Vestibular System Research Articles

Balance performance in aged mice is dependent on unipolar brush cells.

The vestibular processing regions of the cerebellum integrate vestibular information with other sensory modalities and motor signals to regulate balance, gaze stability, and spatial orientation. A class of excitatory glutamatergic interneurons known as unipolar brush cells (UBCs) are highly concentrated within the granule cell layer of these regions. UBCs receive vestibular signals directly from primary vestibular afferents and indirectly from mossy fibers. Each UBC excites numerous granule cells and could contribute to computations necessary for balance-related motor function. Prior research has implicated UBCs in motor function, but their influence on balance performance remains unclear, especially in aged mice that have age-related impairment. Here we tested whether UBCs contribute to motor coordination and balance by disrupting their activity with chemogenetics in aged and young mice. Age-related balance deficits were apparent in mice > 6 months old. Disrupting the activity of a subpopulation of UBCs caused aged mice to fall off a balance beam more frequently and altered swimming behaviors that are sensitive to vestibular dysfunction. These effects were not seen in young (7-week-old) mice. Thus, disrupting the activity of UBCs impairs mice with age-related balance issues and suggest that UBCs are essential for balance and vestibular function in aged mice.

Ocular Movement Examination in Peripheral Vestibular Disorders as a Tool to Improve Diagnosis: A Literature Review.

Background and Objectives: This study reviews the current literature on ocular movements, specifically focusing on nystagmus associated with peripheral vestibular disorders, to enhance diagnostic accuracy. The evaluation of ocular movements, particularly nystagmus, provides essential insights into the function and dysfunction of the vestibular system, helping clinicians distinguish between peripheral and central causes of vertigo and imbalance. Materials and Methods: A comprehensive search of PubMed was conducted using key terms such as "ocular movements", "nystagmus", "vestibular nystagmus", and "peripheral vestibular disorders". Results: The search yielded 2739 titles, and after a rigorous selection process, 52 articles were reviewed in full. Discussion: The review highlights different classifications and types of nystagmus, including physiological and pathological forms, and their diagnostic relevance in vestibular disorders such as benign paroxysmal positional vertigo (BPPV), vestibular neuritis, and Meniere's disease. Diagnostic techniques like video/electro-oculography are emphasized for their role in assessing vestibular function and identifying abnormalities. The study underscores the importance of detailed ocular examination in the diagnosis of peripheral vestibular disorders and proposes an algorithm to aid this process. Conclusions: While not a systematic review, this study highlights the importance of detailed ocular examination in diagnosing peripheral vestibular disorders and presents an algorithm to facilitate this process. It also emphasizes the need for continued research and advancements in vestibular medicine to further understand ocular movements and their clinical significance, ultimately contributing to improved patient outcomes.

Evaluation of VOR function with vHIT in unilateral pediatric cochlear implant users

ObjectiveThe changes in the inner ear affect both the cochlea and the vestibule and these effects are observed after cochlear implantation surgery. The aim of the current study is to evaluate the effect of unilateral cochlear implant use on vestibulo-ocular reflex (VOR) in children. MethodsIn the current study, 29 cochlear implanted children, aged 7–18 years, were include as the study group and 32 children, in the same age range, were included with normal-hearing as the control group. vHIT was used to evaluate VOR and the results of unilateral CI users were compared with the control group. The study group was evaluated in two different situations: cochlear implant sound processor on (CI-ON) and cochlear implant sound processor off (CI-OFF). The data obtained in the evaluations were compared between the implanted ear and the non-implanted ear between the CI-ON and CI-OFF states within the study group and between the study group and the control group. ResultsWhen the CI-ON and CI-OFF conditions in the study group were compared, no significant difference was found (p > 0.05). Similarly, no significant difference was found between the implanted ear and the non-implanted ear (p > 0.05). Also, there was no significant difference in the comparisons between the study group and the control group (p > 0.05). ConclusionvHIT is a functional test method that can be used in children to test vestibular function after cochlear implant. vHIT is a comfortable test to use after cochlear implantation to demonstrate the functionality of the vestibular system. And it provides consistent results regardless of whether the speech processor is on or off.

Evidence of Peripheral Vestibular Impairment Among Adults With Chronic Moderate-Severe Traumatic Brain Injury.

