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  1. Home
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  5. /Pain and fatigue
  6. /Digit Span Test

Clinical trials data

Digit Span Test in pain and fatigue trials: 61 registered studies

Every registered pain and fatigue study on ClinicalTrials.gov that names the Digit Span Test 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
61
Name it in a primary outcome, 48%
29 of 61
Of the condition's 681 studies name it, against 10% of all registered studies
9%
Other conditions
Median participants per study
62
By phase
Try the Digit Span Test

Tests named in the same studies

The library tests that pain and fatigue studies naming the Digit Span Test name most often beside it.
  1. 1

    Trail Making Test25 studies, 13 as a primary outcome

  2. 2

    Verbal Fluency19 studies, 11 as a primary outcome

  3. 3

    Verbal Learning19 studies, 7 as a primary outcome

  4. 4

    Stroop Color-Word Test12 studies, 5 as a primary outcome

  5. 5

    Symbol Coding10 studies, 2 as a primary outcome

  6. 6

    Continuous Performance Test7 studies, 2 as a primary outcome

  7. 7

    Complex Figure Copy and Recall6 studies, 3 as a primary outcome

  8. 8

    Category Fluency5 studies, 3 as a primary outcome

  9. 9

    Tower Planning3 studies, 3 as a primary outcome

  10. 10

    Paced Visual Serial Addition Test3 studies, 2 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: 1 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: 1 studies, 1 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: 1 studies, 1 with a test as a primary outcome2010: 1 studies, 1 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, 1 with a test as a primary outcome2014: 2 studies, 2 with a test as a primary outcome2015: 3 studies, 1 with a test as a primary outcome20152016: 4 studies, 2 with a test as a primary outcome2017: 3 studies, 0 with a test as a primary outcome2018: 2 studies, 0 with a test as a primary outcome2019: 1 studies, 1 with a test as a primary outcome2020: 4 studies, 3 with a test as a primary outcome20202021: 4 studies, 1 with a test as a primary outcome2022: 1 studies, 1 with a test as a primary outcome2023: 6 studies, 3 with a test as a primary outcome2024: 5 studies, 3 with a test as a primary outcome2025: 15 studies, 5 with a test as a primary outcome20252026: 6 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
200010
200100
200200
200300
200411
200500
200600
200700
200800
200911
201011
201100
201200
201311
201422
201531
201642
201730
201820
201911
202043
202141
202211
202363
202453
2025155
202663

Phases and study sizes

By phase

  • Phase 29 studies, 2 as a primary outcome
  • Phase 35 studies, 3 as a primary outcome
  • Not applicable39 studies, 20 as a primary outcome
  • Observational8 studies, 4 as a primary outcome

Participants per study

102050100
  • Not applicable50 median, 38 to 99
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 the Digit Span Test, by phase
PhaseStudies with a sizeMedianMiddle half
Not applicable375038 to 99

When pain and fatigue trials measure it

Half of the primary outcomes that name the Digit Span Test are measured within 8 weeks of the start, and the middle half from 4 weeks to 4 months. 25 primary outcomes give a duration.

Latest time point of each outcome

  • Within a day5 outcomes, 2 as a primary outcome
  • Up to 4 weeks11 outcomes, 6 as a primary outcome
  • 1 to 3 months22 outcomes, 10 as a primary outcome
  • 3 to 6 months6 outcomes, 3 as a primary outcome
  • 6 to 12 months5 outcomes, 1 as a primary outcome
  • 1 to 2 years4 outcomes, 2 as a primary outcome
  • Over 2 years2 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

55 of the 61 outcome measures give a duration. A single visit counts as within a day.

Status, results, interventions and countries

Status

  • Recruiting12 studies, 3 as a primary outcome
  • Not yet recruiting4 studies, 2 as a primary outcome
  • Active, not recruiting2 studies, 1 as a primary outcome
  • Completed31 studies, 15 as a primary outcome
  • Stopped early5 studies, 3 as a primary outcome
  • Status unknown7 studies, 5 as a primary outcome

What they test

  • Behavioral12 studies, 6 as a primary outcome
  • Drug15 studies, 6 as a primary outcome
  • Device9 studies, 5 as a primary outcome
  • Dietary supplement8 studies, 6 as a primary outcome
  • Procedure2 studies, 2 as a primary outcome
  • Diagnostic test2 studies, 1 as a primary outcome
  • Radiation2 studies, 1 as a primary outcome
  • Other15 studies, 5 as a primary outcome
  • None given5 studies, 2 as a primary outcome

