Reviewed by the Help Dementia Editorial Team — our editors review every article for accuracy against guidance from the National Institute on Aging, the Alzheimer’s Association, and peer-reviewed sources.
The SLUMS Test and AD8 are two of the most commonly used screening tools for cognitive decline, but they measure different aspects of brain health and serve different purposes. The SLUMS (Saint Louis University Mental Status) test is a cognitive assessment that directly measures memory, orientation, and thinking skills through questions and tasks, while the AD8 (8-Item Informant Interview to Differentiate Normal Aging from Dementia) gathers information from a family member or caregiver about whether a person’s mental abilities have changed over time.
If you’re trying to understand whether someone is experiencing cognitive decline, knowing which test is right for the situation is crucial because they work in fundamentally different ways. For example, a person might perform well on cognitive tests on a given day due to being well-rested and focused, yet their spouse might report on the AD8 that they’ve been repeating questions and getting lost in familiar places over the past year—a pattern that wouldn’t be captured in a single testing session. The choice between these two tests often depends on who is available to provide information, what signs are being investigated, and whether the goal is detecting early changes or confirming existing concerns.
Table of Contents
- How Do the SLUMS Test and AD8 Differ in What They Measure?
- Why the AD8 Often Catches Cognitive Decline That Tests Miss
- Accuracy and Sensitivity in Detecting Dementia
- Choosing the Right Test for Your Situation
- Common Pitfalls and When These Tests Fail
- When to Repeat Testing and Follow-Up
- The Future of Cognitive Screening
- Conclusion
How Do the SLUMS Test and AD8 Differ in What They Measure?
The slums Test is a direct assessment tool administered by a healthcare provider to the individual being evaluated. It takes about 7-10 minutes and includes tasks like copying shapes, performing simple math, remembering words, and answering questions about current date, place, and person. The test produces a score that indicates normal cognition, mild cognitive impairment, or dementia. A score of 27 or higher generally suggests normal cognition, while lower scores raise red flags about cognitive problems. This approach has the advantage of being objective—the provider sees firsthand how someone performs under controlled conditions.
The AD8, by contrast, never directly tests the person who might have cognitive problems. Instead, it asks someone who knows them well (a spouse, adult child, or close caregiver) eight simple yes-or-no questions about whether the person has shown changes in memory, understanding, traveling, paying bills, forgetting appointments, or staying home. The AD8 is designed to capture real-world functional decline that the person with cognitive changes might not even be aware of. A score of 2 or higher suggests possible cognitive impairment and warrants further evaluation. The fundamental difference is timing and perspective: SLUMS captures a single moment in time from the person being tested, while AD8 captures patterns over months and years as observed by someone in daily contact with them. This is why many doctors use both—the SLUMS provides objective cognitive data, and the AD8 provides the crucial “is this person actually declining in real life?” context.
Why the AD8 Often Catches Cognitive Decline That Tests Miss
One of the biggest limitations of cognitive screening tests like SLUMS is that they can be surprisingly normal even when someone is genuinely developing dementia. This phenomenon is called “test-taking ability sparing”—some people can focus intensely and perform well for 10 minutes in a clinical setting, then go home and can’t remember whether they’ve eaten lunch. The ad8 was specifically designed to address this gap by asking informants about functional changes in everyday life. A caregiver might notice that their mother is asking the same questions repeatedly within a conversation, or that she’s stopped managing her own finances despite having done so for decades.
These real-world changes are often the earliest and most meaningful signs of cognitive decline, sometimes appearing months before formal cognitive test scores drop significantly. However, the AD8 relies entirely on the accuracy and honesty of the informant, which can be problematic if that person is in denial about cognitive changes, has limited contact with the individual, or has motivations to either exaggerate or minimize concerns. The warning here is important: neither test should be used alone for diagnosis. If someone scores concerning on SLUMS but an informant says there’s been no functional change, further evaluation is needed. Conversely, if an informant reports significant functional decline but SLUMS scores are normal, that’s also worth investigating—it might suggest depression, stroke, or other conditions that don’t show up on standard cognitive screening.
Accuracy and Sensitivity in Detecting Dementia
Research has shown that both tests have reasonable accuracy for detecting dementia, but they’re not interchangeable. The SLUMS Test has good sensitivity and specificity for identifying dementia, meaning it catches many cases while avoiding false alarms. Studies show the SLUMS correctly identifies dementia roughly 92% of the time when compared to formal neuropsychological testing. It’s particularly good at distinguishing between normal aging and mild cognitive impairment or dementia, especially in older adults who may have less education. The AD8 is also quite good at what it does—identifying people who need further evaluation based on reported functional decline.
