• acute unilateral vestibulopathy
• amplitude of low-frequency fluctuation
• fMRI
• functional connectivity
• vestibular neuritis

• Aging
• Cortex
• LDDMM
• Shape Analysis
• VEMP
• VOR
• Vestibular

• P41 EB031771 NIBIB NIH HHS
• R01 AG057667 NIA NIH HHS
• R03 DC015583 NIDCD NIH HHS

• acute unilateral vestibulopathy
• functional connectivity
• resting-state fMRI
• thalamus
• vestibular compensation
• vestibular neuritis

• Jiangsu Commission of Health

• Executive function
• Peripheral vestibular dysfunction
• Verbal initiation
• Working memory

• Humans
• Female
• Male
• Executive Function/physiology
• Middle Aged
• Vestibular Diseases/physiopathology
• Vestibular Diseases/diagnosis
• Neuropsychological Tests
• Aged
• Adult
• Memory, Short-Term/physiology
• Functional Laterality/physiology

• 100014_162480 Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
• University of Bern

• cognitive
• dementia
• hearing loss
• hippocampus
• spatial memory
• vestibular dysfunction

• Brain morphometry
• Hippocampus
• MRI
• Presubiculum
• Supramarginal gyrus
• Vestibular dysfunction

• chronic unilateral vestibulopathy
• independent component analysis
• resting-state fMRI
• sensorimotor network
• visual network

Objectives: In this study, based on the known vestibulo-hippocampal connections, we asked whether mild chronic vestibulopathy leads only to vestibular-related deficits or whether there are effects on hippocampal function, structure, and cognition in general. In more detail, we assessed whether chronic vestibulopathy leads to (a) deficits in vestibular tasks without cognitive demand (balancing), (b) deficits in spatial cognitive tasks that require vestibular input (path integration, rotational memory), (c) deficits in spatial cognitive tasks that do not rely on vestibular input, (d) deficits in general cognitive function, and (e) atrophy in the brain. Methods: A total of 15 patients with chronic uni- or bilateral vestibulopathy (56.8 ± 10.1 years; 4 females) were included in this study and were age- and gender-matched by the control participants (57.6 ± 10.5) in a pairwise manner. Given their clinical symptoms and their deficits of the vestibulo-ocular reflex (VOR) the patients could be classified as being mildly affected. All participants of the underwent the following tests: clinical balance (CBT), triangle completion (TCT) for path integration, rotational memory (RM), the visuo-spatial subset of the Berlin intelligence structure test (BIS-4) and d2-R for attention and concentration, and a structural MRI for gray matter analysis using voxel-based morphometry (VBM). Results: Compared to the healthy controls, the vestibulopathy patients performed significantly worse in terms of CBT, TCT, and RM but showed no differences in terms of the BIS-4 and d2-R. There were also no significant volumetric gray matter differences between the two groups. Conclusions: This study provides evidence that both non-cognitive and cognitive functions that rely on vestibular input (balancing, path integration, rotational memory) are impaired, even in mild chronic vestibulopathy, while other cognitive functions, which rely on visual input (visuo-spatial memory, attention), are unimpaired in this condition, together with an overall intact brain structure. These findings may reflect a segregation between vestibular- and visual-dependent processes in the medial temporal lobe on the one hand and a structure–function dissociation on the other.

• VBM
• balance
• hippocampus
• medial temporal lobe
• memory
• spatial
• vestibulopathy

• cognitive effort
• compensation
• cost
• effort
• vestibular

• Aged
• Aged, 80 and over
• Alzheimer Disease/diagnostic imaging
• Brain/diagnostic imaging
• Cognitive Dysfunction/diagnostic imaging
• Disease Progression
• Female
• Humans
• Image Interpretation, Computer-Assisted/methods
• Magnetic Resonance Imaging/methods
• Male
• Middle Aged
• Neural Networks, Computer
• Prognosis

• Cuneus
• PPPD
• Precentral gyrus
• Precuneus
• Resting state functional magnetic resonance imaging

Previous studies using voxel-based morphometry (VBM) revealed changes in gray matter volume (GMV) of patients with depression, but the differences between patients with bipolar disorder (BD) and unipolar depression (UD) are less known.

