Asymmetry of the Subjective Visual Vertical in Patients With Unilateral Peripheral Vestibular Deficit.

BACKGROUND AND OBJECTIVES: Perception of verticality is clinically assessed using the subjective visual vertical (SVV), a test of the otolith system that consists of aligning a bar on the gravitational vertical in darkness. Patients with acute unilateral vestibulopathy (AUVP) show a systematic SVV bias toward the affected side, whichever the side of line orientation. Whether SVV estimates are symmetrical has not been investigated. SUBJECTS AND METHODS: This study included 10 patients with AUVP (vestibular neuritis) and 10 with BPPV (posterior semicircular canal). SVV measurements were made at two preset angles of line orientation (15° and 30°) toward the ipsilateral and contralateral sides, relative to the affected side. RESULTS: The results showed asymmetrical SVV estimates in the AUVP group, with significantly greater SVV errors for ipsilateral than contralateral line orientation, as well as for the preset angle of 30° compared to 15°. SVV estimates were significantly lower in patients with BPPV who also exhibited SVV asymmetry. SVV estimates remained unchanged just after the maneuver and were normalized some days later or after supplementary maneuvers. CONCLUSIONS: SVV asymmetry should be routinely considered in the clinic. We recommend individually assessing ipsilateral and contralateral SVV and using at least two preset angles. This allows for a better assessment and diagnosis of otolith organ imbalance that can trigger chronic instability and dizziness. The contribution of neck afferents related to head position in space seems to be the main source of SVV asymmetry.

Navigating the vestibular maze: text-mining analysis of publication trends over five decades.

Introduction: The field of vestibular science, encompassing the study of the vestibular system and associated disorders, has experienced notable growth and evolving trends over the past five decades. Here, we explore the changing landscape in vestibular science, focusing on epidemiology, peripheral pathologies, diagnosis methods, treatment, and technological advancements. Methods: Publication data was obtained from the US National Center for Biotechnology Information (NCBI) PubMed database. The analysis included epidemiological, etiological, diagnostic, and treatment-focused studies on peripheral vestibular disorders, with a particular emphasis on changes in topics and trends of publications over time. Results: Our dataset of 39,238 publications revealed a rising trend in research across all age groups. Etiologically, benign paroxysmal positional vertigo (BPPV) and Meniere's disease were the most researched conditions, but the prevalence of studies on vestibular migraine showed a marked increase in recent years. Electronystagmography (ENG)/ Videonystagmography (VNG) and Vestibular Evoked Myogenic Potential (VEMP) were the most commonly discussed diagnostic tools, while physiotherapy stood out as the primary treatment modality. Conclusion: Our study presents a unique opportunity and point of view, exploring the evolving landscape of vestibular science publications over the past five decades. The analysis underscored the dynamic nature of the field, highlighting shifts in focus and emerging publication trends in diagnosis and treatment over time.

Refining the Video Head Impulse Test Diagnostic Accuracy: A Case-Control Study.

INTRODUCTION: Current clinical practice considers the vestibulo-ocular reflex (VOR) gain as registered by the video head impulse test (vHIT) as the primary measure for semicircular canal function, while the role of the re-fixation saccades (RSs) is still under evaluation. The goal of the study was to appraise the added benefit of RS towards the improvement of vHIT diagnostic accuracy in cases of suspected left horizontal semicircular canal dysfunction. METHODS: The vHIT recordings of 40 patients with left-sided horizontal VOR gains <0.8 were retrospectively evaluated for the presence of RS. The study groups included 20 patients with a final diagnosis of left horizontal semicircular canal dysfunction and 20 patients for whom vestibular dysfunction was ruled out. RESULTS: Gain values >0.72 were found in all patients with no vestibular disease and in 4 (20%) patients having vestibulopathy. Significantly higher average left-sided RS velocity and frequency were found among the vestibular patients. VOR gain <0.72 was found to be highly specific for the diagnosis of vestibular dysfunction. However, for gain values in the range of 0.72-0.79, the presence of RS with frequency >80% largely improved vHIT diagnostic accuracy. CONCLUSIONS: Although VOR gain <0.8 is considered to reflect dysfunction, a significant false-positive rate for left-sided horizontal vHIT was found for gains in the range of 0.72-0.79. The presence of RS with frequency >80% could improve vHIT diagnostic ability in these patients.

