Vestibular System Research Articles

Plastic Events of the Vestibular Nucleus: the Initiation of Central Vestibular Compensation.

Vestibular compensation is a physiological response of the vestibular organs within the inner ear. This adaptation manifests during consistent exposure to acceleration or deceleration, with the vestibular organs incrementally adjusting to such changes. The molecular underpinnings of vestibular compensation remain to be fully elucidated, yet emerging studies implicate associations with neuroplasticity and signal transduction pathways. Throughout the compensation process, the vestibular sensory neurons maintain signal transmission to the central equilibrium system, facilitating adaptability through alterations in synaptic transmission and neuronal excitability. Notable molecular candidates implicated in this process include variations in ion channels and neurotransmitter profiles, as well as neuronal and synaptic plasticity, metabolic processes, and electrophysiological modifications. This study consolidates the current understanding of the molecular events in vestibular compensation, augments the existing research landscape, and evaluates contemporary therapeutic strategies. Furthermore, this review posits potential avenues for future research that could enhance our comprehension of vestibular compensation mechanisms.

Subjective visual vertical/horizontal and video head impulse test in dyslexic children.

Different studies have tried to establish a relationship between dyslexia and the vestibular system function. Subjective Visual Vertical/Horizontal (SVV and SVH) and Video Head Impulse Test (VHIT) are useful for studying the vestibular system and can be easily performed in children. Our aim was to evaluate the vestibular function in dyslexic children by SVV/SVH and VHIT. We enrolled 18 dyslexic children (10M/8F; mean age 10.7 ± 2.3 years; range 7-14 years) and 18 age-matched children with typical development of learning abilities. All children performed VHIT, SVV and SVH. We found normal gain and symmetry of vestibulo-ocular-reflex both in dyslexic and typically developing children. Fifteen out of 18 dyslexic children (83.3%) showed a difference of at least one amongst SVV or SVH. The mean value of SVV was 2.3° and the mean value of SVH was 2.6°. Statistical analysis showed a significant difference between typically developing and dyslexic children for both SVV and SVH. We confirm a relationship between dyslexia and the alteration of SVV and SVH. Our results could be related to the pathogenetic hypothesis of a visual processing impairment related to a dysfunction of the magnocellular pathway or to a general deficit related to a multimodal cortical network.

Vibration Thresholds Using Conventional Audiometry are Clinically Useful Indicators of Postural Instability in Older Adults.

Falls are a major health concern with potentially dramatic consequences for people over 65 years of age. One crucial determinant in the risk of falls in older adults is postural control, a complex process that requires the contribution of different sensory modalities, namely visual, vestibular, auditory, and somatosensory. While there are well-established methods to screen for age-related vision, hearing, tactile, and vestibular impairments, there are very few widely available methods to screen for somatosensory function, but studies indicate that ankle audiometry (vibration thresholds) using a common B-71 bone vibrator can serve that purpose. To date, unfortunately, this technique has received little attention as a tool to measure postural instability in older adults. The objective of the present study was to examine postural control in older adults with and without degradation of the somatosensory functions, as determined with ankle audiometry. This was standard group comparison. In total, 36 healthy elderly aged between 65 and 80 years old were divided into two groups (low vibration threshold [n = 18] and high vibration threshold [n = 18]). Standard audiometry, video head impulse test, vibration thresholds (big toe, ankle, and tibia), and static postural control task using a force platform were performed. Greater postural instability in participants with higher (worse) vibration thresholds as compared with participants with lower (better) vibration thresholds was observed even though both groups were comparable on hearing threshold and vestibular function. The results indicate that performing a simple vibration threshold evaluation, using a clinically available B-71 with a cut-off value of 42 dB hearing loss, could be an effective, fast, and easy-to-use procedure for detecting people at risk of falls.

Otolith assessment in elderly using combined vestibular-evoked myogenic potentials and subjective visual vertical test

