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  1. Home
  2. /Data
  3. /Clinical trials
  4. /Conditions
  5. /Cognitive impairment and decline
  6. /Digit Span Test

Clinical trials data

Digit Span Test in cognitive impairment and decline trials: 60 registered studies

Every registered cognitive impairment and decline 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 cognitive impairment and decline studies name it in an outcome measure
60
Name it in a primary outcome, 48%
29 of 60
Of the condition's 354 studies name it, against 10% of all registered studies
17%
Other conditions
Median participants per study
66
By phase
Try the Digit Span Test

Tests named in the same studies

The library tests that cognitive impairment and decline studies naming the Digit Span Test name most often beside it.
  1. 1

    Verbal Learning27 studies, 16 as a primary outcome

  2. 2

    Trail Making Test25 studies, 11 as a primary outcome

  3. 3

    Verbal Fluency17 studies, 10 as a primary outcome

  4. 4

    Stroop Color-Word Test15 studies, 7 as a primary outcome

  5. 5

    Symbol Coding11 studies, 4 as a primary outcome

  6. 6

    Category Fluency9 studies, 7 as a primary outcome

  7. 7

    Continuous Performance Test6 studies, 4 as a primary outcome

  8. 8

    Picture Naming Test6 studies, 4 as a primary outcome

  9. 9

    Matrix Reasoning5 studies, 3 as a primary outcome

  10. 10

    Symbol Scan Task5 studies, 3 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: 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: 1 studies, 1 with a test as a primary outcome2009: 0 studies, 0 with a test as a primary outcome2010: 1 studies, 1 with a test as a primary outcome20102011: 2 studies, 1 with a test as a primary outcome2012: 1 studies, 1 with a test as a primary outcome2013: 1 studies, 1 with a test as a primary outcome2014: 1 studies, 0 with a test as a primary outcome2015: 2 studies, 2 with a test as a primary outcome20152016: 3 studies, 1 with a test as a primary outcome2017: 4 studies, 2 with a test as a primary outcome2018: 5 studies, 2 with a test as a primary outcome2019: 6 studies, 1 with a test as a primary outcome2020: 1 studies, 0 with a test as a primary outcome20202021: 2 studies, 1 with a test as a primary outcome2022: 7 studies, 2 with a test as a primary outcome2023: 7 studies, 5 with a test as a primary outcome2024: 5 studies, 1 with a test as a primary outcome2025: 5 studies, 4 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
200000
200100
200200
200300
200400
200500
200600
200700
200811
200900
201011
201121
201211
201311
201410
201522
201631
201742
201852
201961
202010
202121
202272
202375
202451
202554
202663

Phases and study sizes

By phase

  • Phase 1/21 studies, 1 as a primary outcome
  • Phase 22 studies, 0 as a primary outcome
  • Phase 2/31 studies, 0 as a primary outcome
  • Phase 41 studies, 0 as a primary outcome
  • Not applicable46 studies, 26 as a primary outcome
  • Observational9 studies, 2 as a primary outcome

Participants per study

102050100200
  • Not applicable63 median, 35 to 149
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 cognitive impairment and decline study that names the Digit Span Test, by phase
PhaseStudies with a sizeMedianMiddle half
Not applicable466335 to 149

When cognitive impairment and decline trials measure it

Half of the primary outcomes that name the Digit Span Test are measured within 12 weeks of the start, and the middle half from 8 weeks to 6 months. 28 primary outcomes give a duration.

Latest time point of each outcome

  • Within a day7 outcomes, 3 as a primary outcome
  • Up to 4 weeks5 outcomes, 3 as a primary outcome
  • 1 to 3 months20 outcomes, 14 as a primary outcome
  • 3 to 6 months13 outcomes, 2 as a primary outcome
  • 6 to 12 months5 outcomes, 1 as a primary outcome
  • 1 to 2 years4 outcomes, 4 as a primary outcome
  • Over 2 years2 outcomes, 1 as a primary outcome
  • No duration given4 outcomes, 1 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

56 of the 60 outcome measures give a duration. A single visit counts as within a day.