Direction-fixed positional nystagmus following head-roll testing: how is it related with a vestibular pathology?

OBJECTIVE: The goal of this study is to analyze the clinical view of patients with direction-fixed positional nystagmus (DFPN) following head-roll maneuver. METHODS: Sixty patients with DFPN were reviewed retrospectively. Patients were categorized into 3 groups according to the direction of nystagmus based on rotation side. Associated problems were documented, and cumulative data were compared between groups. One-way analysis of variance (ANOVA test) was used for statistical analysis (P < 0.05). RESULTS: Thirty-three patients (55%) had stronger nystagmus beating towards the direction of head-roll (Group-A). Three patients developed geotropic LC-BPPV. Fourteen patients had inner ear disease. Sixteen patients (27%) had stronger nystagmus beating against the direction of head roll (Group-B). Nine patients had inner ear disease. None of the patients tested with head-shaking had change of direction of nystagmus. Eleven patients (18%) had DFPN with equal velocity during right or left head-roll maneuver (Group-C). Of those, nine patients had inner ear disease. None of the patients had change of direction of nystagmus. Comparison of the incidence of associated problems (migraine, vestibular neuronitis, Meniere's disease etc.) in each group was not statistically significant (P˃0.05). CONCLUSION: Patients with DFPN should be followed for a possibility of vestibular pathology since vestibular problem was documented for more than half of the patients in the follow-up. On the other hand, DFPN could be related with a temporary reason (thermal, physical or drug effect etc.) in some patients who do not exhibit any associated disease. Head-shaking testing is recommended to expose the lateral canal BPPV. But the incidence is low.

Effects of Craniosacral Osteopathy in Patients with Peripheral Vestibular Pathology.

INTRODUCTION: Vertigo appears as a result of a sudden neural activity imbalance of the vestibular system. The vertigo prevalence is higher in patients over 60 years of age compared to patients under 40 years of age. OBJECTIVES: The purpose of this study was to analyze the effect of craniosacral osteopathy on dizziness and balance in individuals who have peripheral vestibular pathology. METHODS: A total of 30 individuals, aged 24-50 years, participated in this study. Twenty-four of the participants were female (80%) and 6 were male (20%). The participants were separated into 2 groups, with 15 patients included in the cranial osteopathy treatment group (study group) and 15 patients included in the group that used dimenhydrinate (control group). The individuals were evaluated in terms of dizziness and balance. A visual analog scale was used to evaluate dizziness. Balance was evaluated using the Berg balance scale and the Activities-Specific Balance Confidence scale. The craniosacral treatment program was applied once per week for 6 sessions. All of the individuals included in this study were evaluated 3 times, i.e., prior to treatment, on the third week of treatment, and on the sixth week of treatment. RESULTS: Significant improvement was noted within each group in terms of dizziness and balance (p < 0.05). When the groups were compared with each other, it was observed that craniosacral osteopathy was more effective than dimenhydrinate treatment for dizziness and balance (p < 0.05). CONCLUSION: Craniosacral osteopathy is an effective treatment choice in individuals who have chronic peripheral vestibular pathology. In individuals who have resistant and chronic vestibular pathology, craniosacral osteopathy should be evaluated among the treatment choices.

Identification of New Biomarkers of Posturo-Locomotor Instability in a Rodent Model of Vestibular Pathology.

The vestibular system plays a crucial role in maintaining postural balance. Unilateral vestibular lesions result in a typical syndrome characterized by postural imbalance, altered locomotor patterns and gaze stabilization, as well as cognitive and neurovegetative disorders. One of the main difficulties encountered in the development of new anti-vertigo drugs is the lack of sensitivity in the evaluation of this syndrome. Qualitative assessments of the vestibular syndrome have been developed, but methods of conducting quantitative evaluations are critically lacking. Recently, assessments with a dynamic weight-bearing device (DWB®, Bioseb) revealed postural alterations in rats subjected to unilateral vestibular neurectomy (UVN). Our team is evaluating a new version of this device capable of quantifying additional parameters of postural and locomotor equilibrium. The objective of this study was to use this device to assess these new posturo-locomotor parameters in a rat model of a vestibular pathology. The biomarkers measured by this device are as follows: the barycenter, the support surface and the weight distribution of the rats when they were moving or stationary. Before UVN, the rats showed a symmetric distribution of their weight along the lateral axis. In the acute phase after UVN on the left side, the rats distributed more weight on the right side than on the left side and then distributed more weight on the left side. These results corroborate those presented in our previous study. The support surface of the rats increased between 1 day and 30 days after UVN, and the barycenter distribution reflected the weight distribution. In addition, our results show smaller changes in the weight distributions when the animals are moving compared with when they are stationary in the acute phase after UVN. This study provides new information on the static and dynamic postural balance patterns observed after unilateral vestibular loss in rats. These data are relevant because they objectively quantify the posturo-locomotor component of vestibular syndrome as well as the compensatory strategies used after vestibular loss. These results may guide the development of rehabilitation protocols for vestibular patients and the validation of pharmacological compounds favoring the restoration of equilibrium.

