Mechanism Underlying the Effects of Estrogen Deficiency on Otoconia

The effect of the menstrual cycle on the vestibular system in healthy adult women

AIM

The purpose of this study was to evaluate the effect of menstrual cycle phases on the vestibular system in healthy adult women.

MATERIALS AND METHODS

A total of 40 healthy adult women aged 18-40 years without hearing or balance complaints were included in the study. The participants were administered the Vestibular Evoked Myogenic Potentials (VEMP) test, the Video Head Impulse Test (vHIT), the Dizziness Handicap Inventory (DHI), and the Hospital Anxiety and Depression Scale (HADS). Participants' pre- and post-menstrual test results were compared.

RESULTS

Cervical VEMP (cVEMP) and ocular VEMP (cVEMP) N1, P1 latency measurements and vHIT results of the participants before and after menstruation were not statistically significantly different (p > 0.05). A statistically significant difference was found in the participants' DHI and HADS scores before and after menstruation (p < 0.05).

CONCLUSION

It was observed that symptoms such as dizziness and anxiety, which are more common in the premenstrual period, were reflected in our subjective tests but not in our objective tests and clinic. This study will provide a benchmark for comparison in future studies of hormonal changes in menstrual cycle phases.

The Impact of Serums Calcium 25-Hydroxy Vitamin D, Ferritin, Uric Acid, and Sleeping Disorders on Benign Paroxysmal Positional Vertigo Patients

OBJECTIVE

This study's objective was to identify the factors and impact of serums calcium 25-Hydroxy vitamin D, ferritin, uric acid, and sleeping disorders on benign paroxysmal positional vertigo (BPPV) patients.

METHODS

This is a case and control design study. The consecutive patients' visits (age, older than 25 years) with idiopathic BPPV were recruited in the present study. For each patient, 3:1 sex and age-matched healthy people were assigned as the control. The study comprised 177 patients with BPPV and 656 controls. The study included biochemical, clinical, physical examinations, PSQI sleep quality, supine roll test, and Dix-Hallpike test for the diagnosis of all patients, and pure-tone audiometry (PTA) was used to assess hearing. Univariate and multivariate stepwise regression analyses were used for statistical analysis.

RESULTS

The study comprised 833 patients with 295 males (35.4%) and 538 females (64.6%) who were between 25 and 70 years old. Of a total of 833 participants, 177 were BPPV patients, and 656 subject were normal. The results shown that there were significant differences between the BPPV and the normal group in terms of BMI (p = 0.039), physical activity (p = 0.003), cigarette smoking (p = 0.035), nargile-waterpipe use (p < 0.001), diabetes (p < 0.001), hypertension (p < 0.001), congestive heart failure (CHF) (p < 0.001), neurology (p < 0.001), tinnitus (p < 0.001), dizziness (p < 0.001), headache (p < 0.001), vitamin D (p = 0.004), calcium (p = 0.004), magnesium (p < 0.001), potassium (p = 0.019), phosphorus (p < 0.001), haemoglobin (p < 0.001), serum glucose (p < 0.001), HbA1c (p < 0.001), triglyceride (p < 0.001), systolic BP (p = 0.004), diastolic BP (p = 0.008), and microalbuminuria (p = 0.005); ATP III metabolic syndrome (p = 0.038), IDF metabolic syndrome (p = 0.034), and poor sleep (p = 0.033). In terms of the type of BPPV, the posterior canal was the most commonly affected (n = 126, 71.2%), followed by the horizontal (n = 43, 24.3%) and anterior canal (n = 8, 4.5%). The analysis indicated that serum ferritin (p < 0.001), uric acid (p < 0.001), blood pressure (p < 0.001), dizziness (p < 0.001), cigarette-water-pipe smokers (p = 0.004), headaches/migraines (p = 0.005), calcium (p = 0.007), vitamin D deficiency (p = 0.008), sleepiness (p = 0.016), physical activity (p = 0.022), CHF (p = 0.024), and tinnitus (p = 0.025) were considered as risk predictors for BPPV.

CONCLUSIONS

The results revealed that the serum levels of vitamin D, ferritin, uric acid, and calcium are low among the study population and supplementation could be considered as prevention in BPPV patients.