An AD8 score of 2 or higher has a sensitivity of about 80-90% for dementia in various populations studied. However, the AD8 is less precise about the type of cognitive problem; it can flag functional decline due to depression, anxiety, medication side effects, or other medical conditions, not just dementia. This means the AD8 is excellent at saying “something has changed,” but you typically need additional evaluation to determine what that something is. Consider a real-world scenario: A 72-year-old man scores 24 on the SLUMS (suggesting mild cognitive impairment) and his wife scores him 3 on the AD8 (abnormal, suggesting cognitive problems). In this case, both tools point in the same direction and the evidence is strong. But if he scored 28 on SLUMS (normal) and 4 on AD8, the discrepancy demands explanation—perhaps depression, sleep problems, medication effects, or early neurodegeneration not yet severe enough to affect formal test performance.
Choosing the Right Test for Your Situation
Your circumstances often determine which test makes sense. If you’re a primary care doctor doing a routine cognitive screen during an annual visit and the patient came alone, the SLUMS Test is the practical choice—it’s quick, doesn’t require an informant, and gives you objective data in the office. Doctors often use it as a first-line screen when cognitive complaints are raised or when seeing someone for the first time who might be at risk. If someone is already suspected of cognitive decline and you have a reliable family member or caregiver available, the AD8 is excellent complementary information.
In many neurology and geriatric medicine practices, the AD8 is actually preferred as a starting point because it often provides richer information about real-world functional decline without the patient feeling like they’re being “tested,” which some people find uncomfortable or anxiety-provoking. The tradeoff is that you’re dependent on the informant’s reliability and willingness to report honestly—some family members minimize problems to avoid confronting the issue, while others exaggerate to get medical attention. Many practices now use both, with the AD8 potentially going to a family member to complete before or after the SLUMS is administered in the office. This combined approach provides a more complete picture: objective cognitive performance plus real-world functional changes as reported by someone who knows the person well.
Common Pitfalls and When These Tests Fail
One critical warning: both tests have blind spots. The SLUMS can be falsely reassuring in someone with mild but meaningful cognitive decline, especially if they’re educated and good at problem-solving strategies. A retired engineer might remember facts and complete the test well despite genuine early dementia because their lifetime of technical thinking allows compensation. The AD8 might miss very early decline that hasn’t yet affected daily function, or it can be skewed if the informant isn’t observant or spends limited time with the person. Neither test should be used if language barriers exist, if someone is acutely ill or in pain, or if they’re taking sedating medications.
Both tests also assume the person being evaluated can cooperate and understands the questions. Someone with significant hearing loss, severe anxiety, or delirium won’t perform reliably on either. It’s also important to recognize cultural differences in how cognitive problems are reported—some cultures stigmatize dementia heavily, and family members may deliberately give false reassurance. A specific limitation of the SLUMS is that it was developed using older adults and has less validation in people under 65. The AD8 has better cross-cultural validation but still works best with informants who speak the same language and are familiar with the person’s baseline function. If someone moved to a new area recently, or is living alone, or recently lost their primary caregiver, getting reliable AD8 information becomes difficult.
When to Repeat Testing and Follow-Up
Cognitive decline is a process, not an event, so both tests are most useful when repeated over time. A single SLUMS score of 24 is concerning, but a series of SLUMS scores trending downward—28, 26, 24, 21 over two years—tells a powerful story about progressive decline. Similarly, an AD8 score of 3 today might progress to 6 or 7 on retesting in six months, providing evidence of functional deterioration.
Most guidelines suggest cognitive screening annually for people over 65, or more frequently if there are concerns or baseline cognitive impairment. Repeating tests too often (within weeks) often shows practice effects, meaning people improve simply from familiarity with the test, so the results don’t reflect true change. A good practice interval is 6-12 months when tracking someone with known cognitive concerns.
The Future of Cognitive Screening
The landscape of dementia detection is evolving. Newer biomarkers—blood tests that detect amyloid, tau, and phosphorylated tau levels—are becoming more available and can identify Alzheimer’s disease changes even before cognitive decline appears. However, these blood tests are expensive, not universally accessible, and not yet part of standard screening in many settings.
The SLUMS and AD8 remain valuable because they’re low-cost, quick, and accessible tools that help identify who needs further evaluation. As telemedicine grows, both tests are increasingly administered remotely, though the SLUMS is more challenging to administer fairly over video and the AD8 might be better suited to remote administration since it’s already based on an informant’s observations. The combination of these traditional screening tools with emerging biomarkers and advanced imaging will likely become the future standard for accurately identifying and staging cognitive decline.
Conclusion
The SLUMS Test and AD8 are complementary tools that serve different purposes in cognitive screening. The SLUMS directly measures cognitive function through structured tasks, while the AD8 captures real-world functional changes as reported by someone close to the person.
Neither is perfect alone, and neither should be used for definitive diagnosis, but together they provide valuable information to guide further evaluation and management decisions. If you or a loved one are concerned about cognitive changes, discussing which screening tool might be appropriate is a good starting point for a conversation with a healthcare provider. Cognitive decline isn’t a normal part of aging, and early detection—even if it just means scheduling further evaluation—can make a meaningful difference in understanding what’s happening and planning for next steps.
