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Zwergal A, Grabova D, Schöberl F. Vestibular contribution to spatial orientation and navigation. Curr Opin Neurol 2024; 37:52-58. [PMID: 38010039 PMCID: PMC10779452 DOI: 10.1097/wco.0000000000001230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
PURPOSE OF REVIEW The vestibular system provides three-dimensional idiothetic cues for updating of one's position in space during head and body movement. Ascending vestibular signals reach entorhinal and hippocampal networks via head-direction pathways, where they converge with multisensory information to tune the place and grid cell code. RECENT FINDINGS Animal models have provided insight to neurobiological consequences of vestibular lesions for cerebral networks controlling spatial cognition. Multimodal cerebral imaging combined with behavioural testing of spatial orientation and navigation performance as well as strategy in the last years helped to decipher vestibular-cognitive interactions also in humans. SUMMARY This review will update the current knowledge on the anatomical and cellular basis of vestibular contributions to spatial orientation and navigation from a translational perspective (animal and human studies), delineate the behavioural and functional consequences of different vestibular pathologies on these cognitive domains, and will lastly speculate on a potential role of vestibular dysfunction for cognitive aging and impeding cognitive impairment in analogy to the well known effects of hearing loss.
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Affiliation(s)
- Andreas Zwergal
- German Center for Vertigo and Balance Disorders (DSGZ), LMU University Hospital, LMU Munich
- Department of Neurology, LMU University Hospital, LMU Munich, Munich, Germany
| | - Denis Grabova
- German Center for Vertigo and Balance Disorders (DSGZ), LMU University Hospital, LMU Munich
| | - Florian Schöberl
- German Center for Vertigo and Balance Disorders (DSGZ), LMU University Hospital, LMU Munich
- Department of Neurology, LMU University Hospital, LMU Munich, Munich, Germany
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2
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Gao X, Wang L, Lu X, Yan Y, Guo Y, Wang J, Lu L, Dong K. The Expression of Parthanatos Markers and miR-7 Mimic Protects Photoreceptors from Parthanatos by Repressing α-Synuclein in Retinal Detachment. THE AMERICAN JOURNAL OF PATHOLOGY 2023; 193:1833-1844. [PMID: 37423550 DOI: 10.1016/j.ajpath.2023.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 06/04/2023] [Accepted: 06/15/2023] [Indexed: 07/11/2023]
Abstract
Retinal detachment (RD) refers to the separation between the neuroepithelium and the pigment epithelium layer. It is an important disease leading to irreversible vision damage worldwide, in which photoreceptor cell death plays a major role. α-Synuclein (α-syn) is reportedly involved in numerous mechanisms of neurodegenerative diseases, but the association with photoreceptor damage in RD has not been studied. In this study, elevated transcription levels of α-syn and parthanatos proteins were observed in the vitreous of patients with RD. The expression of α-syn- and parthanatos-related proteins was increased in experimental rat RD, and was involved in the mechanism of photoreceptor damage, which was related to the decreased expression of miR-7a-5p (miR-7). Interestingly, subretinal injection of miR-7 mimic in rats with RD inhibited the expression of retinal α-syn and down-regulated the parthanatos pathway, thereby protecting retinal structure and function. In addition, interference with α-syn in 661W cells decreased the expression of parthanatos death pathway in oxygen and glucose deprivation model. In conclusion, this study demonstrates the presence of parthanatos-related proteins in patients with RD and the role of the miR-7/α-syn/parthanatos pathway in photoreceptor damage in RD.
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Affiliation(s)
- Xueyan Gao
- Department of Ophthalmology, Eye Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Lisong Wang
- Department of Ophthalmology, Eye Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Xing Lu
- Department of Ophthalmology, Eye Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yuanye Yan
- Department of Ophthalmology, The Affiliated Xuzhou Municipal Hospital of Xuzhou Medical University, Xuzhou, China
| | - Yue Guo
- Graduate School, Bengbu Medical College, Bengbu, China
| | - Jing Wang
- Department of Ophthalmology, Eye Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Li Lu
- Department of Ophthalmology, Eye Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
| | - Kai Dong
- Department of Ophthalmology, Eye Center, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China.
