Optimizing tDCS to Improve Dual Task Gait and Balance

NCT04295798 | Completed Results DMC

• 1 other identifier: 2019-23
• Study Type: interventional
• Target: 29
• Locations: 1 country
• Sites: 1

Brief Summary

The objective of this study is to determine the acute effects of single sessions of optimized tDCS, conventional 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.

Conditions

Aging

Keywords

Mobility; Dual Task

Outcome Measures

Primary Outcomes (2)

• Absolute Change in Dual Task Cost to Gait Speed From Baseline to Immediately Post Intervention

  Prior to testing, participants were outfitted with wireless biosensors, each containing a triaxial accelerometer, goniometer and magnetometer, on the low back and feet to record gait kinematics (Mobility Lab™, APDM Inc). Six 25-meter walking trials were completed pre and post tDCS. Two at a preferred speed while walking quietly (single task), two at a preferred speed while performing a cognitive task (dual task) and two fast walking trials. The cognitive task during the dual task condition was verbalized serial subtractions of 3's from a random three-digit number. The absolute change was then calculated using post-intervention dual task cost minus baseline dual task cost. The outcome was calculated by averaging the dual task costs of the four trials. Negative numbers demonstrate lower (i.e., better) dual task cost post intervention. The preferred Unit of Measure is unitless.

  Change from baseline to immediately post-tDCS, up to 60 minutes

• Absolute Change in Dual Task Cost to Standing Postural Sway Speed From Baseline to Immediately Post Intervention

  Postural sway speed was assessed by measuring standing postural sway (ie., center-of pressure fluctuations) during six, 45-second trials of standing with eyes open (single task), eyes closed, or performing a cognitive task (dual task standing) on a stationary force platform (Kistler, Amherst, NY). The cognitive task was verbalized serial subtractions of 3's from a random three-digit number between 200 and 999. Participant responses during each trial were recorded. The absolute change was then calculated using post-intervention dual task cost minus baseline dual task cost. The outcome was obtained by averaging the dual task costs of the four trials. Negative numbers demonstrate lower (i.e., better) dual task cost post intervention. The preferred Unit of Measure is unitless.

  Change from baseline to immediately post-tDCS, up to 60 minutes

Secondary Outcomes (10)

• Absolute Change in Dual Task Cost to Stride Time Variability From Baseline to Immediately Post Intervention

  Change from baseline to immediately post-tDCS, up to 60 minutes

• Absolute Change in Single Task Gait Speed From Baseline to Immediately Post Intervention

  Change from baseline to immediately post-tDCS, up to 60 minutes

• Absolute Change in Dual Task Gait Speed From Baseline to Immediately Post Intervention

  Change from baseline to immediately post-tDCS, up to 60 minutes

• Absolute Change in Single Task Stride Time Variability From Baseline to Immediately Post Intervention

  Change from baseline to immediately post-tDCS, up to 60 minutes

• Absolute Change in Dual Task Stride Time Variability From Baseline to Immediately Post Intervention

  Change from baseline to immediately post-tDCS, up to 60 minutes

Study Arms (4)

Conventional tDCS

EXPERIMENTAL

One 20-minute session of active tDCS using two 35 cm2 sponge electrodes targeting the left dlPFC.

Device: Conventional tDCS

Optimized tDCS

EXPERIMENTAL

One 20-minute session of active tDCS using eight gel electrodes with placement and current parameters optimized to the cohort targeting the left dlPFC.

Device: Optimized tDCS

Conventional sham

SHAM COMPARATOR

One 20-minute session of inactive sham tDCS delivered via two sponge electrodes for a short period of time before it is ramped down to zero for the remainder of the session.

Device: Conventional Sham

Optimized Sham

SHAM COMPARATOR

One 20-minute session of active sham in which the Stimweaver optimization algorithm will be used with the objective of creating a null electric field on the target left dlPFC with the constraint that some gel electrodes deliver low-level currents that still induce cutaneous sensations.

