Spinal Networks of Balance Learning and Retention in Older Adults

Upregulating Spinal Circuits to Enhance Balance and Walking and to Increase Spinal Excitability in Older Adults

Age-related balance and walking issues increase fall risks, leading to injuries, higher healthcare costs, reduced quality of life, and increased morbidity/mortality rates. Preserving functional ability is a crucial public health priority, with the potential to reduce healthcare costs and enhance older adults' quality of life. Declines in balance and walking ability threaten independence. These declines are attributed to spinal network impairments and may be mitigated by targeted interventions aimed at addressing age-related spinal cord impairment to enhance functional outcomes. However, there is a lack of research into how the aging spinal cord affects balance/walking. In older adults, the spinal cord is less excitable, conducts signals more slowly, and is subject to neural noise. Intervening on age-related impairment of the spinal cord to improve balance/walking ability is a very promising but untapped area of research. A therapeutic approach that combines dynamic balance training with non-invasive electrical spinal stimulation may be effective in preserving functional abilities. This study tests whether electrical stimulation of the spinal lumbar regions is more beneficial than sham stimulation.

Study Overview

• Status: Recruiting
• Conditions: Aging
• Intervention / Treatment: Behavioral: Balance Training; Device: Spinal Active tsDCS; Device: Spinal Sham tsDCS

Detailed Description

A high proportion of older adults are currently or soon will be at risk for the well-known decline in walking and balance abilities that occur with aging. Preserving those abilities has become a major public health priority. Balance training can enhance functional abilities or attenuate functional decline; however, age-related motor deficits may impair practice-based motor learning and behavioral performance. Due to the crucial roles of the spinal cord in balance and walking performance, it is important to consider that age-related neural impairment of the spinal cord is a likely contributing factor. Specifically, the spinal cord in older adults has fewer neurons, is less excitable, and conducts signals more slowly.

Despite ample evidence of impaired spinal cord neuronal structure and function with aging, the potential benefit of an intervention targeting spinal control of balance and walking control has been largely unexplored. This dearth of research may be due in part to the lack of a clinically feasible intervention. However, the recent emergence of transcutaneous spinal direct current stimulation (tsDCS) as a non-invasive intervention creates new opportunities for understanding spinal cord contributions to balance and walking performance. Notably, our previous study was the first demonstration of the safety and feasibility of a lab-based intervention that combined tsDCS with complex walking practice. These initial findings support the enhanced efficacy of locomotor learning during a single session when combined with tsDCS in older adults. Building on the success of this preliminary data, the investigators now propose an extended, multisession intervention that combines tsDCS with balance training. The proposed study will be among the first multi-session trial to investigate the effects of tsDCS as an adjunct therapy to dynamic balance training in older adults.

This study aims to enroll 30 older adults aged 65 years or older with balance or walking deficits, determined through objective assessments. All participants will undergo the same five-session balance training over a 2-week period, which will emphasize the use of a unique balance exergaming device called the Dividat Senso. Participants will be randomly assigned to a tsDCS adjuvant group. The "Active group" will receive 30 continuous minutes of 2.5-mA tsDCS over lumbar regions T11/T12. The "Sham group" will receive the sham protocol, which involves an identical montage and stimulation arrangement but delivers no current for 27 minutes. Each 30-minutes session will be preceded and followed by balance and walking assessments to examine the intervention's effects over time. Spinal excitability, measured via soleus H-reflex testing, will be assessed immediately before and after tsDCS at the first and last intervention. Behavioral assessments will occur at baseline, 1 day post-intervention, and 10-day post-intervention to investigate pre vs. post effects and retention intervention effects. Prefrontal activity will be measured using functional near-infrared spectroscopy (fNIRS) during the behavioral assessments to evaluate demand on executive control networks.

The objective of using tsDCS is to upregulate spinal circuits to make them more responsive to task-specific activation, thereby fostering more robust learning and consolidation to enhance performance in dynamic balance tasks. Thus, the overarching hypothesis of the proposed research is that tsDCS will be a potent adjuvant therapy to a dynamic balance intervention by reinforcing task-appropriate spinal excitation to promote skill acquisition and retention, thereby improving balance and walking. This study will focus on achieving the following specific aims:

Specific Aim 1: Acquire preliminary effect size and response variance data to assess whether active adjuvant tsDCS therapy combined with dynamic balance training enhances practice-related gains in balance and walking performance and retention over time.

Specific Aim 2: Establish evidence of increased spinal excitability following tsDCS, positively correlating with gains in balance and walking functions.

The long term deliverable of this line of research will be a clinically feasible multi-modal intervention to assist in preserving motor function and independence in older adults. The knowledge and experience gained from this study will enable us to conduct larger studies to better understand the effects of aging on the spinal cord and to test rehabilitation interventions to promote healthy aging among older adults.