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Stultiens JJA, Lewis RF, Phillips JO, Boutabla A, Della Santina CC, Glueckert R, van de Berg R. The Next Challenges of Vestibular Implantation in Humans. J Assoc Res Otolaryngol 2023; 24:401-412. [PMID: 37516679 PMCID: PMC10504197 DOI: 10.1007/s10162-023-00906-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Accepted: 06/29/2023] [Indexed: 07/31/2023] Open
Abstract
Patients with bilateral vestibulopathy suffer from a variety of complaints, leading to a high individual and social burden. Available treatments aim to alleviate the impact of this loss and improve compensatory strategies. Early experiments with electrical stimulation of the vestibular nerve in combination with knowledge gained by cochlear implant research, have inspired the development of a vestibular neuroprosthesis that can provide the missing vestibular input. The feasibility of this concept was first demonstrated in animals and later in humans. Currently, several research groups around the world are investigating prototype vestibular implants, in the form of vestibular implants as well as combined cochlear and vestibular implants. The aim of this review is to convey the presentations and discussions from the identically named symposium that was held during the 2021 MidWinter Meeting of the Association for Research in Otolaryngology, with researchers involved in the development of vestibular implants targeting the ampullary nerves. Substantial advancements in the development have been made. Yet, research and development processes face several challenges to improve this neuroprosthesis. These include, but are not limited to, optimization of the electrical stimulation profile, refining the surgical implantation procedure, preserving residual labyrinthine functions including hearing, as well as gaining regulatory approval and establishing a clinical care infrastructure similar to what exists for cochlear implants. It is believed by the authors that overcoming these challenges will accelerate the development and increase the impact of a clinically applicable vestibular implant.
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Affiliation(s)
- Joost Johannes Antonius Stultiens
- Department of Otorhinolaryngology & Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, 6202 AZ, The Netherlands.
| | - Richard F Lewis
- Department of Otolaryngology and Neurology, Harvard Medical School, Boston, MA, USA
| | - James O Phillips
- Department of Otolaryngology, University of Washington, Seattle, WA, USA
| | - Anissa Boutabla
- Department of Otorhinolaryngology & Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Charles C Della Santina
- Department of Biomedical Engineering and Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - Raymond van de Berg
- Department of Otorhinolaryngology & Head and Neck Surgery, School for Mental Health and Neuroscience, Faculty of Health Medicine and Life Sciences, Maastricht University Medical Center, P. Debyelaan 25, Maastricht, 6202 AZ, The Netherlands
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Soto E, Pliego A, Vega R. Vestibular prosthesis: from basic research to clinics. Front Integr Neurosci 2023; 17:1161860. [PMID: 37265514 PMCID: PMC10230114 DOI: 10.3389/fnint.2023.1161860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 04/26/2023] [Indexed: 06/03/2023] Open
Abstract
Balance disorders are highly prevalent worldwide, causing substantial disability with high personal and socioeconomic impact. The prognosis in many of these patients is poor, and rehabilitation programs provide little help in many cases. This medical problem can be addressed using microelectronics by combining the highly successful cochlear implant experience to produce a vestibular prosthesis, using the technical advances in micro gyroscopes and micro accelerometers, which are the electronic equivalents of the semicircular canals (SCC) and the otolithic organs. Reaching this technological milestone fostered the possibility of using these electronic devices to substitute the vestibular function, mainly for visual stability and posture, in case of damage to the vestibular endorgans. The development of implantable and non-implantable devices showed diverse outcomes when considering the integrity of the vestibular pathways, the device parameters (current intensity, impedance, and waveform), and the targeted physiological function (balance and gaze). In this review, we will examine the development and testing of various prototypes of the vestibular implant (VI). The insight raised by examining the state-of-the-art vestibular prosthesis will facilitate the development of new device-development strategies and discuss the feasibility of complex combinations of implantable devices for disorders that directly affect balance and motor performance.
