Sensory substitution devices for bilateral vestibular loss
C. Hain, MD • Last revision:
March 20, 2021
When a sense breaks down, it is quite reasonable to attempt to substitute other senses. At this writing, there are several approaches that have been tried, but none of them work well enough for most people to adopt them. The purpose of this page is to review the current state of the art for these devices. The devices that we will review are in the following categories.
- Galvanic stimulation
- Auditory input
- Tongue input
- Direct nerve stimulation (vestibular implant)
In the long run, it seems to us that hair cell regeneration is the most likely to succeed route for recovery from gentamicin ototoxicity. Sensory substitution, using non-vestibular input such as vibrotactile, seems tous to be the most likely route for amelioration of vestibular nerve injury.
It has been suggested that external electrical current might be used to substitute for loss of inner ear function. (Scinicariello, Eaton et al. 2001; Orlov, Stolbkov et al. 2008). At the present writing, these efforts have not been translated into a usable device. Logically, it would seem difficult to imagine that a disorganized mass current flow from an external electrode could substitute for a spatially separate input from each semicircular canal.
Perhap a "hybrid" device with a set of electrodes in a mastoid cavity combined with an external stimulator would be worth trying however.
It seems reasonable that auditory input might be used to assist with balance. Some effort has been made (Lee, Wong et al. 1996; Wong, Mak et al. 2001; Dozza, Chiari et al. 2004; Dozza, Chiari et al. 2005; Dozza, Chiari et al. 2006; Dozza, Horak et al. 2007; Ernst, Singbartl et al. 2007; Basta, Singbartl et al. 2008.
This direction seems reasonable to us and we hope that commercial devices emerge.
As cochlear implants can sometimes restore hearing, why shouldn't vestibular implants be also possible ? Many papers have been published on this topic (Gong and Merfeld 2000; Gong and Merfeld 2002; Lewis, Gong et al. 2002; Ciaravella, Laschi et al. 2006; Merfeld, Gong et al. 2006; Shkel and Zeng 2006; Della Santina, Migliaccio et al. 2007; Wall, Kos et al. 2007; Tang, Melvin et al. 2009; Della Santina et al, 2010; Dai et al, 2011; Boutros et al, 2019; Chow et al, 2021).
Guyot et al (2011) showed in 3 humans undergoing surgery for Meniere's disease that stimulation of the lateral and superior ampullary nerve is possible using an operative approach where the ossicles were removed, and a electrode was placed in a "small well was drilled above the horizontal portion of the facial nerve canal". A predominantly horizontal nystagmus was provoked.
In our opinion, vestibular implants are still experimental and there are major obstacles to overcome. While the cochlear spiral ganglion is spread out in an organized spiral, the nerves to the three semicircular canals are not easily accessible. For example, in the report above by Guyot, stimulation was obtained by sacrificing hearing, and the eye movements were not purely horizontal. More recent reports (e.g. Chow et al, 2021) also encountered reduction of hearing. The otolith organs, which sense linear acceleration, are not stimulated with this approach.
As of 2021, there is a report of outcomes of vestibular implant (for the canals) in 7 patients who had undergone ototoxicity. Generally there was improvement. They stated "Six months and 1 year after unilateral implantation of a vestibular prosthesis for bilateral vestibular hypofunction, measures of posture, gait, and quality of life were generally in the direction of improvement from baseline, but hearing was reduced in the ear with the implant in all but 1 participant." (Chow et al, 2021)
In an earlier publication from the same group, it was reported that "a vestibular implant can selectively, continuously, and chronically provide artificial sensory input to all 3 implanted semicircular canals in individuals disabled by bilateral vestibular loss, driving reflexive VOR eye movements that approximately align in 3D with the head motion axis encoded by the implant." (Boutros et al, 2019).
Tongue Input (TDU) or "brainport" device
In a bizarre twist , there have been efforts to replace vestibular input using a tongue stimulator. (Tyler, Danilov et al. 2003; Danilov, Tyler et al. 2006; Danilov, Tyler et al. 2007; Vuillerme, Chenu et al. 2008; Vuillerme and Cuisinier 2008; Uneri and Polat 2009; Vuillerme and Cuisinier 2009; Wood, Black et al. 2009). Imagine --going around with a head-mounted paddle on your tongue ! Follow the TDU link for more details.
It is somewhat reasonable that vibration input to the body might substitute for vestibular input, and again there has been considerable work done here. (Mackenzie, McCracken et al. 1997; Rochlis and Newman 2000; Kentala, Vivas et al. 2003; Nagel, Carl et al. 2005; Wall and Kentala 2005; Peterka, Wall et al. 2006; Asseman, Bronstein et al. 2007; Dozza, Wall et al. 2007; Basta and Ernst 2008; Guzy, Albery et al. 2008; Sienko, Balkwill et al. 2008; Goebel, Sinks et al. 2009; Horak 2009; Horak, Dozza et al. 2009)
We think that this direction is presently the most logical one
References regarding galvanic input
Orlov, I. V., Y. K. Stolbkov, et al. (2008). "Effects of artificial feedback to the vestibular input on postural instability induced by asymmetric proprioceptive stimulation." Neurosci Behav Physiol 38(2): 195-201.