The Impact of Resistance Training on Equilibrium Abilities and Quality of Life in Older Adults after SARS-CoV-2 Survival

Background: The scientific literature on COVID-19 and its long-term impacts on all-body systems and their treatments is still limited. The aim of the study was to create a safe protocol-based intervention to improve functional and equilibrium abilities in older adults impacted by COVID-19. Methods: This study used a sample of 46 people (intervention group: n = 26; control group: n = 20). Resistance training (RT) was held twice a week, with 60 min per session for 8 weeks. The postural stability and quality of life questionnaire (WHQOOL) was completed during pre- and post-testing. Results: The results indicated significant differences in overall stability index (OSI) with eyes open (EO), anterior-posterior stability index (APSI) EO, fall-risk index 6-2 (FRI6-2) values in males (p < 0.05), and APSI EO (p < 0.05) values in females compared to control groups, respectively. In the training, a significant improvement was reported in OSI EO and APSI EO (p < 0.05) female groups compared to baseline results and in FRI6-2 values in both gender groups (p < 0.01-men, p < 0.05-women). The effect of the intervention was recorded in the intervention group in the OSI EO (Z = -3.12, p < 0.01, R = 0.533) and FRI6-2 (Z = -2.06, p < 0.05, R = 0.354). Additionally, significantly different reactions between the groups were observed in the psychological domain (DOM2) (Z = 2.194, p < 0.028, R = 0.389), social relationship domain (DOM3) (Z = 2.051, p < 0.0403, R = 0.361), and in question 2 concerning general health (Z = 3.309, p < 0.0009, R = 0.535). Conclusions: The findings indicate that RT had a positive effect on older adults affected by COVID-19, led to a significant improvement in their postural stability, and had a significant impact on elements of psychological well-being and quality of life.

Balance in Transition: Unraveling the Link Between Menopause and Vertigo

The onset of menopause, marked by hormonal fluctuations and a decline in estrogen levels, is suggested to be linked to increased susceptibility to vestibular disturbances. Estrogen, beyond its established association with reproductive physiology, plays modulatory roles in various physiological systems, including neurosensory function. The vestibular system, crucial for balance and spatial orientation, is influenced by hormonal changes during menopause, potentially contributing to the emergence of vertigo symptoms. This interplay between hormones and the vestibular system is a burgeoning area of research with clinical implications, offering insights into novel diagnostic and therapeutic approaches for managing postmenopausal women with vestibular disorders. The article reviews current scientific literature, delves into the hormonal intricacies of menopause, and investigates potential mechanisms underlying the connection between hormonal fluctuations and vertigo symptoms.

Pediatric Benign Paroxysmal Positional Vertigo: Degree of Nystagmus and Concurrent Dizziness Differs from Adult BPPV

Background: Benign paroxysmal positional vertigo (BPPV) is characterized by brief, intense episodes of vertigo triggered by abrupt changes in head position. It is generally accepted as being most common in adults, while it is regarded as rare in children. It is necessary to compare the disease between pediatric and adult patients for a better understanding of the disease's characteristics and its natural history. This study aimed to identify the clinical characteristics of BPPV in children and compare them with those of adult BPPV patients. Methods: All children ≤ 18 years old who were diagnosed with BPPV were selected by searching the electronic database of our hospital. Clinical features were identified by medical record review. For adult patients, we collected data from patients > 19 years of age. Results: A total of 30 pediatric (13.65 ± 4.15 years old) and 264 adult patients (60.86 ± 13.74 years old) were included in the study. Among pediatric patients, the lateral canals were involved in 80% and the posterior canals in 16.67%. In adult patients, the lateral and posterior canals were involved similarly (p = 0.007). The degree of nystagmus in pediatric patients was 6.82 ± 12.09, while in adults it was 15.58 ± 20.90 (p < 0.001). The concurrent dizziness disorder was higher in the pediatric group and recurrence was higher in the adult group. In the regression analysis, it was found that adult patients had a stronger nystagmus with a value of 6.206 deg/sec, and the risk of concurrent dizziness disorder was found to be 5.413 times higher in the pediatric group (p < 0.05). Conclusions: BPPV occurs in pediatric patients with lower prevalence, but it cannot be overlooked. In the pediatric group, a relatively high proportion of patients demonstrated lateral canal involvement, weaker nystagmus, and additional dizziness disorder.