To analyze the whole-brain GMV data of patients with untreated UD and BD compared with healthy controls.

Fourteen patients with BD and 20 with UD were recruited from the Mental Health Center of Shantou University between August 2014 and July 2015, and 20 non-depressive controls were recruited. After routine three-plane positioning, axial T2WI scanning was performed. The connecting line between the anterior and posterior commissures was used as the scanning baseline. The scanning range extended from the cranial apex to the foramen magnum. Categorical data are presented as frequencies and were analyzed using the Fisher exact test.

There were no significant intergroup differences in gender, age, or years of education. Disease course, age at the first episode, and Hamilton depression rating scale scores were similar between patients with UD and those with BD. Compared with the non-depressive controls, patients with BD showed smaller GMVs in the right inferior temporal gyrus, left middle temporal gyrus, right middle occipital gyrus, and right superior parietal gyrus and larger GMVs in the midbrain, left superior frontal gyrus, and right cerebellum. In contrast, UD patients showed smaller GMVs than the controls in the right fusiform gyrus, left inferior occipital gyrus, left paracentral lobule, right superior and inferior temporal gyri, and the right posterior lobe of the cerebellum, and larger GMVs than the controls in the left posterior central gyrus and left middle frontal gyrus. There was no difference in GMV between patients with BD and UD.

Using VBM, the present study revealed that patients with UD and BD have different patterns of changes in GMV when compared with healthy controls.

• Bipolar disorder
• Unipolar depression
• Gray matter
• Functional magnetic resonance imaging
• Classification techniques
• Voxel-based morphometry

Previous studies have shown that vestibular migraine (VM) is a cerebral disease with recurrent vertigo. Vestibular rehabilitation (VR) is an effective type of physical therapy for minimizing vestibular symptoms, as it improves vestibular compensation in patients with VM. Currently, the cerebral regions that are associated with the pathogenesis of VM are largely unknown. To further understand the underlying mechanisms of VM, we performed resting-state functional magnetic resonance imaging (fMRI) before and after 1 month of VR in 14 patients with VM. The Dizziness Handicap Inventory (DHI), the 36-Item Short-Form Health Survey (SF-36), the Hamilton Depression Scale (HAMD) and the Hamilton Anxiety Scale (HAMA) scores were included as clinical outcomes. The amplitude of low-frequency fluctuation (ALFF) was assessed to characterize spontaneous brain activity. The correlations between the clinical characteristics and ALFF values were assessed. After 1 month of VR training, the DHI scores in patients with VM were significantly lower than those at baseline (p = 0.03), as were the HAMA scores (p = 0.02). We also found that the ALFF values in the left posterior cerebellum of VM patients increased significantly after 1 month of VR training. Moreover, the ALFF values in the left cerebellum were inversely correlated with the patients’ DHI scores. Overall, this study showed that VR exercise for 1 month has a positive effect on vestibular symptoms in patients with VM. Asymmetric cerebellar hyperactivity might be a functional compensation for vestibular dysfunction in patients with VM.

• amplitude of low-frequency fluctuation
• functional magnetic resonance imaging
• resting state
• vestibular migraine
• vestibular rehabilitation

Balancing is a complex task requiring the integration of visual, somatosensory and vestibular inputs. The vestibular system is linked to the hippocampus, a brain structure crucial for spatial orientation. Here we tested the immediate and sustained effects of a one-month-long slackline training program on balancing and orientation abilities as well as on brain volumes in young adults without any prior experience in that skill. On the corrected level, we could not find any interaction effects for brain volumes, but the effect sizes were small to medium. A subsequent within-training-group analysis revealed volumetric increments within the somatosensory cortex and decrements within posterior insula, cerebellum and putamen remained stable over time. No significant interaction effects were observed on the clinical balance and the spatial orientation task two months after the training period (follow-up). We interpret these findings as a shift away from processes crucial for automatized motor output towards processes related to voluntarily controlled movements. The decrease in insular volume in the training group we propose to result from multisensory interaction of the vestibular with the visual and somatosensory systems. The discrepancy between sustained effects in the brain of the training group on the one hand and transient benefits in function on the other may indicate that for the latter to be retained a longer-term practice is required.