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Affiliation(s)
- Enrique Soto
- Benemérita Universidad Autónoma de Puebla, Instituto de Fisiología, Puebla, Mexico
| | - Adriana Pliego
- Benemérita Universidad Autónoma de Puebla, Instituto de Fisiología, Puebla, Mexico
- Universidad Autónoma del Estado de México (UAEMéx), Facultad de Medicina, Toluca, Mexico
| | - Rosario Vega
- Benemérita Universidad Autónoma de Puebla, Instituto de Fisiología, Puebla, Mexico
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Chow MR, Fernandez Brillet C, Hageman KN, Roberts DC, Ayiotis AI, Haque RM, Della Santina CC. Binocular 3-D otolith-ocular reflexes: responses of chinchillas to natural and prosthetic stimulation after ototoxic injury and vestibular implantation. J Neurophysiol 2023; 129:1157-1176. [PMID: 37018758 PMCID: PMC10151050 DOI: 10.1152/jn.00445.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 03/29/2023] [Accepted: 03/29/2023] [Indexed: 04/07/2023] Open
Abstract
The otolith end organs inform the brain about gravitational and linear accelerations, driving the otolith-ocular reflex (OOR) to stabilize the eyes during translational motion (e.g., moving forward without rotating) and head tilt with respect to gravity. We previously characterized OOR responses of normal chinchillas to whole body tilt and translation and to prosthetic electrical stimulation targeting the utricle and saccule via electrodes implanted in otherwise normal ears. Here we extend that work to examine OOR responses to tilt and translation stimuli after unilateral intratympanic gentamicin injection and to natural/mechanical and prosthetic/electrical stimulation delivered separately or in combination to animals with bilateral vestibular hypofunction after right ear intratympanic gentamicin injection followed by surgical disruption of the left labyrinth at the time of electrode implantation. Unilateral intratympanic gentamicin injection decreased natural OOR response magnitude to about half of normal, without markedly changing OOR response direction or symmetry. Subsequent surgical disruption of the contralateral labyrinth at the time of electrode implantation surgery further decreased OOR magnitude during natural stimulation, consistent with bimodal-bilateral otolith end organ hypofunction (ototoxic on the right ear, surgical on the left ear). Delivery of pulse frequency- or pulse amplitude-modulated prosthetic/electrical stimulation targeting the left utricle and saccule in phase with whole body tilt and translation motion stimuli yielded responses closer to normal than the deficient OOR responses of those same animals in response to head tilt and translation alone.NEW & NOTEWORTHY Previous studies to expand the scope of prosthetic stimulation of the otolith end organs showed that selective stimulation of the utricle and saccule is possible. This article further defines those possibilities by characterizing a diseased animal model and subsequently studying its responses to electrical stimulation alone and in combination with mechanical motion. We show that we can partially restore responses to tilt and translation in animals with unilateral gentamicin ototoxic injury and contralateral surgical disruption.
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Affiliation(s)
- Margaret R Chow
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Celia Fernandez Brillet
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Kristin N Hageman
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Dale C Roberts
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Andrianna I Ayiotis
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
| | - Razi M Haque
- Lawrence Livermore National Laboratory, Livermore, California, United States
| | - Charles C Della Santina
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, United States
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Chepisheva MK. Spatial orientation, postural control and the vestibular system in healthy elderly and Alzheimer's dementia. PeerJ 2023; 11:e15040. [PMID: 37151287 PMCID: PMC10162042 DOI: 10.7717/peerj.15040] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 02/21/2023] [Indexed: 05/09/2023] Open
Abstract
Background While extensive research has been advancing our understanding of the spatial and postural decline in healthy elderly (HE) and Alzheimer's disease (AD), much less is known about how the vestibular system contributes to the spatial and postural processing in these two populations. This is especially relevant during turning movements in the dark, such as while walking in our garden or at home at night, where the vestibular signal becomes central. As the prevention of falls and disorientation are of serious concern for the medical service, more vestibular-driven knowledge is necessary to decrease the burden for HE and AD patients with vestibular disabilities. Overview of the article The review briefly presents the current "non-vestibular based" knowledge (i.e. knowledge based on research that does not mention the "vestibular system" as a contributor or does not investigate its effects) about spatial navigation and postural control during normal healthy ageing and AD pathology. Then, it concentrates on the critical sense of the vestibular system and explores the current expertise about the aspects of spatial orientation and postural control from a vestibular system point of view. The norm is set by first looking at how healthy elderly change with age with respect to their vestibular-guided navigation and balance, followed by the AD patients and the difficulties they experience in maintaining their balance or during navigation. Conclusion Vestibular spatial and vestibular postural deficits present a considerable disadvantage and are felt not only on a physical but also on a psychological level by all those affected. Still, there is a clear need for more (central) vestibular-driven spatial and postural knowledge in healthy and pathological ageing, which can better facilitate our understanding of the aetiology of these dysfunctions. A possible change can start with the more frequent implementation of the "vestibular system examination/rehabilitation/therapy" in the clinic, which can then lead to an improvement of future prognostication and disease outcome for the patients.
