Clinical trials data

Symbol Coding in mild cognitive impairment trials: 84 registered studies

Every registered mild cognitive impairment 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 mild cognitive impairment studies name it in an outcome measure: 84
Name it in a primary outcome, 45%: 38 of 84
Of the condition's 859 studies name it, against 9% of all registered studies: 10%; Other conditions
Median participants per study: 93; By phase

Try the Symbol Key Game Try Symbol Coding

Tests named in the same studies

The library tests that mild cognitive impairment studies naming Symbol Coding name most often beside it.

1
Trail Making Test42 studies, 22 as a primary outcome
2
Verbal Fluency34 studies, 16 as a primary outcome
3
Digit Span Test32 studies, 20 as a primary outcome
4
Verbal Learning28 studies, 16 as a primary outcome
5
Category Fluency26 studies, 15 as a primary outcome
6
Short Story Recall22 studies, 12 as a primary outcome
7
Stroop Color-Word Test18 studies, 8 as a primary outcome
8
Selective Reminding Task14 studies, 5 as a primary outcome
9
Picture Naming Test11 studies, 6 as a primary outcome
10
Clock Drawing Task10 studies, 5 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.

A test as a primary outcomeOnly in secondary or other outcomes

Show as a table

Registered studies by start year
Start year	Studies	A test as a primary outcome
2000	0	0
2001	0	0
2002	0	0
2003	0	0
2004	0	0
2005	0	0
2006	0	0
2007	0	0
2008	1	1
2009	2	1
2010	1	0
2011	3	0
2012	4	2
2013	0	0
2014	1	0
2015	1	0
2016	3	2
2017	2	1
2018	3	3
2019	2	1
2020	3	2
2021	15	7
2022	7	3
2023	11	4
2024	12	8
2025	10	3
2026	3	0

Phases and study sizes

By phase

Phase 11 studies, 0 as a primary outcome
Phase 1/21 studies, 0 as a primary outcome
Phase 215 studies, 6 as a primary outcome
Phase 2/31 studies, 0 as a primary outcome
Phase 32 studies, 2 as a primary outcome
Phase 41 studies, 1 as a primary outcome
Not applicable60 studies, 28 as a primary outcome
Observational3 studies, 1 as a primary outcome

Participants per study

Phase 278 median, 50 to 200
Not applicable85 median, 45 to 180

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.

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Participants per mild cognitive impairment study that names Symbol Coding, by phase
Phase	Studies with a size	Median	Middle half
Phase 2	13	78	50 to 200
Not applicable	60	85	45 to 180

When mild cognitive impairment trials measure it

Half of the primary outcomes that name Symbol Coding are measured within 6 months of the start, and the middle half from 12 weeks to 12 months. 35 primary outcomes give a duration.

Latest time point of each outcome

Within a day2 outcomes, 2 as a primary outcome
Up to 4 weeks6 outcomes, 1 as a primary outcome
1 to 3 months20 outcomes, 11 as a primary outcome
3 to 6 months18 outcomes, 9 as a primary outcome
6 to 12 months19 outcomes, 7 as a primary outcome
1 to 2 years9 outcomes, 4 as a primary outcome
Over 2 years5 outcomes, 1 as a primary outcome
No duration given5 outcomes, 3 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

79 of the 84 outcome measures give a duration. A single visit counts as within a day.

Status, results, interventions and countries

Status

Recruiting17 studies, 8 as a primary outcome
Not yet recruiting6 studies, 3 as a primary outcome
Active, not recruiting5 studies, 3 as a primary outcome
Completed36 studies, 14 as a primary outcome
Stopped early4 studies, 1 as a primary outcome
Status unknown16 studies, 9 as a primary outcome

What they test

Behavioral28 studies, 11 as a primary outcome
Drug16 studies, 7 as a primary outcome
Device17 studies, 4 as a primary outcome
Dietary supplement8 studies, 6 as a primary outcome
Procedure1 studies, 0 as a primary outcome
Diagnostic test2 studies, 1 as a primary outcome
Biological1 studies, 0 as a primary outcome
Combination product4 studies, 4 as a primary outcome
Genetic1 studies, 0 as a primary outcome
Other20 studies, 13 as a primary outcome
None given1 studies, 0 as a primary outcome