- Scinicariello, A. P., K. Eaton, et al. (2001). "Enhancing human balance control with galvanic vestibular stimulation." Biol Cybern 84(6): 475-80.
References for auditory input
- Basta, D., F. Singbartl, et al. (2008). "Vestibular rehabilitation by auditory feedback in otolith disorders." Gait Posture 28(3): 397-404.
- Dozza, M., L. Chiari, et al. (2005). "Influence of a portable audio-biofeedback device on structural properties of postural sway." J Neuroeng Rehabil 2: 13.
- Dozza, M., L. Chiari, et al. (2006). "Effects of linear versus sigmoid coding of visual or audio biofeedback for the control of upright stance." IEEE Trans Neural Syst Rehabil Eng 14(4): 505-12.
- Dozza, M., L. Chiari, et al. (2004). "A portable audio-biofeedback system to improve postural control." Conf Proc IEEE Eng Med Biol Soc 7: 4799-802. [This is not a paper -- it is an abstract]
- Dozza, M., F. B. Horak, et al. (2007). "Auditory biofeedback substitutes for loss of sensory information in maintaining stance." Exp Brain Res 178(1): 37-48.
- Ernst, A., F. Singbartl, et al. (2007). "Short-term rehabilitation of patients with posttraumatic otolith disorders by auditory feedback training: a pilot study." J Vestib Res 17(2-3): 137-44.
- Lee, M. Y., M. K. Wong, et al. (1996). "Clinical evaluation of a new biofeedback standing balance training device." J Med Eng Technol 20(2): 60-6.
- Wong, M. S., A. F. Mak, et al. (2001). "Effectiveness of audio-biofeedback in postural training for adolescent idiopathic scoliosis patients." Prosthet Orthot Int 25(1): 60-70.
References regarding vestibular prostheses
- Boutros, P. J., et al. (2019). "Continuous vestibular implant stimulation partially restores eye-stabilizing reflexes." JCI Insight 4(22).
- Ciaravella, G., C. Laschi, et al. (2006). "Biomechanical modeling of semicircular canals for fabricating a biomimetic vestibular system." Conf Proc IEEE Eng Med Biol Soc 1: 1758-61. [This is not a paper -- it is an abstract]
- Chow, M. R., et al. (2021). "Posture, Gait, Quality of Life, and Hearing with a Vestibular Implant." N Engl J Med 384(6): 521-532.
- Dai, C., G. Y. Fridman, et al. (2011). "Cross-axis adaptation improves 3D vestibulo-ocular reflex alignment during chronic stimulation via a head-mounted multichannel vestibular prosthesis." Exp Brain Res 210(3-4): 595-606.
- Della Santina, C. C., A. A. Migliaccio, et al. (2007). "A multichannel semicircular canal neural prosthesis using electrical stimulation to restore 3-d vestibular sensation." IEEE Trans Biomed Eng 54(6 Pt 1): 1016-30.
- Della Santina, C. C., A. A. Migliaccio, et al. (2010). "Current and future management of bilateral loss of vestibular sensation - an update on the Johns Hopkins Multichannel Vestibular Prosthesis Project." Cochlear Implants Int 11 Suppl 2: 2-11.
- Gong, W. and D. M. Merfeld (2000). "Prototype neural semicircular canal prosthesis using patterned electrical stimulation." Ann Biomed Eng 28(5): 572-81.
- Gong, W. and D. M. Merfeld (2002). "System design and performance of a unilateral horizontal semicircular canal prosthesis." IEEE Trans Biomed Eng 49(2): 175-81.
- Guinand and many others. The video head impulse test to assess the efficacy of vestibular implants in Humans. Frontiers in Neurology, Nov 2017. (this is an open access journal) [This "study" has only 5 subjects. It does not show anything near normal VOR]
- Guyot JP, Sigrist A, Pelizzone M, Feigl GC, Kos MI. Eye movements in response to electrical stimulation of the lateral and superior ampullary nerves. Ann Otol Rhinol Laryngol. 2011 Feb;120(2):81-7.
- Lewis, R. F., W. Gong, et al. (2002). "Vestibular adaptation studied with a prosthetic semicircular canal." J Vestib Res 12(2-3): 87-94.
- Merfeld, D. M., W. Gong, et al. (2006). "Acclimation to chronic constant-rate peripheral stimulation provided by a vestibular prosthesis." IEEE Trans Biomed Eng 53(11): 2362-72.
- Shkel, A. M. and F. G. Zeng (2006). "An electronic prosthesis mimicking the dynamic vestibular function." Audiol Neurootol 11(2): 113-22.
- Tang, S., T. A. Melvin, et al. (2009). "Effects of semicircular canal electrode implantation on hearing in chinchillas." Acta Otolaryngol 129(5): 481-6.