Status, results, interventions and countries

Status

  • Recruiting9 studies, 6 as a primary outcome
  • Not yet recruiting2 studies, 0 as a primary outcome
  • Active, not recruiting4 studies, 3 as a primary outcome
  • Completed26 studies, 13 as a primary outcome
  • Stopped early2 studies, 2 as a primary outcome
  • Status unknown17 studies, 5 as a primary outcome

What they test

  • Behavioral20 studies, 12 as a primary outcome
  • Drug6 studies, 2 as a primary outcome
  • Device9 studies, 4 as a primary outcome
  • Dietary supplement12 studies, 9 as a primary outcome
  • Procedure1 studies, 0 as a primary outcome
  • Diagnostic test3 studies, 1 as a primary outcome
  • Other14 studies, 3 as a primary outcome
  • None given2 studies, 1 as a primary outcome

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

Where their sites are

  • United States17 studies, 12 as a primary outcome
  • Spain8 studies, 4 as a primary outcome
  • Taiwan6 studies, 2 as a primary outcome
  • China4 studies, 1 as a primary outcome
  • Netherlands4 studies, 2 as a primary outcome
  • France3 studies, 1 as a primary outcome
  • South Korea3 studies, 3 as a primary outcome
  • Brazil1 studies, 0 as a primary outcome
  • Canada1 studies, 0 as a primary outcome
  • Denmark1 studies, 0 as a primary outcome
  • Egypt1 studies, 0 as a primary outcome
  • Germany1 studies, 0 as a primary outcome

19 countries in all. A study with sites in several counts in each; 4 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 cognitive impairment and decline studies that name the Digit Span Test: 12 of 26, 46%

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

Completed cognitive impairment and decline studies that name the Digit Span Test and every completed study, by how they reported results
ResultsCompleted cognitive impairment and decline studies that name the Digit Span TestEvery completed study
Results on ClinicalTrials.gov and a paper2, 8%776, 10%
Results on ClinicalTrials.gov only5, 19%1,139, 14%
A results paper only5, 19%1,711, 22%
Neither14, 54%4,327, 54%

The 60 studies

Filter by phase, sponsor, status, country, intervention, outcome list, size and start year. Each study links to its record on ClinicalTrials.gov.
ConditionCognitive impairment and decline
TestThe Digit Span Test

60 studies match. 29 name the Digit Span Test in a primary outcome. Median size 66 participants. Median time to the primary outcome: 12 weeks.

Loading 60 studies; the filters turn on when they arrive.

By start year
024682000: 0 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: 0 studies, 0 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: 1 studies, 1 naming the Digit Span Test in a primary outcome2009: 0 studies, 0 naming the Digit Span Test in a primary outcome2010: 1 studies, 1 naming the Digit Span Test in a primary outcome20102011: 2 studies, 1 naming the Digit Span Test in a primary outcome2012: 1 studies, 1 naming the Digit Span Test in a primary outcome2013: 1 studies, 1 naming the Digit Span Test in a primary outcome2014: 1 studies, 0 naming the Digit Span Test in a primary outcome2015: 2 studies, 2 naming the Digit Span Test in a primary outcome20152016: 3 studies, 1 naming the Digit Span Test in a primary outcome2017: 4 studies, 2 naming the Digit Span Test in a primary outcome2018: 5 studies, 2 naming the Digit Span Test in a primary outcome2019: 6 studies, 1 naming the Digit Span Test in a primary outcome2020: 1 studies, 0 naming the Digit Span Test in a primary outcome20202021: 2 studies, 1 naming the Digit Span Test in a primary outcome2022: 7 studies, 2 naming the Digit Span Test in a primary outcome2023: 7 studies, 5 naming the Digit Span Test in a primary outcome2024: 5 studies, 1 naming the Digit Span Test in a primary outcome2025: 5 studies, 4 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
200000
200100
200200
200300
200400
200500
200600
200700
200811
200900
201011
201121
201211
201311
201410
201522
201631
201742
201852
201961
202010
202121
202272
202375
202451
202554
202663

Library tests named most

  • Digit Span Test60 studies, 29 as a primary outcome
  • Verbal Learning27 studies, 16 as a primary outcome
  • Trail Making Test25 studies, 11 as a primary outcome
  • Verbal Fluency17 studies, 10 as a primary outcome
  • Stroop Color-Word Test15 studies, 7 as a primary outcome
  • Symbol Coding11 studies, 4 as a primary outcome
  • Category Fluency9 studies, 7 as a primary outcome
  • Continuous Performance Test6 studies, 4 as a primary outcome
  • Picture Naming Test6 studies, 4 as a primary outcome
  • Matrix Reasoning5 studies, 3 as a primary outcome

Conditions

  • Cognitive impairment and decline60 studies, 29 as a primary outcome

Phases

Participants

Lead sponsor: industry 5, other 55. Interventional 51, observational 9.