Low vitamin D and uric acid status in patients with benign paroxysmal positional vertigo

PURPOSE

Growing evidence reported that vitamin D and uric acid metabolism played roles in the occurrence of benign paroxysmal positional vertigo, an otoconia-related vestibular disorder. We aimed to investigate the serum 25-hydroxy vitamin D (25(OH)D) and uric acid in patients with benign paroxysmal positional vertigo and to determine the risk factor for benign paroxysmal positional vertigo.

METHODS

This case-control study comprised 182 patients with benign paroxysmal positional vertigo and 182 age- and gender-matched controls. All subjects' age, body mass index, systolic blood pressure, diastolic blood pressure, 25-hydroxyvitamin D (25(OH)D), uric acid and serum calcium measurements were analyzed.

RESULTS

We found a female preponderance of benign paroxysmal positional vertigo patients, with a median of 60 (52-66) years old. The results showed low vitamin D status both in benign paroxysmal positional vertigo and controls, with no significant difference of 25(OH)D levels between benign paroxysmal positional vertigo patients and controls (P > 0.05). Compared with the control group, patients with benign paroxysmal positional vertigo had a higher prevalence of vitamin D deficiency and a lower prevalence of vitamin D sufficiency (P < 0.05). Uric acid was significantly lower in the benign paroxysmal positional vertigo groups (P < 0.05). Logistic regression analysis revealed that age and uric acid were considered higher risk predictors for benign paroxysmal positional vertigo.

CONCLUSION

Our study observed low vitamin D status in patients with benign paroxysmal positional vertigo, with no significant differences of the 25(OH)D level in patients with benign paroxysmal positional vertigo and controls. Elderly, vitamin D deficiency and low uric acid levels may be risk factors for benign paroxysmal positional vertigo occurrence.

Assessment of Osteoporosis and Vitamin D3 Deficiency in Patients with Idiopathic Benign Paroxysmal Positional Vertigo (BPPV)

Background and objectives: Osteoporosis and vitamin D3 deficiency may be risk factors of benign paroxysmal positional vertigo (BPPV). The aim of this study was to assess the prevalence of osteoporosis and 25(OH) vitamin D3 deficiency in a group of patients with idiopathic benign paroxysmal positional vertigo. Materials and Methods: Thirty-five patients (twenty-eight women and seven men) with posterior semicircular canal BPPV were enrolled in the study. The subjects underwent hearing assessment (tonal audiometry and impedance audiometry) and the Dix-Hallpike maneuver. Serum 25(OH) vitamin D3 levels were determined and lumbar spine bone densitometry was performed. The relationships between sex, age, height, Body Mass Index (BMI), vitamin D3 levels and bone densitometry results were assessed. Results: The diagnosis of osteoporosis was confirmed in 1 patient (3%), 3 subjects were osteopenic (8.6%), and normal bone densitometry was found in 31 (88.6%) patients. Conclusions: We found no statistically significant relationships between age, BMI or vitamin D3 levels and bone densitometry results in patients with idiopathic BPPV.

Vestibular Disorders and Hormonal Dysregulations: State of the Art and Clinical Perspectives

The interaction between endocrine and vestibular systems remains poorly documented so far, despite numerous observations in humans and animals revealing direct links between the two systems. For example, dizziness or vestibular instabilities often accompany the menstrual cycle and are highly associated with the pre-menopause period, while sex hormones, together with their specific receptors, are expressed at key places of the vestibular sensory network. Similarly, other hormones may be associated with vestibular disorders either as causal/inductive factors or as correlates of the pathology. This review was carried out according to the PRISMA method, covering the last two decades and using the MEDLINE and COCHRANE databases in order to identify studies associating the terms vestibular system and/or vestibular pathologies and hormones. Our literature search identified 646 articles, 67 of which referred directly to vestibular dysfunction associated with hormonal variations. While we noted specific hormonal profiles depending on the pathology considered, very few clinical studies attempted to establish a direct link between the expression of the vestibular syndrome and the level of circulating hormones. This review also proposes different approaches to shed new light on the link between hormones and vestibular disorders, and to improve both the diagnosis and the therapeutic management of dizzy patients.

