Clinical trials data
Cognitive tests in brain injury and concussion trials: 444 registered studies
Every registered brain injury and concussion study on ClinicalTrials.gov that names a cognitive test in an outcome measure: the tests used most, how often as a primary outcome, which tests go together, how large the studies are and when they measure the outcome.
- Registered brain injury and concussion studies name a cognitive test in an outcome
- 444
- Led by industry
- 28
The tests brain injury and concussion trials use most
The Trail Making Test leads: 115 of the 444 studies name it, 26%. Next comes Verbal Learning (111). As a primary outcome, Verbal Learning leads with 50 studies.
- 1
Trail Making Test115 studies, 44 as a primary outcome
- 2
Verbal Learning111 studies, 50 as a primary outcome
- 3
Digit Span Test98 studies, 40 as a primary outcome
- 4
Verbal Fluency86 studies, 39 as a primary outcome
- 5
Stroop Color-Word Test59 studies, 29 as a primary outcome
- 6
Symbol Coding43 studies, 17 as a primary outcome
- 7
Continuous Performance Test39 studies, 22 as a primary outcome
- 8
N-Back Task26 studies, 14 as a primary outcome
- 9
Symbol Scan Task24 studies, 8 as a primary outcome
- 10
Category Fluency22 studies, 12 as a primary outcome
- 11
Paced Visual Serial Addition Test18 studies, 13 as a primary outcome
- 12
Task Switching Test18 studies, 8 as a primary outcome
- 13
Card Sorting Test (Berg)17 studies, 9 as a primary outcome
- 14
Cancellation Test17 studies, 8 as a primary outcome
- 15
Letter-Number Sequencing Task17 studies, 7 as a primary outcome
- 16
Simple Reaction Time15 studies, 9 as a primary outcome
- 17
Picture Naming Test15 studies, 7 as a primary outcome
- 18
Complex Figure Copy and Recall15 studies, 3 as a primary outcome
- 19
Go/No-Go Task12 studies, 7 as a primary outcome
- 20
Eriksen Flanker Task10 studies, 5 as a primary outcome
- 21
Short Story Recall10 studies, 5 as a primary outcome
- 22
Pattern and Letter Comparison10 studies, 4 as a primary outcome
- 23
Matrix Reasoning10 studies, 3 as a primary outcome
- 24
Size Order Memory Test10 studies, 3 as a primary outcome
- 25
AX Continuous Performance Test10 studies, 0 as a primary outcome
A test as a primary outcomeOnly in secondary or other outcomes
17% of brain injury and concussion studies name only instruments outside the library, such as clinician-administered screening scales. They count in every figure on this page and are not listed. The explorer below holds all 92 tests.
Tests used together
- Trail Making Test and Verbal Fluency48 studies name both
- Trail Making Test and Verbal Learning46 studies name both
- Digit Span Test and Verbal Learning43 studies name both
- Verbal Fluency and Verbal Learning42 studies name both
- Digit Span Test and Trail Making Test39 studies name both
- Digit Span Test and Verbal Fluency34 studies name both
- Stroop Color-Word Test and Trail Making Test26 studies name both
- Symbol Coding and Verbal Learning25 studies name both
- Digit Span Test and Stroop Color-Word Test23 studies name both
- Stroop Color-Word Test and Verbal Fluency22 studies name both
Studies by start year
A test as a primary outcomeOnly in secondary or other outcomes
Show as a table
| Start year | Studies | A test as a primary outcome |
|---|---|---|
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 2 | 1 |
| 2004 | 1 | 1 |
| 2005 | 1 | 0 |
| 2006 | 1 | 1 |
| 2007 | 4 | 4 |
| 2008 | 4 | 3 |
| 2009 | 10 | 7 |
| 2010 | 10 | 5 |
| 2011 | 11 | 7 |
| 2012 | 13 | 11 |
| 2013 | 21 | 16 |
| 2014 | 28 | 16 |
| 2015 | 21 | 12 |
| 2016 | 26 | 11 |
| 2017 | 26 | 7 |
| 2018 | 26 | 15 |
| 2019 | 26 | 13 |
| 2020 | 20 | 11 |
| 2021 | 36 | 21 |
| 2022 | 21 | 8 |
| 2023 | 34 | 18 |
| 2024 | 30 | 13 |
| 2025 | 34 | 19 |
| 2026 | 32 | 8 |
Phases and sponsors
By phase
- Early phase 16 studies, 2 as a primary outcome
- Phase 114 studies, 7 as a primary outcome
- Phase 1/28 studies, 2 as a primary outcome
- Phase 230 studies, 15 as a primary outcome
- Phase 2/33 studies, 1 as a primary outcome
- Phase 313 studies, 5 as a primary outcome
- Phase 413 studies, 9 as a primary outcome
- Not applicable294 studies, 158 as a primary outcome
- Observational63 studies, 30 as a primary outcome
Sponsors and study types
Lead sponsor: industry 28, NIH 7, universities, hospitals and others 409. Interventional 381, observational 63.
