Background: Sensorimotor and blood-based biomarkers are promising dementia biomarkers with high accessibility and limited invasiveness. Although sensorimotor changes appear with aging, more severe changes may precede cognitive decline, dementia, and other neurological diseases. Additionally, blood-based neurofilament light (NfL), a broad marker of neuroaxonal injury, is commonly elevated in many types of neurological disease. Prior studies have suggested that increased blood levels of NfL in conjunction with sensorimotor decline may allow for earlier neurological disease diagnosis and/or prediction of disease severity, but little is known about the correlation of these markers in the general population. We examined the association between NfL and sensorimotor markers in a predominantly Hispanic population in San Antonio, Texas.
Method: Our sample included older adults from our San Antonio MarkVCID and South Texas Alzheimer’s Disease Research Center (ADRC) cohorts (n=152, mean age 71.2±7.63, 60.4% women, 79.5% Hispanic) with available plasma NfL, olfaction (B-SIT age-adjusted percentile), grip strength, and touch (monofilament) data (Table 1). NfL concentrations were log-transformed to achieve a normal distribution. We used linear or logistic regression models, as appropriate, to assess the association between NfL and sensorimotor outcomes, adjusting for age, sex, race, ethnicity, and cognitive diagnosis.
Result: Higher plasma NfL was significantly associated with decreased olfaction score percentiles (Beta [95% Confidence Interval], β=-8.79; [95% CI -16.89; -0.12], p=0.05), grip strength in either hand (left: β=-3.62; [95% CI -5.51; -1.74], p=0.0002; right: β=-2.99; [95% CI -5.01; -1.03], p=0.003), and impaired touch perception (Odds Ratio [95% CI], OR=2.56; [95% CI 1.01; 6.48]; p=0.05), independent of the potential confounders listed above.
Conclusion: These results highlight the association of plasma NfL with several markers of sensorimotor function, which may reflect central and peripheral neuroaxonal injury. Additional studies are needed in larger community samples to confirm these findings and explore the potential of NfL as a marker of functional decline in longitudinal studies. We plan to continue collecting these markers, as well as gait and balance, longitudinally to gain a better understanding of the link between neurodegeneration, sensorimotor markers, and neurological disease trajectory in our unique South Texas population