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

29 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 mild cognitive impairment studies that name Symbol Coding: 19 of 36, 53%

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

Completed mild cognitive impairment studies that name Symbol Coding and every completed study, by how they reported results
Results	Completed mild cognitive impairment studies that name Symbol Coding	Every completed study
Results on ClinicalTrials.gov and a paper	6, 17%	776, 10%
Results on ClinicalTrials.gov only	6, 17%	1,139, 14%
A results paper only	7, 19%	1,711, 22%
Neither	17, 47%	4,327, 54%

The 84 studies

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

84 studies match. 38 name Symbol Coding in a primary outcome. Median size 93 participants. Median time to the primary outcome: 6 months.

Loading 84 studies; the filters turn on when they arrive.

By start year

2026 is partly planned starts.

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Matching studies by start year
Start year	Studies	As a primary outcome
2000	0	0
2001	0	0
2002	0	0
2003	0	0
2004	0	0
2005	0	0
2006	0	0
2007	0	0
2008	1	1
2009	2	1
2010	1	0
2011	3	0
2012	4	2
2013	0	0
2014	1	0
2015	1	0
2016	3	2
2017	2	1
2018	3	3
2019	2	1
2020	3	2
2021	15	7
2022	7	3
2023	11	4
2024	12	8
2025	10	3
2026	3	0

Library tests named most

Largest condition groups

Mild cognitive impairment84 studies, 38 as a primary outcome
Dementia and Alzheimer's25 studies, 6 as a primary outcome
Aging, frailty and exercise8 studies, 4 as a primary outcome
Brain injury and concussion4 studies, 3 as a primary outcome
Cancer4 studies, 1 as a primary outcome
Parkinson's disease3 studies, 0 as a primary outcome
Multiple sclerosis3 studies, 0 as a primary outcome
Depression and bipolar disorder3 studies, 2 as a primary outcome
Obesity and diabetes2 studies, 2 as a primary outcome
Sleep and sleep disorders2 studies, 2 as a primary outcome
COVID-19 and long COVID2 studies, 1 as a primary outcome
Anxiety, PTSD and OCD2 studies, 1 as a primary outcome

Phases

Participants

Lead sponsor: industry 12, other 72. Interventional 81, observational 3.

