PMID- 21888961 OWN - NLM STAT- MEDLINE DCOM- 20120224 LR - 20211020 IS - 1878-5891 (Electronic) IS - 0378-5955 (Print) IS - 0378-5955 (Linking) VI - 281 IP - 1-2 DP - 2011 Nov TI - Restoration of 3D vestibular sensation in rhesus monkeys using a multichannel vestibular prosthesis. PG - 74-83 LID - 10.1016/j.heares.2011.08.008 [doi] AB - Profound bilateral loss of vestibular hair cell function can cause chronically disabling loss of balance and inability to maintain stable vision during head and body movements. We have previously shown that chinchillas rendered bilaterally vestibular-deficient via intratympanic administration of the ototoxic antibiotic gentamicin regain a more nearly normal 3-dimensional vestibulo-ocular reflex (3D VOR) when head motion information sensed by a head-mounted multichannel vestibular prosthesis (MVP) is encoded via rate-modulated pulsatile stimulation of vestibular nerve branches. Despite significant improvement versus the unaided condition, animals still exhibited some 3D VOR misalignment (i.e., the 3D axis of eye movement responses did not precisely align with the axis of head rotation), presumably due to current spread between a given ampullary nerve's stimulating electrode(s) and afferent fibers in non-targeted branches of the vestibular nerve. Assuming that effects of current spread depend on relative orientation and separation between nerve branches, anatomic differences between chinchilla and human labyrinths may limit the extent to which results in chinchillas accurately predict MVP performance in humans. In this report, we describe the MVP-evoked 3D VOR measured in alert rhesus monkeys, which have labyrinths that are larger than chinchillas and temporal bone anatomy more similar to humans. Electrodes were implanted in five monkeys treated with intratympanic gentamicin to bilaterally ablate vestibular hair cell mechanosensitivity. Eye movements mediated by the 3D VOR were recorded during passive sinusoidal (0.2-5 Hz, peak 50 degrees /s) and acceleration-step (1000 degrees /s(2) to 150 degrees /s) whole-body rotations in darkness about each semicircular canal axis. During constant 100 pulse/s stimulation (i.e., MVP powered ON but set to stimulate each ampullary nerve at a constant mean baseline rate not modulated by head motion), 3D VOR responses to head rotation exhibited profoundly low gain [(mean eye velocity amplitude)/(mean head velocity amplitude) < 0.1] and large misalignment between ideal and actual eye movements. In contrast, motion-modulated sinusoidal MVP stimuli elicited a 3D VOR with gain 0.4-0.7 and axis misalignment of 21-38 degrees , and responses to high-acceleration transient head rotations exhibited gain and asymmetry closer to those of unilaterally gentamicin-treated animals (i.e., with one intact labyrinth) than to bilaterally gentamicin-treated animals without MVP stimulation. In comparison to responses observed under similar conditions in chinchillas, acute responses to MVP stimulation in rhesus macaque monkeys were slightly better aligned to the desired rotation axis. Responses during combined rotation and prosthetic stimulation were greater than when either stimulus was presented alone, suggesting that the central nervous system uses MVP input in the context of multisensory integration. Considering the similarity in temporal bone anatomy and VOR performance between rhesus monkeys and humans, these observations suggest that an MVP will likely restore a useful level of vestibular sensation and gaze stabilization in humans. CI - Copyright A(c) 2011 Elsevier B.V. All rights reserved. FAU - Dai, Chenkai AU - Dai C AD - Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins University School of Medicine, 720 Rutland Ave.,Baltimore, MD 21205, USA. FAU - Fridman, Gene Y AU - Fridman GY FAU - Davidovics, Natan S AU - Davidovics NS FAU - Chiang, Bryce AU - Chiang B FAU - Ahn, Joong Ho AU - Ahn JH FAU - Della Santina, Charles C AU - Della Santina CC LA - eng GR - R01 DC009255/DC/NIDCD NIH HHS/United States GR - K08 DC006216/DC/NIDCD NIH HHS/United States GR - R01 DC009255-02S1/DC/NIDCD NIH HHS/United States GR - R01 DC002390/DC/NIDCD NIH HHS/United States GR - K08 DC006216-05/DC/NIDCD NIH HHS/United States GR - R01 DC002390-15/DC/NIDCD NIH HHS/United States GR - F32 DC009917/DC/NIDCD NIH HHS/United States GR - F31 DC010099/DC/NIDCD NIH HHS/United States GR - R01 DC009255-03/DC/NIDCD NIH HHS/United States GR - 5F32DC009917/DC/NIDCD NIH HHS/United States GR - R01DC0255/DC/NIDCD NIH HHS/United States GR - K08DC6216/DC/NIDCD NIH HHS/United States GR - R01DC2390/DC/NIDCD NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural DEP - 20110826 PL - Netherlands TA - Hear Res JT - Hearing research JID - 7900445 RN - 0 (Gentamicins) SB - IM MH - Acceleration MH - Animals MH - Disease Models, Animal MH - Electric Stimulation MH - Eye Movements MH - Female MH - Gentamicins MH - Head Movements MH - Macaca mulatta MH - Male MH - *Neural Prostheses MH - Orientation MH - *Postural Balance MH - Prosthesis Design MH - *Prosthesis Implantation MH - *Reflex, Vestibulo-Ocular MH - Rotation MH - Time Factors MH - Vestibular Diseases/chemically induced/physiopathology/*therapy MH - Vestibular Function Tests MH - Vestibule, Labyrinth/*innervation PMC - PMC3254699 MID - NIHMS321116 EDAT- 2011/09/06 06:00 MHDA- 2012/03/01 06:00 PMCR- 2012/11/01 CRDT- 2011/09/06 06:00 PHST- 2011/05/28 00:00 [received] PHST- 2011/08/19 00:00 [revised] PHST- 2011/08/19 00:00 [accepted] PHST- 2011/09/06 06:00 [entrez] PHST- 2011/09/06 06:00 [pubmed] PHST- 2012/03/01 06:00 [medline] PHST- 2012/11/01 00:00 [pmc-release] AID - S0378-5955(11)00207-3 [pii] AID - 10.1016/j.heares.2011.08.008 [doi] PST - ppublish SO - Hear Res. 2011 Nov;281(1-2):74-83. doi: 10.1016/j.heares.2011.08.008. Epub 2011 Aug 26.