BackgroundDizziness in elderly patients is classified as a multifactorial geriatric syndrome leading to pathological conditions or changes endemic to the aging process, it is characterized by increased susceptibility to accidents and instability. This is considered a major public health problem. In our study, we assessed age related changes in vestibular function via measurement of combined Vestibular-Evoked Myogenic potentials (VEMPs) as well as Static Subjective Visual Vertical Test (SVVT) for otolith function.MethodsSeventy-five subjects (150 ears) were enrolled in this research. They were categorized into a control group composed of twenty-five adults from 18–40 years and a study group which divided into symptomatic and asymptomatic groups, each group consisted of twenty-five subjects, fifteen subjects aged 55- < 65 years & ten subjects aged 65 to 85 years. All subjects were submitted to combined VEMPs and static SVVT.ResultsDetectability of combined VEMPs decreased with age with significant difference among the older age group (> 65- < 85 years) and the subjects aged (55- < 65 years). Percentage of abnormal cVEMPs & oVEMPs latencies and amplitudes was more detected in the older age group than subjects aged (55- < 65 years). The symptomatic group aged > 65 years showed higher percentage of affection of both cVEMPs & oVEMPs, while the younger group aged 55- < 65 showed higher absence of bilateral oVEMPs. There were no statistically significant differences in the asymmetrical ratio of cVEMPs & oVEMPs between elderly and adults. Static SVV perception does not change with age.ConclusionsThe elderly showed variable degrees of otolith dysfunction with a high percentage of affection in cVEMPs and oVEMPs. Also, they showed symptoms of imbalance and light-headedness. Static SVVT perception doesn’t change with age.

Specific features of bilateral otolith manifestations in patients with vestibular balance disorder

Bilateral asymmetry in the function of the semicircular canals underlies dizziness and vestibular balance disorders. According to the traditional view, otolith dysfunction does not have a significant effect on the clinical picture in individuals with peripheral vestibular disorders. In recent years, interest in studying the contribution of vestibular function to the control of posture and movements has increased. However, we have not identified any studies addressing the reactivity of otolith organs in vestibular balance disorders in the available literature.Aim: To study bilateral otolith reactions in patients with vestibular balance disorders using the method of cervical vestibular evoked myogenic potentials (cVEMP) in patients with episodic and chronic vestibular disorders.Material and Methods. A clinical examination was carried out in 63 patients complaining of dizziness and balance problems. They were hospitalized on an emergency and planned basis in the neurological departments of the clinics of the Siberian State Medical University and the Medical and Sanitary Unit No 2 in Tomsk. From the total group, 28 patients (8 men and 20 women aged from 22 to 84 years) were selected for assessment of vestibular function; the average age was 63.87 ± 11.52 years and 57.2 ± 18.5 years for men and women respectively. They had chronic and episodic vestibular dysfunction unrelated to acute or progressive neurological disease and inflammatory pathology of the inner ear.Results. 27 patients (96.4%) complained of dizziness. Systemic dizziness, characterized by a feeling of objects rotating around the subject, was detected in 29.63% of patients; non-systemic dizziness, including a feeling of “failing” – in 81.48%. Both types of complaints appeared in 10.71% of those examined, which made it possible to identify 2 groups of patients: Group A – with chronic vestibular disorders (7 patients) and Group B – with episodic vestibular disorders (21 patients). During the study of the groups of patients, differences were found in the amplitudes of cVEMP latency P13 and the coefficient of vestibular asymmetry between Groups A and B, as well as the absence of a difference in amplitudes in Group A and the presence of a difference in Group B on the right.Conclusion. Despite the fact that patients presented with predominantly one complaint of dizziness, clinical and instrumental tests of vestibular dysfunction showed the presence of damage to both the semicircular canals and otolithic organs; asymmetry of vestibular reflexes and/or bilateral damage to the vestibular organs. The results of the study allow us to consider the cVEMP method as one of the methods for objectively assessing the condition of the otolithic apparatus in patients with impaired vestibular function. In this regard, it is recommended to use this method in routine neurological practice.

Sensorineural Hearing Loss Negatively Impacts Cognition in Older Subjects with Normal Lateral Semi-Circular Canal Function

Plain Language SummaryWithin the current study, the authors aimed to explore the effect of hearing loss on cognitive functioning in older adults, considering the effects of vestibular function, anxiety and depression on cognitive performance. There is increasing evidence that hearing loss is a modifiable risk factor for cognitive decline but also vestibular dysfunction, depression and anxiety symptoms may play a role in this association. Cognitive functioning was evaluated in a group with moderate-to-severe hearing loss and a matched control group based on sex, age, education level, vestibular function, anxiety and depression rates. The patients with a hearing impairment performed significantly worse on cognitive testing and the differences were most pronounced for the cognitive subdomains of Attention and Visuospatial/Constructional memory. Results from this study confirm that hearing loss negatively impacts cognitive functioning, even in older adults with normal vestibular function.

The Impact of Sleep Deprivation on Video Head Impulse Test Results.