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.
Study	Start	Phase	Conditions	Participants	Lead sponsor	Status	Library tests named, with the latest time point
NCT07856043	Start2026	PhasePhase 1	ConditionsDementia and Alzheimer's, Mild cognitive impairment, Cardiovascular disease	Participants18	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestSecondary12 weeks Symbol CodingSecondary12 weeks Selective Reminding TaskSecondary12 weeks
NCT07842146	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants60	Lead sponsorOther	StatusRecruiting	Library tests named Verbal FluencySecondary11 months Symbol CodingSecondary11 months Category FluencySecondary11 months Delayed Recall ModuleSecondary11 months
NCT07651787	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants40	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingOther outcome12 weeks N-Back TaskPrimary12 weeks Dimensional Change Card SortOther outcome12 weeks Size Order Memory TestOther outcome12 weeks Pattern and Letter ComparisonOther outcome12 weeks Picture Order Memory TestOther outcome12 weeks
NCT07497334	Start2025	PhaseNot applicable	ConditionsMild cognitive impairment, Aging, frailty and exercise	Participants45	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary6 months Stroop Color-Word TestSecondary6 months Digit Span TestSecondary6 months Symbol CodingSecondary6 months Task Switching TestSecondary6 months
NCT07376135	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants300	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestOther outcome18 months Stroop Color-Word TestOther outcome18 months Verbal LearningOther outcome18 months Digit Span TestOther outcome18 months Symbol CodingOther outcome18 months Short Story RecallOther outcome18 months Complex Figure Copy and RecallOther outcome18 months
NCT07241598	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants70	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestSecondary12 months Verbal FluencySecondary12 months Digit Span TestSecondary12 months Symbol CodingSecondary12 months Go/No-Go TaskSecondary12 months Category FluencySecondary12 months
NCT07089303	Start2025	PhaseObservational	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants750	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary12 months Stroop Color-Word TestSecondary12 months Verbal LearningSecondary12 months Digit Span TestSecondary12 months Symbol CodingSecondary12 months Picture Naming TestSecondary12 months Clock Drawing TaskSecondary12 months Complex Figure Copy and RecallSecondary12 months
NCT06977815	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment, Aging, frailty and exercise	Participants70	Lead sponsorOther	StatusCompleted	Library tests named Trail Making TestPrimary12 weeks Digit Span TestPrimary12 weeks Symbol CodingPrimary12 weeks
NCT06935812	Start2025	PhaseNot applicable	ConditionsMild cognitive impairment	Participants106	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestPrimary8 weeks Verbal FluencyPrimary8 weeks Digit Span TestPrimary8 weeks Symbol CodingPrimary8 weeks Clock Drawing TaskPrimary8 weeks Arithmetic Fluency TaskPrimary8 weeks
NCT06854731	Start2025	PhaseNot applicable	ConditionsMild cognitive impairment, Aging, frailty and exercise	Participants328	Lead sponsorOther	StatusRecruiting	Library tests named Verbal LearningSecondary18 months Symbol CodingSecondary18 months Dimensional Change Card SortSecondary18 months
NCT06825403	Start2025	PhaseNot applicable	ConditionsMild cognitive impairment	Participants30	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingPrimary6 months Category FluencyPrimary6 months Short Story RecallPrimary6 months Selective Reminding TaskPrimary6 months
NCT06773416	Start2025	PhaseNot applicable	ConditionsMild cognitive impairment, Aging, frailty and exercise, Sleep and sleep disorders	Participants206	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestPrimary7 months Verbal LearningPrimary7 months Digit Span TestPrimary7 months Symbol CodingPrimary7 months Letter-Number Sequencing TaskPrimary7 months
NCT06719297	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment	Participants40	Lead sponsorOther	StatusNot yet recruiting	Library tests named Digit Span TestPrimary10 weeks Symbol CodingPrimary10 weeks Continuous Performance TestPrimary10 weeks Paced Visual Serial Addition TestPrimary10 weeks AX Continuous Performance TestWording unclear Letter-Number Sequencing TaskPrimary10 weeks
NCT06601933	Start2024	PhasePhase 2	ConditionsMild cognitive impairment	Participants240	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingOther outcome18 months Category FluencyOther outcome18 months Short Story RecallOther outcome18 months Selective Reminding TaskOther outcome18 months
NCT06413173	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment, Brain injury and concussion	Participants160	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingPrimary6 weeks N-Back TaskPrimary6 weeks Hidden Path LearningPrimary6 weeks
NCT06408103	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment	Participants102	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestPrimary9 months Verbal LearningPrimary9 months Verbal FluencyPrimary9 months Symbol CodingPrimary9 months Picture Naming TestPrimary9 months Complex Figure Copy and RecallPrimary9 months Token Commands TaskPrimary9 months
NCT06399731	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment, Parkinson's disease	Participants20	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary Verbal LearningSecondary Verbal FluencySecondary Digit Span TestSecondary Symbol CodingSecondary Tower PlanningSecondary Line Angle MatchingOther outcomesame day
NCT06375720	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment	Participants350	Lead sponsorOther	StatusStatus unknown	Library tests named Stroop Color-Word TestSecondary12 months Verbal LearningSecondary12 months Verbal FluencySecondary12 months Symbol CodingSecondary12 months Picture Naming TestSecondary12 months
NCT06347315	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment	Participants380	Lead sponsorIndustry	StatusRecruiting	Library tests named Symbol CodingPrimary12 months Short Story RecallPrimary12 months Selective Reminding TaskPrimary12 months
NCT06278688	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment	Participants120	Lead sponsorOther	StatusNot yet recruiting	Library tests named Stroop Color-Word TestPrimary12 months Verbal FluencyPrimary12 months Digit Span TestPrimary12 months Symbol CodingPrimary12 months Short Story RecallPrimary12 months
NCT06155721	Start2023	PhaseNot applicable	ConditionsMild cognitive impairment	Participants45	Lead sponsorOther	StatusCompleted Results	Library tests named Trail Making TestSecondary1 week Digit Span TestSecondary1 week Symbol CodingSecondary1 week
NCT06112639	Start2024	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment, Multiple sclerosis, Cancer	Participants192	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary6 months Stroop Color-Word TestSecondary6 months Verbal FluencySecondary6 months Symbol CodingSecondary6 months Category FluencySecondary6 months Selective Reminding TaskSecondary6 months Delayed Recall ModuleSecondary6 months
NCT06083350	Start2023	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants144	Lead sponsorOther	StatusStatus unknown	Library tests named Trail Making TestSecondary7 months Verbal FluencySecondary7 months Symbol CodingSecondary7 months Clock Drawing TaskSecondary7 months
NCT06041152	Start2023	PhasePhase 2	ConditionsMild cognitive impairment	Participants10	Lead sponsorOther	StatusCompleted	Library tests named Trail Making TestSecondary3 years Verbal LearningSecondary3 years Verbal FluencySecondary3 years Symbol CodingSecondary3 years Category FluencySecondary3 years Picture Naming TestSecondary3 years Card Sorting Test (Berg)Secondary3 years Short Story RecallSecondary3 years Clock Drawing TaskSecondary3 years Complex Figure Copy and RecallSecondary3 years Block Copy TestSecondary3 years
NCT05997316	Start2023	PhaseNot applicable	ConditionsMild cognitive impairment, Obesity and diabetes	Participants33	Lead sponsorOther	StatusCompleted Results	Library tests named Trail Making TestPrimary12 weeks Verbal LearningPrimary12 weeks Verbal FluencyPrimary12 weeks Digit Span TestPrimary12 weeks Symbol CodingPrimary12 weeks Category FluencyPrimary12 weeks