Traumatic brain injury (TBI) is a leading cause of death and disability among adults in the United States. There is evidence to suggest the peripheral vestibular system is vulnerable to damage in individuals with TBI. However, there are limited prospective studies that describe the type and frequency of vestibular impairment in individuals with chronic moderate-severe TBI (> 6 months postinjury). Cervical and ocular vestibular evoked myogenic potentials (VEMPs) and video head impulse test (vHIT) were used to assess the function of otolith organ and horizontal semicircular canal (hSCC) pathways in adults with chronic moderate-severe TBI and in noninjured comparison (NC) participants. Self-report questionnaires were administered to participants with TBI to determine prevalence of vestibular symptoms and quality of life associated with those symptoms. Chronic moderate-severe TBI was associated with a greater degree of impairment in otolith organ, rather than hSCC, pathways. About 63% of participants with TBI had abnormal VEMP responses, compared to only ~10% with abnormal vHIT responses. The NC group had significantly less abnormal VEMP responses (~7%), while none of the NC participants had abnormal vHIT responses. As many as 80% of participants with TBI reported vestibular symptoms, and up to 36% reported that these symptoms negatively affected their quality of life. Adults with TBI reported vestibular symptoms and decreased quality of life related to those symptoms and had objective evidence of peripheral vestibular impairment. Vestibular testing for adults with chronic TBI who report persistent dizziness and imbalance may serve as a guide for treatment and rehabilitation in these individuals.

A 5-week centrifuge-based G training with feedback on the magnitude of G force does not improve the perception of roll tilt during simulated coordinated turns.

When entering a coordinated flight turn without visual references, the perception of roll-angular displacement is determined by vestibular cues, and/or probably by assessment of the gravitoinertial (G) load (G magnitude) and its translation into the corresponding bank angle. Herein, we examined whether repeated exposures to hypergravity (G training) in a centrifuge, would advance, not only the ability to accurately assess the G load but also the capacity to detect or estimate the corresponding roll inclination of the centrifuge gondola. To this end, in nine men without piloting experience, the subjective estimation of G load and roll tilt were assessed, in complete darkness, during 5-min coordinated turns in the centrifuge, performed at 1.1 G (25° roll-tilt angle) and 2.0 G (60° roll tilt angle). These trials were conducted before and after 5 wk of G training {3 × 40-min sessions·wk-1; protocol: 20 × 1 min at G levels close to the individual relaxed G-level tolerance [range: ∼2.6 G (∼67°)-3.6 G (74°)], separated by 1-min intervals at idle speed (1.4 G)}, whereas continual feedback to the subjects was limited to the G load. As expected, G training improved subjects' capacity to assess G load, especially at 2.0 G (P = 0.006). The perception of roll tilt, however, was consistently underestimated (by ∼70%-80%), and not enhanced by G training (P ≥ 0.51). The present findings demonstrate that prolonged repeated G-induced roll-tilts in a centrifuge gondola, while external feedback is restricted to graviception, enhance the capacity to perceive G load, but fail to advance the ability to detect or consciously estimate the magnitude of roll-angular displacement during a coordinated turn.NEW & NOTEWORTHY During a coordinated flight turn without external visual references, the pilot typically underestimates the aircraft bank angle, because unreliable information of roll tilt is conveyed by the vestibular system. The present results demonstrate that prolonged repeated gravitoinertial (G)-induced roll-tilts in a centrifuge gondola, while external feedback is restricted to graviception, enhance the capacity to perceive G load, but fail to advance the ability to consciously estimate the magnitude of roll angular displacement.

The Role of Pericytes in Inner Ear Disorders: A Comprehensive Review.

Inner ear disorders, including sensorineural hearing loss, Meniere's disease, and vestibular neuritis, are prevalent conditions that significantly impact the quality of life. Despite their high incidence, the underlying pathophysiology of these disorders remains elusive, and current treatment options are often inadequate. Emerging evidence suggests that pericytes, a type of vascular mural cell specialized to maintain the integrity and function of the microvasculature, may play a crucial role in the development and progression of inner ear disorders. The pericytes are present in the microvasculature of both the cochlea and the vestibular system, where they regulate blood flow, maintain the blood-labyrinth barrier, facilitate angiogenesis, and provide trophic support to neurons. Understanding their role in inner ear disorders may provide valuable insights into the pathophysiology of these conditions and lead to the development of novel diagnostic and therapeutic strategies, improving the standard of living. This comprehensive review aims to provide a detailed overview of the role of pericytes in inner ear disorders, highlighting the anatomy and physiology in the microvasculature, and analyzing the mechanisms that contribute to the development of the disorders. Furthermore, we explore the potential pericyte-targeted therapies, including antioxidant, anti-inflammatory, and angiogenic approaches, as well as gene therapy strategies.

