A Cortical Stress Signature of Fear-Induced Walking: Mobile Electroencephalography Theta Suppression in Older Women With Fear of Falling.

backgroundFear of falling is one of the most common and disabling stress responses of later life, yet how it is expressed in the brain during real walking is poorly understood. We examined whether walking under a naturalistic psychological threat, a fear-of-falling stressor, changes cortical oscillatory activity in older women, using mobile electroencephalography.

methodsIn this within-subject study, 30 community-dwelling women aged 65 years or older underwent three-dimensional gait analysis with concurrent 14-channel electroencephalography (128 Hz) during habitual walking and after introduction of a fictional disturbing factor, a psychological, nonmotor agent that elicits fear of falling without any mechanical perturbation. Relative band power and the theta/beta ratio were compared with paired t tests and Cohen's dz., with sign-flip permutation, false-discovery-rate correction and bootstrap confidence intervals; signal validity was confirmed by the eyes-closed alpha increase, and head movement and gait speed served as controls.

resultsWalking under threat reduced relative theta power across frontal, temporal, occipital and sensorimotor regions (p = 0.004-0.014; dz. around -0.5; confidence intervals excluding zero), confirmed by permutation and by seven electrodes surviving correction, while the frontal and central theta/beta ratio fell. The theta change was not accounted for by head movement, and in a smaller subgroup showed no detectable association with the change in gait speed, while gait became more cautious.

conclusionsA naturalistic fear stressor produces a measurable cortical signature during walking, positioning fear of falling as a neurobehavioural stress response with implications for the health and mobility of older women.