# Spinal excitation to enhance mobility in elderly adults

> **NIH VA I21** · VETERANS HEALTH ADMINISTRATION · 2021 · —

## Abstract

It is well known that age-related impairments of the brain and peripheral nerves contribute to a decline in
walking function. Age-related impairment of the spinal cord is also a likely contributing factor, as the literature
describes a variety of changes in spinal cord structure and function with aging. Specifically, the elderly spinal
cord is less excitable, conducts signals more slowly, and is subject to neural noise. Therefore, we are initiating
a new line of research with the goal of enhancing walking function in elderly Veterans by intervening on age-
related neural impairment of the spinal cord. The objective of the proposed study is to establish the feasibility,
preliminary efficacy, and variance of response for using transcutaneous spinal direct current stimulation
(tsDCS) and textured shoe insoles to excite spinal locomotor circuits and enhance practice-related
performance and retention on an obstacle walking task. Enhanced practice and retention effects will support
future efforts to translate this approach into a longer term rehabilitation intervention.
Excitatory tsDCS is a non-invasive neuromodulation approach in which a relatively weak electrical current is
delivered to the desired region of the spinal cord via electrodes placed on the skin. The electrical current does
not cause discharge of action potentials, but rather is designed to bring neurons closer to their discharge
threshold by inducing a sub-threshold depolarization of membrane potentials. When combined with a
behavioral task, tsDCS has the potential to upregulate neural circuits in a task-specific manner and promote
Hebbian neuroplasticity (‘fire together, wire together’). We will use a previously established electrode montage
to deliver excitatory tsDCS to the lumbosacral spinal cord during practice of a complex obstacle walking task.
We also propose to combine the use of textured shoe insoles with tsDCS. This combinatorial approach may be
a potent strategy for simultaneously optimizing spinal responsiveness to input from both descending and
ascending excitatory signals to spinal centers of locomotor control. One anticipated benefit of increasing the
excitation of spinal locomotor circuits is a reduction in the executive demand of walking, as measured by
prefrontal cortical activation. Our research shows that elderly adults rely heavily on compensatory executive
control while walking. This is widely considered to be a risk factor for adverse outcomes including falls.
We propose a parallel groups study design in which 40 older adults who have walking deficits and who
demonstrate a compensatory executive locomotor control strategy will be randomized into one of four groups:
1) active tsDCS with smooth insoles (active/smooth); 2) sham tsDCS with smooth insoles (sham/smooth); 3)
active tsDCS with textured insoles (active/textured); and 4) sham tsDCS with textured insole (sham/textured).
Participants will be blinded to group assignment. While receiving stimulation, participa...

## Key facts

- **NIH application ID:** 10247445
- **Project number:** 5I21RX002874-03
- **Recipient organization:** VETERANS HEALTH ADMINISTRATION
- **Principal Investigator:** David J Clark
- **Activity code:** I21 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2021
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2018-11-01 → 2021-09-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10247445

## Citation

> US National Institutes of Health, RePORTER application 10247445, Spinal excitation to enhance mobility in elderly adults (5I21RX002874-03). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10247445. Licensed CC0.

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