Differentiating the Structural and Functional Instability of the Craniocervical Junction.

This paper presents the anatomical and biomechanical aspects of chronic instability of the craniocervical junction (CCJ) with a discussion on clinical diagnostics based on mobility tests and provocative tests related to ligamentous system injuries, as well as radiological criteria for CCJ instability. In addition to the structural instability of the CCJ, the hypothesis of its functional form resulting from cervical proprioceptive system (CPS) damage is discussed. Clinical and neurophysiological studies have shown that functional disorders or organic changes in the CPS cause symptoms similar to those of vestibular system diseases: dizziness, nystagmus, and balance disorders. The underlying cause of the functional form of CCJ instability may be the increased activity of mechanoreceptors, leading to "informational noise" which causes vestibular system disorientation. Due to the disharmony of mutual stimulation and the inhibition of impulses between the centers controlling eye movements, the cerebellum, spinal motoneurons, and the vestibular system, inadequate vestibulospinal and vestibulo-ocular reactions occur, manifesting as postural instability, dizziness, and nystagmus. The hyperactivity of craniocervical mechanoreceptors also leads to disturbances in the reflex regulation of postural muscle tone, manifesting as "general instability". Understanding this form of CCJ instability as a distinct clinical entity is important both diagnostically and therapeutically as it requires different management strategies compared to true instability. Chronic CCJ instability significantly impacts the quality of life (QOL) of affected patients, contributing to chronic pain, psychological distress, and functional impairments. Addressing both structural and functional instability is essential for improving patient outcomes and enhancing their overall QOL.

Hippotherapy As An Effective Treatment Strategy For Paediatric Population With Disabilities - A Literature Review

Background: Hippotherapy is an equine-assisted therapeutic method for the development of physical, occupational, and emotional performance in people suffering from various maladies. The neurophysiology of hippotherapy is characterized by the cyclical rhythmic movement of the horses, which is a kind of sensory input providing the rider with the information needed to maintain the proprioceptive and vestibular systems. It is the act of falling and jumping process that encourages neural pathways responsible for the development of the motor system which gradually results in the development of balance and coordination. To wit, the motion of those animals is one such that they imitate the normal human body’s walking pattern and in effect, like physiotherapy, they provide familiarity and thereby help in reskilling the rider’s core muscles and postural alignment. Furthermore, the relationship between the horse and the human being can also contribute to the emotional and spiritual side of the human being, thus, resulting in a more holistic approach to therapy that could be shown in practice through such modes as horse therapy. Methodology: We performed literature searching multiple electronic databases. The searches generated 50 potentially relevant studies. After applying inclusion and exclusion criteria, eliminating repeated articles, and critically evaluating the obtained results, nine papers were selected for the analysis. The selected papers were published between the period of January 2019 to July 2024. This comprised two cross-sectional studies, one experimental study, one exploratory study, one randomized controlled trial, and one survey investigation. Results: This literature review noticed a connection between hippotherapy and observable improvements in balance, coordination, gait, motor functions, cognitive functions, flexibility, functional mobility in children with disabilities. Conclusion: Hippotherapy has benefited balance, coordination, gait, motor functions, cognitive functions, flexibility, and functional mobility in children with disabilities, and thus, it should be considered as a treatment strategy for treating children with disabilities.

Correlation between the etiology of severe hearing loss and endolymphatic hydrops.