Device: Optimized Sham

Interventions

Conventional tDCS DEVICE

The anode will be placed over F3 and the cathode over the contralateral supraorbital margin. At the beginning of stimulation, the current will be increased from 0.1 mA, in 0.1 mA increments over 60 seconds, up to a maximum of 1.8 mA. At the end of each session, current will be automatically ramped down to 0.0 mA over a 60 second period.

Conventional tDCS

Optimized tDCS DEVICE

This intervention will utilize eight gel electrodes with placement and current parameters optimized to the cohort, with the goal of generating an average nE over the left dlPFC of the same size as the one delivered by a conventional montage using sponges. The direct current delivered by any one electrode will however never exceed 2.0 mA; the total amount of current from all electrodes will not exceed 4 mA. Each 20- minute session will begin and end with a 60-second ramp up/down of current amplitude to maximize comfort.

Optimized tDCS

Conventional Sham DEVICE

Conventional sham will be used to maximize blinding of conventional sponge-based stimulation. The same sponge placement, ramp-up procedure, and session duration described above will be used; however, current will be automatically ramped down 60 seconds after ramp-up.

Conventional sham

Optimized Sham DEVICE

An active sham will be used in which very low-level currents (0.5 mA max) are transferred between the same electrodes used in the active condition throughout the entire 20-minute session. This intervention will be optimized to deliver currents designed to not significantly influence their cortical tissue, but still mimic the cutaneous sensations induced by tDCS. We have shown that this active sham effectively blinds participants and operators to stimulation condition and does not affect functional outcomes.

Optimized Sham

Eligibility Criteria

• Age: 65 Years - 85 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Older Adult (65+)

You may qualify if:

• Men and women aged 65-85 years
• Poor dual task performance, defined as a preferred gait speed that is \>10% slower when walking and simultaneously performing verbalized serial subtractions (i.e., dual tasking), as compared to walking normally (i.e. single tasking)

You may not qualify if:

• 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

Sponsors & Collaborators

• Hebrew SeniorLife: lead

Study Sites (1)

Hebrew Rehabilitation Center

Roslindale, Massachusetts, 02131, United States

Location

Results Point of Contact

• Title: Junhong Zhou
• Organization: Hebrew SeniorLife

JunhongZhou@hsl.harvard.edu

617-971-5346

Study Officials

• Brad Manor, PhD

  Hebrew SeniorLife

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Study personnel administering tDCS and the participants will not be aware of tDCS intervention arm assignment. The investigators will ensure such double-blinding by programming the tDCS software with intervention-specific stimulation codes, as supplied by personnel uninvolved in data collection, prior to study initiation.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Scientist

Model Details: The investigators will conduct a "within-subject," double-blinded, randomized controlled study comparing the after-effects of single sessions of conventional tDCS, optimized tDCS, and two different sham conditions on dual task performance in men and women aged 65-85 years with poor baseline dual task performance. Participants will complete an optional structural brain MRI. They will then complete four visits during which they will receive one of the four interventions in random order.

Study Record Dates

• First Submitted: March 2, 2020
• First Posted: March 5, 2020
• Study Start: February 10, 2020
• Primary Completion: March 2, 2023
• Study Completion: March 2, 2023
• Last Updated: January 30, 2025
• Results First Posted: January 30, 2025

Record last verified: 2025-01

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, ANALYTIC CODE
• Time Frame: The investigators will make the data and associated documentation available once summary data are published or otherwise made available, starting six months after publication.
• Access Criteria: The investigators will make the data and associated documentation available to users only under a data-sharing agreement that provides for: 1) a commitment to using data only for research purposes and not to identify any particular participant; 2) a commitment to securing the data using appropriate computer technology; and 3) a commitment to destroying or returning the data after analyses are completed. The availability of data will be advertised over the Internet through websites maintained by Hebrew SeniorLife and Harvard Medical School. All investigators wishing to access the data will submit a brief proposal describing their research project, data needs, regulatory approvals, and mechanisms to assure patient confidentiality. Upon affirmative review by the Principal Investigator and co-investigators of this study, a data-sharing agreement will be signed and the requesting investigators will be given a working data file and appropriate documentation.

Locations

US (1)