Status, results, interventions and countries
Status
- Recruiting83 studies, 39 as a primary outcome
- Not yet recruiting26 studies, 9 as a primary outcome
- Active, not recruiting17 studies, 7 as a primary outcome
- Completed203 studies, 115 as a primary outcome
- Stopped early45 studies, 23 as a primary outcome
- Status unknown70 studies, 36 as a primary outcome
What they test
- Behavioral140 studies, 70 as a primary outcome
- Drug70 studies, 37 as a primary outcome
- Device113 studies, 67 as a primary outcome
- Dietary supplement9 studies, 2 as a primary outcome
- Procedure19 studies, 7 as a primary outcome
- Diagnostic test13 studies, 8 as a primary outcome
- Biological7 studies, 1 as a primary outcome
- Radiation1 studies, 1 as a primary outcome
- Combination product5 studies, 3 as a primary outcome
- Genetic2 studies, 1 as a primary outcome
- Other96 studies, 50 as a primary outcome
- None given25 studies, 12 as a primary outcome
Intervention types as registered. A study can list several; observational studies often list none.
Where their sites are
- United States257 studies, 138 as a primary outcome
- France24 studies, 5 as a primary outcome
- Italy19 studies, 12 as a primary outcome
- Canada15 studies, 7 as a primary outcome
- Spain12 studies, 8 as a primary outcome
- China11 studies, 5 as a primary outcome
- Sweden10 studies, 7 as a primary outcome
- United Kingdom10 studies, 4 as a primary outcome
- Israel9 studies, 4 as a primary outcome
- Norway9 studies, 0 as a primary outcome
- Denmark7 studies, 3 as a primary outcome
- Netherlands7 studies, 2 as a primary outcome
45 countries in all. A study with sites in several counts in each; 22 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 brain injury and concussion studies: 102 of 203, 50%
Every completed study with a cognitive outcome: 3,626 of 7,953, 46%
| Results | Completed brain injury and concussion studies | Every completed study |
|---|---|---|
| Results on ClinicalTrials.gov and a paper | 18, 9% | 776, 10% |
| Results on ClinicalTrials.gov only | 49, 24% | 1,139, 14% |
| A results paper only | 35, 17% | 1,711, 22% |
| Neither | 101, 50% | 4,327, 54% |
How many participants they enroll
- Phase 140 median, 27 to 60
- Phase 243 median, 22 to 60
- Phase 3133 median, 69 to 252
- Phase 440 median, 15 to 60
- Not applicable41 median, 24 to 80
- Observational92 median, 42 to 200
Show as a table
| Phase | Studies with a size | Median | Middle half |
|---|---|---|---|
| Phase 1 | 13 | 40 | 27 to 60 |
| Phase 2 | 29 | 43 | 22 to 60 |
| Phase 3 | 12 | 133 | 69 to 252 |
| Phase 4 | 13 | 40 | 15 to 60 |
| Not applicable | 288 | 41 | 24 to 80 |
| Observational | 61 | 92 | 42 to 200 |
When the cognitive outcome is measured
Latest time point of each outcome
- Within a day124 outcomes, 56 as a primary outcome
- Up to 4 weeks171 outcomes, 104 as a primary outcome
- 1 to 3 months335 outcomes, 157 as a primary outcome
- 3 to 6 months173 outcomes, 71 as a primary outcome
- 6 to 12 months86 outcomes, 25 as a primary outcome
- 1 to 2 years34 outcomes, 5 as a primary outcome
- Over 2 years10 outcomes, 5 as a primary outcome
- No duration given65 outcomes, 34 as a primary outcome
A test as a primary outcomeOnly in secondary or other outcomes
933 of the 998 outcome measures give a duration. A single visit counts as within a day.