This study aimed to investigate correlation between the presence of endolymphatic hydrops(EH) and factors such as causes of hearing loss, patient age, duration of deafness, and results of vestibular function tests. We retrospectively reviewed medical charts of 128 ears of cochlear implantees who were not considered relevant to Meniere's disease. When comparing group with genetic variants of GJB2, SLC26A4, LMX1A and other genetic mutation group, the proportion of vestibular EH and cochlear EH found in group with genetic variants of GJB2, SLC26A4, LMX1A was significantly higher than group with other genetic etiology (p < 0.01) or the group with all the other causes of hearing loss (p < 0.01). The rate of vestibular and cochlear EH detection was higher in younger patients (41.5% and 35.4%) than in older patients (25.4% and 20.6%). A higher ratio of vestibular and cochlear EH was observed in patients with a longer duration of deafness (37.5% and 31.3%) than those with a shorter duration of deafness (29.7% and 25.0%). The group with vestibular EH showed a higher incidence of abnormal findings in the caloric test (42.9%) than the group without vestibular EH (28.2%). Patients with genetic variants of GJB2, SLC26A4, LMX1A, younger patients, those with longer deaf durations showed a higher prevalence of vestibular and cochlear EH, implying EH appears to be formed as a developmental disorder in association with a certain set of genetic variants, rather than a phenotypic marker as a result of severe to profound hearing loss.

Transiently worse postural effects after vestibulo-ocular reflex gain-down adaptation in healthy adults.

Suffering an acute asymmetry in vestibular function (i.e., vestibular neuritis) causes increased sway. Non-causal studies report associations between lateral semicircular canal function and balance ability, but direct links remain controversial. We investigate the immediate effect on body sway after unilateral vestibulo-ocular reflex (VOR) gain down adaptation simulating acute peripheral vestibular hypofunction. Eighteen healthy adults, mean age 27.4 (± 12.4), stood wearing an inertial measurement device with their eyes closed on foam before and after incremental VOR gain down adaptation to simulate mild unilateral vestibular neuritis. Active head impulse VOR gain was measured before and after the adaptation to ensure VOR gain adaptation. Percentage change for VOR gain was determined. Sway area was compared before and after VOR adaptation. VOR gain decreased unilaterally exceeding meaningful change values. Sway area was significantly greater immediately after VOR gain down adaptation, but quickly returned to baseline. In a subset of subjects VOR gain was re-assessed and found to remain adapted despite sway normalization. These results indicate that oculomotor adaptation targeting the lateral semicircular canal VOR pathway has an immediate, albeit transient increase in body sway. Rapid return of body sway to baseline levels suggests dynamic sensory reweighting between vestibular and somatosensory inputs to resolve the undesirable increased body sway.

Cisplatin vestibulotoxicity: a current review.

Cisplatin, a commonly used chemotherapy drug, is well-established for its ototoxic effects, primarily attributed to the damage it inflicts on cochlear hair cells. However, its impact on the vestibular system remains inadequately understood. Here, we provide a comprehensive review of existing literature concerning cisplatin-induced vestibulotoxicity. Animal studies have shown that cisplatin induces a vestibular hair cell loss that is dose-dependent, with the severity of damage also varying according to the route of administration. Notably, intratympanic and systemic injections in animal models have manifested significant damage primarily to utricular hair cells, with a lesser degree of damage observed for the other vestibular end organs. The underlying mechanisms of cisplatin induced vestibular hair cell loss include apoptosis, oxidative stress, and inflammatory cytokines. Several protective agents, such as Pifithrin-α, DAPT, Ginkgolide B, and heat shock proteins, have demonstrated efficacy in inhibiting cisplatin-induced vestibular damage in preclinical studies. Human clinical findings indicate that cisplatin treatment can cause vestibular dysfunction, characterized by symptoms ranging from transient dizziness to persistent vertigo. Challenges in diagnosis, including the limited utilization of comprehensive vestibular testing for many patients, contribute to the variability in reported outcomes. Cisplatin-induced vestibulotoxicity is a significant complication of chemotherapy, necessitating further research to understand its mechanisms and to improve diagnosis and management, ultimately aiming to enhance the quality of life for cancer patients undergoing cisplatin therapy.

Assessment of hearing and balance functions in patients with acromegaly by the use of an audiovestibular test battery: a cross-sectional study.

