Mobility Function and Aperiodic EEG in Younger and Older Adults

Mobility function declines with age to the extent that walking speed is often considered the sixth vital sign. Currently, there are no clear neurological mechanisms behind this decline, which limits early diagnosis and intervention. Measures of electrocortical dynamics using electroencephalography (EEG) may provide insight into mobility decline with aging. Prior work focuses on oscillatory EEG, but recent research has shown a differentiation in the aperiodic EEG (exponent and offset) across different age groups, cognitive abilities, and populations with neurological injury. The purpose of this study is to 1) compare aperiodic EEG in older and younger adults at rest and while walking and 2) determine if oscillatory and aperiodic EEG in the sensorimotor regions are predictors of declining mobility in older adults. We analyzed EEG collected at rest and while walking on a treadmill at a subject-specific speed for 31 (age: 24 ± 4) younger adults and 59 (age: 74 ± 6) older adults. Age-related decreases in aperiodic exponent and offset found at rest were maintained during walking. We also saw that only a subset of brain regions showed age-related decreases in aperiodic EEG. Using machine learning methods, we found that between the oscillatory and aperiodic EEG metrics in the left and right sensorimotor areas, left sensorimotor offset and right sensorimotor alpha had the largest effect on predicting individualized walking speed. These results suggest aperiodic EEG may give additional insights into brain health and function beyond oscillatory EEG. Future work should consider if interventions for older adults are able to modulate aperiodic EEG and if this affects mobility.