To investigate the association between sleep deprivation and vestibular dysfunction by Video Head Impulse Test (vHIT). This prospective clinical trial explores the impact of acute sleep deprivation on the vestibular-ocular reflex (VOR) in medical residents. The study involved healthy physicians from diverse medical disciplines. Participants underwent vHIT assessments before and after a 26-h shift. The examinations focused solely on the right lateral semicircular canal. Participants further completed a demographics and fatigue questionnaire, including the Fatigue Severity Scale (FSS) questionnaire and a Visual Analog Fatigue Score (VAFS). The study involved 30 medical residents. Participants experienced a statistically significant decrease in VOR gain in the right horizontal semicircular canal during a 26-h shift (p < 0.01). While the FSS and VAFS questionnaires showed no significant difference before and after the shift, the analysis of ∆VOR gain indicated a statistically significant increase associated with decreased sleep time during the shift (p = 0.018, 95% Confidence Interval [0.08, 0.68]). The most substantial increase in ∆VOR occurred between 22-26 h of sleep deprivation. No significant differences were observed in ∆VOR between genders, ages, disciplines, department shifts versus emergency room shifts, or years of residency. vHIT can be used as an objective, reliable screening tool for severe sleep deprivation among physicians. The decrease in the VOR gain may indicate that vestibular function is influenced by sleep deprivation. The clinical significance of these findings is still questioned, more studies may help to assess this effect. 3 Laryngoscope, 2024.

Association of Vitamin-D Deficiency with Vestibular Function in Patients with Idiopathic Benign Paroxysmal Positional Vertigo.

Association of Vitamin-D Deficiency with Vestibular Function in Patients with Idiopathic Benign Paroxysmal Positional Vertigo.

Hearing and balance functions in patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a chronic, inflammatory, autoimmune disease, characterized by multiple organ involvement, which is seen more often in young females. To evaluate the hearing and balance functions in SLE patients. 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). 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. 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.

"Pathological Insights into Lassa Virus-Induced Vestibular Dysfunction in Mice: Histopathological Analysis of the Inner Ear Vestibular Apparatus".

Lassa fever (LF), caused by Lassa virus (LASV) infection, typically leads to mild symptoms in humans, yet some survivors experience audiovestibular problems. Here we present vestibular histopathological insights in our LF model mice. We observed: 1) hemorrhage within the vestibular ganglion and stroma beneath the sensory epithelium, 2) preserved hair cells and supporting cells, 3) LASV antigen presence in the vestibular ganglion cells and the stroma beneath the sensory epithelium, and 4) CD3-positive T lymphocyte infiltration in the vestibular ganglion and the stroma underlying the sensory epithelium. LASV and/or its immune response likely contributes to the pathogenesis of vestibular dysfunction.

Spike-based rotation detection using a self-powered triboelectric sensor with mimicry of a vestibular system

The biological vestibular system in semicircular canals detects head rotation with high energy efficiency through its unique spike-based processing. We propose a self-powered vestibular sensory neuron inspired by the biological vestibular system and utilizing a triboelectric nanogenerator (TENG) as a rotation sensor and a neuron transistor (neuristor) as a spiking neuron. This artificial vestibular neuron simultaneously detects the angular velocity and encodes it into spikes. When the angular velocity that is applied to the TENG increases, the spiking frequency increases, and this is a desired property of the vestibular neuron. Therefore, the vestibular neuron can serve as an input neuron in a spiking neural network (SNN). We also demonstrate a fully hardware-based neuromorphic system that is attractive for its improved energy efficiency to recognize rotation axes. Compared to a vestibular system based on conventional von-Neumann computing, that based on the proposed neuromorphic computing can effectively reduce power consumption by adopting spike transmission and employing the self-powered sensor. The proposed system is promising for applications related to rotation that demands high energy-efficiency.

Correlation Between Functional Ability and Great Toe Flexor Strength in Young Adults

Background: Functional ability refers to the capacity to perform daily tasks efficiently, which relies on maintaining balance and stability. Balance is essential for keeping the body’s center of gravity aligned over a stable base and is supported by the coordination of the vestibular, visual, proprioceptive, and musculoskeletal systems. Factors such as proprioception, muscle strength, and lower extremity range of motion significantly impact functional ability. Toe flexor muscles play a vital role in providing the necessary force for anterior-posterior stability, especially when leaning forward, and contribute to the proprioceptive feedback loop that is essential for maintaining balance. Objective: To find correlation between functional ability and great toe flexor strength in young adults. Methodology: 12 male and female young adults with normal BMI were selected for the study. functional ability was measured using Functional Reach Test, great toe flexor strength was assessed using Pinch Guage Dynamometer. Karl Pearson’s Correlation Coefficient was used for statistical analysis, with a p value &lt; 0.05 considered as significant. Result: Statistically significant strong correlation was found between Functional Reach Test score and great toe flexor strength ( r = 0.887, p=0.035) suggesting that higher the great toe flexion strength higher the functional ability score. Conclusion: This study conluded that an increase in great toe flexor strength is associated With Improved Functional Ability In Young Adults.

