Sensorimotor Performance, Vestibular Function Tests
Conditions
Brief summary
This randomized crossover interventional study evaluated the effects of different frequency ranges of noisy galvanic vestibular stimulation (nGVS) on vestibular perception, perceptual motion tracking, and manual control performance in healthy adults. Each participant completed three experimental conditions in randomized order: no stimulation (control), low-frequency nGVS, and high-frequency nGVS. Vestibular perceptual thresholds, perceptual tracking, and manual control performance were assessed during each condition to determine whether stimulation frequency influenced sensorimotor function.
Detailed description
The purpose of this study was to investigate whether the frequency content of noisy galvanic vestibular stimulation influences vestibular perceptual sensitivity, tracking accuracy, and manual control performance. Healthy adult participants completed a randomized crossover protocol in which they received no stimulation, low-frequency nGVS, and high-frequency nGVS during separate experimental conditions within a single study session. Outcome measures included vestibular perceptual thresholds, tracking error rate, and measures of manual control performance. The results were intended to improve understanding of vestibular neuromodulation and inform optimization of nGVS parameters for future aerospace and clinical applications.
Interventions
DEVICELow-frequency noisy galvanic vestibular stimulation (nGVS)
Participants received low-frequency noisy galvanic vestibular stimulation through electrodes placed over the bilateral mastoid processes during experimental testing. Stimulation parameters were consistent with the approved study protocol. Frequency was 0-2Hz white noise, 300uA amplitude.
DEVICEHigh-frequency noisy galvanic vestibular stimulation (nGVS)
Participants received high-frequency noisy galvanic vestibular stimulation through electrodes placed over the bilateral mastoid processes during experimental testing. Stimulation parameters were consistent with the approved study protocol. Frequency was 10-30Hz white noise, 300uA amplitude.
Sponsors
National Aeronautics and Space Administration (NASA)
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
22 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Subjects were required to pass a physical exam adminisitrated by NASA JSC Clinic.
Exclusion criteria
* No history of neurologic, vestibular, or autonomic disease.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Vestibular Direction Recognition Threshold | Day 1 (single study visit): Participants completed outcome assessments during each randomized intervention condition (No nGVS, Low-Frequency nGVS, and High-Frequency nGVS). Each assessment required approximately 5 minutes to complete. | Vestibular perceptual sensitivity was assessed using roll-tilt and interaural translation direction recognition tasks performed on a six-degree-of-freedom motion platform. Direction recognition thresholds were estimated from participant responses using an adaptive three-down, one-up staircase procedure and cumulative Gaussian psychometric curve fitting. Lower threshold values indicate greater vestibular sensitivity and improved perception of self-motion. |
| Perceptual Motion Tracking Accuracy | Day 1 (single study visit): Participants completed outcome assessments during each randomized intervention condition (No nGVS, Low-Frequency nGVS, and High-Frequency nGVS). Each assessment required approximately 5 minutes to complete. | Perceptual motion tracking performance was evaluated during continuous pseudorandom roll motion. Participants used a joystick to continuously indicate their perceived direction and magnitude of platform motion. Performance was quantified using the root mean square error (RMSE) between joystick responses and the programmed motion stimulus, with lower RMSE values indicating more accurate perception and tracking of self-motion. |
| Manual Control Nulling Accuracy | Day 1 (single study visit): Participants completed outcome assessments during each randomized intervention condition (No nGVS, Low-Frequency nGVS, and High-Frequency nGVS). Each assessment required approximately 5 minutes to complete. | Manual control performance was evaluated during continuous pseudorandom roll motion while participants used a joystick to actively minimize platform motion by generating corrective control inputs. Performance was quantified using the root mean square error (RMSE) between the platform tilt angle and the upright position over time. Lower RMSE values indicate more effective manual control and disturbance rejection. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Roll-Tilt Vestibular Direction Recognition Threshold | Day 1 (single study visit): Participants completed outcome assessments during each randomized intervention condition (No nGVS, Low-Frequency nGVS, and High-Frequency nGVS). Each assessment required approximately 5 minutes to complete. | Vestibular perceptual threshold for roll-tilt motion was measured using a computerized three-down, one-up adaptive staircase procedure during a 1 Hz sinusoidal motion stimulus. Thresholds were estimated by fitting a cumulative Gaussian psychometric function to participants' left/right direction recognition responses. Lower threshold values indicate greater vestibular sensitivity. |
| Interaural Translation Vestibular Direction Recognition Threshold | Day 1 (single study visit): Participants completed outcome assessments during each randomized intervention condition (No nGVS, Low-Frequency nGVS, and High-Frequency nGVS). Each assessment required approximately 5 minutes to complete. | Vestibular perceptual threshold for interaural translation motion was measured using a computerized three-down, one-up adaptive staircase procedure during a 1 Hz sinusoidal motion stimulus. Thresholds were estimated by fitting a cumulative Gaussian psychometric function to participants' left/right direction recognition responses. Lower threshold values indicate greater vestibular sensitivity. |
| Vestibular Direction Recognition Bias | Day 1 (single study visit): Participants completed outcome assessments during each randomized intervention condition (No nGVS, Low-Frequency nGVS, and High-Frequency nGVS). Each assessment required approximately 5 minutes to complete. | Response bias during the vestibular direction recognition task was estimated from the mean of the cumulative Gaussian psychometric function. Bias represents the stimulus magnitude at which participants were equally likely to perceive motion in either direction, providing a measure of systematic perceptual offset. |
| Perceptual Motion Tracking Variability | Day 1 (single study visit): Participants completed outcome assessments during each randomized intervention condition (No nGVS, Low-Frequency nGVS, and High-Frequency nGVS). Each assessment required approximately 5 minutes to complete. | Variability of perceptual motion tracking performance during continuous pseudorandom roll motion. Tracking variability was quantified using statistical measures including standard deviation and variance of tracking performance, providing an assessment of the consistency and precision of participant responses. |
| Manual Control Nulling Variability | Day 1 (single study visit): Participants completed outcome assessments during each randomized intervention condition (No nGVS, Low-Frequency nGVS, and High-Frequency nGVS). Each assessment required approximately 5 minutes to complete. | Variability of manual control performance during the nulling task was quantified using standard deviation, variance, and mean absolute deviation of chair tilt relative to the upright position. These measures assessed the consistency and precision of participants' ability to minimize platform motion. |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORScott J Wood, PhD
National Aeronautics and Space Administration (NASA)
Outcome results
None listed