • Verbal FluencySecondary13 weeks
  • Digit Span TestSecondary13 weeks
  • Symbol CodingSecondary
  • N-Back TaskSecondary13 weeks
  • Go/No-Go TaskSecondary13 weeks
  • Simple Reaction TimeSecondary13 weeks
  • Corsi Block-Tapping TestSecondary13 weeks
NCT07310862Start2026PhaseNot applicableConditionsMultiple sclerosis, Pain and fatigueParticipants30Lead sponsorIndustryStatusRecruitingLibrary tests named
  • Symbol CodingSecondary8 weeks
NCT07304843Start2023PhasePhase 1/2ConditionsPain and fatigueParticipants207Lead sponsorIndustryStatusCompletedLibrary tests named
  • Verbal LearningSecondary4 weeks
  • Verbal FluencySecondary4 weeks
  • Symbol CodingSecondary4 weeks
  • Category FluencySecondary4 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
NCT07168447Start2025PhaseObservationalConditionsDepression and bipolar disorder, Anxiety, PTSD and OCD, Pain and fatigueParticipants85Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Digit Span TestSecondary1 week
  • Symbol CodingSecondary1 week
NCT06956183Start2025PhaseNot applicableConditionsStroke, Pain and fatigueParticipants30Lead sponsorOtherStatusRecruitingLibrary tests named
  • Symbol CodingSecondary1 week
NCT06831916Start2025PhasePhase 2ConditionsAnxiety, PTSD and OCD, Pain and fatigueParticipants104Lead sponsorOtherStatusCompletedLibrary tests named
  • Trail Making TestSecondary13 weeks
  • Stroop Color-Word TestSecondary13 weeks
  • Verbal LearningSecondary13 weeks
  • Verbal FluencySecondary13 weeks
  • Digit Span TestSecondary13 weeks
  • Symbol CodingSecondary
  • N-Back TaskSecondary13 weeks
  • Go/No-Go TaskSecondary13 weeks
  • Simple Reaction TimeSecondary13 weeks
  • Corsi Block-Tapping TestSecondary13 weeks
  • DRM False Memory TaskSecondary13 weeks
NCT06721416Start2024PhaseNot applicableConditionsMultiple sclerosis, Pain and fatigueParticipants12Lead sponsorOtherStatusCompletedLibrary tests named
  • Stroop Color-Word TestPrimary
  • Symbol CodingPrimary
  • N-Back TaskPrimary
NCT06569550Start2024PhaseNot applicableConditionsMultiple sclerosis, Pain and fatigueParticipants60Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningOther outcome6 days
  • Symbol CodingOther outcome6 days
NCT06386133Start2026PhaseNot applicableConditionsMultiple sclerosis, Pain and fatigueParticipants208Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Symbol CodingSecondarysame day
NCT06368492Start2024PhaseNot applicableConditionsPain and fatigueParticipants35Lead sponsorOtherStatusRecruitingLibrary tests named
  • Symbol CodingSecondarysame day
  • Psychomotor Vigilance TaskSecondarysame day

Page 1 of 4

Questions, answered from the data

How many pain and fatigue trials use Symbol Coding?

82 registered pain and fatigue studies on ClinicalTrials.gov name it in an outcome measure, 17 of them in a primary outcome: 12% of the condition's 681 studies with a cognitive outcome, against 9% of all of them. It is the 3rd most named test in pain and fatigue trials.

Which tests do pain and fatigue trials use with Symbol Coding?

Verbal Learning (22 studies), the Trail Making Test (13 studies) and the Stroop Color-Word Test (10 studies).

How many participants do phase 2 pain and fatigue trials that use Symbol Coding enroll?

Half of the phase 2 studies that name it enroll 104 participants or fewer, and the middle half enroll 38 to 131. 17 of them give a size.

When do pain and fatigue trials measure Symbol Coding?

Half of the primary outcomes that name Symbol Coding are measured within 9 weeks of the start, and the middle half from 5 weeks to 6 months. 15 primary outcomes give a duration.

How many completed pain and fatigue trials that use Symbol Coding have reported results?

23 of the 42 completed studies that name it, 55%, have reported results: 17 posted them on ClinicalTrials.gov, 15 have a results paper linked to the registry record, and 9 did both. The other 19 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.

More on Symbol Coding and pain and fatigue

  • Every cognitive test in pain and fatigue trials: 681 studies
  • Symbol Coding in all clinical trials: 1,457 studies

Symbol Coding in other conditions

  • Multiple sclerosis375
  • Depression and bipolar disorder143
  • Dementia and Alzheimer's117
  • Aging, frailty and exercise116
  • Sleep and sleep disorders89
  • Mild cognitive impairment84
  • Stroke61
  • Substance use and addiction60
  • Obesity and diabetes59
  • Cancer58
  • Healthy volunteers56

Other tests in pain and fatigue trials

  • Stroop Color-Word Test114
  • Trail Making Test94
  • Verbal Learning72
  • Digit Span Test61
  • Verbal Fluency53

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.

Start free
ConductCognition

Hosted browser-native cognitive testing for academic and commercial research workflows.

A product of ConductScience, Inc.

New tests and features, about once a month. Unsubscribe at any time.

Tests

  • All cognitive tests
  • Test batteries
  • Use and evidence
  • Test norms
  • Trail Making Test
  • N-Back Task
  • Automated scoring
  • Study design
  • New tests by email

Guides

  • Methods and questions
  • Blog
  • Recruitment setup
  • Participant devices
  • Prolific
  • Sona Systems
  • CloudResearch Connect
  • Qualtrics

Use cases

  • Student participant pools
  • Aging and dementia research
  • Clinical trials
  • US clinical research
  • Remote testing

Compare and buy

  • Pricing
  • Compare platforms
  • Offline edition
  • FAQ

Trust

  • Study Quality Monitor
  • HIPAA-ready testing
  • Data export
  • Privacy Policy
  • Terms of Use
  • Data Policy

Company

  • ConductScience
  • Affiliate Program
© 2026 ConductScience, Inc. Research use only.