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

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ClinicalTrials.gov Identifier: NCT04155333
Recruitment Status : Recruiting
First Posted : November 7, 2019
Last Update Posted : November 7, 2019
Sponsor:
Information provided by (Responsible Party):
United States Army Aeromedical Research Laboratory

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.

Condition or disease Intervention/treatment Phase
Performance Enhancement Device: Transcranial direct current stimulation Not Applicable

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 40 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Intervention Model Description: A double-blind, randomized, sham-controlled, within-subjects design
Masking: Single (Investigator)
Masking Description: 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.
Primary Purpose: Basic Science
Official Title: Effects of Non-Invasive Brain Stimulation on Soldiers' Cognitive and Functional Performance
Estimated Study Start Date : November 2019
Estimated Primary Completion Date : September 2020
Estimated Study Completion Date : September 2021

Arm Intervention/treatment
Experimental: Active anodal stimulation
active anodal stimulation at F3, cathode placed on contralateral bicep
Device: Transcranial direct current stimulation
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.

Experimental: Active cathodal stimulation
active cathodal stimulation at F3, anode placed on contralateral bicep
Device: Transcranial direct current stimulation
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.

Sham Comparator: Sham stimulation
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
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.




Primary Outcome Measures :
  1. Military task performance [ Time Frame: Folllowing stimulation; task lasts approximately 20 min ]
    Patrol exertion multitask

  2. Military task performance [ Time Frame: Folllowing stimulation; task lasts approximately 40 min ]
    Target acquisition

  3. Cognitive function - Selective Attention [ Time Frame: Approximately 3 minutes during stimulation ]
    Stroop test

  4. Cognitive function - Multitasking/Working Memory [ Time Frame: Approximately 5 minutes during stimulation ]
    Dual n-back

  5. Cognitive function - Working Memory [ Time Frame: Approximately 2 minutes during stimulation ]
    Digit span task

  6. Cognitive function - Sustained attention [ Time Frame: Approximately 7 minutes during stimulation ]
    Rapid Visual Information Processing Task

  7. Cognitive function - Executive function [ Time Frame: Approximately 2 minutes during stimulation ]
    Shifting Attention Task: Digit symbol substitution task


Secondary Outcome Measures :
  1. Cognitive function - Impulsivity/Motor Control [ Time Frame: Approximately 3 minutes after stimulation ]
    Stop signal task - response inhibition

  2. Cognitive function - Risk Taking/ Decision Making [ Time Frame: Approximately 1 minute after stimulation ]
    Delayed Discounting Task

  3. Cognitive function - Cognitive Flexibility [ Time Frame: Approximately 5 minutes after stimulation ]
    Uses Task


Other Outcome Measures:
  1. Confounding factor - Sleepiness [ Time Frame: Approximately 1 minute, before and after stimulation ]
    Karolinska Sleepiness Scale

  2. Confounding factor - Circadian typology [ Time Frame: Approximately 15 minutes during intake ]
    Morningness-Eveningness Questionnaire

  3. Moderator variable - Intelligence [ Time Frame: Approximately 15 minutes during intake ]
    Shipley's Institute of Living Scale

  4. Moderator variable - Trait motivation [ Time Frame: Approximately 10 minutes during intake ]
    Behavioral Avoidance/ Inhibition Scales

  5. Side effects - mood symptoms [ Time Frame: Approximately 3 minutes before and after stimulation ]
    Profile of Mood States - Short Form

  6. Side effects - Physical side effects [ Time Frame: Approximately 2 minutes before and after stimulation ]
    Symptom Checklist

  7. Side effects - Physiology/health [ Time Frame: Approximately 5 minutes before and after stimulation ]
    Welch Allyn Connex 6000



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Ages Eligible for Study:   18 Years to 40 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

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

Exclusion Criteria:

  1. The following medically-related exclusionary criteria will be used, as assessed and verified by the study physician:

    1. 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
    2. No current medical conditions or medications affecting cognitive function or attention.
    3. Any history of any attention deficit condition requiring medication.
    4. Any history of psychological/psychiatric disorder.
    5. Any history of seizures, migraines, or neurological disorders.
    6. History of a head injury involving loss of consciousness.
    7. Any metal implanted within the head (e.g., shrapnel, surgical clips) or any implanted devices (e.g., cardiac pacemaker, brain stimulator, hydrocephalic shunt).
    8. Skin condition on the scalp, such as psoriasis or eczema, or wounds on the head.
    9. Currently receiving hormonal therapy treatments, other than birth control or as determined by physicians.
    10. Potential for caffeine withdrawal symptoms that will impede cognitive testing.
  2. 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.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04155333


Contacts
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Contact: Katie Feltman, PhD 334-497-4512 kathryn.a.feltman.civ@mail.mil
Contact: Amanda Kelley, PhD 334-498-2456 amanda.m.kelley.civ@mail.mil

Locations
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United States, Alabama
U.S. Army Aeromedical Research Laboratory Recruiting
Fort Rucker, Alabama, United States, 36362
Contact: Katie Feltman, PhD    334-497-4512    kathryn.a.feltman.civ@mail.mil   
Sponsors and Collaborators
United States Army Aeromedical Research Laboratory
Investigators
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Principal Investigator: Katie Feltman, PhD US Army Aeromedical Research Laboratory

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Responsible Party: United States Army Aeromedical Research Laboratory
ClinicalTrials.gov Identifier: NCT04155333     History of Changes
Other Study ID Numbers: USAARL 2018-002; M-10782
First Posted: November 7, 2019    Key Record Dates
Last Update Posted: November 7, 2019
Last Verified: November 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No