CENC0008P - Otolith Dysfunction and Postural Stability

This research study is part of a long-term goal to establish a unique treatment platform to diagnose, localize, and treat dizziness and imbalance related to inner ear balance issues associated with mTBI. In the recent wars in Iraq and Afghanistan, many soldiers have been exposed to blasts from IEDs or roadside bombs, and TBI has been called the signature condition of Operation Enduring Freedom and Operation Iraqi Freedom (OEF/OIF) combat Veterans.

The objective of the study is to determine the effect of inner ear balance (vestibular) dysfunction on balance, gait, and quality of life. The primary function of the inner ear balance function is to keep vision steady when the head is in motion and to maintain balance. Loss of inner ear balance function can result in dizziness and/or imbalance, and individuals with these symptoms are at risk of falling. The incidence of dizziness and imbalance increases in two populations relevant to VA and military healthcare: older individuals and individuals who have suffered a head injury or blast exposure.

Until recently, inner ear balance assessment was limited to measuring only one part of the inner ear balance system, the horizontal semicircular canal and its connections to the eyes (called vestibulo-ocular reflex). In addition, treatment for inner ear balance problems has been based on the principles of vestibulo-ocular reflex recovery from injury. Recently though, clinical tests have been developed that provide information about otolith organ function – two inner ear balance organs that sense gravity and contribute to maintaining upright posture or balance. Although new otolith organ tests are available, they are used less widely than horizontal canal tests, and one reason may be that it is unclear if  abnormal otolith organ function affects a person negatively in terms of maintaining balance and participating in activities of everyday living. Thus, determining the impact of abnormal otolith organ function is important in developing clinical recommendations for evaluating patients suffering from dizziness and imbalance.

There is recent evidence to suggest that otolith organ dysfunction can occur in patients with mild traumatic brain injury (TBI) or blast exposure. This is important because symptoms of dizziness and imbalance resulting from mTBI or blast exposure can last six months or longer, which is often longer than recovery from other types of inner ear balance disturbances. If the dizziness and imbalance symptoms that occur following head injury or blast exposure are related to injury to the otolith organs rather the horizontal semicircular canal, than new treatment approaches may be necessary to focus on otolith organ pathway recovery rather than horizontal canal recovery.

The main purpose of this study is to determine the impact of abnormal otolith function on a person’s ability to maintain balance while standing and walking and on his or her quality of life. In addition, we hope to determine the further impact of head injury/blast exposure and older age on postural stability and quality of life. To address these objectives, we will compare performance on balance tasks while standing and walking and questionnaires on the impact on quality of life in several groups of people with and without head injury/blast exposure and across a wide range of ages. The groups will include individuals with otolith organ dysfunction, horizontal canal dysfunction, both otolith and horizontal canal dysfunction, and healthy individuals.

This study is the first step toward novel therapeutic approaches to reduce the negative impact of dizziness and imbalance on individuals with otolith organ dysfunction. In addition, our research findings may direct the development of new clinical protocols to better assess individuals with dizziness and balance problems particularly.

At a Glance

Study type:

Prospective case-controlled study

Objective:

Determine the effect of inner ear balance (vestibular) dysfunction on balance, gait and quality of life

Population:

Veterans that attend the Vestibular/Balance Clinic at Mountain Home Veterans Affairs Medical Center (MHVAMC)

Number of participants:

Total of 124 adults from all races/ethnicities and both genders from the Johnson City, TN area
3 case groups (vestibular groups (n = 60)) will include Veterans complaining of dizziness and/or imbalance with documented vestibular dysfunction with and without mTBI/blast
2 control groups (n = 64) will include Veterans with and without complaints of dizziness and/or imbalance with normal vestibular function and a Healthy Control group recruited from healthy age-matched Veterans living in the community via the Audiology data repository

Data collection:

To determine the impact of otolith organ dysfunction on postural stability, measures of balance, gait, mobility, and questionnaires will be used to evaluate postural stability at the level of impairment, and activity limitation/ participation restriction across groups

Participating sites:

Mountain Home Veterans Affairs Medical Center (MHVAMC), Mountain Home TN

Principal investigator:

Faith Akin, Ph.D., James H. Quillen VA Medical Center, Mountain Home, TN

Duration:

3 years