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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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Smith PF. Interpreting the meaning of changes in hippocampal volume associated with vestibular loss. Front Integr Neurosci 2023; 17:1254972. [PMID: 37608860 PMCID: PMC10440551 DOI: 10.3389/fnint.2023.1254972] [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: 07/07/2023] [Accepted: 07/21/2023] [Indexed: 08/24/2023] Open
Abstract
Many studies have documented cognitive deficits, especially spatial cognitive deficits, in patients with some form of vestibular loss. Almost 20 years ago, hippocampal (HPC) atrophy was reported to be correlated with spatial memory deficits in such patients and the idea has gradually emerged that HPC atrophy may be causally responsible for the cognitive deficits. However, the results of studies of HPC volume following vestibular loss have not always been consistent, and a number of studies have reported no evidence of HPC atrophy. This paper argues that HPC atrophy, if it does occur following vestibular loss, may not be directly, causally responsible for the cognitive deficits, and that it is more likely that rapid functional changes in the HPC are responsible, due to the interruption of the transmission of vestibular information to the HPC. The argument presented here rests on 3 tranches of evidence: (1) Cognitive deficits have been observed in humans even in the absence of HPC atrophy; (2) HPC atrophy has not been reported in animal studies following vestibular loss, despite cognitive deficits; and (3) Animal studies have shown that the interruption of the transmission of vestibular information to the HPC has immediate consequences for HPC place cells, far too quickly to be explained by HPC atrophy. It is possible that HPC atrophy, when it does occur, is related to the longer-term consquences of living with vestibular loss, which are likely to increase circulating cortisol.
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Affiliation(s)
- Paul F. Smith
- Department of Pharmacology and Toxicology, Brain Health Research Centre, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
- The Brain Research New Zealand Centre of Research Excellence, Eisdell Moore Centre for Hearing and Balance Research, University of Auckland, Auckland, New Zealand
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Ide R, Ota M, Hada Y, Takahashi T, Tamura M, Nemoto K, Arai T. Relationship between hippocampal subfields volume and balance function in healthy older adults. Gait Posture 2023; 101:90-94. [PMID: 36764212 DOI: 10.1016/j.gaitpost.2023.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/08/2023] [Accepted: 02/03/2023] [Indexed: 02/12/2023]
Abstract
BACKGROUND The volume of the hippocampus and its subfields is known to be affected by aging, disease, and physical training. In regard to training, the differential effects of aerobic exercise and dance training on the subfield volume suggest that balance function may be involved. However, the relationship between balance function and the volume of the hippocampus and its subfields remains unclear. METHODS Subjects were 30 cognitively intact individuals. They underwent balance tests, cognitive tests and structural MRI scans. The balance index measured was the index of postural stability (IPS) under a visual block condition and/or a proprioception block condition. MR images acquired using a 3-tesla system and three-dimensional T1-weighted images were segmented in the hippocampal subfield with Freesurfer 6.0.0. The relationship between the IPS and hippocampal volume was evaluated. RESULTS A positive correlation was observed only between the IPS closed eyes/soft surface condition and whole hippocampal volume ratio. In the subfields, positive correlations were found between the IPS and molecular layer of the hippocampus, granule cell layer of the dentate gyrus (GC-ML-DG), and cornu ammonis areas (CA)3 and CA4. These correlations were stronger under the closed eyes/soft surface condition than under the other conditions. CONCLUSIONS A correlation between balance function and the volume of the hippocampus and subfields was found in healthy elderly subjects. The balance function may be involved in the volume of the whole hippocampus and specific subfields. The IPS closed eyes/soft surface condition is considered to reflect vestibular function. Thus, IPS may be useful in evaluations of the relationship between the vestibular system function via the hippocampus and balance.
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Affiliation(s)
- Ryotaro Ide
- Doctoral Program in Medical Sciences, Graduate School of Comprehensive Human Science, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan
| | - Miho Ota
- Department of Neuropsychiatry, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan.