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jungyun Hwang, PhD; Phone Number: 352-294-5458; Email: jungyunhwang@ufl.edu

Study Locations

• United States
  • Florida
    • Gainesville, Florida, United States, 32608
      • Recruiting
      • Malcom Randall VA Medical Center Brain Rehabilitation Research Center
      • Contact: Brigette J Cox; Phone Number: 107735 352-376-1611; Email: brigette.cox@phhp.ufl.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• age range: 65 to 95 years
• no severe high blood pressure: Resting systolic < 180 mmHg and diastolic < 100 mmHg
• no severe vision impairment: Visual acuity ≥ 20/70 as determined by Snellen eye chart
• walking problem: Preferred walking speed slower than 1.0 m/s over 10 meters
• balance problem: Berg Balance Scale score < 45
• no cognitive impairment: Montreal Cognitive Assessment (MoCA) score ≥ 26 out of 30

Exclusion Criteria:

• diagnosed neurological disorder or injury of the central nervous system, or observation of symptoms consistent with such a condition (Alzheimer's, Parkinson's, stroke, etc.)
• severe arthritis, such as awaiting joint replacement
• current cardiovascular, lung or renal disease; untreated diabetes; terminal illness
• myocardial infarction or major heart surgery in the previous year
• cancer treatment in the past year, except for nonmelanoma skin cancers and cancers having an excellent prognosis (e.g., early stage breast or prostate cancer)
• current diagnosis of schizophrenia, other psychotic disorders, or bipolar disorder
• currently taking medications that affect the central nervous system, such as benzodiazepines, anti-cholinergic medication, and GABAergic medication, among others
• uncontrolled hypertension at rest (systolic > 180 mmHg and/or diastolic > 100 mmHg)
• bone fracture or joint replacement in the previous six months
• current enrollment in any other clinical trial
• planning to relocate out of the area during the study period
• non-English* speaking, due to the likelihood of difficulties following instructions and communicating remotely
• clinical judgment of the investigative team

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Active tsDCS treatment; Participants will receive 30 minutes of continuous 2.5-mA tsDCS over the lumbar regions while engaging in a 30-minute complex balance task during each intervention session over a period of 2 weeks (every other day), totaling 5 intervention visits.	Behavioral: Balance Training; Complex balance task involving static and dynamic weight shifting and coordinated stepping; Device: Spinal Active tsDCS; Active tsDCS over lumbar regions
Sham Comparator: Sham tsDCS control; Participants will receive 3 minutes of 2.5-mA tsDCS over the lumbar regions while engaging in a 30-minute complex balance task during each intervention session over a period of 2 weeks (every other day), totaling 5 intervention visits.	Behavioral: Balance Training; Complex balance task involving static and dynamic weight shifting and coordinated stepping; Device: Spinal Sham tsDCS; Sham tsDCS over lumbar regions

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Center of Pressure (COP) balance control	Change in the center of pressure during static and dynamic postural control on a Dividat Senso pressure-sensitive plate will be assessed from baseline to post-intervention and follow-up.	Baseline, 1-day post-intervention (after intervention), 10-day follow-up (after post-intervention)
Walking speed over obstacle course	Change in fastest walking speed over a 10-meter obstacle course on the GAITRite system will be assessed from baseline to post-intervention and follow-up.	Baseline, 1-day post-intervention (after intervention), 10-day follow-up (after post-intervention)
Spinal excitability via Soleus H-reflex testing	Change in spinal excitability, measured via the soleus H-reflex testing using electromyography, will be assessed before and immediately following active or sham tsDCS (combined with balance training) during the 1st and 5th of the total five intervention sessions. The magnitude of change will be compared between these sessions.	Baseline and immediately following 30-minute intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Score on standardized balance assessment (Berg Balance Scale)	Change in balance scores will be assessed using the Berg Balance Scale from baseline to post-intervention and follow-up. The scale ranges from 0 to 56, with higher scores indicating better balance performance.	Baseline, 1-day post-intervention (after intervention), 10-day follow-up (after post-intervention)
Score on standardized walking assessment (Functional Gait Assessment)	Change in walking scores will be assessed using the Functional Gait Assessment from baseline to post-intervention and follow-up. The scale ranges from 0 to 30, with higher scores indicating better walking performance.	Baseline, 1-day post-intervention (after intervention), 10-day follow-up (after post-intervention)
Completion time on test of executive function (Trail Making Test)	Change in completion time from baseline to post-intervention and follow-up will be assessed using the Trail Making Test. Shorter times indicate better cognitive performance.	Baseline, 1-day post-intervention (after intervention), 10-day follow-up (after post-intervention)
tsDCS treatment-related adverse events as assessed by a survey questionnaire.	Change in the score of side effects from tsDCS (e.g., sensations of burning, tingling, itching, and pain) will be assessed before and following active or sham tsDCS (combined with balance training) for every 30-minute intervention session using a survey questionnaire. Each question on the scale ranges from 0 to 10, and the scores will be averaged. A higher mean score indicates a higher severity of side effects.	Baseline and following 30-minute intervention
Prefrontal cortical activity using fNIRS	Change in prefrontal brain activity during static and dynamic balance control and fastest walking assessments will be assessed using functional Near-Infrared Spectroscopy (fNIRS) from baseline to post-intervention and follow-up.	Baseline, 1-day post-intervention (after intervention), 10-day follow-up (after post-intervention)

Collaborators and Investigators

• Sponsor: University of Florida
• Collaborators: National Institute on Aging (NIA)

Study record dates

Study Major Dates

• Study Start (Actual): January 22, 2025
• Primary Completion (Estimated): September 30, 2026
• Study Completion (Estimated): October 31, 2026

Study Registration Dates

• First Submitted: July 8, 2024
• First Submitted That Met QC Criteria: July 23, 2024
• First Posted (Actual): July 24, 2024

Study Record Updates

• Last Update Posted (Actual): June 4, 2026
• Last Update Submitted That Met QC Criteria: June 2, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: electrical stimulation; aging; walking; balance; spinal cord
• Other Study ID Numbers: IRB202400382; R21AG084944 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: 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.
• IPD Sharing Time Frame: The Limited Dataset will be completed after the study is completed and primary/secondary data accepted for publication.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No