Primitive Reflexes in Older Adults Signal Nearly Double the Dementia Risk
Simple bedside neurological signs present at birth may return in aging and predict dementia up to 7 years before diagnosis.
Summary
A longitudinal study of 873 older adults found that the reappearance of primitive reflexes — neurological responses normal in infants but absent in healthy adults — significantly predicts dementia risk. Researchers at West Virginia University tracked participants over 7 years and found that cognitively normal adults with two or more so-called frontal release signs, such as the grasp, snout, or rooting reflex, were 78% more likely to develop dementia. These reflexes disappear as the brain matures and can re-emerge when brain degeneration occurs. The findings suggest a simple, no-cost neurological exam could serve as an early screening tool alongside expensive biomarker tests, making it a potentially powerful addition to routine checkups for older adults.
Detailed Summary
Dementia affects millions of older adults, and early detection remains one of the field's greatest challenges. A new study published in JAMA Network Open suggests that a simple bedside neurological examination could help identify who is at elevated risk years before cognitive symptoms appear. The tool in question involves checking for the return of primitive reflexes that are normal in newborns but should disappear as the brain matures.
Researchers from West Virginia University followed 873 older adults from the University of Kentucky Alzheimer's Disease Research Center between 2005 and 2024. Participants were either cognitively normal or had mild cognitive impairment at baseline. Those who tested positive for two or more frontal release signs — a category of primitive reflexes including grasp, snout, rooting, palmomental, and Myerson reflexes — were classified as high-risk.
The key finding was striking: cognitively intact adults with two or more frontal release signs had a hazard ratio of 1.78 for progressing to dementia over seven years compared to those without these signs. In concrete terms, 25.4% of those with multiple signs developed dementia versus 14.5% of those with fewer signs. In participants with mild cognitive impairment, nearly one in four already showed these signs at baseline.
The study underscores that clinical examination skills remain powerful diagnostic tools even as expensive biomarker testing expands. Lead researcher Dr. Lauren Bojarski emphasized that neurological bedside skills are declining in medical training, which could reduce diagnostic accuracy going forward.
Important caveats apply. This was an observational cohort, so frontal release signs cannot be considered causal. The sample was older, well-educated, and largely female, limiting generalizability. Individual reflexes also carry low sensitivity and specificity on their own. Still, for health-conscious adults and their clinicians, requesting a thorough neurological exam that includes frontal release sign assessment may be a low-cost, actionable step worth adding to routine aging checkups.
Key Findings
- Two or more frontal release signs linked to 78% higher dementia risk over 7 years in cognitively normal adults.
- Simple bedside reflex tests — grasp, snout, rooting — could serve as low-cost early dementia screening tools.
- 25.4% of cognitively intact adults with multiple primitive reflexes developed dementia vs 14.5% with fewer signs.
- Nearly 24% of adults with mild cognitive impairment already showed two or more frontal release signs at baseline.
- A prior meta-analysis found dementia patients up to 16 times more likely to show frontal release signs than healthy adults.
Methodology
This is a news report summarizing a peer-reviewed longitudinal cohort study published in JAMA Network Open, a credible open-access journal. The study followed 873 older adults over roughly 7 years with annual standardized neurological and neuropsychological assessments, providing robust longitudinal data. Evidence quality is moderate-to-strong for an observational study, though causality cannot be inferred.
Study Limitations
The cohort was predominantly female, older, and highly educated, which may limit applicability to broader populations. Observational design means these signs are predictive markers, not proven causal factors, and individual reflexes have low sensitivity and specificity. The article does not report full hazard ratios for the mild cognitive impairment subgroup, so primary source review is advisable.
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