Humoral serotonin and neuropsychological status of patients with dizziness

Dizziness is often accompanied by affective disorders such as anxiety and depression, in the occurrence of which the role of the serotonergic system is discussed.Objective: to investigate the serotonin content in blood serum and neuropsychological status in patients with vestibular and non-vestibular dizziness.Material and methods. The study included 97 patients. Two observation groups were formed according to the type of dizziness complaints. The first group (n=47) comprised patients with vestibular (systemic) dizziness against a background of peripheral vestibulopathy, the second group (n=35) comprised patients with non-vestibular (non-systemic) dizziness with a diagnosis of probable persistent postural-perceptual dizziness (PPPD). The control group (n=15) consisted of patients without complaints of dizziness. Neurological and otoneurological status, psychoemotional parameters (level of anxiety and depression) and cognitive functions were analyzed, and the quantitative level of serotonin in blood serum was determined by enzyme immunoassay.Results. The study revealed a significant decrease in the serum serotonin levels in vestibular and non-vestibular dizziness; a lower serotonin level was found in non-vestibular dizziness (p&lt;0.05). The presence of affective disorders did not correlate with a decrease in serotonin levels in vestibular dizziness against a background of peripheral vestibulopathy. It is assumed that a decrease in serotonin content plays a role in pathogenesis of vestibular dizziness on the background of peripheral part of vestibular system involvement.Conclusion. We demonstrated possibility of using the level of serotonin in peripheral blood as an objective laboratory marker of vestibular and non-vestibular dizziness in general clinical medical practice.

Toward Intelligent Head Impulse Test: A Goggle-Free Approach Using a Monocular Infrared Camera.

To assess vestibular function, video head impulse test (vHIT) is taken as the gold standard by evaluating the vestibulo-ocular reflex (VOR). However, vHIT requires the patient to wear a specialized head-mounted goggle equipment that needs to be calibrated before each use. For this, we proposed an intelligent head impulse test (iHIT) setting with a monocular infrared camera instead of the head-mounted goggle and contributed correspondingly a video classification approach with deep learning to vestibular function determination. Within the iHIT framework, a monocular infrared camera was set in front of the patient to capture test videos, based on which a dataset DiHIT of HIT video clips was set up. We then proposed a two-stage multi-modal video classification network, trained on the dataset DiHIT, that took as input the eye motion and head motion data extracted from the facial keypoints via HIT clips and outputted the identification of the semicircular canal (SCC) being tested (SCC identification) and determination of VOR abnormality (SCC qualitation). Experiments on this dataset DiHIT showed that it achieved the accuracy of 100% in prediction of SCC identification. Furthermore, it attained predictive accuracies of 84.1% in horizontal and 79.0% in vertical SCC qualitation. Compared with existing video-based HIT, iHIT eliminates goggles, does not require equipment calibration, and achieves complete automation. Furthermore, iHIT will bring more benefits to users due to its low cost and ease of operation. Codes and use case pipeline are available at: https://github.com/dec1st2023/iHIT. 3 Laryngoscope, 2024.

Determination of stability indicators as the main criteria for assessing the development of special endurance of cadets

