Cognitive Testing and Brain Health Screening
What memory and thinking tests can and cannot show, what the US task force says about screening older adults, how accurate common tests are, and where Alzheimer's blood tests fit.
Content last updated . This page has not been medically reviewed.
What this page covers
Memory worries are common, and brain health checks are increasingly offered in clinics, apps and longevity programs. This page separates three different things: screening people with no symptoms, testing people who do have concerns, and newer blood tests for Alzheimer's disease. It is information only. It does not diagnose, and nothing here replaces an evaluation by a clinician. Evidence labels used: approved device (cleared by a regulator for a stated use), established, mixed, insufficient evidence and marketing claim.If you or someone you know is worried now
Memory problems do not necessarily mean dementia. The NHS lists other possible causes, including depression and anxiety, sudden confusion (delirium) from a medical condition such as an infection, an underactive thyroid and side effects of some medicines. [1] A doctor can look for these. Sudden confusion is a reason to contact a clinician promptly.Screening versus diagnosing
Screening means testing people who have no recognized symptoms. In 2020 the US Preventive Services Task Force concluded that the evidence is insufficient to assess the balance of benefits and harms of screening for cognitive impairment in older adults. [2] This applies to community-dwelling adults aged 65 and over without recognized symptoms, not to people in hospitals or nursing homes. [2] Its advice for clinicians is to stay alert to early signs such as problems with memory or language and evaluate as appropriate. [2] Label: insufficient evidence (screening people without symptoms).The task force noted the possible reasons for early detection, such as finding reversible causes, and a possible harm: labeling a person with an illness that is typically progressive and for which treatment appears to have limited effectiveness. [2] The evidence about harms of screening is limited. [2]
What brief cognitive tests are
Many brief tests exist. [2] They ask a person to perform a series of tasks, and they are not intended to diagnose mild cognitive impairment (MCI) or dementia; a positive screen should lead to further testing. [2] In the NHS process, a GP asks about symptoms, may arrange blood and urine tests to look for other causes, and asks the person to do a memory or cognitive test; referral to a specialist may follow. [1]How accurate are common tests?
| Test | Finding | Label |
|---|---|---|
| Montreal Cognitive Assessment (MoCA) for dementia | A Cochrane review of seven studies found high sensitivity (0.94 or more) at the usual cut-off of 26 but low specificity (0.60 or less), meaning many people without dementia scored below the cut-off [3] | Mixed |
| Mini-Mental State Examination (MMSE) to predict dementia in people with MCI | A Cochrane review found no support for a substantial role as a stand-alone single test [4] | Insufficient evidence |
In plain terms: a short test can flag someone for a closer look, but a low score is not a diagnosis,. These reviews were done in 2021 using older studies, so check for newer guidance.
Mild cognitive impairment is not always progressive
The task force reports that between 10% and 40% of people with MCI may return to normal cognition over about 4 to 5 years. [2] This is one reason a single test result should not be treated as a final answer.Alzheimer's blood tests
In May 2025 the FDA cleared the first blood test to aid in diagnosing Alzheimer's disease. It is for adults 55 and older who already have signs and symptoms of the disease, and it is not intended as a screening or stand-alone diagnostic test. [5] The FDA lists false positives and false negatives as the main risks. [5] Label: approved device for aiding diagnosis in symptomatic people; insufficient evidence for use as a check in people without symptoms. Direct-to-consumer brain-health blood panels sold for people without symptoms were not covered by the sources read, so no claim is made about them. This page names no products.Who should be extra careful
The NHS advises seeing a GP if you are worried about your memory or think you may have dementia, rather than relying on an app score. [1] Older adults in hospitals or care homes are outside the task force's screening statement. [2]How to evaluate a brain-health test claim
- Is it a screening test or a diagnostic test, and for whom was it studied?
- Does it report sensitivity and specificity, and how many people without the condition get flagged?
- Does it say what happens after a positive result?
- Does it claim to predict or prevent dementia? Look for trial evidence, not just marketing.
Related guides
Read Cognitive Health and Brain Aging, Mild Cognitive Impairment and Dementia and Preventive Care, Vaccines and Screening in Older Adults.Frequently asked questions
Should older adults without symptoms have routine memory screening?
The US task force found the evidence insufficient to decide for or against screening in adults 65 and older without recognized symptoms. [2]
Can a memory test diagnose dementia?
No. Brief tests are not intended to diagnose; a positive result should lead to further evaluation. [2]
Is a normal memory test reassuring?
It is one piece of information. Cochrane reviewers found that a common test had low specificity at the usual cut-off, and the other reviewed test was not reliable alone for predicting dementia from MCI. [3][4]
Is there an FDA-cleared blood test for Alzheimer's disease?
Yes, one was cleared in 2025 for adults 55 and older with signs and symptoms, not as a screening test. [5]
How common is dementia?
The task force estimates 3.2% of people aged 65 to 74, 9.9% of those 75 to 84, and 29.3% of those 85 and older. [2]
More details: evidence, limits and cautions
The details behind this page: cautions, limits of the evidence and where sources disagree. Open any note to read it.
APOE and other genetic risk markers
References
- NHS (UK). How to get a dementia diagnosis. Read 2026-10-22.
- U.S. Preventive Services Task Force. Cognitive Impairment in Older Adults: Screening (2020) Read 2026-10-22.
- Montreal Cognitive Assessment for the detection of dementia. Cochrane Database Syst Rev 2021. PMID 34255351. Read 2026-10-22.
- Mini-Mental State Examination (MMSE) for the early detection of dementia in people with mild cognitive impairment. Cochrane Database Syst Rev 2021. PMID 34313331. Read 2026-10-22.
- U.S. Food and Drug Administration. FDA Clears First Blood Test Used in Diagnosing Alzheimer's Disease (May 16, 2025). Read 2026-10-22.
- MedlinePlus Genetics. APOE gene Read 2026-10-22.