A Phase 1 interventional study of practice of a complex walking task and Active transcranial direct current stimulation (Active tDCS) in Aging, sponsored by VA Office of Research and Development. Completed at 1 site in United States. Open to participants aged 65 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-09-22.
Sponsored by VA Office of Research and Development · Phase 1, Interventional, and Treatment
Older adults often experience substantial deficits in walking ability, especially for walking tasks that are more complex such as obstacle crossing. This is due in part to changes in the brain that make performance of physical and cognitive tasks more difficult. Rehabilitation can help to improve walking ability, but effective rehabilitation is time consuming and expensive. New approaches are needed to improve the efficiency of rehabilitation so that gains in walking ability are widely attainable. A promising strategy is to focus on enhancing motor learning, which is defined as improved ability to perform a motor task due to practice or experience. The investigators will investigate the use of non-invasive brain stimulation to increase motor learning and retention of the newly learned walking skills. The investigators will also use neuroimaging to assess brain characteristics that explain how motor learning works. The knowledge gained from this study is expected to contribute to better understanding of mechanistic targets and intervention approaches to improve rehabilitation of walking.
Aging often leads to substantial declines in walking function, especially for walking tasks that are more complex such as obstacle crossing. This is due in part to a lack of continued practice of complex walking (sedentary lifestyle) combined with age-related deficits of brain structure and the integrity of brain networks. Neurorehabilitation can contribute to recovery of lost walking function in older adults, but major and persistent improvements are elusive. A cornerstone of neurorehabilitation is motor learning, defined as an enduring change in the ability to perform a motor task due to practice or experience. Unfortunately, in most clinical settings, the time and cost demands of delivering a sufficiently intensive motor learning intervention is not feasible. There is a need for research to develop strategies for enhancing motor learning of walking ("locomotor learning") in order to improve the effectiveness of neurorehabilitation.
The objective of this study is to use non-invasive brain stimulation to augment locomotor learning and to investigate brain networks that are responsible for locomotor learning in mobility-compromised older adults. The investigators have shown that frontal brain regions, particularly prefrontal cortex, are crucial to control of complex walking tasks. The investigators' neuroimaging and neuromodulation studies also show that prefrontal cortex structure and network connectivity are important for acquisition and consolidation of new motor skills. However, a major gap exists regarding learning of walking tasks. The proposed study is designed to address this gap. The investigators' pilot data from older adults shows that prefrontal transcranial direct current stimulation (tDCS) administered during learning of a complex obstacle walking task contributes to multi-day retention of task performance. In the proposed study the investigators will build upon this pilot work by conducting a full scale trial that also investigates mechanisms related to brain structure, functional activity, and network connectivity. The investigators will address the following specific aims:
Specific Aim 1: Determine the extent to which prefrontal tDCS augments the effect of task practice for retention of performance on a complex obstacle walking task.
Specific Aim 2: Determine the extent to which retention of performance is associated with individual differences in baseline and practice-induced changes in brain measures (including gray matter volume and brain network segregation).
Specific Aim 3: Investigate the extent to which tDCS modifies resting state network segregation.
The investigators anticipate that prefrontal tDCS will augment retention of locomotor learning, and that the data will provide the first evidence of specific brain mechanisms responsible for locomotor learning/retention in older adults with mobility deficits. This new knowledge will provide a clinically feasible intervention approach as well as reveal mechanistic targets for future interventions to enhance locomotor learning and retention.
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Exclusion Criteria:
20 minutes of mild electrical stimulation delivered to the frontal region of the brain during practice of a complex walking task
Behavioral: practice of a complex walking task · Device: Active transcranial direct current stimulation (Active tDCS)
30 seconds of mild electrical stimulation delivered to the frontal region of the brain during practice of a complex walking task
Behavioral: practice of a complex walking task · Device: Sham transcranial direct current stimulation (Sham tDCS)
walking over obstacles
mild electrical stimulation delivered to the frontal region of the brain
30 seconds of mild electrical stimulation delivered to the frontal region of the brain
Walking Speed Change From Baseline
Change in the fastest safe walking speed over a complex walking course
Time frame: Measured at follow up visit (approximately three weeks after baseline)
Prefrontal Cortex Gray Matter Volume Change From Baseline
Change in the volume of gray matter in the prefrontal cortex, as measured by MRI
Time frame: Measured at follow up visit (approximately three weeks after baseline)
Brain Resting State Network Segregation (Z-transformed Correlation Coefficient)
Resting-state functional MRI was used to measure the segregation of large-scale brain networks. Connectivity strength was quantified using Fisher z-transformed correlation coefficients, averaged across regions of interest within each network. Results are reported as mean z-scores for each group. Higher values reflect greater segregation (i.e., stronger within-network compared to between-network connectivity).
