A measure that combines sensory and motor function assessments may be useful in gauging the risk of mild cognitive impairment, a condition that is often undetected and can progress to dementia, according to a study led by researchers at the Johns Hopkins Bloomberg School of Public Health.
The researchers evaluated sensory and motor function scores for things like hearing, grip strength, and balance in more than 1,500 older adults across two large cohort studies. For each group, they found a strong association between higher sensorimotor function and a lower risk of mild cognitive impairment.
The findings were published online May 14 in Alzheimer's & Dementia: The Journal of the Alzheimer’s Association.
The authors believe an overall measure of combined sensorimotor performance in older adults could be a relatively easy screening tool for mild cognitive impairment and dementia risk.
“The more complex cognitive processes tend to diminish first with cognitive decline, and for sensorimotor function, the complexity lies in the integration of sensory and motor functions to perform everyday tasks—for example, seeing where you need to go and then planning and executing the movements needed to get there,” says Amal Wanigatunga, PhD, MPH, an assistant professor in the Bloomberg School’s Department of Epidemiology. “So that relative complexity and its interplay with cognition is what we would try to capture with this single sensorimotor measure.”
A 2023 study estimated that 8 million Americans age 65 and older have mild cognitive impairment, with more than 90% of expected cases undiagnosed. Progression to dementia is not inevitable, but estimates vary. An estimated 10% to 20% of people with mild cognitive impairment develop dementia each year, according to the Alzheimer’s Association. Early detection or prediction of mild cognitive impairment would allow for earlier introduction of interventions that could be more effective in delaying dementia progression.
Prior research has separately linked declines in individual sensory and motor function to mild cognitive impairment. Wanigatunga and colleagues investigated whether a combined measure could be more useful in assessing mild cognitive impairment risk.
The measure combines separately weighted scores from tests of hearing, vision, olfaction, grip strength, balance, and gait speed. To develop the measure, the team used data collected between June 2016 and December 2017 from 880 individuals—average age 79 years—from the long-running Atherosclerosis Risk in Communities (ARIC) study.
Wanigatunga and colleagues found that, in this ARIC dataset, a higher score using the new sensorimotor measure was robustly associated with a lower chance of having mild cognitive impairment, even after adjusting for potentially confounding factors including age, race, sex, education, and body mass index.
The researchers then validated the new measure by applying it to sensory and motor function scores collected between October 2012 and December 2018 from 681 adults enrolled in a different study, the Baltimore Longitudinal Study of Aging. Although the individuals in this study were, on average, younger and healthier than those in the ARIC sample, higher scores for the new sensorimotor measure were again robustly associated with lower mild cognitive impairment risk.
The researchers also observed that for both datasets, higher scores on the new combined measure, compared with each individual sensory or motor-skill function score, was more strongly linked to lower risk of mild cognitive impairment.
Wanigatunga and his team are now planning to conduct longitudinal studies to determine how far in advance sensorimotor function declines can predict the onset of mild cognitive impairment.
Wanigatunga also intends to develop a related sensorimotor scoring algorithm or checklist that also has a robust association with mild cognitive impairment risk but is simple enough for clinicians or at-home use by older people as a routine screening tool.
“Ultimately, we want it to be very clinician-friendly and scalable, so it can be widely adopted to improve community health,” he says.
“A Sensorimotor Function Construct to Assess Mild Cognitive Impairment Risk” was co-authored by Amal Wanigatunga, Hang Wang, Di Huang, Anis Davoudi, Ryan Dougherty, Qu Tian, Jennifer Deal, Alison Abraham, Eleanor Simonsick, Alden Gross, Susan Resnick, Luigi Ferrucci, and Jennifer Schrack.
Support for the research was provided by the National Institute on Aging (R01AG061786); National Institutes of Health (K01AG076967, K01AG080122); the National Heart, Lung, and Blood Institute (75N92022D00001, 75N92022D00002, 75N92022D00003, 75N92022D00004, 75N92022D00005); the ARIC Neurocognitive Study (U01HL096812, U01HL096814, U01HL096899, U01HL096902, U01HL096917); and the National Institute on Aging Intramural Research Program (ZIAAG000015).
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