Mobility Function and Aperiodic Electrocortical Activity in Younger and Older Adults

Mobility declines with age to the extent that walking speed is often considered a vital sign. Identifying neurological mechanisms behind this decline would aid with early identification and intervention. Electroencephalography (EEG) metrics may provide insight into neural factors contributing to mobility decline with aging. Recent research has shown a differentiation in aperiodic EEG metrics (exponent and offset) across age groups, cognitive abilities, and populations with neurological injury. However, it is unknown if aperiodic EEG differs between mobility tasks or brain regions. The purpose of this study was to 1) compare aperiodic EEG in older and younger adults at rest and while walking and 2) determine if oscillatory and aperiodic EEG in sensorimotor brain regions are predictors of a lower walking speed, regardless of age and other demographic factors. We analyzed EEG collected while participants were sitting at rest and walking on a treadmill in 31 younger adults (age: 24 {+/-} 4, mean {+/-} s.d.) and 59 older adults (age: 74 {+/-} 6). We found that older adults had lower aperiodic exponent and offset at rest and during walking, but only a subset of brain regions showed age group differences. Using machine learning methods, we found that right sensorimotor alpha and left sensorimotor offset and beta had the largest effect on individualized walking speed, after the demographics of age, waist circumference, and sex. These results suggest aperiodic and oscillatory EEG in specific brain areas may give additional insights into brain health.