DizzinessNCT01021137
Vestibular Consequences of Blast-related Mild Traumatic Brain Injury (TBI)
An observational study of Dizziness and Brain Injury, run by VA Office of Research and Development at 1 site in United States.
Trial summary
The purpose of this project is to determine the effects of mild traumatic brain injury and blast exposure on the inner ear balance and central nervous systems. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Dizziness, Brain Injury
- How many people
- 140 participants
- Where
- 1 siteUnited States
- Study dates
- 1 May 2011to Dec 2017
- Phase
- Observational
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: OEF/OIF Veterans
Who may be able to join
- Complaint of dizziness and/or imbalance
- History of blast exposure
- Diagnosis of mild traumatic brain injury
Who cannot join
- Prior history of vestibular or neurological disorder
- Presence of internal metal
- Pregnancy
Trial locations and contacts
1 site in 1 country.
United States1 site
Mountain Home VA Medical Center James H. Quillen VA Medical Center, Mountain Home, TN
Mountain Home, Tennessee, 37684
About this study
Official title: Vestibular Consequences of Blast-related Mild Traumatic Brain Injury
The purpose of this project is to determine the effects of mild traumatic brain injury and blast exposure on the inner ear balance and central nervous systems.
Read the detailed description
The goal of this project is to determine the effects of mild traumatic brain injury (mTBI) and blast exposure on the vestibular system and CNS. Dizziness and balance disorders are common symptoms associated with mTBI or head injury. Numerous studies have provided significant evidence that mTBI or head injury can cause damage to the vestibular system; however, most have limited the vestibular evaluation to assessment of horizontal semicircular canal function. Recently, methods have been developed to assess otolith function, and there is some evidence that head injury may affect the otolith organs to a greater degree than the semicircular canals.
mTBI has been called the signature condition of Veterans returning from Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF), and the cause is often related to blast exposure from improvised explosive devices, mortars or rocket-propelled grenades. Some investigators have presumed that dizziness and balance disorders following blast exposure are related to CNS damage caused by the TBI rather than the pressure wave from the blast injury. Thus, most research has focused on the vestibular consequences of TBI (or head injury), and there is limited data on the effects of blast exposure on vestibular function or balance. Recently, magnetic resonance imaging techniques have been developed that may allow for testing the assumption that the symptoms of dizziness or imbalance related to head injury or blast exposure are often due to central vestibular or CNS involvement.
Specific aims of this project are to determine the effect of mTBI and blast exposure on (1) peripheral vestibular system function (specifically, horizontal semicircular canal function, and otolith organ function), (2) central vestibular/CNS function, (3) postural stability, and (4) dizziness-related quality of life. Four subject groups will include Veterans complaining of dizziness/imbalance with (1) a history of blast exposure, (2) with mTBI, (3) with blast exposure and mTBI, and (4) a control group. Each subject will undergo tests of horizontal semicircular canal function (caloric and rotary chair), tests of otolith function (vestibular evoked myogenic potentials, subjective visual vertical), central vestibular function/CNS function (ocular motor tests, diffusion tensor and susceptibility weighting imaging), gait and balance testing, and the Dizziness Handicap Inventory.