Questions, answered from the data

How many mild cognitive impairment trials use Symbol Coding?

84 registered mild cognitive impairment studies on ClinicalTrials.gov name it in an outcome measure, 38 of them in a primary outcome: 10% of the condition's 859 studies with a cognitive outcome, against 9% of all of them. It is the 7th most named test in mild cognitive impairment trials.

Which tests do mild cognitive impairment trials use with Symbol Coding?

The Trail Making Test (42 studies), Verbal Fluency (34 studies) and the Digit Span Test (32 studies).

How many participants do phase 2 mild cognitive impairment trials that use Symbol Coding enroll?

Half of the phase 2 studies that name it enroll 78 participants or fewer, and the middle half enroll 50 to 200. 13 of them give a size.

When do mild cognitive impairment trials measure Symbol Coding?

Half of the primary outcomes that name Symbol Coding are measured within 6 months of the start, and the middle half from 12 weeks to 12 months. 35 primary outcomes give a duration.

How many completed mild cognitive impairment trials that use Symbol Coding have reported results?

19 of the 36 completed studies that name it, 53%, have reported results: 12 posted them on ClinicalTrials.gov, 13 have a results paper linked to the registry record, and 6 did both. The other 17 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.

The census counts Symbol Key Game and Symbol Coding as one test family, so this page counts their studies together.

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Clinical trials data

Symbol Coding in mild cognitive impairment trials: 84 registered studies

Registered mild cognitive impairment studies name it in an outcome measure: 84
Name it in a primary outcome, 45%: 38 of 84
Of the condition's 859 studies name it, against 9% of all registered studies: 10%; Other conditions
Median participants per study: 93; By phase

Try the Symbol Key Game Try Symbol Coding

Tests named in the same studies

The library tests that mild cognitive impairment studies naming Symbol Coding name most often beside it.

1
Trail Making Test42 studies, 22 as a primary outcome
2
Verbal Fluency34 studies, 16 as a primary outcome
3
Digit Span Test32 studies, 20 as a primary outcome
4
Verbal Learning28 studies, 16 as a primary outcome
5
Category Fluency26 studies, 15 as a primary outcome
6
Short Story Recall22 studies, 12 as a primary outcome
7
Stroop Color-Word Test18 studies, 8 as a primary outcome
8
Selective Reminding Task14 studies, 5 as a primary outcome
9
Picture Naming Test11 studies, 6 as a primary outcome
10
Clock Drawing Task10 studies, 5 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.