Patients with acromegaly may have abnormalities in their hearing and balance as a result of modifications in body composition and involvement of the temporal bone. The objective of this study is to examine if there are any changes in the auditory and vestibular systems in individuals with acromegaly by using audiogram and vestibular function tests. This prospective study included 33 healthy controls and 33 acromegaly patients who were matched for age and gender distribution. A pure-tone audiometry test was conducted, including frequencies ranging from 250Hz to 8000Hz. Videonystagmography (VNG) was employed to assess nystagmus, an essential parameter used for assessing vestibular functions. The Video Head Impulse Test (v-HIT) was used to assess the vestibulo-ocular reflex (VOR). The Dizziness Handicap Inventory (DHI) was applied to evaluate the subjective complaints of the participants. The acromegaly patients had significantly elevated hearing thresholds at all frequencies (250, 500, 1000, 2000, 4000, and 6000Hz) compared to the control group (p < 0.005). The VNG tests, including gaze horizontal, gaze vertical, saccade, spontaneous nystagmus, optokinetic, smooth pursuit, and positioning tests, did not show any statistically significant difference between the two groups (p values > 0.05). The patient group demonstrated reduced VOR gains compared to the control group in the anterior and posterior channels (p < 0.005). There was no statistically significant difference between the two groups for the occurrence of aberrant eye movements (p values > 0.05). The patient group had a total DHI score of 6.6 ± 3.2, while the control group had a score of 3.2 ± 2.6 (independent samples t-test; p < 0.001). Therefore, The patient group exhibited significantly greater subjective vestibular symptoms. Patients with acromegaly experience impaired auditory function. The central vestibular system remains unaffected, while the gains of the vestibulo-ocular reflex (VOR) in the posterior and anterior semicircular canals are decreased. Additionally, these patients report experiencing subjective dizziness. Screening for hearing and balance in patients with acromegaly may improve the quality of life of patients and prevent problems related to balance disorders at an early stage.

Increased Perception of Head Tilt to Galvanic Vestibular Stimulation Correlates to Motion Sickness Susceptibility in Vestibular Migraine.

Vestibular migraine is associated with vertigo, persistent swaying, tilting, and disorientation, which suggests a heightened sensitivity of the neural mechanisms subserving spatial orientation. Whether a heightened sense of motion to vestibular stimulation in vestibular migraine is associated with sensitivity to visual motion (visual dependency) or physical motion (motion sickness susceptibility) is unclear. The aim of this study was to explore whether a heightened sense of self-motion sensitivity in vestibular migraine is associated with visual dependency or motion sickness susceptibility. This is a prospective cross-over study. Fifteen participants with vestibular migraine and 20 healthy controls (all right handed) were included in this study. In the main experiment, participants were asked to align a rod to the perceived head position. Head tilt was generated by DC galvanic vestibular stimulation at 1 mA to produce head tilts to the right (left anodal/right cathodal stimulation, LA/RC) or left (right anodal/left cathodal, RA/LC). The perception of head tilt was measured in a dark room using laptop software that allowed participants to turn an illuminated rod to any angle about the midpoint. Participants were instructed to align the rod to the perceived head position before and during galvanic stimulation and the line angle was saved. Head position was objectively monitored with an ultrasound motion system. After completing the perceptual test, visual dependency was measured with a static and rotating background and the Motion Sickness Susceptibility Questionnaire (MSSQ) was completed. In an upright head position, without stimulation, the perceived head position was 1.1 degrees in controls and -0.69 degrees in vestibular migraine participants with no significant difference between groups. During galvanic vestibular stimulation, participants with vestibular migraine had an increased perception of head tilt compared with controls (RA/LC: controls -4.7 degrees and vestibular migraine -9.29, p = 0.002; and LA/RC: controls 6.5 degrees and vestibular migraine 11.12 degrees, p = 0.017), although the size of head movement was similar between groups. The average perception of head tilt correlated to the MSSQ score, but not to the degree of visual dependency in a static or moving background. A heightened sensitivity of the vestibular system to vestibular stimulation in vestibular migraine is consistent with reports of self-motion sensitivity in vestibular migraine.

Protective Effects of Gastrodin Against Gentamicin-Induced Vestibular Damage by the Notch Signaling Pathway.

