(H-311) Sensory Feedback Device for Balance

Introduction:: Nearly 20% of Americans 65-75 years of age currently have a balance disorder with that number increasing to 25% by age 75 [1]. While there is no cure for balance disorders, sensory substitution may be a viable solution to help one regain a sense of balance. Sensory substitution circumvents the loss of one sense by feeding its information through another channel [2]. The electrotactile tongue biofeedback (BrainPort®) is a widely used sensory substitution device used in treating vestibular disorders. The device transmits an artificial sense of the head's position in space through electric stimulation to the tongue [3]. While the device has proven effective, its placement is disruptive to everyday life. There is a need for a sensory substitution device that provides feedback for balance less obtrusively. The goal of the Sensory Feedback Device for Balance is to provide a solution to this prevalent problem.


Materials and Methods:: The Sensory Feedback Device for Balance was created with an Arduino Uno, MPU6050 6-DoF Accelerometer IMU, four small vibrating motors, and a cloth headband (Figure 1). The MPU6050 is placed on top of the head and measures the acceleration due to gravity in three dimensions. This internal measurement unit sensor (IMU) connects to an Arduino Uno microcontroller. Four small vibrating motors are implanted in the cloth headband on the front, back, and sides of the head. The Arduino is programmed to send vibrational stimulation using pulse width modulation to the motors based on the accelerometer’s reading of the position of the head in space.

To test the effectiveness of the device, a preliminary study was conducted. The subjects were eight young healthy adults (5 Females and 3 Males; Ages 20.75 +/- 2.25 years) with no history of vestibular disorders. The study consisted of 3 sessions with six runs of a static balance test conducted in each session. The balance test is based on the FICSIT-4 balance test [4]. It consists of standing semi-tandem, tandem, and on one foot for ten seconds each or until failure (Figure 2). During each session, this test was conducted twice with the subjects’ eyes open, and the device turned off, twice with the subjects’ eyes closed and the device turned off, and twice with the subjects’ eyes closed and the device turned on. The goal of the three sessions was for the subjects to learn the device over time.


Results, Conclusions, and Discussions:: Acceleration data from the device was collected during each test. One-sided paired t-tests were conducted comparing the average acceleration data collected from the first and third sessions for each subject with the device turned on and the device turned off. The null hypothesis was that there was no difference between the acceleration with and without the device. The average acceleration was in horizontal X-Y planes computed as the vector sum of the X and Y accelerations.
For the first session, the P value was 0.065. The mean acceleration for the device turned off was 1.15 m/s^2 and 0.91 m/s^2 for the device turned on.
For the third session, the P value was 0.077. The mean acceleration for the device turned off was 1.39 m/s^2 and 0.91 m/s^2 for the device turned on.
In each case, the mean acceleration in the horizontal plane was less when using the device. This indicates that the subjects were more stable with the device turned on and providing acceleration and position feedback back to them.

Because the P value was greater than 0.05 for both sessions, the data was not statistically significant. However, given the improvement in average acceleration values with the device turned on, the data seems promising and testing will continue with a larger sample size.
While the data from this preliminary study did not reveal itself to be statistically significant, it still seems promising given the small size of the study (n=8). In the future to better understand how the device can be learned over time, it may be beneficial to have the subject wear the device for a couple hours per day between each session. The test proved to be not difficult enough for the subjects to lose their balance. Because of this, time data could not be analyzed. It may be beneficial to add dynamic elements or have subjects balance on a narrow beam in future testing.




Acknowledgements (Optional): :

References (Optional): : [1] “Facts about dizziness: Vertigo: The Hearing and Balance Clinic: Denison,” The Hearing and Balance Clinic, 22-Oct-2019. [Online]. Available: https://www.thehearingclinic.org/services/facts-about-dizziness/.

[2] P. Bach-y-Rita and S. W. Kercel, “Sensory substitution and the Human–Machine Interface,” Trends in Cognitive Sciences, vol. 7, no. 12, pp. 541–546, 2003.

[3] C. G. Barros, R. S. Bittar, and Y. Danilov, “Effects of electrotactile vestibular substitution on rehabilitation of patients with bilateral vestibular loss,” Neuroscience Letters, vol. 476, no. 3, pp. 123–126, 2010.

[4] J. E. Rossiter-Fornoff, S. L. Wolf, L. I. Wolfson, and D. M. Buchner, “A cross-sectional validation study of the FICSIT common data base static balance measures,” The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, vol. 50A, no. 6, 1995.