- Conditions
- Dizziness, Brain Injury
- Keywords
- vestibular function tests, postural balance, neuroimaging
- Medical subject headings
- Dizziness, Brain Injuries
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| TBI & Blast | OEF/OIF Veterans complaining of dizziness and/or imbalance with history of blast exposure and a diagnosis of mild TBI | |
| Blast Only | OEF/OIF Veterans complaining of dizziness and/or imbalance with history of blast exposure without TBI | |
| TBI Only | OEF/OIF Veterans complaining of dizziness and/or imbalance with a history of mild TBI and no blast exposure | |
| Healthy Controls | Age and gender matched control participants with no complaints of dizziness and/or imbalance or history of TBI or blast exposure | |
| Excluded | Participants who did not meet inclusion criteria, did not return to complete evaluation, and/or were excluded from data analysis. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Peripheral Vestibular Function (Vestibulo-ocular Reflex/Semicircular Canal): Caloric Weakness
The caloric weakness was determined using monothermal warm inter-ear difference (MWIED) which was calculated as: (|RW| - |LW| )/( |RW| + |LW|) x 100, where RW = the maximum slow phase velocity (SPV) of nystagmus induced by warm water irrigation in the right ear and LW = the maximum SPV of nystagmus induced by warm water irrigation in the left ear. For participants with MWIED > 10, then cool caloric irrigation was also performed and caloric weakness was determined using a bithermal inter-ear difference (BIED) calculated as: (|RW| + |RC|) - (|LW| + |LC|) / (|RW| + |RC| + |LW| + |LC|) x 100, where RC = maximum SPV of nystagmus induced by cool water irrigation in the right ear and LC = maximum SPV of nystagmus induced by cool water irrigation in the left ear.
Measured: up to 30 minutes
Rotary Chair Slow Harmonic Acceleration (SHA) Gain
Rotary chair slow harmonic acceleration (SHA) vestibulo-ocular reflex (VOR) gain at 0.01 Hz was used as a measure of peripheral vestibular function (VOR/horizontal semicircular canal). VOR gain is defined as the ratio of the slow component velocity eye movement (output) to the velocity of the head movement (input).
Measured: up to 30 minutes
Peripheral Vestibular Function (Saccular-collic Pathway): Cervical Vestibular Evoked Potential (cVEMP)
Air-conducted cervical vestibular evoked potential (cVEMP) inter-ear amplitude asymmetry ratio was used as a measure of otolith organ function (saccular-collic pathway). Inter-ear amplitude asymmetry ratio was calculated as: [(|L_P1-N1| - |R_P1-N1|)/ (|L_P1-N1| + |R_P1-N1|)] x100, where L_P1-N1 = peak-to-peak cVEMP amplitude of the left side and R_P1-N1 = peak-to-peak cVEMP amplitude of the right side. The amplitudes were calculated from cVEMP responses at a stimulus intensity of 120 dB peakSPL. The criterion for abnormal cVEMP was defined as an absent cVEMP or a corrected cVEMP amplitude asymmetry ratio greater than or equal to 40%, either of which would indicate a unilateral vestibular loss. A bilateral vestibular loss was indicated by absent cVEMPs bilaterally.
Measured: Up to 30 minutes
Rotary Chair Slow Harmonic Acceleration (SHA) Phase
Rotary chair slow harmonic acceleration (SHA) vestibulo-ocular reflex (VOR) phase at 0.01 Hz was used as a measure of peripheral vestibular function (VOR/horizontal semicircular canal). The phase is the timing difference between the velocity of head movement and the slow-phase eye velocity. This parameter is normalized for a full cycle of a sinusoid (360 degrees) and presented in an angular unit of degrees rather than a unit of time. For perfectly compensatory eye movements the phase is 0 degrees, meaning there is no difference between the actual eye velocity and the ideal VOR (by convention, degrees is added to the phase so that the comparison is based on the ideal VOR responses instead of the actual head motion).
Measured: Up to 30 minutes (SHA phase is obtained simultaneously with SHA gain)
Peripheral Vestibular Function (Utricular-ocular Pathway): Ocular Vestibular Evoked Potential (oVEMP)
Bone-conducted ocular vestibular evoked potential (oVEMP) inter-ear amplitude asymmetry ratio was used as a measure of otolith organ function (utricular-ocular pathway). Inter-ear amplitude asymmetry ratio was calculated as: [(|L_N1-P1| - |R_N1-P1|)/ (|L_N1-P1| + |R_N1-P1|)] x100, where L_N1-P1 = peak-to-peak oVEMP amplitude of the left eye/right ear and R_N1-P1 = peak-to-peak oVEMP amplitude of the right eye/left ear. The oVEMP is a contralateral response; therefore, recordings from the left eye reflect the response of the right ear and vice versa. The amplitudes were calculated from oVEMP responses at a stimulus intensity of 155 dB peakFL. The criterion for abnormal oVEMP was defined as an absent oVEMP or a corrected oVEMP amplitude asymmetry ratio greater than or equal to 40%, either of which would indicate a unilateral vestibular loss. A bilateral vestibular loss was indicated by absent oVEMPs bilaterally.
