To take the test, a patient sits in front of a laptop, watching images flash by. They don’t have to respond to any questions or remember anything. As their brain processes each picture, sensors track subtle patterns that may reveal early memory problems.

This is Fastball, a new test designed to detect the first signs of Alzheimer’s disease. According to a new study, it could be our best tool for early Alzheimer’s detection.

A Flicker of Recognition

Traditionally, Alzheimer’s diagnosis relies on a mix of patient interviews, cognitive tests, brain scans, and sometimes spinal taps to check for amyloid and tau proteins. These methods can be invasive, costly, and hard to scale. Even new blood biomarkers, while promising, are influenced by other health conditions, race, sex, and even time of day. Cognitive tests like the ACE-III or MoCA are also imperfect. They can be skewed by a person’s education, language skills, or test anxiety. Fastball, by contrast, asks nothing of the participant except to sit and watch.

Developed by researchers at the University of Bath and the University of Bristol, the Fastball test is, well, fast. It’s also very simple to carry out. Participants are just shown a rapid stream of images while their brain’s electrical activity is recorded using EEG. There’s no instructions, just passive viewing. There also aren’t right or wrong answers.

What Fastball looks for is far more subtle than a correct answer. It detects a specific brainwave pattern, akin to a neural double-take, when a person sees a familiar image. In people with mild cognitive impairment (MCI), especially those at risk of progressing to Alzheimer’s, this pattern is noticeably weakened.

In a study published this week in the journal Brain Communications, the team tested 53 patients with MCI and 54 healthy older adults. The results were striking. Fastball reliably picked up memory deficits in people with amnestic MCI, the form most likely to lead to Alzheimer’s. These differences emerged without the need for verbal responses or instructions.

The core idea behind Fastball comes from fast periodic visual stimulation, a neuroscience technique that uses repeated images to elicit predictable brain responses. In this study, participants were shown hundreds of images over just three minutes. Some images were repeated; others were not. The brain’s reaction to the repeated images formed the basis for analysis.

The researchers grouped MCI patients into two categories: amnestic MCI, where memory loss is the primary symptom, and non-amnestic MCI, which involves other cognitive problems. Fastball signals were significantly weaker in the amnestic group and correlated specifically with memory scores, not attention or general cognition.

Early Detection Matters More Than Ever

“We’re missing the first 10 to 20 years of Alzheimer’s with current diagnostic tools,” said Dr. George Stothart, lead author and cognitive neuroscientist at the University of Bath. “Fastball offers a way to change that—detecting memory decline far earlier and more objectively, using a quick and passive test.”

MCI is a murky middle ground between healthy aging and dementia. Some patients never get worse. Others go on to develop Alzheimer’s. But identifying who is most at risk early enough to intervene has remained a major challenge.

That challenge has grown more urgent with the arrival of new treatments. Two drugs, donanemab and lecanemab, have shown promise in slowing Alzheimer’s progression. But they only work if given early, before significant brain damage has occurred.

Despite this, as many as 1 in 3 people in England currently do not have a dementia diagnosis. For those patients, Fastball could offer a chance to begin treatment while there’s still time.

Dr. Elizabeth Coulthard, a neurologist at the University of Bristol, put it plainly: “Early diagnosis is key to effective treatment of Alzheimer’s and other causes of dementia. Fastball and new blood tests for Alzheimer’s potentially offer an accurate diagnosis that is low stress for patients in clinic.”

Importantly, Fastball showed moderate to good test-retest reliability after a year, outperforming some widely used cognitive assessments. Even more compelling, among patients who progressed to Alzheimer’s over the course of the year, many had already shown weakened Fastball signals at baseline—a hint that the method could become a predictive biomarker.

The test was also conducted in people’s homes. That’s a first for this kind of EEG-based cognitive screening.

“There’s an urgent need for accurate, practical tools to diagnose Alzheimer’s at scale,” said Dr. Stothart. “Fastball is cheap, portable, and works in real-world settings.”

A Glimpse Into the Future

The study carries its own limitations. Only six patients converted from MCI to Alzheimer’s within a year. That’s too small a sample size to statistically validate Fastball as a long-term predictor. But all six had shown below-average Fastball responses at the start, a trend the researchers plan to track with further follow-ups.

The potential is there, and researchers want to expand the scope of their research.

“Fastball is an incredible tool that could offer anyone who, for whatever reason, cannot access a dementia diagnosis in a clinical setting,” said Chris Williams, CEO of the charity BRACE Dementia Research, which funded the project. “We are excited to see what Dr. Stothart’s team will achieve over the next few years.”

This is all the more promising because the technology behind Fastball is relatively simple: a laptop, a set of eight EEG electrodes, and software to analyze brainwaves. In principle, it could be deployed anywhere, from a memory clinic to a care home, or even a patient’s kitchen table.

As Alzheimer’s looms as one of the defining health challenges of our time, a test that is fast, affordable, and equitable could make all the difference. Fastball may not stop the disease. But it might give people something they’ve rarely had before: a head start.