Gentamicin is a broad-spectrum antibiotic commonly used in clinical practice. However, the drug causes side effects of ototoxicity, leading to disruption in balance functionality. This study investigated the effect of gastrodin, a prominent compound present in Gastrodia, and the underlying mechanism on the development of gentamicin-induced vestibular dysfunction. Wild-type C57BL/6 mice were randomly assigned to three groups: control, gentamicin, and gentamicin + gastrodin groups. The extent of gentamicin-induced vestibular impairment was assessed through a series of tests including the swimming test, contact righting reflex test, and air-righting reflex. Alterations in vestibular hair cells were monitored through immunofluorescence assay, and cellular apoptosis was observed using TUNEL staining. The mRNA and protein expression of Notch1, Jagged1, and Hes1 was quantified through qRT-PCR, immunofluorescence, and western blot analyses. Gentamicin treatment led to pronounced deficits in vestibular function and otolith organ hair cells in mice. Nevertheless, pretreatment with gastrodin significantly alleviated these impairments. Additionally, the Notch signaling pathway was activated by gentamicin in the utricle, contributing to a notable increase in the expression levels of apoptosis-associated proteins. By contrast, gastrodin treatment effectively suppressed the Notch signaling pathway, thereby mitigating the occurrence of apoptosis. Collectively, these findings underscore the crucial role of gastrodin in safeguarding against gentamicin-induced vestibular dysfunction through the modulation of the Notch signaling pathway. This study suggests the potential of gastrodin as a promising therapeutic agent for preventing vestibular injuries.

The Effect Of Concussion History On The Vestibular System And Postural Stability In Reserve Officers' Training Corps Cadets

The Effect Of Concussion History On The Vestibular System And Postural Stability In Reserve Officers' Training Corps Cadets

Hearing and balance functions in patients with systemic lupus erythematosus

Background Systemic lupus erythematosus (SLE) is a chronic, inflammatory, autoimmune disease, characterized by multiple organ involvement, which is seen more often in young females. Objectives To evaluate the hearing and balance functions in SLE patients. Materials and methods Twenty-four SLE patients, 24 healthy controls underwent pure tone audiometry (0.125–16 kHz), VNG, vestibular evoked myogenic potential (VEMP), and video head impulse test (vHIT). Results A statistically significant difference was determined between the control group and the SLE group at 0.125, 0.25, 0.5, 1.0, 6.0, 8.0, 10, 12, 14, and 16 kHz frequencies. Sensorineural hearing loss was observed in 37.5% of the SLE group. The pursuit test was pathological at the rate of 25% in the SLE group. No response was obtained in six SLE patients in the oVEMP test and four SLE patients in the cVEMP test. The mean posterior SCC VOR gain values were 0.64 ± 0.2 in the SLE group. A significant difference was determined between the groups with respect to posterior SCC VOR gains. Conclusions and significance Our findings show that SLE disease may negatively affect the hearing system and the vestibular system as well. The current study is the first study to comprehensively evaluate SLE patients with VNG, VEMP, and vHIT tests.

Comparing saccades in Visually Enhanced Vestibular-Ocular Reflex and video head impulse test in vestibular assessment

ObjectiveThis study aimed to develop and evaluate a novel software tool for robust analysis of the Visually Enhanced Vestibular-Ocular Reflex (VVOR) and video head impulse test (vHIT) saccades. MethodsA retrospective study was conducted on 94 patients with Meniere's Disease (MD), unilateral vestibular hypofunction (UVH), and vestibular migraine (VM). The MATLAB-based VVOR Analysis System and Saccades All in One software were utilized for data processing. New techniques, VVOR_diff and VVOR_cycle, were deployed for saccade parameter extraction. ResultsSaccade incidence rates, examined through vHIT, VVOR_diff, and VVOR_cycle, exhibited distinct patterns in MD, UVH, and VM patients. Frequent instances of multiple saccades within a single cycle were noted on the affected side in MD and UVH patients. Statistically significant differences in saccade gain and incidence rates between the affected and unaffected sides were evident in MD and UVH patients. Notably, high inter-method and intra-method correlations suggested consistency across different methods and potential interactions within one. ConclusionThe software proved effective in extracting saccades and reducing noise in VVOR data, thereby enhancing the evaluation of vestibular function and potentially improving diagnostic accuracy for vestibular disorders.

Reference ranges and test-retest reliability of subject visual horizontal from different head-tilt angles in young healthy adults