Median time to the primary outcome, by test
| Test | Primary outcomes | Median |
|---|---|---|
| Verbal Learning | 47 | 12 weeks |
| Trail Making Test | 42 | 11 weeks |
| Digit Span Test | 37 | 10 weeks |
| Verbal Fluency | 37 | 9 weeks |
| Stroop Color-Word Test | 27 | 8 weeks |
| Continuous Performance Test | 21 | 7 weeks |
| Symbol Coding | 16 | 9 weeks |
| Category Fluency | 12 | 9 weeks |
| N-Back Task | 12 | 7 weeks |
| Paced Visual Serial Addition Test | 12 | 7 weeks |
Explore the brain injury and concussion studies
370 studies match. 205 name a library test in a primary outcome. Median size 44 participants. Median time to the primary outcome: 8 weeks.
Loading 370 studies; the filters turn on when they arrive.
2026 is partly planned starts. Not shown: 1 that started before 2000 and 3 planned to start after 2026.
Show as a table
| Start year | Studies | As a primary outcome |
|---|---|---|
| 2000 | 0 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 2 | 1 |
| 2004 | 1 | 1 |
| 2005 | 1 | 0 |
| 2006 | 1 | 1 |
| 2007 | 4 | 4 |
| 2008 | 4 | 3 |
| 2009 | 9 | 7 |
| 2010 | 8 | 4 |
| 2011 | 11 | 7 |
| 2012 | 11 | 10 |
| 2013 | 21 | 16 |
| 2014 | 26 | 16 |
| 2015 | 19 | 11 |
| 2016 | 21 | 9 |
| 2017 | 24 | 7 |
| 2018 | 19 | 12 |
| 2019 | 23 | 12 |
| 2020 | 18 | 11 |
| 2021 | 32 | 20 |
| 2022 | 15 | 7 |
| 2023 | 27 | 14 |
| 2024 | 19 | 10 |
| 2025 | 25 | 14 |
| 2026 | 25 | 7 |
Library tests named most
Largest condition groups
Phases
Participants
Lead sponsor: industry 22, NIH 7, other 341. Interventional 321, observational 49.
As a primary outcomeSecondary or other outcome
The studies, newest registration first
Each number opens the study's record on ClinicalTrials.gov.
