Optimizing tDCS to Improve Dual Task Gait and Balance

Aging Clinical Trial

— OptiStim  

Official title:

Optimizing Transcranial Direct Current Stimulation (tDCS) to Improve Dual Task Gait and Balance in Older Adults

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT04295798
• Other study ID #: 2019-23
• Status: Completed
• Phase: N/A
• Start date: February 10, 2020
• Est. completion date: March 2, 2023

Study information

• Verified date: March 2023
• Source: Hebrew SeniorLife
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The objective of this study is to determine the acute effects of single sessions of personalized tDCS, traditional tDCS, and sham stimulation on dual task standing and walking in older adults who are free of overt disease yet who present with poor baseline dual task performance.

Description:

Standing and walking are almost always completed in unison with other cognitive tasks such as talking, reading or making decisions. The ability to perform this important type of "dual tasking" is critical to daily activities and dependent upon one's capacity to effectively activate appropriate brain networks that include the left dorsolateral prefrontal cortex (dlPFC). Transcranial direct current stimulation (tDCS) is a safe, noninvasive technology that can selectively modulate brain excitability (i.e., the likelihood of activation) by passing low-level currents between electrodes placed upon the scalp. The investigators have demonstrated through a series of studies that a single, 20-minute exposure of tDCS targeting the left dlPFC-administered via two large sponge electrodes-reduces dual task costs to metrics of standing postural control and gait, when tested immediately following stimulation. Still, the investigators and others have also observed relatively high between-subject variability in the effects of this 'traditional' bipolar form of tDCS. The investigators contend that this variability in effectiveness arises in part from relatively diffuse and unspecific current flow when using large sponge electrodes, in combination with individual variability in head and brain anatomy that significantly alters current flow and the generated electric field in the target brain region. In this project, the investigators will apply recent advances in tDCS modeling and administration to 1) model the electric fields generated by traditional tDCS in older adults using their individual structural brain MRIs, and 2) develop personalized tDCS-delivered via an array of eight small gel electrodes-by using optimization algorithms to determine electrode placement and current parameters needed to generate desired electrical field with the brain region of interest.

The Specific Aim is to examine the immediate after-effects of personalized tDCS, traditional tDCS, and sham stimulation on dual task standing and walking in older adults. The study population will be older men and women without overt disease or illness, yet with poor baseline dual task performance defined as a dual task cost (i.e., reduction) to gait speed of at least 20% induced by simultaneously performing a serial subtraction task when walking.

The investigators hypothesize that across participants, the effect of traditional tDCS on dual task standing and walking performance will correlate with a specific component of the electric field generated over the left dlPFC target. The investigators also hypothesize that personalized tDCS will induce A) greater effects on dual task standing and walking performance as compared to traditional tDCS and sham stimulation, and B) these effects will be more consistent across individuals as compared to traditional tDCS. This project will provide important insights into tDCS "dosage" that will enable the investigators and many other researchers to better understand, control, and optimize this form of noninvasive brain stimulation to individual head and brain anatomy. It is also expected to demonstrate that personalized tDCS, as compared to the traditional approach, significantly improves the size and consistency of observed benefits to dual task standing and walking in vulnerable older adults.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 33
• Est. completion date: March 2, 2023
• Est. primary completion date: March 2, 2023
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 65 Years to 85 Years

Eligibility

Inclusion Criteria:

• Men and women aged 65-85 years

• Poor dual task performance, defined as a preferred gait speed that is >20% slower when walking and simultaneously performing verbalized serial subtractions (i.e., dual tasking), as compared to walking normally (i.e. single tasking)

Exclusion Criteria:

• Unwillingness to cooperate or participate in the study protocol

• An inability to walk or stand for 30 continuous seconds without an assistive device

• A diagnosis of a gait disorder, Parkinson's disease, Alzheimer's disease or dementia, multiple sclerosis, previous stroke or other neurodegenerative disorder

• Self-report of acute illness, injury or other unstable medical condition; Any report of severe lower-extremity arthritis or pain, physician-diagnosis of peripheral neuropathy, or other peripheral neuromuscular disease that may confound the effects of tDCS on gait or postural control

• Use of antipsychotics, anti-seizure, benzodiazepines, or other neuroactive medications

• Severe depression defined by a Geriatric Depression Scale score greater than 11;

• Any report or physician-diagnosis of schizophrenia, bipolar disorder or other psychiatric illness

• Contraindications to MRI or tDCS, including reported seizure within the past two years, use of neuro-active drugs, the risk of metal objects anywhere in the body, self-reported presence of specific implanted medical devices (e.g., deep brain stimulator, medication infusion pump, cochlear implant, pacemaker, etc.), or the presence of any active dermatological condition, such as eczema, on the scalp

Related Conditions & MeSH terms

• Aging

Intervention

Other:
• Traditional tDCS
The participant will receive a single-session of traditional tDCS for 20 minutes.
• Traditional Sham
The participant will receive a single-session of traditional sham for 20 minutes.
• Personalized tDCS
The participant will receive a single-session of personalized tDCS for 20 minutes.
• Personalized Sham
The participant will receive a single-session of personalized sham for 20 minutes.

Locations

Country	Name	City	State
United States	Hebrew Rehabilitation Center	Roslindale	Massachusetts

Sponsors (1)

Lead Sponsor	Collaborator
Hebrew SeniorLife

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Dual task cost to gait speed	Assesses the percent difference in gait speed between single and dual task walking conditions.	Change from baseline to immediate post-tDCS follow-up
Primary	Dual task cost to postural sway speed	Assesses the percent difference in postural sway speed between single and dual task standing conditions.	Change from baseline to immediate post-tDCS follow-up
Secondary	Dual task cost to stride time variability	Assesses the percent difference in stride time variability between single and dual task walking conditions.	Change from baseline to immediate post-tDCS follow-up
Secondary	Single task gait speed	Assesses gait speed within single task walking conditions	Change from baseline to immediate post-tDCS follow-up
Secondary	Dual task gait speed	Assesses gait speed within dual task walking conditions	Change from baseline to immediate post-tDCS follow-up
Secondary	Single task stride time variability	Assesses stride time variability within single task walking conditions	Change from baseline to immediate post-tDCS follow-up
Secondary	Dual task stride time variability	Assesses stride time variability within dual task walking conditions	Change from baseline to immediate post-tDCS follow-up
Secondary	Dual task cost to postural sway area	Assesses the percent difference in postural sway elliptical area between single and dual task standing conditions	Change from baseline to immediate post-tDCS follow-up
Secondary	Single task postural sway speed	Assesses postural sway speed within single task standing conditions	Change from baseline to immediate post-tDCS follow-up
Secondary	Dual task postural sway speed	Assesses postural sway speed within dual task standing conditions	Change from baseline to immediate post-tDCS follow-up
Secondary	Single task postural sway area	Assesses postural sway area within single task standing conditions	Change from baseline to immediate post-tDCS follow-up
Secondary	Dual task postural sway area	Assesses postural sway area within dual task standing conditions	Change from baseline to immediate post-tDCS follow-up