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
NCT07891650Start2026PhaseNot applicableConditionsCognitive impairment and declineParticipants160Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Trail Making TestSecondary6 months
  • Verbal LearningSecondary6 months
  • Digit Span TestSecondary6 months
NCT07802392Start2026PhaseNot applicableConditionsCognitive impairment and declineParticipants230Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal FluencyPrimary1 week
  • Digit Span TestPrimary1 week
NCT07766642Start2026PhaseNot applicableConditionsCognitive impairment and declineParticipants35Lead sponsorIndustryStatusActive, not recruitingLibrary tests named
  • Digit Span TestPrimary8 weeks
NCT07751510Start2026PhaseNot applicableConditionsCognitive impairment and declineParticipants75Lead sponsorOtherStatusNot yet recruitingLibrary tests named
  • Stroop Color-Word TestSecondary13 weeks
  • Verbal LearningPrimary13 weeks
  • Verbal FluencyPrimary13 weeks
  • Digit Span TestSecondary13 weeks
  • Symbol CodingSecondary13 weeks
NCT07564804Start2025PhaseNot applicableConditionsCognitive impairment and declineParticipants60Lead sponsorIndustryStatusCompletedLibrary tests named
  • Digit Span TestPrimary8 weeks
NCT07531888Start2026PhaseNot applicableConditionsCognitive impairment and declineParticipants20Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningPrimary6 weeks
  • Verbal FluencyPrimary6 weeks
  • Digit Span TestPrimary6 weeks
  • Tower PlanningPrimary6 weeks
  • Corsi Block-Tapping TestPrimary6 weeks
NCT07463391Start2026PhaseNot applicableConditionsCognitive impairment and declineParticipants60Lead sponsorOtherStatusRecruitingLibrary tests named
  • Stroop Color-Word TestSecondary6 months
  • Verbal LearningSecondary6 months
  • Digit Span TestSecondary6 months
  • Picture Naming TestSecondary6 months
NCT07334366Start2025PhaseNot applicableConditionsCognitive impairment and declineParticipants100Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningPrimary12 weeks
  • Digit Span TestPrimary12 weeks
  • Continuous Performance TestPrimary12 weeks
NCT07198399Start2025PhaseNot applicableConditionsCognitive impairment and declineParticipants35Lead sponsorIndustryStatusCompletedLibrary tests named
  • Digit Span TestPrimary8 weeks
NCT07042633Start2024PhaseObservationalConditionsCognitive impairment and declineParticipants150Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondary
  • Verbal LearningSecondary12 months
  • Digit Span TestSecondary
  • Picture Naming TestSecondary12 months
  • Clock Drawing TaskSecondary
NCT07011680Start2025PhaseNot applicableConditionsCognitive impairment and declineParticipants100Lead sponsorOtherStatusRecruitingLibrary tests named
  • Verbal LearningPrimary12 weeks
  • Digit Span TestPrimary12 weeks
  • Continuous Performance TestPrimary12 weeks
NCT06783465Start2025PhaseNot applicableConditionsCognitive impairment and declineParticipants30Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Digit Span TestOther outcome16 weeks
NCT06523218Start2024PhaseNot applicableConditionsCognitive impairment and declineParticipants50Lead sponsorIndustryStatusStatus unknownLibrary tests named
  • Digit Span TestPrimary13 weeks
NCT06515106Start2023PhaseNot applicableConditionsCognitive impairment and declineParticipants20Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestPrimary12 months
  • Stroop Color-Word TestPrimary12 months
  • Verbal LearningPrimary12 months
  • Verbal FluencyPrimary12 months
  • Digit Span TestPrimary12 months
  • Category FluencyPrimary12 months
  • Picture Naming TestPrimary12 months
  • Symbol Scan TaskPrimary12 months
NCT06501755Start2024PhaseNot applicableConditionsCognitive impairment and declineParticipants36Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Digit Span TestSecondary2 weeks
  • N-Back TaskSecondary2 days
  • Spatial N-Back TaskSecondary2 days
NCT06466642Start2023PhaseNot applicableConditionsCognitive impairment and declineParticipants43Lead sponsorOtherStatusStatus unknown

Paper 1Paper 2

Library tests named
  • Trail Making TestPrimary10 weeks
  • Verbal LearningPrimary10 weeks
  • Digit Span TestPrimary10 weeks
  • Category FluencyPrimary10 weeks
  • Task Switching TestPrimary10 weeks
  • Symbol Scan TaskPrimary10 weeks
NCT06433037Start2024PhaseNot applicableConditionsCognitive impairment and declineParticipants164Lead sponsorOtherStatusActive, not recruiting