Measured: Up to 20 minutes
Secondary outcomes (3)
Central Vestibular/Central Nervous System (CNS) Function: Visual Fixation Suppression
Visual fixation suppression was used as a measure of central vestibular/CNS function. Visual fixation suppression is a measure of vestibulo-ocular reflex (VOR) gain obtained during visual fixation at 0.16 Hz slow harmonic acceleration on the rotary chair. VOR gain was defined as the ratio of the slow component velocity eye movement (output) to the velocity of the head movement (input). Visual fixation suppression was considered normal if VOR gain is suppressed > 50% with visual fixation compared to no fixation.
Measured: 1 minute
Postural Stability: Sensory Organization Test (SOT)
This measure is the composite equilibrium score from six conditions of the sensory organization test obtained with the Neurocom Equitest. Results of the SOT were calculated based on maximum peak-to-peak anterior-posterior sway expressed as an equilibrium score ranging from 0 to 100, with 0 indicating loss of balance (i.e., required support of harness, took a step, touched walls for support or opened eyes in eyes closed conditions) and 100 indicating perfect stability. The outcome measure was the equilibrium composite score and was calculated by the software as the weighted average of the equilibrium scores for the six conditions. For ages 18-59 years, the normative value (mean - 1.67 SD) for the composite score is at least 70 (NeuroCom, 2011).
Measured: Up to 20 minutes
Dizziness Handicap Inventory
The Dizziness Handicap Inventory (DHI) was used as a quality of life measure.The DHI measures the subject's self-perceived dizziness. The scale has 25 questions with 3 possible answers each: "Yes" = 4 points, "Sometimes" = 2 points, and "No" = 0 points. The minimum number of points that a subject can score is 0 and the maximum number of points is 100. The subject's self-perceived dizziness is reported as a percentage with a range of 0-100%, and is calculated by: subject's total number of points/maximum number of points (100) x 100%. The higher the score on the DHI, the worse a patient's self-perceived dizziness.
Measured: Up to 10 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Nov 2009 (estimated)
- Study start1 May 2011
- Primary completion30 Dec 2016
- Study completionDec 2017
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for DizzinessStudies of the same condition, open and under way.
- More trials run by VA Office of Research and DevelopmentThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 140 participants (actual)
Sponsor and investigators
- Lead sponsor
- VA Office of Research and Development
- Sponsor type
- US federal agency
- Responsible party
- Sponsor
- Investigators
- Faith Akin, PhD, Principal investigator, Mountain Home VA Medical Center James H. Quillen VA Medical Center, Mountain Home, TN
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01021137
- Sponsor's protocol ID
- C6841-R
- Status last verified
- Jun 2019
- First submitted
- 24 Nov 2009
- Last updated
- 5 Aug 2019
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 5 Aug 2019. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Vestibular Consequences of Blast-related Mild Traumatic Brain Injury
- ClinicalTrials.gov ID
- NCT01021137
- Acronym / sponsor ID
- C6841-R
- Conditions
- Dizziness, Brain Injury
- Keywords
- vestibular function tests, postural balance, neuroimaging
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 140 participants (actual)
- Lead sponsor
- VA Office of Research and DevelopmentUS federal agency
- Study start
- 1 May 2011 (actual)
- Primary completion
- 30 Dec 2016 (actual)
- Study completion
- Dec 2017 (actual)
- First posted
- 26 Nov 2009 (estimated)
- Results
- Posted 5 Aug 2019
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this project is to determine the effects of mild traumatic brain injury and blast exposure on the inner ear balance and central nervous systems.