Effect of hormonal therapy on the otoconial changes caused by estrogen deficiency

Benign paroxysmal positional vertigo (BPPV) is associated with menopause and/or osteopenia. Morphological changes in the otoconial layer have been reported after ovariectomy (OVX). Moreover, hormone replacement therapy decreases BPPV risk. However, knowledge concerning the effect of hormonal therapy on the otoconial changes caused by estrogen deficiency is limited. We aimed to examine the effect of hormonal therapy on otoconial changes caused by estrogen deficiency. We hypothesized that hormonal therapy could reduce otoconial changes caused by OVX. Eight-week-old C57BL/6 mice were divided into four groups: sham operation with implantation of vehicle (sham + v), OVX with implantation of vehicle (OVX + v), OVX with implantation of estradiol (E2) (OVX + E2), and OVX with implantation of raloxifene (RAL) (OVX + RAL) groups. Otoconial layer volume was measured by micro-CT at 4 weeks after OVX or the sham operation. The otic bullae were removed; immunohistochemistry was performed for estrogen receptor alpha and 4-hydroxynonenal. Otoconial layer volume was significantly higher in the OVX + v than in the sham + v group. E2 and RAL significantly reduced these changes in the endometrial layer. The staining of estrogen receptor alpha and 4-hydroxynonenal were stronger in the OVX + v than in the sham + v group but equal in the sham + v, OVX + E2, and OVX + RAL groups. These results indicate that E2 and RAL are effective against morphological changes of the otoconial layer caused by estrogen deficiency via oxidative stress reduction.

Advances in otolith-related protein research

Otoliths are biological crystals formed by a layer of calcium carbonate crystal that adhere to the ciliary surface of the utricular and saccular receptors in the vestibule of all vertebrates inner ear, enabling the utricle and saccule to better perceive the changes in linear and gravitational acceleration. However, the molecular etiology of otolith related diseases is still unclear. In this review, we have summarized the recent findings and provided an overview of the proteins that play important roles in otolith formation and maintenance (Otoconin-90, Otolin-1, Otolith Matrix Protein-1, Cochlin, Otogelin, α-Tectorin, β-Tectorin, Otopetrin-1, and Otopetrin-2, PMCA2, etc.), providing new insight for the prevention and management of benign paroxysmal positional vertigo (BPPV) with basis for otolith-related proteins as potential biomarkers of vestibular disease.

Hormones and Vestibular Disorders: The Quest for Biomarkers

The vestibular system exerts control over various functions through neural pathways that are not yet fully mapped. Functional dysregulations or tissue lesions at different levels of the peripheral and the central vestibular networks can alter these different functions, causing a wide variety of symptoms, ranging from posturo-locomotor alterations to psychiatric syndromes such as PPPD, including the deregulation of the main biological functions. These different symptoms differ by their expression kinetics (they each appear and regress with their own kinetics) by the targets affected (muscles, organs, and brain areas) and by the sensitivity specific to each individual. Vestibular pathologies thus cover a mosaic of distinct effects, and they involve various effectors—which constitute the many markers of their different types and stages. It is therefore crucial, to predict the onset of a vertigo syndrome, to follow its temporal course, or to monitor the impact of therapeutic approaches, and to have specific and reliable biomarkers. Hormonal variations are among the possible sources of biomarkers for neurotology. We know that specific hormonal profiles can promote the appearance of vestibular disorders. We also know that the expression of vertigo syndrome is accompanied by measurable hormonal variations. The link between endocrine deregulation and vestibular alterations therefore no longer needs to be proven. However, there are still few data on their precise correlations with the vertigo syndrome. This study was undertaken with the aim to deliver an extensive review of the hormonal alterations linked to vestibular disorders. A review of the literature covering the last two decades was carried out using the MEDLINE and COCHRANE databases in order to identify studies associating the terms vestibular system or vestibular pathologies and hormones. Bibliographic data provides several outcomes in terms of therapeutic innovation in the diagnosis and therapeutic follow-up of vestibular pathologies.

Influence of sex hormones on vestibular disorders

PURPOSE OF REVIEW

Vestibular disorders are gender distributed with a higher prevalence in women. Although research has increased in this field, the mechanisms underlying this unbalance is unclear. This review summarises recent advances in this research sphere, and briefly discusses sex hormone effects on various vestibular conditions and highlights some recent theories.