A test as a primary outcomeOnly in secondary or other outcomes

Show as a table

Registered studies by start year
Start year	Studies	A test as a primary outcome
2000	0	0
2001	0	0
2002	0	0
2003	0	0
2004	0	0
2005	0	0
2006	0	0
2007	0	0
2008	1	1
2009	2	1
2010	1	0
2011	3	0
2012	4	2
2013	0	0
2014	1	0
2015	1	0
2016	3	2
2017	2	1
2018	3	3
2019	2	1
2020	3	2
2021	15	7
2022	7	3
2023	11	4
2024	12	8
2025	10	3
2026	3	0

Phases and study sizes

By phase

Phase 11 studies, 0 as a primary outcome
Phase 1/21 studies, 0 as a primary outcome
Phase 215 studies, 6 as a primary outcome
Phase 2/31 studies, 0 as a primary outcome
Phase 32 studies, 2 as a primary outcome
Phase 41 studies, 1 as a primary outcome
Not applicable60 studies, 28 as a primary outcome
Observational3 studies, 1 as a primary outcome

Participants per study

Phase 278 median, 50 to 200
Not applicable85 median, 45 to 180

Show as a table

Participants per mild cognitive impairment study that names Symbol Coding, by phase
Phase	Studies with a size	Median	Middle half
Phase 2	13	78	50 to 200
Not applicable	60	85	45 to 180

When mild cognitive impairment trials measure it

Half of the primary outcomes that name Symbol Coding are measured within 6 months of the start, and the middle half from 12 weeks to 12 months. 35 primary outcomes give a duration.

Latest time point of each outcome

Within a day2 outcomes, 2 as a primary outcome
Up to 4 weeks6 outcomes, 1 as a primary outcome
1 to 3 months20 outcomes, 11 as a primary outcome
3 to 6 months18 outcomes, 9 as a primary outcome
6 to 12 months19 outcomes, 7 as a primary outcome
1 to 2 years9 outcomes, 4 as a primary outcome
Over 2 years5 outcomes, 1 as a primary outcome
No duration given5 outcomes, 3 as a primary outcome

A test as a primary outcomeOnly in secondary or other outcomes

79 of the 84 outcome measures give a duration. A single visit counts as within a day.

Status, results, interventions and countries

Status

Recruiting17 studies, 8 as a primary outcome
Not yet recruiting6 studies, 3 as a primary outcome
Active, not recruiting5 studies, 3 as a primary outcome
Completed36 studies, 14 as a primary outcome
Stopped early4 studies, 1 as a primary outcome
Status unknown16 studies, 9 as a primary outcome

What they test

Behavioral28 studies, 11 as a primary outcome
Drug16 studies, 7 as a primary outcome
Device17 studies, 4 as a primary outcome
Dietary supplement8 studies, 6 as a primary outcome
Procedure1 studies, 0 as a primary outcome
Diagnostic test2 studies, 1 as a primary outcome
Biological1 studies, 0 as a primary outcome
Combination product4 studies, 4 as a primary outcome
Genetic1 studies, 0 as a primary outcome
Other20 studies, 13 as a primary outcome
None given1 studies, 0 as a primary outcome

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

29 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 mild cognitive impairment studies that name Symbol Coding: 19 of 36, 53%

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

Completed mild cognitive impairment studies that name Symbol Coding and every completed study, by how they reported results
Results	Completed mild cognitive impairment studies that name Symbol Coding	Every completed study
Results on ClinicalTrials.gov and a paper	6, 17%	776, 10%
Results on ClinicalTrials.gov only	6, 17%	1,139, 14%
A results paper only	7, 19%	1,711, 22%
Neither	17, 47%	4,327, 54%

The 84 studies

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

84 studies match. 38 name Symbol Coding in a primary outcome. Median size 93 participants. Median time to the primary outcome: 6 months.

Loading 84 studies; the filters turn on when they arrive.

By start year

2026 is partly planned starts.