The paper investigates the main biomechanical indicators of the statokinesiogram to assess the coordination criteria of resistance before and after load in physical training classes of cadets of Military Higher Education Institutions (VHE), as well as the registration of posture indicators that characterize the development of the main muscles of the trunk, i.e.: amplitude- frequency, vector and integral indicators of oscillations of the general center of mass. Back in the 20th century, the Hungarian physician Romberg introduced into clinical practice the observation of the upright position of the body and developed a method for assessing the degree of body oscillation and tremor of the limbs. He found that the assessment of the vertical position of the body due to quantitative biomechanical stability criteria is an important indicator of the functional state of the cadets' body and their health [3; 4; 5;7;10]. In the practice of physical training, various static positions and postures are often encountered. Such static positions include various racks, hangs, stops in gymnastic exercises, starting positions in athletics, swimming and other sports, postures of weightlifters, shooters, etc. The role of these positions and postures as elements of sports technique can be completely different if we consider their main three phases - initial, intermediate and final. Depending on which of these phases the studied static posture belongs to, it is possible to specifically assess its role in the effective solution of the motor task. The significant role of static positions and postures in sports is also evidenced by the fact that in competitions for the court, the girls' rules regulate the fixation of static postures [ 1, 2, 8, 9, 11]. Object of research. Cadets of the main group of 1-4 courses with an average level of development of physical condition (Fig. 1). Subject of research. Oscillations of the CMR of the body during stabilometry, where the leading human sensory systems: vestibular, proprioceptive and visual systems unequally integrate their contribution. As a result of the research, the leading role of proprioceptive, amplitude-frequency characteristics of CMR oscillations in the control of equilibrium has been proved, which is confirmed by the studies of M.O. Bernstein (1947), V.S. Gurfinkel (1965-1980), Bretz (1993) and other specialists [3; 4; 6; 7; 9]. Thus, the stabilographic method can be useful in assessing the body's response to stress, as well as in assessing and predicting the effectiveness of the development of special endurance of cadets in various conditions of professional activity.

Molecular specializations underlying phenotypic differences in inner ear hair cells of zebrafish and mice

IntroductionHair cells (HCs) are the sensory receptors of the auditory and vestibular systems in the inner ears of vertebrates that selectively transduce mechanical stimuli into electrical activity. Although all HCs have the hallmark stereocilia bundle for mechanotransduction, HCs in non-mammals and mammals differ in their molecular specialization in the apical, basolateral, and synaptic membranes. HCs of non-mammals, such as zebrafish (zHCs), are electrically tuned to specific frequencies and possess an active process in the stereocilia bundle to amplify sound signals. Mammalian HCs, in contrast, are not electrically tuned and achieve amplification by somatic motility of outer HCs (OHCs).MethodsTo understand the genetic mechanisms underlying differences between adult zebrafish and mammalian HCs, we compared their RNA-seq-characterized transcriptomes, focusing on protein-coding orthologous genes related to HC specialization.ResultsThere was considerable shared expression of gene orthologs among the HCs, including those genes associated with mechanotransduction, ion transport/channels, and synaptic signaling. However, there were some notable differences in expression among zHCs, OHCs, and inner HCs (IHCs), which likely underlie the distinctive physiological properties of each cell type. For example, OHCs highly express Slc26a5 which encodes the motor protein prestin that contributes to OHC electromotility. However, zHCs have only weak expression of slc26a5, and subsequently showed no voltage-dependent electromotility when measured. Notably, the zHCs expressed more paralogous genes including those associated with HC-specific functions and transcriptional activity, though it is unknown whether they have functions similar to their mammalian counterparts. There was overlap in the expressed genes associated with a known hearing phenotype.DiscussionOur analyses unveil substantial differences in gene expression patterns that may explain phenotypic specialization of zebrafish and mouse HCs. This dataset also includes several protein-coding genes to further the functional characterization of HCs and study of HC evolution from non-mammals to mammals.

Current perspectives on vestibular insights into spatial cognition: A narrative review

Abstract: Conventionally, the focus on vestibular information has centered on basic functions such as adjusting eye movements, controlling posture, and gaze stabilization. However, there has been a noteworthy transformation in recent years as researchers seek to unravel the mysterious relationship between the vestibular system and spatial cognition. This narrative review endeavors, to provide a thorough analysis of current perspectives by delving into a vast body of research in this domain. The principal aim is to critically assess existing studies, offering nuanced insights into the complex interplay between the vestibular system and spatial abilities. For this the electronic database such as PubMed, EMBASE, CINAHL, and Google Scholar was searched for available literature from 2014 onward based on inclusion and exclusion criteria. After reviewing the literature by different authors, a brief review was conceptualized from the same. This article thoroughly explores brain regions related to vestibular function and their connections to spatial orientation and clinical implications. It identifies research gaps and proposes future avenues to deepen our understanding of the vestibular system’s role in spatial cognition, aiming for a holistic perspective. The intricate link between the vestibular system and spatial memory processing is a significant area in neuroscience, with vestibular exercises holding potential for personalized interventions, emphasizing the need to address research gaps for optimal cognitive well-being.

POLD3 haploinsufficiency is linked to non-syndromic sensorineural adult-onset progressive hearing and balance impairments.