Time frame: Measured at follow up visit (approximately three weeks after baseline)
| Milestone | Active tDCS | Sham tDCS |
|---|---|---|
| Started | 34 | 38 |
| Completed | 32 | 36 |
| Not completed | 2 | 2 |
| Withdrew: Adverse event | 1 | 1 |
| Withdrew: Withdrawal by subject | 1 | 1 |
Change in the fastest safe walking speed over a complex walking course
| meters per second | Active tDCS | Sham tDCS |
|---|---|---|
| Walking Speed Change From Baseline | 0.033 ± 0.097 | 0.041 ± 0.104 |
Change in the volume of gray matter in the prefrontal cortex, as measured by MRI
| cubic millimeters | Active tDCS | Sham tDCS |
|---|---|---|
| Prefrontal Cortex Gray Matter Volume Change From Baseline | -14.66 ± 81.75 | -3.45 ± 90.60 |
Resting-state functional MRI was used to measure the segregation of large-scale brain networks. Connectivity strength was quantified using Fisher z-transformed correlation coefficients, averaged across regions of interest within each network. Results are reported as mean z-scores for each group. Higher values reflect greater segregation (i.e., stronger within-network compared to between-network connectivity).
| z-transformed correlation coefficient | Active tDCS | Sham tDCS |
|---|---|---|
| Brain Resting State Network Segregation (Z-transformed Correlation Coefficient) | -.0017 ± .0253 | -.0002 ± .0215 |
Collected over From enrollment until the end of follow-up, up to 8 weeks. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Active tDCS | 0/32 (0%) | 0/32 (0%) | 1/32 (3.1%) |
| Sham tDCS | 0/36 (0%) | 0/36 (0%) | 1/36 (2.8%) |
| Event | Active tDCS | Sham tDCS |
|---|---|---|
| Musculoskeletal injury (not serious)Musculoskeletal and connective tissue disorders | 1/32 | 1/36 |
These numbers are those who passed the onsite screening visit.
| Age, Continuous(years) | Active tDCS | Sham tDCS | Total |
|---|---|---|---|
| Mean | 72.97 ± 5.65 | 75.83 ± 8.06 | 74.49 ± 7.03 |
| Sex: Female, Male(Participants) | Active tDCS | Sham tDCS | Total |
|---|---|---|---|
| Female | 8 | 17 | 25 |
| Male | 24 | 19 | 43 |
| Race (NIH/OMB)(Participants) | Active tDCS | Sham tDCS | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 1 | 1 |
| Asian | 1 | 0 | 1 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 1 | 2 | 3 |
| White | 30 | 33 | 63 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Ethnicity (NIH/OMB)(Participants) | Active tDCS | Sham tDCS | Total |
|---|---|---|---|
| Hispanic or Latino | 2 | 2 | 4 |
| Not Hispanic or Latino | 30 | 34 | 64 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Walking speed(meters per second) | Active tDCS | Sham tDCS | Total |
|---|---|---|---|
| Mean | 1.25 ± 0.23 | 1.19 ± 0.19 | 1.22 ± 0.21 |
| Montreal Cognitive Assessment(units on a scale) | Active tDCS | Sham tDCS | Total |
|---|---|---|---|
| Mean | 26.41 ± 1.88 | 26.58 ± 2.6 | 26.5 ± 2.29 |
Documents are hosted by the registry — open the source record to download them.
Plan to share: Yes — A Limited Dataset will be created and shared pursuant to a Data Use Agreement appropriately limiting use of the dataset and prohibiting the recipient from identifying or re-identifying (or taking steps to identify or re-identify) any individual whose data are included in the dataset.
Supporting information: Study protocol, Icf, Csr
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