- Wall, C., 3rd, M. I. Kos, et al. (2007). "Eye movements in response to electric stimulation of the human posterior ampullary nerve." Ann Otol Rhinol Laryngol 116(5): 369-74.
References regarding tongue input -- also see (TDU)
- Danilov, Y. P., M. E. Tyler, et al. (2006). "Efficacy of electrotactile vestibular substitution in patients with bilateral vestibular and central balance loss." Conf Proc IEEE Eng Med Biol Soc Suppl: 6605-9. [This is not a paper -- it is an abstract]
- Danilov, Y. P., M. E. Tyler, et al. (2007). "Efficacy of electrotactile vestibular substitution in patients with peripheral and central vestibular loss." J Vestib Res 17(2-3): 119-30.
- Tyler, M., Y. Danilov, et al. (2003). "Closing an open-loop control system: vestibular substitution through the tongue." J Integr Neurosci 2(2): 159-64. Uneri, A. and S. Polat (2009). "Vestibular rehabilitation with electrotactile vestibular substitution: early effects." Eur Arch Otorhinolaryngol 266(8): 1199-203.
- Vuillerme, N., O. Chenu, et al. (2008). "Can a plantar pressure-based tongue-placed electrotactile biofeedback improve postural control under altered vestibular and neck proprioceptive conditions?" Neuroscience 155(1): 291-6.
- Vuillerme, N. and R. Cuisinier (2008). "Head position-based electrotactile tongue biofeedback affects postural responses to Achilles tendon vibration in humans." Exp Brain Res 186(3): 503-8.
- Vuillerme, N. and R. Cuisinier (2009). "Sensory supplementation through tongue electrotactile stimulation to preserve head stabilization in space in the absence of vision." Invest Ophthalmol Vis Sci 50(1): 476-81.
- Wood, S. J., F. O. Black, et al. (2009). "Electrotactile feedback of sway position improves postural performance during galvanic vestibular stimulation." Ann N Y Acad Sci 1164: 492-8.
References regarding vibrotactile input
- Asseman, F., A. M. Bronstein, et al. (2007). "Using vibrotactile feedback of instability to trigger a forward compensatory stepping response." J Neurol 254(11): 1555-61.
- Basta, D. and A. Ernst (2008). "[Modern rehabilitation for vestibular disorders using neurofeedback training procedures]." HNO 56(10): 990-5.
- Dozza, M., C. Wall, 3rd, et al. (2007). "Effects of practicing tandem gait with and without vibrotactile biofeedback in subjects with unilateral vestibular loss." J Vestib Res 17(4): 195-204.
- Goebel, J. A., B. C. Sinks, et al. (2009). "Effectiveness of head-mounted vibrotactile stimulation in subjects with bilateral vestibular loss: a phase 1 clinical trial." Otol Neurotol 30(2): 210-6.
- Guzy, L. T., W. B. Albery, et al. (2008). "Vibrotactile stimulators and virtual 3-D audio countermeasures, training and motion sickness symptoms with a simulated graveyard spin illusion." J Vestib Res 18(5-6): 287-94.
- Horak, F. B. (2009). "Postural compensation for vestibular loss." Ann N Y Acad Sci 1164: 76-81.
- Horak, F. B., M. Dozza, et al. (2009). "Vibrotactile biofeedback improves tandem gait in patients with unilateral vestibular loss." Ann N Y Acad Sci 1164: 279-81.
- Kentala, E., J. Vivas, et al. (2003). "Reduction of postural sway by use of a vibrotactile balance prosthesis prototype in subjects with vestibular deficits." Ann Otol Rhinol Laryngol 112(5): 404-9.
- Mackenzie, I., W. McCracken, et al. (1997). "A pilot investigation into the use of vestibulometric measures in predicting neural pathways in relation to vibrotactile stimulation." Scand Audiol Suppl 47: 14-8.
- Nagel, S. K., C. Carl, et al. (2005). "Beyond sensory substitution--learning the sixth sense." J Neural Eng 2(4): R13-26.
- Peterka, R. J., C. Wall, 3rd, et al. (2006). "Determining the effectiveness of a vibrotactile balance prosthesis." J Vestib Res 16(1-2): 45-56.
- Rochlis, J. L. and D. J. Newman (2000). "A tactile display for international space station (ISS) extravehicular activity (EVA)." Aviat Space Environ Med 71(6): 571-8.
- Sienko, K. H., M. D. Balkwill, et al. (2008). "Effects of multi-directional vibrotactile feedback on vestibular-deficient postural performance during continuous multi-directional support surface perturbations." J Vestib Res 18(5-6): 273-85.
- Wall, C., 3rd and E. Kentala (2005). "Control of sway using vibrotactile feedback of body tilt in patients with moderate and severe postural control deficits." J Vestib Res 15(5-6): 313-25.
- Norman Doidge, MD | The Brain That Changes Itself https://www.normandoidge.com/normandoidge/MAIN.html [This is not a research article - -it is a popular book]