• VBM
• balance
• gray matter
• neuroplasticity
• path integration

• Electroencephalography
• Rehabilitation
• Vestibular Diseases
• Virtual Reality

• Brain perfusion
• Persistent postural-perceptual dizziness
• Regional cerebral blood flow
• Single photon emission computed tomography

Vestibular neuritis (VN) is characterised by acute vertigo due to a sudden loss of unilateral vestibular function. A considerable proportion of VN patients proceed to develop chronic symptoms of dizziness, including visually induced dizziness, specifically during head turns. Here we investigated whether the development of such poor clinical outcomes following VN, is associated with abnormal visuo-vestibular cortical processing. Accordingly, we applied functional magnetic resonance imaging to assess brain responses of chronic VN patients and compared these to controls during both congruent (co-directional) and incongruent (opposite directions) visuo-vestibular stimulation (i.e. emulating situations that provoke symptoms in patients). We observed a focal significant difference in BOLD signal in the primary visual cortex V1 between patients and controls in the congruent condition (small volume corrected level of p < .05 FWE). Importantly, this reduced BOLD signal in V1 was negatively correlated with functional status measured with validated clinical questionnaires. Our findings suggest that central compensation and in turn clinical outcomes in VN are partly mediated by adaptive mechanisms associated with the early visual cortex.

•

VN clinical status related to V1 response to congruent visuo-vestibular stimuli

• Oscillopsia
• Vertigo
• Vestibular compensation
• Vestibular neuritis
• Visual-cortex
• fMRI

• Notch3
• Purkinje neurons
• adult neurogenesis
• cerebellum
• chronic pain
• cross-modal perception
• proprioception
• structural plasticity

• Cerebral
• Group analysis
• Neuroimaging
• Vertigo
• Vestibular neuritis

Why vestibular compensation (VC) after an acute unilateral vestibular loss is the neuro-otologist’s best friend is the question at the heart of this paper. The different plasticity mechanisms underlying VC are first reviewed, and the authors present thereafter the dual concept of vestibulo-centric versus distributed learning processes to explain the compensation of deficits resulting from the static versus dynamic vestibular imbalance. The main challenges for the plastic events occurring in the vestibular nuclei (VN) during a post-lesion critical period are neural protection, structural reorganization and rebalance of VN activity on both sides. Data from animal models show that modulation of the ipsilesional VN activity by the contralateral drive substitutes for the normal push–pull mechanism. On the other hand, sensory and behavioural substitutions are the main mechanisms implicated in the recovery of the dynamic functions. These newly elaborated sensorimotor reorganizations are vicarious idiosyncratic strategies implicating the VN and multisensory brain regions. Imaging studies in unilateral vestibular loss patients show the implication of a large neuronal network (VN, commissural pathways, vestibulo-cerebellum, thalamus, temporoparietal cortex, hippocampus, somatosensory and visual cortical areas). Changes in gray matter volume in these multisensory brain regions are structural changes supporting the sensory substitution mechanisms of VC. Finally, the authors summarize the two ways to improve VC in humans (neuropharmacology and vestibular rehabilitation therapy), and they conclude that VC would follow a “top-down” strategy in patients with acute vestibular lesions. Future challenges to understand VC are proposed.

• Animal models
• Dynamic deficits recovery
• Human brain imaging
• Static deficits recovery
• Unilateral vestibular loss
• Vestibular compensation

• bilateral vestibular failure
• hippocampus
• magnetic resonance imaging
• voxel-based morphometry