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

Where their sites are

  • United States21 studies, 11 as a primary outcome
  • Brazil4 studies, 2 as a primary outcome
  • Norway4 studies, 0 as a primary outcome
  • China3 studies, 1 as a primary outcome
  • Sweden3 studies, 1 as a primary outcome
  • United Kingdom3 studies, 2 as a primary outcome
  • Denmark2 studies, 1 as a primary outcome
  • Netherlands2 studies, 1 as a primary outcome
  • Canada1 studies, 0 as a primary outcome
  • Egypt1 studies, 1 as a primary outcome
  • Finland1 studies, 0 as a primary outcome
  • France1 studies, 0 as a primary outcome

21 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 the Digit Span Test: 9 of 31, 29%

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

Completed pain and fatigue studies that name the Digit Span Test and every completed study, by how they reported results
ResultsCompleted pain and fatigue studies that name the Digit Span TestEvery completed study
Results on ClinicalTrials.gov and a paper3, 10%776, 10%
Results on ClinicalTrials.gov only1, 3%1,139, 14%
A results paper only5, 16%1,711, 22%
Neither22, 71%4,327, 54%

The 61 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
TestThe Digit Span Test

61 studies match. 29 name the Digit Span Test in a primary outcome. Median size 62 participants. Median time to the primary outcome: 8 weeks.

Loading 61 studies; the filters turn on when they arrive.

By start year
0510152000: 1 studies, 0 naming the Digit Span Test in a primary outcome20002001: 0 studies, 0 naming the Digit Span Test in a primary outcome2002: 0 studies, 0 naming the Digit Span Test in a primary outcome2003: 0 studies, 0 naming the Digit Span Test in a primary outcome2004: 1 studies, 1 naming the Digit Span Test in a primary outcome2005: 0 studies, 0 naming the Digit Span Test in a primary outcome20052006: 0 studies, 0 naming the Digit Span Test in a primary outcome2007: 0 studies, 0 naming the Digit Span Test in a primary outcome2008: 0 studies, 0 naming the Digit Span Test in a primary outcome2009: 1 studies, 1 naming the Digit Span Test in a primary outcome2010: 1 studies, 1 naming the Digit Span Test in a primary outcome20102011: 0 studies, 0 naming the Digit Span Test in a primary outcome2012: 0 studies, 0 naming the Digit Span Test in a primary outcome2013: 1 studies, 1 naming the Digit Span Test in a primary outcome2014: 2 studies, 2 naming the Digit Span Test in a primary outcome2015: 3 studies, 1 naming the Digit Span Test in a primary outcome20152016: 4 studies, 2 naming the Digit Span Test in a primary outcome2017: 3 studies, 0 naming the Digit Span Test in a primary outcome2018: 2 studies, 0 naming the Digit Span Test in a primary outcome2019: 1 studies, 1 naming the Digit Span Test in a primary outcome2020: 4 studies, 3 naming the Digit Span Test in a primary outcome20202021: 4 studies, 1 naming the Digit Span Test in a primary outcome2022: 1 studies, 1 naming the Digit Span Test in a primary outcome2023: 6 studies, 3 naming the Digit Span Test in a primary outcome2024: 5 studies, 3 naming the Digit Span Test in a primary outcome2025: 15 studies, 5 naming the Digit Span Test in a primary outcome20252026: 6 studies, 3 naming the Digit Span Test in a primary outcome

2026 is partly planned starts.

Show as a table
Matching studies by start year
Start yearStudiesAs a primary outcome
200010
200100
200200
200300
200411
200500
200600
200700
200800
200911
201011
201100
201200
201311
201422
201531
201642
201730
201820
201911
202043
202141
202211
202363
202453
2025155
202663

Library tests named most

  • Digit Span Test61 studies, 29 as a primary outcome
  • Trail Making Test25 studies, 13 as a primary outcome
  • Verbal Fluency19 studies, 11 as a primary outcome
  • Verbal Learning19 studies, 7 as a primary outcome
  • Stroop Color-Word Test12 studies, 5 as a primary outcome
  • Symbol Coding10 studies, 2 as a primary outcome
  • Continuous Performance Test7 studies, 2 as a primary outcome
  • Complex Figure Copy and Recall6 studies, 3 as a primary outcome
  • Category Fluency5 studies, 3 as a primary outcome
  • Tower Planning3 studies, 3 as a primary outcome

Largest condition groups

  • Pain and fatigue61 studies, 29 as a primary outcome
  • Anxiety, PTSD and OCD11 studies, 6 as a primary outcome
  • Depression and bipolar disorder10 studies, 7 as a primary outcome
  • Cancer8 studies, 6 as a primary outcome
  • Sleep and sleep disorders7 studies, 5 as a primary outcome
  • COVID-19 and long COVID6 studies, 3 as a primary outcome
  • Delirium, surgery and intensive care4 studies, 1 as a primary outcome
  • Stroke3 studies, 1 as a primary outcome
  • Aging, frailty and exercise3 studies, 2 as a primary outcome
  • Cardiovascular disease3 studies, 2 as a primary outcome
  • Brain injury and concussion2 studies, 1 as a primary outcome
  • Healthy volunteers2 studies, 1 as a primary outcome

Phases

Participants

Lead sponsor: industry 5, other 56. Interventional 53, observational 8.

