Effects of Non-Invasive Brain Stimulation on Soldiers' Cognitive and Functional Performance

NCT04155333 | Completed

• 1 other identifier: USAARL 2018-002; M-10782
• Study Type: interventional
• Target: 28
• Locations: 1 country
• Sites: 1

Brief Summary

Non-invasive brain stimulation has been shown to alter performance in both clinical and healthy populations on cognitive tasks. While the performance alterations have generally been shown to result in enhancement, mixed results remain in the literature. Much of the mixed results within the literature have been attributed to the use of different stimulation parameters, targeting of different brain areas, and using a variety of performance measures or assessing different constructs. However, non-invasive brain stimulation is a desirable method for enhancing Soldier performance given the ease of administration and minimal side effects as compared to other forms of performance enhancement (e.g., pharmaceuticals, caffeine). The objective of the current study is to evaluate the effects of non-invasive brain stimulation to the left dorsolateral prefrontal cortex in enhancing Soldier cognitive skills and performance on military tasks. A double blind within-subjects design will be used with healthy, rested Soldiers who will receive non-invasive brain stimulation and perform basic cognitive and operationally relevant tasks.

Conditions

Performance Enhancement

Outcome Measures

Primary Outcomes (7)

• Military task performance

  Patrol exertion multitask

  Folllowing stimulation; task lasts approximately 20 min

• Military task performance

  Target acquisition

  Folllowing stimulation; task lasts approximately 40 min

• Cognitive function - Selective Attention

  Stroop test

  Approximately 3 minutes during stimulation

• Cognitive function - Multitasking/Working Memory

  Dual n-back

  Approximately 5 minutes during stimulation

• Cognitive function - Working Memory

  Digit span task

  Approximately 2 minutes during stimulation

• Cognitive function - Sustained attention

  Rapid Visual Information Processing Task

  Approximately 7 minutes during stimulation

• Cognitive function - Executive function

  Shifting Attention Task: Digit symbol substitution task

  Approximately 2 minutes during stimulation

Secondary Outcomes (3)

• Cognitive function - Impulsivity/Motor Control

  Approximately 3 minutes after stimulation

• Cognitive function - Risk Taking/ Decision Making

  Approximately 1 minute after stimulation

• Cognitive function - Cognitive Flexibility

  Approximately 5 minutes after stimulation

Other Outcomes (7)

• Confounding factor - Sleepiness

  Approximately 1 minute, before and after stimulation

• Confounding factor - Circadian typology

  Approximately 15 minutes during intake

• Moderator variable - Intelligence

  Approximately 15 minutes during intake

Study Arms (3)

Active anodal stimulation

EXPERIMENTAL

active anodal stimulation at F3, cathode placed on contralateral bicep

Device: Transcranial direct current stimulation

Active cathodal stimulation

EXPERIMENTAL

active cathodal stimulation at F3, anode placed on contralateral bicep

Device: Transcranial direct current stimulation

Sham stimulation

SHAM COMPARATOR

sham stimulation that will be counterbalanced between subjects such that half will receive sham stimulation configured as condition 1 (anode F3, cathode bicep) and half will receive condition 2 (cathode F3, anode bicep)

Device: Transcranial direct current stimulation

Interventions

Transcranial direct current stimulation DEVICE

Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation that stimulates the brain through the application of a low-intensity electrical current, typically ranging from 1 to 2 milliamps (mA), via electrodes placed on an individual's scalp. During the active stimulation sessions, 2 mA of stimulation will be applied for 30 minutes. During the sham stimulation session, 2 mA of stimulation will be applied over the course of 90 sec, the electrodes will remain in place for the 30 minute duration.

Active anodal stimulation; Active cathodal stimulation; Sham stimulation

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Must be 18 (if active duty), 19 (if non-active duty) up to 40 years old.
• Must have normal hearing, vision or corrected to normal vision, and cognitive function as determined by self-report and screening by study physician
• Must have obtained at minimum 6 hours of sleep prior to data collection, as assessed by actigraphy data and self-report.
• Must have refrained from consumption of caffeine, 16 hours, nicotine, 2 hours, and alcohol, 24 hours, prior to the study, assessed by self-report.

You may not qualify if:

• Haven taken any medications which induce drowsiness, such as over-the-counter antihistamines within 24 hours of participation in the study. Any self-medication will be assessed through self-report
• No current medical conditions or medications affecting cognitive function or attention.
• Any history of any attention deficit condition requiring medication.
• Any history of psychological/psychiatric disorder.
• Any history of seizures, migraines, or neurological disorders.
• History of a head injury involving loss of consciousness.
• Any metal implanted within the head (e.g., shrapnel, surgical clips) or any implanted devices (e.g., cardiac pacemaker, brain stimulator, hydrocephalic shunt).
• Skin condition on the scalp, such as psoriasis or eczema, or wounds on the head.
• Currently receiving hormonal therapy treatments, other than birth control or as determined by physicians.
• Potential for caffeine withdrawal symptoms that will impede cognitive testing.
• Females with a known pregnancy, who test positively for pregnancy, or refuse the test will be excluded, given the lack of available research regarding the effects of tDCS during pregnancy. Known pregnancy will be assessed during screening, females without a known pregnancy will be requested to provide a urine sample during the screening procedures to ensure the absence of pregnancy.

Sponsors & Collaborators

• United States Army Aeromedical Research Laboratory: lead

Study Sites (1)

U.S. Army Aeromedical Research Laboratory

Fort Rucker, Alabama, 36362, United States

Location

MeSH Terms

Interventions

Transcranial Direct Current Stimulation

Intervention Hierarchy (Ancestors)

Electric Stimulation Therapy; Therapeutics; Convulsive Therapy; Psychiatric Somatic Therapies; Behavioral Disciplines and Activities; Electroshock; Psychological Techniques

Study Officials

• Katie Feltman, PhD

  US Army Aeromedical Research Laboratory

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: INVESTIGATOR
• Masking Details: Subjects and the research team will both be blind to the stimulation condition delivered at each test session. Access will be limited to the study physicians, investigators, and device programmers.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: FED
• Responsible Party: SPONSOR

Model Details: A double-blind, randomized, sham-controlled, within-subjects design

Study Record Dates

• First Submitted: November 5, 2019
• First Posted: November 7, 2019
• Study Start: December 12, 2019
• Primary Completion: June 1, 2021
• Study Completion: September 30, 2021
• Last Updated: January 25, 2022

Record last verified: 2022-01

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)