| Study | Start | Phase | Conditions | Participants | Lead sponsor | Status | Library tests named, with the latest time point |
|---|---|---|---|---|---|---|---|
| NCT07895797 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion | Participants38 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07867015 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion | Participants30 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07817316 | Start2026 | PhaseNot applicable | ConditionsStroke, Brain injury and concussion | Participants30 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07733336 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion | Participants30 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07733284 | Start2026 | PhaseEarly phase 1 | ConditionsBrain injury and concussion | Participants40 | Lead sponsorOther | StatusActive, not recruiting | Library tests named
|
| NCT07730099 | Start2027 | PhaseNot applicable | ConditionsBrain injury and concussion | Participants40 | Lead sponsorIndustry | StatusNot yet recruiting | Library tests named
|
| NCT07717866 | Start2022 | PhaseObservational | ConditionsBrain injury and concussion, Depression and bipolar disorder, Anxiety, PTSD and OCD | Participants52 | Lead sponsorIndustry | StatusActive, not recruiting | Library tests named
|
| NCT07702513 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion | Participants33 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07642739 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion | Participants24 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07636408 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion, Sleep and sleep disorders | Participants70 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07606651 | Start2026 | PhaseObservational | ConditionsBrain injury and concussion | Participants250 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07586566 | Start2026 | PhaseNot applicable | ConditionsStroke, Brain injury and concussion | Participants15 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07557615 | Start2027 | PhaseEarly phase 1 | ConditionsBrain injury and concussion | Participants50 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07549529 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion | Participants80 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07456475 | Start2025 | PhaseNot applicable | ConditionsStroke, Brain injury and concussion, Parkinson's disease, Multiple sclerosis | Participants25 | Lead sponsorOther | StatusActive, not recruiting | Library tests named
|
| NCT07448103 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion, Cancer | Participants30 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07441798 | Start2026 | PhaseNot applicable | ConditionsStroke, Brain injury and concussion | Participants60 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07431320 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion, Healthy volunteers | Participants100 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07429526 | Start2013 | PhaseNot applicable | ConditionsStroke, Brain injury and concussion, Pain and fatigue | Participants12 | Lead sponsorOther | StatusCompleted | Library tests named
|
| NCT07428980 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion | Participants7 | Lead sponsorOther | StatusCompleted | Library tests named
|
| NCT07414537 | Start2027 | PhasePhase 2 | ConditionsBrain injury and concussion, Anxiety, PTSD and OCD | Participants46 | Lead sponsorOther | StatusNot yet recruiting | Library tests named
|
| NCT07413562 | Start2025 | PhaseNot applicable | ConditionsBrain injury and concussion | Participants30 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07378592 | Start2025 | PhaseNot applicable | ConditionsBrain injury and concussion | Participants50 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07345481 | Start2026 | PhaseObservational | ConditionsStroke, Brain injury and concussion | Participants40 | Lead sponsorOther | StatusRecruiting | Library tests named
|
| NCT07332299 | Start2026 | PhaseNot applicable | ConditionsBrain injury and concussion, Aging, frailty and exercise | Participants40 | Lead sponsorOther | StatusRecruiting | Library tests named
|
Questions, answered from the data
Which cognitive test do brain injury and concussion trials use most?
The Trail Making Test: 115 of the 444 registered studies name it in an outcome measure, 26%. Next come Verbal Learning (111) and the Digit Span Test (98).
Which cognitive test do brain injury and concussion trials use most as a primary outcome?
Verbal Learning, named in a primary outcome by 50 studies. 229 of the 444 studies, 52%, name a cognitive test in a primary outcome.
How many participants does a phase 2 brain injury and concussion trial enroll?
Half of the phase 2 brain injury and concussion studies enroll 43 participants or fewer, and the middle half enroll 22 to 60. 29 of them give a size.
How long after the start do brain injury and concussion trials measure a cognitive outcome?
Half of the primary outcomes that name a library test are measured within 8 weeks of the start, and the middle half from 2 weeks to 14 weeks. 423 primary outcomes give a duration.
Which cognitive tests do brain injury and concussion trials use together?
The Trail Making Test with Verbal Fluency most often: 48 studies name both. Next, the Trail Making Test with Verbal Learning (46).
How many completed brain injury and concussion trials have reported results?
102 of the 203 completed brain injury and concussion studies, 50%, have reported results: 67 posted them on ClinicalTrials.gov, 53 have a results paper linked to the registry record, and 18 did both. The other 101 show neither. Of all completed studies with a cognitive outcome, 46% have reported results.
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.
Plan the cognitive outcomes of a brain injury and concussion trial
Choose tests with a record in registered trials, and run them in a browser at every site, on the same version each visit.