As a primary outcomeSecondary or other outcomeThe Digit Span Test

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
NCT07906847Start2026PhaseObservationalConditionsPain and fatigueParticipants80Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Trail Making TestPrimary
  • Stroop Color-Word TestPrimary
  • Digit Span TestPrimary
NCT07755475Start2025PhaseNot applicableConditionsPain and fatigueParticipants50Lead sponsorIndustryStatusCompletedLibrary tests named
  • Digit Span TestPrimary4 weeks
NCT07742605Start2025PhaseNot applicableConditionsPain and fatigueParticipants35Lead sponsorIndustryStatusCompletedLibrary tests named
  • Digit Span TestPrimary6 weeks
NCT07740967Start2026PhaseNot applicableConditionsSleep and sleep disorders, Pain and fatigue, Cardiovascular diseaseParticipants34Lead sponsorOtherStatusRecruitingLibrary tests named
  • Stroop Color-Word TestSecondary8 weeks
  • Digit Span TestSecondary8 weeks
  • Pattern and Letter ComparisonSecondary8 weeks
NCT07729930Start2026PhaseNot applicableConditionsSleep and sleep disorders, Pain and fatigue, Cardiovascular diseaseParticipants38Lead sponsorOtherStatusRecruitingLibrary tests named
  • Stroop Color-Word TestPrimary8 weeks
  • Digit Span TestPrimary8 weeks
  • Pattern and Letter ComparisonPrimary8 weeks
NCT07429526Start2013PhaseNot applicableConditionsStroke, Brain injury and concussion, Pain and fatigueParticipants12Lead sponsorOtherStatusCompleted

