The research team, led by Erzsébet Stephens-Sarlós and Attila Szabo of Széchenyi István University in Győr, Hungary, recruited 115 community-dwelling adults aged 60 and over, with a mean age of 75.9 years. Participants were drawn from nine social associations for older adults and screened to exclude dizziness, cardiovascular disease, balance disorders, untreated hypertension, and previously diagnosed mental or behavioral disorders. Each volunteer underwent a standardized assessment of thirteen primitive reflexes on both sides of the body, including the symmetrical and asymmetrical tonic neck reflexes, the tonic labyrinthine reflex, the Galant, Moro, palmar grasp, sucking, Babkin, Babinski, and glabellar reflexes, the core tendon guard reflex, the Schilder test, and the vestibular-ocular reflex. A reflex was scored present if it appeared in at least four of six elicitation trials, and side totals were summed separately for the right and left body.

The rigor of the reflex assessment matters, because primitive reflex testing has long been dismissed as imprecise. The protocol used in the study had previously undergone formal psychometric validation, demonstrating near-perfect intra-rater and inter-rater agreement, with weighted Cohen’s kappa values ranging from 0.912 to 1.000. Cognitive functioning was gauged with the Mini-Mental State Examination, physical activity with the World Health Organization’s Global Physical Activity Questionnaire, and psychological resilience with the ten-item Connor-Davidson Resilience Scale. Data collection proceeded individually in quiet, familiar rooms, with one researcher administering the reflex battery and a second conducting the cognitive and questionnaire measures, and the study received ethical approval from the university’s research ethics board in accordance with the Declaration of Helsinki.

The headline findings are striking. In hierarchical linear regressions, right-sided primitive reflexes alone explained 41.5 percent of the variance in cognitive functioning and a remarkable 50.9 percent of the variance in psychological resilience. Adding left-sided reflexes and physical activity pushed the cognitive model to 57.4 percent explained variance and the resilience model to 66.2 percent, with age failing to contribute significant predictive power once the reflex and activity measures were accounted for. In a population of supposedly healthy older adults, no conventional demographic variable came close to this explanatory strength, which is precisely why the authors argue that primitive reflex assessment deserves a place in research on healthy aging and, potentially, in clinical screening.

Equally intriguing was the lateralization effect. The average number of reflexes on the right side of the body, 4.85, was significantly higher than the 3.99 observed on the left, and the right-sided total emerged as the dominant predictor in every model, contributing more than six times the explanatory variance of its left-sided counterpart. The authors speculate that this asymmetry may reflect hemisphere-specific aging of the cortex. Longitudinal MRI research has shown that the cerebral cortex is normally slightly thicker on the left, and that age-related cortical asymmetry progressively diminishes as the left hemisphere thins faster, a process accelerated in Alzheimer’s disease. Handedness may also play a role, since right-handedness favors stronger left-hemisphere motor control over the right side of the body. The authors caution, however, that no neuroimaging was performed and that this interpretation remains hypothesis-generating.

The study also examined whether primitive reflexes simply track age. The answer, surprisingly, is mostly no. Of the thirteen reflexes, only the symmetrical tonic neck reflex correlated significantly with age, and even that relationship explained less than 5 percent of the variance. Total right-sided reflex burden showed a weak positive association with age, accounting for roughly 6.6 percent of variance. This echoes the Maastricht Aging Study, which found the highest reflex prevalence in adults aged 66 to 82, and more recent work showing that about a third of adults aged 45 to 91 exhibit primitive reflexes that increase with age and accompany poorer cognitive task performance. But the new data suggest that reflex reappearance is not an inevitable calendar-driven process; it appears to index something more specific about the integrity of cortical inhibitory control.

That something, the authors argue, may be the progressive erosion of frontal networks. Primitive reflexes are normally suppressed as prefrontal and frontal regions mature, and their re-emergence in adulthood may signal reduced cortical command over phylogenetically older brainstem motor circuits. A 2024 meta-analysis found that primitive reflexes occurred 13.94 to 16.38 times more often in older adults with dementia than in healthy controls, with the grasp reflex most closely implicated. If persistent reflexes are the behavioral fingerprint of declining hierarchical sensorimotor regulation, then their strong inverse relationship with cognitive functioning, and now with psychological resilience, becomes biologically coherent rather than coincidental. Resilience itself is a robust predictor of health in later life, and the study is the first to link its erosion to the return of infantile motor patterns.

Physical activity added its own twist. Using mediation analysis, the researchers found that habitual physical activity statistically accounted for part of the association between primitive reflexes and both cognitive functioning and psychological resilience, exerting significant negative indirect effects that partially attenuated the reflexes’ adverse relationships with the outcome measures. In other words, staying active appears to buffer, though not eliminate, the damage signaled by returning reflexes. This aligns with a large body of evidence showing that physically active adults over 60 face lower risks of cognitive deterioration, dementia, and Alzheimer’s disease, and that even a 16-week functional fitness intervention can measurably raise psychological resilience in this age group. The mediation pattern suggests that sensorimotor integrity, physical activity, cognition, and resilience may be interconnected facets of a single neurobiological system rather than independent dimensions of healthy aging.

The authors are careful to temper these conclusions. The cross-sectional design precludes causal inference, and mediation in this context reflects statistical association, not proven mechanism. Physical activity was self-reported, leaving room for recall bias, and objective accelerometry would strengthen future work. The sample underrepresented men at 23.5 percent, was recruited from a limited set of community organizations, and recorded MMSE means below 24 for both sexes, a score that can indicate mild cognitive impairment, raising questions about how ‘healthy’ the sample truly was. Generalizability to institutionalized or socioeconomically diverse populations remains uncertain, and the authors stress that primitive reflex assessment should not be treated as a stand-alone diagnostic tool.

Nevertheless, the implications are hard to ignore. If validated longitudinally, a cheap, quick, and standardized reflex examination could give geriatricians, rehabilitation physicians, physiotherapists, and occupational therapists an early, low-cost window into cortical health that conventional cognitive screening misses, identifying older adults who might benefit from individualized movement-based interventions and closer monitoring of functional decline. The study also opens an evolutionary-flavored question that is likely to fascinate researchers and the public alike: the same brainstem circuits that help a newborn grasp its mother’s hand may, when they resurface in a 75-year-old, be telling us something profound about the aging brain, and about how much of that story regular movement can still rewrite. Larger, longitudinal studies integrating reflex assessment with brain imaging and objective activity monitoring are the clear next step.

Subject of Research: The reappearance of primitive reflexes in older adults and its relationship with cognitive functioning, psychological resilience, and physical activity

Article Title: Primitive Reflexes Predict Cognitive Functioning and Psychological Resilience in Older Adults: Physical Activity Mediates the Relationship

Article References: Stephens-Sarlós, E., Tóth, E. E., Alföldi, Z., Somogyi, A., Ihász, F., & Szabo, A. (2026). Primitive Reflexes Predict Cognitive Functioning and Psychological Resilience in Older Adults: Physical Activity Mediates the Relationship. Ageing International, 51(3), Article 32. https://doi.org/10.1007/s12126-026-09676-6

Image Credits: AI Generated

DOI: 10.1007/s12126-026-09676-6

Keywords: primitive reflexes, cognitive functioning, psychological resilience, physical activity, aging, brainstem reflexes, MMSE, mediation analysis, healthy aging, neurodegeneration, older adults, motor control