Head stability in older adults during walking with and without visual input.

The purposes of this study were to 1) characterize head stabilization in older adults across the frequency spectrum of walking, and 2) assess the ability of older adults to adapt head-trunk coordination to maintain head stability in the absence of vision. Sagittal plane head and trunk angular velocities in space were measured for 17 healthy older adults while walking with eyes open (EO) and eyes closed (EC). Average walking velocity and cadence were also determined. Frequency analyses were used to examine head velocities in space and head-on-trunk with respect to trunk gain and phase values across the frequency spectrum of walking. Average walking velocity decreased with EC. Head stability was maintained during EO, but decreased during EC as indicated by increased head velocities across the frequency spectrum. Gain values increased while phase values remained similar during EC walking demonstrating diminished coordination of head-trunk movements. When relying on vestibular and proprioceptive information, older adults were unable to adapt head-trunk movements suggesting impaired plasticity of these systems with age.