Hearing impairment (HI) is a significant health concern globally, influenced by genetic and environmental factors. We had identified a homozygous pathogenic variant in POLD3 in a Lebanese patient with an autosomal congenital recessive syndromic hearing loss (MIM#620869). This variant was found at heterozygous state in the parents, who developed progressive hearing impairment around age 40. We conducted a thorough clinical and genetic assessment of sixteen family members, including physical exams, audiometry and vestibular function evaluations. Additionally, gene expression analysis of the Pold3 gene was performed in mice using RNAscope. Twelve individuals were heterozygous for the variant in POLD3, of whom eight showed bilateral adult-onset HI, typically starting around ages 40-50, and two older patients displaying unilateral vestibular weakness. Additionally, two carriers of the variant developed cancer at an early age. RNAscope confirmed Pold3 expression in auditory and vestibular neurons. Exome sequencing analysis excluded the presence of pathogenic variants in any known hearing impairment or cancer predisposition genes. We present herein, for the first time, evidence of a heterozygous pathogenic POLD3 variant associated with a novel form of autosomal dominant progressive adult-onset hearing and vestibular impairments. We also highlight the necessity for further exploration of the role of POLD3 in cancer predisposition.

Constant Dizziness Versus Episodic Vertigo in Ménière's Disease: Health-Related Quality of Life, Cognitive Dissonance, and Postural Problems.

The aim was to explore and characterize dizziness and vertigo (constant vs episodic) and associated problems in patients with Ménière's disease (MD) to allow characterization of the impact of the disease. The study used a retrospective survey design. A total of 539 people with MD participated in this study. The online questionnaire included 36 items which had mixture of structured and open-ended questions that were focusing on MD symptoms, impact of their symptoms, vestibular rehabilitation, as well as health-related quality of life (HRQoL). Forty-six percent of the patients had episodic vertigo, 6% had constant dizziness, 15% had both episodic vertigo and constant dizziness, and 31% did not have vertigo or dizziness within the last 2 years. Patients with MD without any vertigo rated their HRQoL as 73.9%, those with episodic vertigo as 71.1%, those with constant dizziness as 56.9%, and those with constant dizziness and episodic vertigo as 57.9% indicating significant reduction in HRQoL in constant dizziness patients. Constant dizziness was associated with cognitive visual problems, fatigue, balance problems, vestibular drop attacks and syncope. The impact of balance problem was more severe among those with constant dizziness. The most common balance problem was tripping-off (34%), followed by swaying (25%) or rocking (8%) sensations. In the self-administered rehabilitative training, there were no differences between any of the vertigo or dizziness groups although disease profile of MD differed significantly. We emphasize that constant dizziness in MD constitutes a long-term maladaptation to a vestibular and visual cognitive function causing cognitive dissonance. Different types of vertigo and their associated complaints require different treatment strategies to the manage balance problems and to cope with the disease, but best practices is still under research.

Investigating the Subacute Effects of Two Vestibular Stimulation Methods and Their Combination on Spatial Memory in a Rat Model of Alzheimer’s Disease

Background and Aim: Alzheimer’s Disease (AD) is a neurodegenerative disorder characterized by progressive cognitive decline and spatial memory deficits. Recent studies have suggested a potential link between the vestibular system and cognitive function.‏ ‏Despite advancements in understanding the role of vestibular stimulation in neurological disorders, there is a paucity of research on this subject. In this regard, this study aims to assess the subacute effects two vestibular stimulation methods and their combination on spatial memory in a rat model of AD. Methods: Thirty Wistar rats were divided into five groups of AD (without intervention), Rotational Vestibular Stimulation (RVS), noisy Galvanic Vestibular Stimulation (nGVS), nGVS+RVS, and healthy control. The intervention groups received stimulation for 14 days. After AD induction and its confirmation, to examine the sub-acute effects of the stimulation, their performance was assessed using the Morris Water Maze (MVM) test one month later. Results: Statistically significant improvements were observed in the MVM test parameters in the RVS and nGVS+RVS groups compared to the AD group, in the training days and in the probe day, especially in the time to reach the platform and the time spent in the target quarter. Time spent in goal quarter improved in the RVS group compared to the nGVS+RVS group, but the difference was not statistically significant. Conclusion: The RVS alone or in combination with nGVS can improve spatial memory of rats with AD. Keywords: Alzheimer’s disease; vestibular stimualtion; spatial memory; rat; rotational vestibular stimulation; noisy galvanic vestibular stimulation