Progression of changes in the sensorial elements of the cochlear and peripheral vestibular systems: The otitis media continuum.

Our study aimed to evaluate pathologic changes in the cochlear (inner and outer hair cells and stria vascularis) and vestibular (vestibular hair cells, dark, and transitional cells) sensorial elements in temporal bones from donors who had otitis media. We studied 40 temporal bones from such donors, which were categorized in serous otitis media (SOM), serous-purulent otitis media (SPOM), mucoid/mucoid-purulent otitis media (MOM/MPOM), and chronic otitis media (COM); control group comprised 10 nondiseased temporal bones. We found significant loss of inner and outer cochlear hair cells in the basal turn of the SPOM, MOM/MPOM and COM groups; significant loss of vestibular hair cells was observed in the MOM/MPOM and COM groups. All otitis media groups had smaller mean area of the stria vascularis in the basal turn of the cochlea when compared to controls. In conclusion, our study demonstrated more severe pathologic changes in the later stages of the continuum of otitis media (MOM/MPOM and COM). Those changes seem to progress from the basal turn of the cochlea (stria vascularis, then inner and outer hair cells) to the middle turn of the cochlea and to the saccule and utricle in the MOM/MPOM and COM stages.

Dynamical analysis of balance in vestibular schwannoma patients.

The analysis of the complexity of postural fluctuations is a recent method for assessing postural control. Complexity relates to the irregularity of the center of pressure time series and characterizes the ability of postural control to meet a changing environment. In our study, we used the sample entropy (SampEn) parameter to evaluate the complexity of postural sway velocity time series in patients with vestibular schwannoma (n=19) compared to healthy controls (n=20), using the sensory organization test. Patients performed postural assessments three days before surgical ablation of the tumor, then three times after surgery, at eight, thirty, and ninety days. The control group underwent posturographic tests only once. Our results demonstrated that SampEn values distinguished both groups before surgery only in postural tasks where vestibular afferences significantly contribute to maintaining balance. We also found an immediate decrease of complexity after the surgical resection of the tumor. Our results are in line with the theory of complexity loss of physiological systems stating that reducing the number of their structural components or altering their coupling leads to a decrease in complexity. Finally, our findings showed that progressive restoration of complexity over time was such that no difference was found between the two groups ninety days after surgery, due to the implementation of central adaptive mechanisms and the substitution by other sensory afferences. Thus, the SampEn parameter can highlight the postural effects of vestibular pathology, and complexity analysis appears to be a valuable tool for investigating the temporal structure of CoP time series.

The efficacy of vestibular electrical stimulation on patients with unilateral vestibular pathologies.

OBJECTIVES: This study aims to investigate the efficacy of vestibular electrical stimulation (VES) in unilateral vestibular lesions including benign paroxysmal positional vertigo (BPPV). PATIENTS AND METHODS: Between June 2007 and August 2007, a total of 19 patients diagnosed with BPPV were included in this study and they were randomized into two groups using the 1:1 method. Ten patients were administered medical treatment plus VES (treatment group; 1 male, 9 females; mean age 55.8 years; range 27 to 74 years), whereas nine patients were only administered medicine (control group; 2 males, 6 females; mean age 54.9 years; range 34 to 73 years). Both groups received the same medical treatment throughout the study. Vestibular electrical stimulation was performed for 30 min long twice a day, three times a week; 12 sessions in total with 80 Hz high-frequency Transcutaneous Electrical Nerve Stimulation (TENS). Before and after the treatment, patients' severity of dizziness was assessed with Visual Analog Scale (VAS) and daily life activities with Dizziness Handicap Inventory (DHI), and their duration (sec) of single leg stance with eyes open and closed was recorded. RESULTS: Compared to prior to the treatment, VAS-dizziness and DHI scores, and the duration of single leg stance on one foot with eyes open and closed at the end of the treatment showed statistically significant improvement in both groups; however, although VES provided a positive contribution, we did not find a statistically significant difference between the two groups. CONCLUSION: It can be concluded that VES has positive contribution to medical treatment of patients with dizziness due to unilateral vestibular lesions; however the results of this study should be further investigated with larger groups of patients.