Detailed description
The goal of this project is to determine the effects of mild traumatic brain injury (mTBI) and blast exposure on the vestibular system and CNS. Dizziness and balance disorders are common symptoms associated with mTBI or head injury. Numerous studies have provided significant evidence that mTBI or head injury can cause damage to the vestibular system; however, most have limited the vestibular evaluation to assessment of horizontal semicircular canal function. Recently, methods have been developed to assess otolith function, and there is some evidence that head injury may affect the otolith organs to a greater degree than the semicircular canals.
mTBI has been called the signature condition of Veterans returning from Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF), and the cause is often related to blast exposure from improvised explosive devices, mortars or rocket-propelled grenades. Some investigators have presumed that dizziness and balance disorders following blast exposure are related to CNS damage caused by the TBI rather than the pressure wave from the blast injury. Thus, most research has focused on the vestibular consequences of TBI (or head injury), and there is limited data on the effects of blast exposure on vestibular function or balance. Recently, magnetic resonance imaging techniques have been developed that may allow for testing the assumption that the symptoms of dizziness or imbalance related to head injury or blast exposure are often due to central vestibular or CNS involvement.
Specific aims of this project are to determine the effect of mTBI and blast exposure on (1) peripheral vestibular system function (specifically, horizontal semicircular canal function, and otolith organ function), (2) central vestibular/CNS function, (3) postural stability, and (4) dizziness-related quality of life. Four subject groups will include Veterans complaining of dizziness/imbalance with (1) a history of blast exposure, (2) with mTBI, (3) with blast exposure and mTBI, and (4) a control group. Each subject will undergo tests of horizontal semicircular canal function (caloric and rotary chair), tests of otolith function (vestibular evoked myogenic potentials, subjective visual vertical), central vestibular function/CNS function (ocular motor tests, diffusion tensor and susceptibility weighting imaging), gait and balance testing, and the Dizziness Handicap Inventory.
Study design
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Number of arms
- 5
| Arm | Type | Receives |
|---|---|---|
| TBI & Blast | – | –OEF/OIF Veterans complaining of dizziness and/or imbalance with history of blast exposure and a diagnosis of mild TBI |
| Blast Only | – | –OEF/OIF Veterans complaining of dizziness and/or imbalance with history of blast exposure without TBI |
| TBI Only | – | –OEF/OIF Veterans complaining of dizziness and/or imbalance with a history of mild TBI and no blast exposure |
| Healthy Controls | – | –Age and gender matched control participants with no complaints of dizziness and/or imbalance or history of TBI or blast exposure |
| Excluded | – | –Participants who did not meet inclusion criteria, did not return to complete evaluation, and/or were excluded from data analysis. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- OEF/OIF Veterans
Key inclusion criteria (3 listed)
- Complaint of dizziness and/or imbalance
- History of blast exposure
- Diagnosis of mild traumatic brain injury
Key exclusion criteria (3 listed)
- Prior history of vestibular or neurological disorder
- Presence of internal metal
- Pregnancy
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Peripheral Vestibular Function (Vestibulo-ocular Reflex/Semicircular Canal): Caloric Weakness
Time frame: up to 30 minutes
The caloric weakness was determined using monothermal warm inter-ear difference (MWIED) which was calculated as: (|RW| - |LW| )/( |RW| + |LW|) x 100, where RW = the maximum slow phase velocity (SPV) of nystagmus induced by warm water irrigation in the right ear and LW = the maximum SPV of nystagmus induced by warm water irrigation in the left ear. For participants with MWIED > 10, then cool caloric irrigation was also performed and caloric weakness was determined using a bithermal inter-ear difference (BIED) calculated as: (|RW| + |RC|) - (|LW| + |LC|) / (|RW| + |RC| + |LW| + |LC|) x 100, where RC = maximum SPV of nystagmus induced by cool water irrigation in the right ear and LC = maximum SPV of nystagmus induced by cool water irrigation in the left ear.
Rotary Chair Slow Harmonic Acceleration (SHA) Gain
Time frame: up to 30 minutes
Rotary chair slow harmonic acceleration (SHA) vestibulo-ocular reflex (VOR) gain at 0.01 Hz was used as a measure of peripheral vestibular function (VOR/horizontal semicircular canal). VOR gain is defined as the ratio of the slow component velocity eye movement (output) to the velocity of the head movement (input).