Show as a table

Matching studies by start year
Start year	Studies	As a primary outcome
2000	0	0
2001	0	0
2002	0	0
2003	0	0
2004	0	0
2005	0	0
2006	0	0
2007	0	0
2008	1	1
2009	2	1
2010	1	0
2011	3	0
2012	4	2
2013	0	0
2014	1	0
2015	1	0
2016	3	2
2017	2	1
2018	3	3
2019	2	1
2020	3	2
2021	15	7
2022	7	3
2023	11	4
2024	12	8
2025	10	3
2026	3	0

Library tests named most

Largest condition groups

Mild cognitive impairment84 studies, 38 as a primary outcome
Dementia and Alzheimer's25 studies, 6 as a primary outcome
Aging, frailty and exercise8 studies, 4 as a primary outcome
Brain injury and concussion4 studies, 3 as a primary outcome
Cancer4 studies, 1 as a primary outcome
Parkinson's disease3 studies, 0 as a primary outcome
Multiple sclerosis3 studies, 0 as a primary outcome
Depression and bipolar disorder3 studies, 2 as a primary outcome
Obesity and diabetes2 studies, 2 as a primary outcome
Sleep and sleep disorders2 studies, 2 as a primary outcome
COVID-19 and long COVID2 studies, 1 as a primary outcome
Anxiety, PTSD and OCD2 studies, 1 as a primary outcome

Phases

Participants

Lead sponsor: industry 12, other 72. Interventional 81, observational 3.