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Coughlan G, Plumb W, Zhukovsky P, Aung MH, Hornberger M. Vestibular contribution to path integration deficits in 'at-genetic-risk' for Alzheimer's disease. PLoS One 2023; 18:e0278239. [PMID: 36595510 PMCID: PMC9810179 DOI: 10.1371/journal.pone.0278239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 11/14/2022] [Indexed: 01/04/2023] Open
Abstract
Path integration changes may precede a clinical presentation of Alzheimer's disease by several years. Studies to date have focused on how spatial cell changes affect path integration in preclinical AD. However, vestibular input is also critical for intact path integration. Here, we developed the vestibular rotation task that requires individuals to manually point an iPad device in the direction of their starting point following rotational movement, without any visual cues. Vestibular features were derived from the sensor data using feature selection. Machine learning models illustrate that the vestibular features accurately classified Apolipoprotein E ε3ε4 carriers and ε3ε3 carrier controls (mean age 62.7 years), with 65% to 79% accuracy depending on task trial. All machine learning models produced a similar classification accuracy. Our results demonstrate the cross-sectional role of the vestibular system in Alzheimer's disease risk carriers. Future investigations should examine if vestibular functions explain individual phenotypic heterogeneity in path integration among Alzheimer's disease risk carriers.
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Affiliation(s)
- Gillian Coughlan
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States of America
| | - William Plumb
- Department of Computing, Imperial College London, London, United Kingdom
| | - Peter Zhukovsky
- Centre for Addiction and Mental Health, Kimel Family Translational Imaging Genetics Laboratory, Toronto, Ontario, Canada
| | - Min Hane Aung
- School of Computing Sciences, University of East Anglia, Norwich, United Kingdom
| | - Michael Hornberger
- Norwich Medical School, University of East Anglia, Norwich, United Kingdom
- * E-mail:
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Teaford M, Keller K, Merfeld DM. The contribution of interoceptive signals to spatial orientation: A mini-review. Neurosci Biobehav Rev 2022; 143:104943. [DOI: 10.1016/j.neubiorev.2022.104943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/15/2022] [Accepted: 10/31/2022] [Indexed: 11/07/2022]
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Wiboonsaksakul KP, Roberts DC, Della Santina CC, Cullen KE. A prosthesis utilizing natural vestibular encoding strategies improves sensorimotor performance in monkeys. PLoS Biol 2022; 20:e3001798. [PMID: 36103550 PMCID: PMC9473632 DOI: 10.1371/journal.pbio.3001798] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Accepted: 08/16/2022] [Indexed: 11/19/2022] Open
Abstract
Sensory pathways provide complex and multifaceted information to the brain. Recent advances have created new opportunities for applying our understanding of the brain to sensory prothesis development. Yet complex sensor physiology, limited numbers of electrodes, and nonspecific stimulation have proven to be a challenge for many sensory systems. In contrast, the vestibular system is uniquely suited for prosthesis development. Its peripheral anatomy allows site-specific stimulation of 3 separate sensory organs that encode distinct directions of head motion. Accordingly, here, we investigated whether implementing natural encoding strategies improves vestibular prosthesis performance. The eye movements produced by the vestibulo-ocular reflex (VOR), which plays an essential role in maintaining visual stability, were measured to quantify performance. Overall, implementing the natural tuning dynamics of vestibular afferents produced more temporally accurate VOR eye movements. Exploration of the parameter space further revealed that more dynamic tunings were not beneficial due to saturation and unnatural phase advances. Trends were comparable for stimulation encoding virtual versus physical head rotations, with gains enhanced in the latter case. Finally, using computational methods, we found that the same simple model explained the eye movements evoked by sinusoidal and transient stimulation and that a stimulation efficacy substantially less than 100% could account for our results. Taken together, our results establish that prosthesis encodings that incorporate naturalistic afferent dynamics and account for activation efficacy are well suited for restoration of gaze stability. More generally, these results emphasize the benefits of leveraging the brain's endogenous coding strategies in prosthesis development to improve functional outcomes.
