Somatosensory Feedback to Improve Neural Control of Walking in Older Adults

Preserving mobility function in older adults is crucial for ensuring safe walking in complex environments, including home and community settings. A common example is navigating a busy street with obstacles like uneven sidewalks and pedestrians, or a home with furniture, stairs, and narrow hallways, all while engaging in a conversation or mental task. Such environments create a potential risk for older adults, who may show declines in function across multiple systems, including sensation, cognition, and mobility. Successfully walking in complex environments depends on cognitive control processes, such as attention and motor planning, which rely on sufficient sensory information from peripheral receptors. Somatosensory impairment, particularly in the feet, is common among older adults and tends to increase progressively with age, often worsened by the presence of certain diseases. Age-related somatosensory impairments disrupt essential input to central motor and cognitive networks, raising the risk of accidental collisions, slips, trips, and injurious falls. Older adults may compensate by increasing cognitive load (attention and executive control of movement). However, this shift may overburden cognitive systems, again raising the risk of collisions, slips, trips, and falls. There is a critical, yet underexplored, need to restore somatosensory input to the nervous system during walking in older adults with foot sensory impairments. Therefore, the objective of this study is to investigate whether the use of a novel lower-limb sensory prosthesis, Walkasins, improves complex walking performance and reduces cognitive load. This crossover study will enroll 30 participants with foot sensory impairment, who will undergo complex walking performance assessments while wearing the Walkasins in both the "on" and "off" settings. These settings will be assessed in separate visits occurring at least one week apart, to allow for a washout period. The walking course will use a pressure-sensitive instrumented walkway to analyze kinetic and kinematic variability of the gait pattern. These assessments will include typical walking, as well as dual-task walking with and without obstacle crossing as a behavioral assessment of cognitive load. Furthermore, cognitive load will be assessed by measuring prefrontal cortical activity with functional near infrared spectroscopy (fNIRS). We will address the following specific aims:

Specific Aim 1 is to test whether Walkasins can improve walking performance, hypothesizing greater reductions in dual-task costs and gait variability when using Walkasins in the "on" setting compared to the "off" setting.

Specific Aim 2 is to assess the potential of Walkasins to reduce cognitive load during walking, hypothesizing lower prefrontal cortical activity when using Walkasins in the "on" setting compared to the "off" setting.

This pilot study enhances our understanding of age-related sensory impairments in neural control and walking performance and will prepare us for larger-scale trials with more intervention sessions, larger sample sizes, and a focus on the underlying neurophysiological mechanisms. This study and future research contribute to the development of rehabilitation strategies that support healthy aging and enhance functional mobility.