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.
Study	Start	Phase	Conditions	Participants	Lead sponsor	Status	Library tests named, with the latest time point
NCT07856043	Start2026	PhasePhase 1	ConditionsDementia and Alzheimer's, Mild cognitive impairment, Cardiovascular disease	Participants18	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestSecondary12 weeks Symbol CodingSecondary12 weeks Selective Reminding TaskSecondary12 weeks
NCT07842146	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants60	Lead sponsorOther	StatusRecruiting	Library tests named Verbal FluencySecondary11 months Symbol CodingSecondary11 months Category FluencySecondary11 months Delayed Recall ModuleSecondary11 months
NCT07651787	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants40	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingOther outcome12 weeks N-Back TaskPrimary12 weeks Dimensional Change Card SortOther outcome12 weeks Size Order Memory TestOther outcome12 weeks Pattern and Letter ComparisonOther outcome12 weeks Picture Order Memory TestOther outcome12 weeks
NCT07497334	Start2025	PhaseNot applicable	ConditionsMild cognitive impairment, Aging, frailty and exercise	Participants45	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary6 months Stroop Color-Word TestSecondary6 months Digit Span TestSecondary6 months Symbol CodingSecondary6 months Task Switching TestSecondary6 months
NCT07376135	Start2026	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants300	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestOther outcome18 months Stroop Color-Word TestOther outcome18 months Verbal LearningOther outcome18 months Digit Span TestOther outcome18 months Symbol CodingOther outcome18 months Short Story RecallOther outcome18 months Complex Figure Copy and RecallOther outcome18 months
NCT07241598	Start2025	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants70	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestSecondary12 months Verbal FluencySecondary12 months Digit Span TestSecondary12 months Symbol CodingSecondary12 months Go/No-Go TaskSecondary12 months Category FluencySecondary12 months
NCT07089303	Start2025	PhaseObservational	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants750	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary12 months Stroop Color-Word TestSecondary12 months Verbal LearningSecondary12 months Digit Span TestSecondary12 months Symbol CodingSecondary12 months Picture Naming TestSecondary12 months Clock Drawing TaskSecondary12 months Complex Figure Copy and RecallSecondary12 months
NCT06977815	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment, Aging, frailty and exercise	Participants70	Lead sponsorOther	StatusCompleted	Library tests named Trail Making TestPrimary12 weeks Digit Span TestPrimary12 weeks Symbol CodingPrimary12 weeks
NCT06935812	Start2025	PhaseNot applicable	ConditionsMild cognitive impairment	Participants106	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestPrimary8 weeks Verbal FluencyPrimary8 weeks Digit Span TestPrimary8 weeks Symbol CodingPrimary8 weeks Clock Drawing TaskPrimary8 weeks Arithmetic Fluency TaskPrimary8 weeks
NCT06854731	Start2025	PhaseNot applicable	ConditionsMild cognitive impairment, Aging, frailty and exercise	Participants328	Lead sponsorOther	StatusRecruiting	Library tests named Verbal LearningSecondary18 months Symbol CodingSecondary18 months Dimensional Change Card SortSecondary18 months
NCT06825403	Start2025	PhaseNot applicable	ConditionsMild cognitive impairment	Participants30	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingPrimary6 months Category FluencyPrimary6 months Short Story RecallPrimary6 months Selective Reminding TaskPrimary6 months
NCT06773416	Start2025	PhaseNot applicable	ConditionsMild cognitive impairment, Aging, frailty and exercise, Sleep and sleep disorders	Participants206	Lead sponsorOther	StatusNot yet recruiting	Library tests named Trail Making TestPrimary7 months Verbal LearningPrimary7 months Digit Span TestPrimary7 months Symbol CodingPrimary7 months Letter-Number Sequencing TaskPrimary7 months
NCT06719297	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment	Participants40	Lead sponsorOther	StatusNot yet recruiting	Library tests named Digit Span TestPrimary10 weeks Symbol CodingPrimary10 weeks Continuous Performance TestPrimary10 weeks Paced Visual Serial Addition TestPrimary10 weeks AX Continuous Performance TestWording unclear Letter-Number Sequencing TaskPrimary10 weeks
NCT06601933	Start2024	PhasePhase 2	ConditionsMild cognitive impairment	Participants240	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingOther outcome18 months Category FluencyOther outcome18 months Short Story RecallOther outcome18 months Selective Reminding TaskOther outcome18 months
NCT06413173	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment, Brain injury and concussion	Participants160	Lead sponsorOther	StatusRecruiting	Library tests named Symbol CodingPrimary6 weeks N-Back TaskPrimary6 weeks Hidden Path LearningPrimary6 weeks
NCT06408103	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment	Participants102	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestPrimary9 months Verbal LearningPrimary9 months Verbal FluencyPrimary9 months Symbol CodingPrimary9 months Picture Naming TestPrimary9 months Complex Figure Copy and RecallPrimary9 months Token Commands TaskPrimary9 months
NCT06399731	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment, Parkinson's disease	Participants20	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary Verbal LearningSecondary Verbal FluencySecondary Digit Span TestSecondary Symbol CodingSecondary Tower PlanningSecondary Line Angle MatchingOther outcomesame day
NCT06375720	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment	Participants350	Lead sponsorOther	StatusStatus unknown	Library tests named Stroop Color-Word TestSecondary12 months Verbal LearningSecondary12 months Verbal FluencySecondary12 months Symbol CodingSecondary12 months Picture Naming TestSecondary12 months
NCT06347315	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment	Participants380	Lead sponsorIndustry	StatusRecruiting	Library tests named Symbol CodingPrimary12 months Short Story RecallPrimary12 months Selective Reminding TaskPrimary12 months
NCT06278688	Start2024	PhaseNot applicable	ConditionsMild cognitive impairment	Participants120	Lead sponsorOther	StatusNot yet recruiting	Library tests named Stroop Color-Word TestPrimary12 months Verbal FluencyPrimary12 months Digit Span TestPrimary12 months Symbol CodingPrimary12 months Short Story RecallPrimary12 months
NCT06155721	Start2023	PhaseNot applicable	ConditionsMild cognitive impairment	Participants45	Lead sponsorOther	StatusCompleted Results	Library tests named Trail Making TestSecondary1 week Digit Span TestSecondary1 week Symbol CodingSecondary1 week
NCT06112639	Start2024	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment, Multiple sclerosis, Cancer	Participants192	Lead sponsorOther	StatusRecruiting	Library tests named Trail Making TestSecondary6 months Stroop Color-Word TestSecondary6 months Verbal FluencySecondary6 months Symbol CodingSecondary6 months Category FluencySecondary6 months Selective Reminding TaskSecondary6 months Delayed Recall ModuleSecondary6 months
NCT06083350	Start2023	PhaseNot applicable	ConditionsDementia and Alzheimer's, Mild cognitive impairment	Participants144	Lead sponsorOther	StatusStatus unknown	Library tests named Trail Making TestSecondary7 months Verbal FluencySecondary7 months Symbol CodingSecondary7 months Clock Drawing TaskSecondary7 months
NCT06041152	Start2023	PhasePhase 2	ConditionsMild cognitive impairment	Participants10	Lead sponsorOther	StatusCompleted	Library tests named Trail Making TestSecondary3 years Verbal LearningSecondary3 years Verbal FluencySecondary3 years Symbol CodingSecondary3 years Category FluencySecondary3 years Picture Naming TestSecondary3 years Card Sorting Test (Berg)Secondary3 years Short Story RecallSecondary3 years Clock Drawing TaskSecondary3 years Complex Figure Copy and RecallSecondary3 years Block Copy TestSecondary3 years
NCT05997316	Start2023	PhaseNot applicable	ConditionsMild cognitive impairment, Obesity and diabetes	Participants33	Lead sponsorOther	StatusCompleted Results	Library tests named Trail Making TestPrimary12 weeks Verbal LearningPrimary12 weeks Verbal FluencyPrimary12 weeks Digit Span TestPrimary12 weeks Symbol CodingPrimary12 weeks Category FluencyPrimary12 weeks