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Affiliation(s)
- Kantapon Pum Wiboonsaksakul
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine; Baltimore, Maryland, United States of America
- Kavli Neuroscience Discovery Institute, Johns Hopkins University; Baltimore, Maryland, United States of America
| | - Dale C. Roberts
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine; Baltimore, Maryland, United States of America
| | - Charles C. Della Santina
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine; Baltimore, Maryland, United States of America
| | - Kathleen E. Cullen
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine; Baltimore, Maryland, United States of America
- Kavli Neuroscience Discovery Institute, Johns Hopkins University; Baltimore, Maryland, United States of America
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine; Baltimore, Maryland, United States of America
- Department of Neuroscience, Johns Hopkins University School of Medicine; Baltimore, Maryland, United States of America
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Chari DA, Madhani A, Sharon JD, Lewis RF. Evidence for cognitive impairment in patients with vestibular disorders. J Neurol 2022; 269:5831-5842. [PMID: 35930032 DOI: 10.1007/s00415-022-11289-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Extensive animal research has shown that vestibular damage can be associated with cognitive deficits. More recently, new evidence has emerged linking vestibular disorders to cognitive impairment in humans. Herein, we review contemporary research on the pathophysiology of cognitive-vestibular interactions and discuss its emerging clinical relevance. DATA SOURCES PubMed, Embase, and Cochrane databases. REVIEW METHODS A systematic literature search was performed with combinations of search terms: "cognition," "cognitive impairment," "chronic fatigue," "brain fog," "spatial navigation," "attention," "memory," "executive function," "processing speed," and "vestibular hypofunction." Relevant articles were considered for inclusion, including basic and clinical studies, case series, and major reviews. CONCLUSIONS Patients with vestibular disorders can demonstrate long-term deficits in both spatial and nonspatial cognitive domains. The underlying mechanism(s) linking the vestibular system to cognitive function is not well characterized, but several neuro-biologic correlates have been identified. Additional screening tools are required to identify individuals at risk for cognitive impairment, and further research is needed to determine whether treatment of vestibular dysfunction has the capacity to improve cognitive function. IMPLICATIONS FOR PRACTICE Physicians should be aware of emerging data supporting the presence of cognitive deficits in patients with vestibular disorders. Prevention and treatment of long-term cognitive deficits may be possible through screening and rehabilitation.
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Affiliation(s)
- Divya A Chari
- Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA.
- Department of Otolaryngology - Head and Neck Surgery, University of Massachusetts Medical School, Worcester, MA, USA.
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear, Boston, MA, USA.
| | - Amsal Madhani
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear, Boston, MA, USA
| | - Jeffrey D Sharon
- Department of Otolaryngology - Head and Neck Surgery, University of California San Francisco, San Francisco, CA, USA
| | - Richard F Lewis
- Department of Otolaryngology - Head and Neck Surgery, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear, Boston, MA, USA
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Madhani A, Lewis RF, Karmali F. How Peripheral Vestibular Damage Affects Velocity Storage: a Causative Explanation. J Assoc Res Otolaryngol 2022; 23:551-566. [PMID: 35768706 PMCID: PMC9437187 DOI: 10.1007/s10162-022-00853-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 05/30/2022] [Indexed: 10/17/2022] Open
Abstract
Velocity storage is a centrally-mediated mechanism that processes peripheral vestibular inputs. One prominent aspect of velocity storage is its effect on dynamic responses to yaw rotation. Specifically, when normal human subjects are accelerated to constant angular yaw velocity, horizontal eye movements and perceived angular velocity decay exponentially with a time constant circa 15-30 s, even though the input from the vestibular periphery decays much faster (~ 6 s). Peripheral vestibular damage causes a time constant reduction, which is useful for clinical diagnoses, but a mechanistic explanation for the relationship between vestibular damage and changes in these behavioral dynamics is lacking. It has been hypothesized that Bayesian optimization determines ideal velocity storage dynamics based on statistics of vestibular noise and experienced motion. Specifically, while a longer time constant would make the central estimate of angular head velocity closer to actual head motion, it may also result in the accumulation of neural noise which simultaneously degrades precision. Thus, the brain may balance these two effects by determining the time constant that optimizes behavior. We applied a Bayesian optimal Kalman filter to determine the ideal velocity storage time constant for unilateral damage. Predicted time constants were substantially lower than normal and similar to patients. Building on our past work showing that Bayesian optimization explains age-related changes in velocity storage, we also modeled interactions between age-related hair cell loss and peripheral damage. These results provide a plausible mechanistic explanation for changes in velocity storage after peripheral damage. Results also suggested that even after peripheral damage, noise originating in the periphery or early central processing may remain relevant in neurocomputations. Overall, our findings support the hypothesis that the brain optimizes velocity storage based on the vestibular signal-to-noise ratio.
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Affiliation(s)
- Amsal Madhani
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear Infirmary, Boston, MA USA
| | - Richard F. Lewis
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear Infirmary, Boston, MA USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA USA
- Department of Neurology, Harvard Medical School, Boston, MA USA
| | - Faisal Karmali
- Jenks Vestibular Physiology Lab, Massachusetts Eye and Ear Infirmary, Boston, MA USA
- Department of Otolaryngology, Harvard Medical School, Boston, MA USA
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