Paper

Library tests named
  • Digit Span TestSecondary6 months
  • Symbol CodingSecondary6 months
  • N-Back TaskPrimary6 months
  • Category FluencySecondary6 months
NCT06352749Start2024PhaseNot applicableConditionsCognitive impairment and declineParticipants120Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Trail Making TestPrimary6 months
  • Digit Span TestSecondary6 months
NCT06227962Start2023PhaseObservationalConditionsCognitive impairment and declineParticipants240Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestPrimary
  • Stroop Color-Word TestPrimary
  • Verbal LearningPrimary
  • Verbal FluencyPrimary
  • Digit Span TestPrimary
  • Matrix ReasoningPrimary
  • Symbol Scan TaskPrimary
NCT06183788Start2023PhaseNot applicableConditionsCognitive impairment and declineParticipants20Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Trail Making TestPrimary18 months
  • Stroop Color-Word TestPrimary18 months
  • Verbal LearningPrimary18 months
  • Verbal FluencyPrimary18 months
  • Digit Span TestPrimary18 months
  • Continuous Performance TestPrimary18 months
  • Category FluencyPrimary18 months
  • Picture Naming TestPrimary18 months
  • Complex Figure Copy and RecallSecondary18 months
  • Emoji Emotion RecognitionSecondary18 months
  • Spatial Working MemorySecondary18 months
  • Line Angle MatchingSecondary18 months
  • Intra/Extra Dimensional Set ShiftSecondary18 months
NCT05990023Start2023PhaseNot applicableConditionsCognitive impairment and declineParticipants150Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Trail Making TestSecondary3 years
  • Stroop Color-Word TestSecondary3 years
  • Digit Span TestSecondary3 years
NCT05854433Start2023PhaseObservationalConditionsCognitive impairment and declineParticipants100Lead sponsorOtherStatusRecruitingLibrary tests named
  • Trail Making TestSecondarysame day
  • Verbal LearningSecondarysame day
  • Verbal FluencySecondarysame day
  • Digit Span TestSecondarysame day
  • Size Order Memory TestSecondarysame day
  • Pattern and Letter ComparisonSecondarysame day
  • Picture Order Memory TestSecondarysame day
NCT05737498Start2023PhaseNot applicableConditionsCognitive impairment and declineParticipants40Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Trail Making TestPrimary2 weeks
  • Digit Span TestPrimary2 weeks
NCT05642169Start2022PhaseNot applicableConditionsCognitive impairment and declineParticipants75Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Digit Span TestSecondary6 months
  • Card Sorting Test (Berg)Secondary6 months
NCT05640440Start2022PhaseObservationalConditionsCognitive impairment and declineParticipants45Lead sponsorOtherStatusStatus unknownLibrary tests named
  • Stroop Color-Word TestPrimary12 months
  • Digit Span TestSecondary12 months
  • Card Sorting Test (Berg)Primary12 months
  • Numerical Stroop TaskPrimary12 months

Page 1 of 3

Questions, answered from the data

How many cognitive impairment and decline trials use the Digit Span Test?

60 registered cognitive impairment and decline studies on ClinicalTrials.gov name it in an outcome measure, 29 of them in a primary outcome: 17% of the condition's 354 studies with a cognitive outcome, against 10% of all of them. It is the 4th most named test in cognitive impairment and decline trials.

Which tests do cognitive impairment and decline trials use with the Digit Span Test?

Verbal Learning (27 studies), the Trail Making Test (25 studies) and Verbal Fluency (17 studies).

When do cognitive impairment and decline trials measure the Digit Span Test?

Half of the primary outcomes that name the Digit Span Test are measured within 12 weeks of the start, and the middle half from 8 weeks to 6 months. 28 primary outcomes give a duration.

How many completed cognitive impairment and decline trials that use the Digit Span Test have reported results?

12 of the 26 completed studies that name it, 46%, have reported results: 7 posted them on ClinicalTrials.gov, 7 have a results paper linked to the registry record, and 2 did both. The other 14 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.

More on the Digit Span Test and cognitive impairment and decline

  • Every cognitive test in cognitive impairment and decline trials: 354 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
  • Pain and fatigue61
  • Cardiovascular disease59
  • ADHD58

Other tests in cognitive impairment and decline trials

  • Verbal Learning79
  • Trail Making Test77
  • Verbal Fluency63

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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