Questions, answered from the data

How many mild cognitive impairment trials use Symbol Coding?

Which tests do mild cognitive impairment trials use with Symbol Coding?

The Trail Making Test (42 studies), Verbal Fluency (34 studies) and the Digit Span Test (32 studies).

How many participants do phase 2 mild cognitive impairment trials that use Symbol Coding enroll?

Half of the phase 2 studies that name it enroll 78 participants or fewer, and the middle half enroll 50 to 200. 13 of them give a size.

When do mild cognitive impairment trials measure Symbol Coding?

Half of the primary outcomes that name Symbol Coding are measured within 6 months of the start, and the middle half from 12 weeks to 12 months. 35 primary outcomes give a duration.

How many completed mild cognitive impairment trials that use Symbol Coding have reported results?

How the studies are counted

The census counts Symbol Key Game and Symbol Coding as one test family, so this page counts their studies together.

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Symbol Coding in mild cognitive impairment trials: 84 registered studies

Tests named in the same studies

Studies by start year

Phases and study sizes

By phase

Participants per study

When mild cognitive impairment trials measure it

Latest time point of each outcome

Status, results, interventions and countries

Status

What they test

Where their sites are

Reported results

The 84 studies

Library tests named most

Largest condition groups

Phases

Participants

The studies, newest registration first

Questions, answered from the data

How many mild cognitive impairment trials use Symbol Coding?

Which tests do mild cognitive impairment trials use with Symbol Coding?

How many participants do phase 2 mild cognitive impairment trials that use Symbol Coding enroll?

When do mild cognitive impairment trials measure Symbol Coding?

How many completed mild cognitive impairment trials that use Symbol Coding have reported results?

More on Symbol Coding and mild cognitive impairment

Symbol Coding in other conditions

Other tests in mild cognitive impairment trials

How the studies are counted

Run Symbol Coding in your trial

Symbol Coding in mild cognitive impairment trials: 84 registered studies

Tests named in the same studies

Studies by start year

Phases and study sizes

By phase

Participants per study

When mild cognitive impairment trials measure it

Latest time point of each outcome

Status, results, interventions and countries

Status

What they test

Where their sites are

Reported results

The 84 studies

Library tests named most

Largest condition groups

Phases

Participants

The studies, newest registration first

Questions, answered from the data

How many mild cognitive impairment trials use Symbol Coding?

Which tests do mild cognitive impairment trials use with Symbol Coding?

How many participants do phase 2 mild cognitive impairment trials that use Symbol Coding enroll?

When do mild cognitive impairment trials measure Symbol Coding?

How many completed mild cognitive impairment trials that use Symbol Coding have reported results?

More on Symbol Coding and mild cognitive impairment

Symbol Coding in other conditions

Other tests in mild cognitive impairment trials

How the studies are counted

Run Symbol Coding in your trial