A simple marker of future memory decline has been identified in older people
Certain physical responses that are common in babies almost always disappear in adults. For example, a baby might clench their fist tightly if you place your finger in their palm. Or they might pucker their lips if you lightly touch the area around their mouth.
In older people, these reflexes sometimes reappear. A new study has shown that if a person over the age of 70 with no memory or cognitive impairments exhibits two or more of these reflexes, this may be linked to a higher risk of dementia in the future.
An important caveat: this is not a home test or a diagnosis. These reflexes cannot be used on their own to diagnose dementia. They must be assessed by a doctor, and only in conjunction with other tests.
Details
The study was published in JAMA Network Open.
The researchers used data from 873 participants aged over 70 from the University of Kentucky Alzheimer’s Disease Centre. The study ran from 2005 to 2024.
At the start, 672 participants had preserved memory and thinking skills. A further 201 people already had mild cognitive impairment — that is, minor problems with memory or thinking, but not dementia.
During annual check-ups, doctors checked for so-called ‘frontal release signs’. These can be described as ‘primitive reflexes’, which are usually present in infants and disappear as the brain matures.
These include the grasp reflex, where the palm clenches involuntarily; the snout reflex, where the lips pucker when the area around the mouth is stimulated; the palmar-chin reflex, where the chin twitches when the palm is stimulated; and the response to tapping between the eyebrows, where the person continues to blink rapidly.
The main findings were observed in people who had no cognitive impairments at the start of the study. Among those in whom two or more such reflexes were found, dementia later developed in 25.4%. Among people with one such reflex or none at all, the figure was 14.5%. In other words, the risk was almost 1.8 times higher.
Interestingly, in people who already had mild cognitive impairment, these reflexes were not as effective at predicting the future risk of dementia. In other words, the signal proved most useful at an earlier stage — when there were no obvious memory problems yet.
Why this is important
Efforts are made to detect dementia as early as possible. The sooner doctors identify the risk, the more time there is for monitoring, further diagnosis, and support for the patient and their family.
Various methods are currently used to assess risk: memory and thinking tests, MRI, PET scans, cerebrospinal fluid analyses, as well as new blood tests for biomarkers of Alzheimer’s disease and other conditions. However, such methods are not always available; they can be expensive or require specialised equipment.
Checking reflexes is a simple, quick and inexpensive part of a neurological examination. The authors believe that it could provide an additional clue for the doctor. However, they explicitly emphasise that the sensitivity of such signs is low, so they cannot be used on their own as a screening tool.
In other words, it is not a substitute for blood tests, brain scans or cognitive tests. It is simply another small indicator that may help a doctor decide who requires closer monitoring.
Background
In infants, primitive reflexes are a normal part of development. They occur because the nervous system is still maturing. As the brain develops, these reactions are usually suppressed.
If similar reflexes appear in adults or older people, this may indicate that the brain’s control has weakened. This can occur with brain injuries, certain neurological disorders and neurodegenerative processes — that is, conditions in which nerve cells are gradually damaged or die.
Previously, such reflexes had already been linked to dementia. The new study is significant in that it investigated whether they might appear early enough — even before any obvious decline in memory and thinking.
The study does have limitations. It was conducted at a single centre, and the participants were, on average, well-educated and not particularly diverse in terms of background. Furthermore, different doctors may assess such reflexes slightly differently. The results therefore need to be confirmed in larger groups of people.
Source
Study: Lauren G. Bojarski, Gregory A. Jicha, Elif Pinar Coskun, Frederick A. Schmitt, Linda Van Eldik, Erin L. Abner. Frontal Release Signs and Future Decline in Research Participants With Intact Cognition. JAMA Network Open, 2026.