Peripheral Vestibular Function (Saccular-collic Pathway): Cervical Vestibular Evoked Potential (cVEMP)
Time frame: Up to 30 minutes
Air-conducted cervical vestibular evoked potential (cVEMP) inter-ear amplitude asymmetry ratio was used as a measure of otolith organ function (saccular-collic pathway). Inter-ear amplitude asymmetry ratio was calculated as: [(|L_P1-N1| - |R_P1-N1|)/ (|L_P1-N1| + |R_P1-N1|)] x100, where L_P1-N1 = peak-to-peak cVEMP amplitude of the left side and R_P1-N1 = peak-to-peak cVEMP amplitude of the right side. The amplitudes were calculated from cVEMP responses at a stimulus intensity of 120 dB peakSPL. The criterion for abnormal cVEMP was defined as an absent cVEMP or a corrected cVEMP amplitude asymmetry ratio greater than or equal to 40%, either of which would indicate a unilateral vestibular loss. A bilateral vestibular loss was indicated by absent cVEMPs bilaterally.
Rotary Chair Slow Harmonic Acceleration (SHA) Phase
Time frame: Up to 30 minutes (SHA phase is obtained simultaneously with SHA gain)
Rotary chair slow harmonic acceleration (SHA) vestibulo-ocular reflex (VOR) phase at 0.01 Hz was used as a measure of peripheral vestibular function (VOR/horizontal semicircular canal). The phase is the timing difference between the velocity of head movement and the slow-phase eye velocity. This parameter is normalized for a full cycle of a sinusoid (360 degrees) and presented in an angular unit of degrees rather than a unit of time. For perfectly compensatory eye movements the phase is 0 degrees, meaning there is no difference between the actual eye velocity and the ideal VOR (by convention, degrees is added to the phase so that the comparison is based on the ideal VOR responses instead of the actual head motion).
Peripheral Vestibular Function (Utricular-ocular Pathway): Ocular Vestibular Evoked Potential (oVEMP)
Time frame: Up to 20 minutes
Bone-conducted ocular vestibular evoked potential (oVEMP) inter-ear amplitude asymmetry ratio was used as a measure of otolith organ function (utricular-ocular pathway). Inter-ear amplitude asymmetry ratio was calculated as: [(|L_N1-P1| - |R_N1-P1|)/ (|L_N1-P1| + |R_N1-P1|)] x100, where L_N1-P1 = peak-to-peak oVEMP amplitude of the left eye/right ear and R_N1-P1 = peak-to-peak oVEMP amplitude of the right eye/left ear. The oVEMP is a contralateral response; therefore, recordings from the left eye reflect the response of the right ear and vice versa. The amplitudes were calculated from oVEMP responses at a stimulus intensity of 155 dB peakFL. The criterion for abnormal oVEMP was defined as an absent oVEMP or a corrected oVEMP amplitude asymmetry ratio greater than or equal to 40%, either of which would indicate a unilateral vestibular loss. A bilateral vestibular loss was indicated by absent oVEMPs bilaterally.
3 secondary outcomes
Central Vestibular/Central Nervous System (CNS) Function: Visual Fixation Suppression
Time frame: 1 minute
Postural Stability: Sensory Organization Test (SOT)
Time frame: Up to 20 minutes
Dizziness Handicap Inventory
Time frame: Up to 10 minutes
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 5 Aug 2019.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Faith Akin, PhD principal investigator
Mountain Home VA Medical Center James H. Quillen VA Medical Center, Mountain Home, TN
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Dizziness and Brain Injury, run by VA Office of Research and Development at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 5 Aug 2019. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
Yes. Results are posted in the registry (first posted 5 Aug 2019). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Peripheral Vestibular Function (Vestibulo-ocular Reflex/Semicircular Canal): Caloric Weakness (time frame: up to 30 minutes). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 5 Aug 2019.