Vestibular Rehabilitation and Otolith Dysfunction

VA Office of Research and Development

Status: Completed

Conditions: Dizziness

Treatments: Behavioral: Centrifugation Distance; Behavioral: Centrifugation Schedule; Behavioral: Centrifugation Duration

Study type: Interventional

Funder types: Other U.S. Federal agency

Identifiers

NCT02652442

C2058-P

Details and patient eligibility

About

Recent studies suggest that otolith dysfunction is a common finding in individuals with a history of head trauma/blast exposure and/or noise-induced hearing loss. Therefore, otolith dysfunction may be a significant health concern for the Veteran population, and determining optimal intervention strategies for otolith dysfunction is important for VA healthcare. The purpose of this project is to identify optimum stimulus parameters of a novel treatment, off-axis rotation (centrifugation) for otolith dysfunction, in healthy participants.

Full description

The primary function of the vestibular (inner ear balance) system is to maintain gaze and postural stability. The vestibular system is comprised of two types of sensory organs (semicircular canals and otolith organs) each with unique contributions to balance.

Vestibular Rehabilitation (VR) is the treatment of choice for patients experiencing dizziness, imbalance, and mobility impairments related to vestibular dysfunction. VR typically includes gaze stability exercises, gait and balance training, and general conditioning. Gaze stability exercises were developed based on the concepts of adaptation and substitution with the goal of improving gaze stability by facilitating vestibular compensation of the semicircular canal-mediated vestibulo-ocular reflex (VOR).

Many factors that might influence recovery, such as the involvement of different vestibular sensory organs (semicircular canals versus otolith organs) have not been examined to determine their impact on recovery. Most studies examining the effectiveness of VR have used only tests of VOR function (caloric and rotational tests) that measure horizontal semicircular canal to determine vestibular loss. Thus, little is known about interventions to facilitate vestibular compensation of the otolith organs.

Recent studies have demonstrated adaptation following otolith organ stimulation using centrifugation (or linear acceleration), but there is no data regarding optimum stimulus parameters. The concept of using centrifugation for otolith adaptation may be similar to using gaze stability exercises for VOR adaptation. Healthy control subjects (n = 5 per experiment) will participate in three separate experiments to determine: (1) the optimum off-axis distance of the rotary chair, (2) the optimum duration of off-axis rotation (OAR), and (3) the optimum OAR stimulation/training schedule.

Enrollment: 6 patients

Sex: All

Ages: 18 to 69 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• At least 18 years of age
• Documented balance or mobility problems, or healthy control without imbalance
• Otolith dysfunction or healthy control without vestibular dysfunction

Exclusion criteria

• Progressive neurological disorders and central vestibular abnormalities
• Benign paroxysmal positional vertigo
• Superior semicircular canal dehiscence
• Middle-ear pathology with conductive hearing loss
• Lower extremity joint replacement
• Cognitive impairment (Mini Mental Status Exam < 24/30)
• Severe depression (geriatric depression scale 10)
• Severe anxiety (geriatric anxiety inventory 11/30)
• Best-corrected visual acuity worse than 20/40 in the better eye

Trial design

Primary purpose: Other

Allocation: N/A

Interventional model: Sequential Assignment

Masking: None (Open label)

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6 participants in 1 patient group

Centrifugation Parameters

Experimental group

Description:

Three experiments were performed to identify optimal centrifugation parameters: (1) distance off-axis (3.5 vs 7 cm); (2) duration (1 min vs 3 mins); (3) schedule (daily vs biweekly). The comparisons were all within subjects; i.e., each subject was tested systematically for each centrifugation parameter under both conditions. The change in the outcome measure SVV (from pre- to post-off-axis rotation) for each condition (e.g., 3.5 vs 7 cm) within a parameter was compared.

Treatment:

Behavioral: Centrifugation Distance

Behavioral: Centrifugation Duration

Behavioral: Centrifugation Schedule