Prueba de impulso cefálico: bases fisiológicas y métodos de registro del reflejo vestíbulo oculomotor / Head impulse test: physiological basis and registration methods of the vestibulo-ocular reflex

En la historia de la evaluación clínica vestibular, siempre se ha buscado la manera de medir en forma individual los seis canales semicirculares y los cuatro órganos otolíticos. Basados en el conocimiento de la fisiología vestibular, en 1988 Halmagyi y Curthoys describieron la Prueba de Impulso Cefálico o Head Impulse Test (HIT) como un método diagnóstico para evaluar la efectividad del reflejo vestíbulo oculomotor en pacientes con sintomatología vestibular. Esta revisión pretende dar a conocer las bases fisiológicas del HIT y su evolución hasta el video HIT (vHIT) actual.

In the history of vestibular clinical evaluation, it has always been sought the way to measure individually each of the six semicircular canals and the four otolith organs. Based on vestibular physiology, in 1988 Halmagyi and Curthoys described the Head impulse test (HIT) as a diagnostic method to evaluate the effectiveness of the vestibulo-oculomotor reflex in patients with vestibular symptoms. This review shows the physiological basis for HIT and its evolution towards nowdays video HIT (vHIT).

Vestibular and stabilometric findings in whiplash injury and minor head trauma.

Vertigo and postural instability following whiplash and/or minor head injuries is very frequent. According to some authors, post-whiplash vertigo cannot be caused by real injury to vestibular structures; other authors maintain that vestibular damage is possible even in the case of isolated whiplash, with vascular or post-traumatic involvement. Furthermore, many of the balance disorders reported after trauma can be justified by post-traumatic modification to the cervical proprioceptive input, with consequent damage to the vestibular spinal reflex. The aim of this study was to evaluate the vestibular condition and postural status in a group of patients (Group A, n = 90) affected with balance disorders following whiplash, and in a second group (Group B, n = 20) with balance disorders after minor head injury associated with whiplash. Both groups were submitted to videonystagmography (VNG) and stabilometric investigation (open eyes - O E, closed eyes - CE, closed eyes with head retroflexed - CER) within 15 days of their injuries and repeated within 10 days after conclusion of cervical physiotherapy treatment. The VNG tests revealed vestibulopathy in 19% of cases in Group A (11% peripheral, 5% central, 3% in an undefined site) and in 60% of subjects in Group B (50% peripheral, 10% central). At the follow-up examination, all cases of non-compensated labyrinth deficit showed signs of compensation, while there were two cases (2%) in Group A and one case (5%) in Group B of PPV. As far as the altered posturographic recordings are concerned, while there was no specific pattern in the two groups, they were clearly pathologic, especially during CER. Both in OE and in CE there was an increase in the surface values and in those pertaining to shifting of the gravity centre on the sagittal plane, which was even more evident during CER. In Group A, the pre-post-physiotherapy comparison of CER results showed that there was a statistically significant improvement in the majority of the parameters after treatment. Moreover, in Group B there was frequent lateral shifting of the centre of gravity that was probably linked with the high percentage of labyrinth deficits. The comparison between the first and second stabilometric examinations was statistically significant only in those parameters referring to gravity centre shifting on the frontal plane, which was probably due to the progressive improvement in the associated vestibulopathy rather than to the physiotherapy treatment performed for the cervical damage. Hence, our study confirms that only in a minority of cases can whiplash cause central or peripheral vestibulopathy, and that this is more probable after minor head injury associated with whiplash. In addition, our data confirm that static stabilometry is fundamental for assessing postural deficits following a cervical proprioceptive disorder. In these cases, in fact, analysis of the different parameters and the indices referring to cervical interference not only permits evaluation of altered postural performance, but also detects and quantifies destabilisation activity within the cervical proprioceptive component.