Objective:To establish the normal values of subjective visual horizontal（SVH） under different head tilt angles, analyze the test-retest reliability, and provide a normal value reference for the refined diagnosis and functional assessment of SVH in clinical vestibular disorders. Methods:Thirty-one healthy young people were selected to wear visual reality glasses to test SVH data in five different head tilt angles: upright head position 0°, head tilted 45°to the left（L45°）, head tilted 45° to the right（R45°）, head tilted 90° to the left（L90°）, and head tilted 90° to the right（R90°）, and were re-tested 2 weeks later. Results:①The normal values of SVH at 0°, L45°, R45°, L90°, and R90°were 0.30±1.32, 5.94±5.54, -11.44±5.32, -0.87±8.63, -2.70±8.02, respectively. ②The 95% confidence intervals of SVH at 0°, L45°, R45°, L90°, and R90° were: （-2.34,2.94）,（-5.14,17.02）,（-22.08,-0.80）,（-18.13,16.39）,（-18.74，13.34）, respectively. The ratio of asymmetry in the absolute value of bilateral 45° deviation was 26.4% and the ratio of asymmetry in the absolute value of bilateral 90° deviation was 1.3%. ③The intra-class correlation coefficient（ICC） for 0°, L45°, R45°, L90° and R90° was 0.625, 0.641, 0.564, 0.769, 0.656, respectively. Conclusion:SVH has good test-retest reliability and high clinical test stability and stability. The data on normal values of SVH at different head tilt angles established in this study can provide clinical references for the refined diagnosis and functional assessment of vestibular system disorders.

The IgLON family of cell adhesion molecules expressed in developing neural circuits ensure the proper functioning of the sensory system in mice

Deletions and malfunctions of the IgLON family of cell adhesion molecules are associated with anatomical, behavioral, and metabolic manifestations of neuropsychiatric disorders. We have previously shown that IgLON genes are expressed in sensory nuclei/pathways and that IgLON proteins modulate sensory processing. Here, we examined the expression of IgLON alternative promoter-specific isoforms during embryonic development and studied the sensory consequences of the anatomical changes when one of the IgLON genes, Negr1, is knocked out. At the embryonal age of E12.5 and E13.5, various IgLONs were distributed differentially and dynamically in the developing sensory areas within the central and peripheral nervous system, as well as in limbs and mammary glands. Sensory tests showed that Negr1 deficiency causes differences in vestibular function and temperature sensitivity in the knockout mice. Sex-specific differences were noted across olfaction, vestibular functioning, temperature regulation, and mechanical sensitivity. Our findings highlight the involvement of IgLON molecules during sensory circuit formation and suggest Negr1’s critical role in somatosensory processing.

Brain Functional Alterations in Patients With Benign Paroxysmal Positional Vertigo Demonstrate the Visual-Vestibular Interaction and Integration.

This study aimed to analyze the features of resting-state functional magnetic resonance imaging (rs-fMRI) and clinical relevance in patients with benign paroxysmal positional vertigo (BPPV) that have undergone repositioning maneuvers. A total of 38 patients with BPPV who have received repositioning maneuvers and 38 matched healthy controls (HCs) were enrolled in the present study from March 2018 to August 2021. Imaging analysis software was employed for functional image preprocessing and indicator calculation, mainly including the amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), percent amplitude of fluctuation (PerAF), and seed-based functional connectivity (FC). Statistical analysis of the various functional indicators in patients with BPPV and HCs was also conducted, and correlation analysis with clinical data was performed. Patients with BPPV displayed decrease in ALFF, fALFF, and PerAF values, mainly in the bilateral occipital lobes in comparison with HCs. Additionally, their ALFF and fALFF values in the proximal vermis region of the cerebellum increased relative to HCs. The PerAF values in the bilateral paracentral lobules, the right supplementary motor area (SMA), and the left precuneus decreased in patients with BPPV and were negatively correlated with dizziness visual analog scale (VAS) scores 1 week after repositioning (W1). In addition, in the left fusiform gyrus and lingual gyrus, the PerAF values show a negative correlation with dizziness handicap inventory (DHI) scores at initial visit (W0). Seed-based FC analysis using the seeds from differential clusters of fALFF, ALFF, and PerAF showed reductions between the left precuneus and bilateral occipital lobe, the left precuneus and left paracentral lobule, and within the occipital lobes among patients with BPPV. The spontaneous activity of certain brain regions in the bilateral occipital and frontoparietal lobes of patients with BPPV was reduced, whereas the activity in the cerebellar vermis was increased. Additionally, there were reductions in FC between the precuneus and occipital cortex or paracentral lobule, as well as within the occipital cortex. The functional alterations in these brain regions may be associated with the inhibitory interaction and functional integration of visual, vestibular, and sensorimotor systems. The functional alterations observed in the visual cortex and precuneus may represent adaptive responses associated with residual dizziness.