Vestibular Consequences of Blast-related Mild Traumatic Brain Injury (TBI)

VA Office of Research and Development

Status: Completed

Conditions: Brain Injury; Dizziness

Study type: Observational

Funder types: Other U.S. Federal agency

Identifiers

NCT01021137

C6841-R

Details and patient eligibility

About

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.

Full 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.

Enrollment: 140 patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Complaint of dizziness and/or imbalance
• History of blast exposure
• Diagnosis of mild traumatic brain injury

Exclusion criteria

• Prior history of vestibular or neurological disorder
• Presence of internal metal
• Pregnancy

Trial design

140 participants in 5 patient groups

TBI & Blast

Description:

OEF/OIF Veterans complaining of dizziness and/or imbalance with history of blast exposure and a diagnosis of mild TBI

Blast Only

Description:

OEF/OIF Veterans complaining of dizziness and/or imbalance with history of blast exposure without TBI

TBI Only

Description:

OEF/OIF Veterans complaining of dizziness and/or imbalance with a history of mild TBI and no blast exposure

Healthy Controls

Description:

Age and gender matched control participants with no complaints of dizziness and/or imbalance or history of TBI or blast exposure

Excluded

Description:

Participants who did not meet inclusion criteria, did not return to complete evaluation, and/or were excluded from data analysis.