| | - Yasushi Hada
- Department of Rehabilitation Medicine, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan
| | - Takumi Takahashi
- Department of Neuropsychiatry, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan
| | - Masashi Tamura
- Department of Neuropsychiatry, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan
| | - Kiyotaka Nemoto
- Department of Neuropsychiatry, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan
| | - Tetsuaki Arai
- Department of Neuropsychiatry, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tennodai, Tsukuba, Ibaraki, Japan
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Smith PF. Recent developments in the understanding of the interactions between the vestibular system, memory, the hippocampus, and the striatum. Front Neurol 2022; 13:986302. [PMID: 36119673 PMCID: PMC9479733 DOI: 10.3389/fneur.2022.986302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/08/2022] [Indexed: 12/05/2022] Open
Abstract
Over the last two decades, evidence has accumulated to demonstrate that the vestibular system has extensive connections with areas of the brain related to spatial memory, such as the hippocampus, and also that it has significant interactions with areas associated with voluntary motor control, such as the striatum in the basal ganglia. In fact, these functions are far from separate and it is believed that interactions between the striatum and hippocampus are important for memory processing. The data relating to vestibular-hippocampal-striatal interactions have considerable implications for the understanding and treatment of Alzheimer's Disease and Parkinson's Disease, in addition to other neurological disorders. However, evidence is accumulating rapidly, and it is difficult to keep up with the latest developments in these and related areas. The aim of this review is to summarize and critically evaluate the relevant evidence that has been published over the last 2 years (i.e., since 2021), in order to identify emerging themes in this research area.
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Affiliation(s)
- Paul F. Smith
- Department of Pharmacology and Toxicology, School of Biomedical Sciences and Brain Health Research Centre, University of Otago, Dunedin, New Zealand
- Eisdell Moore Centre for Hearing and Balance Research, University of Auckland, Auckland, New Zealand
- *Correspondence: Paul F. Smith
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Curthoys IS, Smith PF, de Miguel AR. Why Should Constant Stimulation of Saccular Afferents Modify the Posture and Gait of Patients with Bilateral Vestibular Dysfunction? The Saccular Substitution Hypothesis. J Clin Med 2022; 11:jcm11041132. [PMID: 35207405 PMCID: PMC8874433 DOI: 10.3390/jcm11041132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/18/2022] [Accepted: 02/19/2022] [Indexed: 02/01/2023] Open
Abstract
An ongoing EU Horizon 2020 Project called BionicVEST is investigating the effect of constant electrical stimulation (ES) of the inferior vestibular nerve in patients with bilateral vestibular dysfunction (BVD). The evidence is that constant ES results in improved postural stability and gait performance, and so the question of central importance concerns how constant ES of mainly saccular afferents in these BVD patients could cause this improved performance. We suggest that the constant ES substitutes for the absent saccular neural input to the vestibular nuclei and the cerebellum in these BVD patients and indirectly via these structures to other structures, which have been of great recent interest in motor control. One target area, the anterior midline cerebellum (the uvula), has recently been targeted as a location for deep-brain stimulation in human patients to improve postural stability and gait. There are projections from midline cerebellum to basal ganglia, including the striatum, which are structures involved in the initiation of gait. It may be that the effect of this activation of peripheral saccular afferent neurons is analogous to the effect of deep-brain stimulation (DBS) by electrodes in basal ganglia acting to help alleviate the symptoms of patients with Parkinson’s disease.
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Affiliation(s)
- Ian S. Curthoys
- Vestibular Research Laboratory, School of Psychology, The University of Sydney, Sydney, NSW 2006, Australia
- Correspondence:
| | - Paul F. Smith
- Department of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin 9016, New Zealand;
- The Brain Health Research Centre, University of Otago, Dunedin 9016, New Zealand
| | - Angel Ramos de Miguel
- Department of Otolaryngology, and Head and Neck Surgery, Complejo Hospitalario Universitario Insular Materno Infantil de Gran Canaria, 35016 Las Palmas de Gran Canaria, Spain;
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Hearing loss versus vestibular loss as contributors to cognitive dysfunction. J Neurol 2022; 269:87-99. [PMID: 33387012 DOI: 10.1007/s00415-020-10343-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 11/23/2020] [Accepted: 12/04/2020] [Indexed: 02/02/2023]
Abstract
In the last 5 years, there has been a surge in evidence that hearing loss (HL) may be a risk factor for cognitive dysfunction, including dementia. At the same time, there has been an increase in the number of studies implicating vestibular loss in cognitive dysfunction. Due to the fact that vestibular disorders often present with HL and other auditory disorders such as tinnitus, it has been suggested that, in many cases, what appears to be vestibular-related cognitive dysfunction may be due to HL (e.g., Dobbels et al. Front Neurol 11:710, 2020). This review analyses the studies of vestibular-related cognitive dysfunction which have controlled HL. It is suggested that despite the fact that many studies in the area have not controlled HL, many other studies have (~ 19/44 studies or 43%). Therefore, although there is certainly a need for further studies controlling HL, there is evidence to suggest that vestibular loss is associated with cognitive dysfunction, especially related to spatial memory. This is consistent with the overwhelming evidence from animal studies that the vestibular system transmits specific types of information about self-motion to structures such as the hippocampus.
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