Nociceptive Primitive Reflexes in Neurologically and Cognitively Healthy Aging Subjects

Abstract

ABSTRACT:Background: To assess the prevalence of three nociceptive primitive reflexes (nPR), i.e., glabellar tap, snout reflex, and palmomental reflex, in neurologically and cognitively healthy (NCH) aging subjects. Objective: To investigate whether nPR are cross-sectionally associated with white matter hyperintensities (WMH), lacunes, atrophy of the caudate nuclei, and global brain atrophy. Methods: A total of 1246 NCH subjects aged 45–91 years were included in the study and underwent standard brain MRI. Atrophy of the caudate nuclei and global brain atrophy were assessed through the bicaudate ratio (BCr) and lateral ventricles to brain ratio (LVBr), respectively. WMH were assessed through visual rating scales. Lacunes were also rated. Association of nPR with vascular risk factors/diseases and imaging findings was evaluated using logistic regression analysis. Results: nPR were exhibited by 33.1% of subjects and increased with age. Subjects with nPR performed less than subjects without nPR in tests evaluating global cognition, executive functions, attention, and language. Snout reflex was the most common nPR, followed by glabellar tap and palmomental reflex. Glabellar tap was associated with parieto-temporal WMH, BCr, and LVBr; snout reflex was associated with frontal lacunes, temporal WMH, BCr, and LVBr; palmomental reflex was associated with parieto-occipital WMH, basal ganglia lacunes, BCr, and LVBr. Conclusions: This study demonstrates that in NCH aging individuals, nPR are associated with WMH, lacunes, BCr, and LVBr and are probably a warning sign of incipient cognitive decline. Therefore, NCH subjects presenting nPR should manage their vascular risk factors/vascular diseases rigorously in order to prevent or delay progression of small vessel disease, and future neurological and cognitive disabilities.

Isolated, Subtle Neurological Abnormalities in Mild Cognitive Impairment Types

“…Many vascular risk factors (VRFs) and vascular diseases (VDs) were considered and assessed as reported elsewhere. 20,29 Since multiple VRFs and VDs often coexist, we created the VRF and VD summary scores indicating for each participant the sum of the individual VRFs and VDs that were concurrently present. APOE genotypes were determined by using standard methods.…”

Primitive reflexes and dementia in older adults: a meta‐analysis of observational and cohort studies

“…These reflexes have been found in a significant proportion of patients with vascular risk factors, vascular diseases, ApoE ε4 carrier status, and imaging-detected cerebrovascular lesions. 11 Among them, palmomental reflex has been suggested to manifest even before brain atrophy in patients with AD. 58 Moreover, there is a robust connection between these reflexes and dementia in the neurological assessment of older adults.…”

“…Despite this, the quick and cost-effective nature of this physical examination makes it potentially valuable in diagnostic studies as a predictive marker of neurodegeneration, particularly when multiple PRs are observed in older adults. [11][12][13] Some studies suggest a significant association between PRs and cognitive impairment, considering them as an indicator of diffuse cerebral dysfunction and frontal lesions. On the other hand, other studies demonstrate that PRs lack specific diagnostic value in routine neurological examinations and are merely indicative of physiological ageing.…”

“…In clinical practice, PRs are generally considered to have limited diagnostic significance. Despite this, the quick and cost‐effective nature of this physical examination makes it potentially valuable in diagnostic studies as a predictive marker of neurodegeneration, particularly when multiple PRs are observed in older adults 11–13 . Some studies suggest a significant association between PRs and cognitive impairment, considering them as an indicator of diffuse cerebral dysfunction and frontal lesions.…”

Retained Primitive Reflexes and Potential for Intervention in Autistic Spectrum Disorders

“…The extant PMR is found in infants up to ∼12 months of age and then wanes and disappears, largely due to the frontal lobe maturation (19,222). Consequentially, its recurrence in aged individuals with the pathology of the frontal lobe is thought of as a "cortical release" or "frontal lobe" sign, with a presumption of a lack of frontal inhibition on subcortical motor networks (223)(224)(225).…”