Paper

Library tests named
  • Verbal LearningPrimary13 weeks
  • Digit Span TestPrimary13 weeks
  • Paced Visual Serial Addition TestPrimary13 weeks
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
NCT07379164Start2025PhaseNot applicableConditionsHealthy volunteers, Pain and fatigueParticipants80Lead sponsorOtherStatusCompletedLibrary tests named
  • Digit Span TestSecondarysame day
NCT07357688Start2026PhaseNot applicableConditionsPain and fatigueParticipants99Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Trail Making TestSecondary8 weeks
  • Stroop Color-Word TestSecondary8 weeks
  • Verbal LearningSecondary8 weeks
  • Verbal FluencySecondary8 weeks
  • Digit Span TestSecondary8 weeks
  • Category FluencySecondary8 weeks
  • Picture Naming TestSecondary8 weeks
  • Complex Figure Copy and RecallSecondary8 weeks
NCT07319117Start2025PhaseNot applicableConditionsDepression and bipolar disorder, Sleep and sleep disorders, Anxiety, PTSD and OCD, Pain and fatigue, Cardiovascular diseaseParticipants40Lead sponsorOtherStatusRecruitingLibrary tests named
  • Digit Span TestPrimary
  • Stop-Signal TaskPrimary
  • Rapid Visual Information ProcessingPrimary
  • Intra/Extra Dimensional Set ShiftPrimary
NCT07236229Start2025PhaseNot applicableConditionsSleep and sleep disorders, Pain and fatigueParticipants34Lead sponsorOtherStatusCompletedLibrary tests named
  • Digit Span TestSecondary6 weeks
  • Card Sorting Test (Berg)Secondary6 weeks
NCT07203339Start2025PhaseNot applicableConditionsPain and fatigueParticipants610Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondary8 weeks
  • Digit Span TestSecondary8 weeks
  • Stop-Signal TaskSecondary8 weeks
  • Symbol Scan TaskSecondary8 weeks
NCT07168447Start2025PhaseObservationalConditionsDepression and bipolar disorder, Anxiety, PTSD and OCD, Pain and fatigueParticipants85Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Digit Span TestSecondary1 week
  • Symbol CodingSecondary1 week
NCT07141550Start2026PhaseNot applicableConditionsPain and fatigueParticipants30Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Trail Making TestPrimary8 weeks
  • Stroop Color-Word TestPrimary8 weeks
  • Digit Span TestPrimary8 weeks
NCT07035327Start2025PhaseNot applicableConditionsAging, frailty and exercise, Pain and fatigueParticipants38Lead sponsorOtherStatusCompletedLibrary tests named
  • Digit Span TestSecondary10 weeks
NCT07005921Start2025PhaseNot applicableConditionsCOVID-19 and long COVID, Pain and fatigueParticipants40Lead sponsorOtherStatusCompletedLibrary tests named
  • Digit Span TestPrimary5 weeks
NCT06905587Start2025PhasePhase 3ConditionsCancer, Pain and fatigueParticipants50Lead sponsorOtherStatusRecruitingLibrary tests named
  • Digit Span TestSecondary16 weeks
  • Continuous Performance TestSecondary16 weeks
NCT06837857Start2025PhasePhase 2ConditionsPain and fatigueParticipants200Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondary12 months
  • Verbal LearningSecondary12 months
  • Digit Span TestSecondary12 months
  • Category FluencySecondary12 months
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
NCT06808048Start2025PhaseNot applicableConditionsSubstance use and addiction, Pain and fatigueParticipants180Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningPrimary4 months
  • Verbal FluencyPrimary4 months
  • Digit Span TestPrimary4 months
  • Go/No-Go TaskPrimary4 months
  • Tower PlanningPrimary4 months
  • Paired Associate LearningPrimary4 months
  • Iowa Gambling LitePrimary4 months
  • Word Pair LearningPrimary4 months
NCT06638996Start2024PhaseNot applicableConditionsAnxiety, PTSD and OCD, Pain and fatigueParticipants100Lead sponsorOtherStatusCompletedLibrary tests named
  • Verbal LearningPrimary1 week
  • Digit Span TestPrimary1 week
  • DRM False Memory TaskPrimary1 week
NCT06569849Start2024PhaseNot applicableConditionsAnxiety, PTSD and OCD, Pain and fatigueParticipants60Lead sponsorIndustryStatusStatus unknownLibrary tests named
  • Trail Making TestPrimary9 weeks
  • Digit Span TestPrimary9 weeks
  • Complex Figure Copy and RecallPrimary9 weeks
NCT06503874Start2024PhaseNot applicableConditionsCOVID-19 and long COVID, Pain and fatigueParticipants58Lead sponsorOtherStatusCompletedLibrary tests named
  • Digit Span TestOther outcome2 years
  • Continuous Performance TestSecondary2 years
NCT06448923Start2025PhasePhase 2ConditionsPain and fatigueParticipants225Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningSecondary13 weeks
  • Verbal FluencySecondary13 weeks
  • Digit Span TestSecondary13 weeks
  • Symbol Scan TaskSecondary13 weeks

Page 1 of 3

Questions, answered from the data

How many pain and fatigue trials use the Digit Span Test?

61 registered pain and fatigue studies on ClinicalTrials.gov name it in an outcome measure, 29 of them in a primary outcome: 9% of the condition's 681 studies with a cognitive outcome, against 10% of all of them. It is the 5th most named test in pain and fatigue trials.

Which tests do pain and fatigue trials use with the Digit Span Test?

The Trail Making Test (25 studies), Verbal Fluency (19 studies) and Verbal Learning (19 studies).

When do pain and fatigue trials measure the Digit Span Test?

Half of the primary outcomes that name the Digit Span Test are measured within 8 weeks of the start, and the middle half from 4 weeks to 4 months. 25 primary outcomes give a duration.

How many completed pain and fatigue trials that use the Digit Span Test have reported results?

9 of the 31 completed studies that name it, 29%, have reported results: 4 posted them on ClinicalTrials.gov, 8 have a results paper linked to the registry record, and 3 did both. The other 22 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.

More on the Digit Span Test and pain and fatigue

  • Every cognitive test in pain and fatigue trials: 681 studies
  • The Digit Span Test in all clinical trials: 1,629 studies

The Digit Span Test in other conditions

  • Dementia and Alzheimer's181
  • Mild cognitive impairment169
  • Depression and bipolar disorder143
  • Aging, frailty and exercise129
  • Cancer107
  • Stroke100
  • Brain injury and concussion98
  • Parkinson's disease86
  • Anxiety, PTSD and OCD72
  • Schizophrenia and psychosis66
  • Healthy volunteers64
  • Obesity and diabetes64
  • Sleep and sleep disorders63
  • Cognitive impairment and decline60
  • Cardiovascular disease59
  • ADHD58

Other tests in pain and fatigue trials

  • Stroop Color-Word Test114
  • Trail Making Test94
  • Symbol Coding82
  • Verbal Learning72
  • 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.

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