RECENT FINDINGS

Recent work has identified a direct link between aberrant gonadal hormone levels and vestibular dysfunction. Benign paroxysmal positional vertigo research suggests that the disorder may be linked to the rapid decrease in oestrogen, observed in menopausal women, which disrupts otoconial metabolism within the inner ear. A successful hormonal therapeutic intervention study has advanced our knowledge of hormonal influences in the inner ear in Ménière's disease. Also, several studies have focused on potential mechanisms involved in the interaction between Vestibular Migraine, Mal de Debarquement Syndrome, and gonadal hormones.

SUMMARY

In females, gonadal hormones and sex-specific synaptic plasticity may play a significant role in the underlying pathophysiology of peripheral and central vestibular disorders. Overall, this review concludes that clinical assessment of female vestibular patients requires a multifaceted approach which includes auditory and vestibular medicine physicians, gynaecologists and/or endocrinologists, in conjunction with hormonal profile evaluations.

Association of Serum Calcium and Vitamin D with Benign Paroxysmal Positional Vertigo

Introduction  Benign paroxysmal positional vertigo (BPPV) is one of the common disorders of the peripheral vestibular system. The prevalence of BPPV is found to be higher among middle-aged women.

Objectives  To estimate the serum levels of calcium and vitamin D in patients with BPPV, and to study their association.

Methods  The present is a hospital-based prospective case-control study. Venous blood samples of the 49 patients with BPPV and an equal number of age- and gender-matched individuals were recruited and submitted to an analysis of the serum levels of calcium and vitamin D.

Results  Among the cases, 67.3% were found to be females, and 32.7% were males. Most of the 30 cases (61.3%) were aged > 40 years. The mean age of the cases was 44.39 years. The mean serum level of vitamin D in the cases was of 21.26 ng/ml compared with 17.59 ng/ml in the controls. The mean serum level of calcium was of 9.33 mg/dl in the cases, compared with 8.95 mg/dl in the controls. There was no significant difference in the serum levels of vitamin D and calcium between cases and controls.

Conclusion  We could not establish any correlation between the serum levels of calcium and vitamin D with BPPV. However, a negative relationship was found between the serum levels of vitamin D and the number of episodes of BPPV ( p  = 0.012).

Assessment of the effects of menopause on semicircular canal using the video head impulse test

This cross-sectional study included early menopausal and late menopausal women aged between 40 and 60 years to evaluate the effects of menopause on semicircular canal function. A video head impulse test (vHIT) was performed for all subjects. Vestibulo-ocular reflex (VOR) mean gains of each semicircular canal and gain asymmetry were compared between groups. Of the 87 subjects, 37(42.5%) were reproductive age 28(32.5%) were early menopausal and 22(25.3%) were late menopausal patients. VOR gain of semicircular canals or gain asymmetry values did not differ between groups. In postmenopausal women, presence of vasomotor symptoms was associated with higher gain asymmetry of the left anterior-right posterior (LARP) plane (p = .01), and presence of balance problems was associated with lower right anterior (RA) VOR gain (p = .01). In conclusion semicircular canal function in postmenopausal women was similar to that in women of reproductive age.IMPACT STATEMENTWhat is already known on this subject? During menopause, women face potential risks such as dizziness, balance problems, falls and fractures. Postmenopausal patients were tested with dynamic posturography to measure balance before and after oestrogen treatment, and it was shown that balance problems significantly improved with oestrogen treatment. Healthy vestibular system is one of the components for sustaining normal balance.What do the results of this study add? In postmenopausal women the function of the semicircular canals is normal and the balance deficit in postmenopausal women may not be caused by the vestibular system. In this study changes within normal limits were observed in vestibular system of postmenopausal women.What are the implications of these findings for clinical practice and/or further research? Reported balance deficits might have been due to central origin. Further research to differentiate origin of balance deficits are needed. Specific research on symptomatic postmenopausal patients would reveal more information.

Association between benign paroxysmal positional vertigo and osteoporosis: two nested case-control studies

Benign paroxysmal positional vertigo (BPPV) was related to a 1.28 times higher risk of osteoporosis. In addition, osteoporosis was associated with a 1.34 times higher risk of BPPV. This bidirectional relation was maintained after adjusting past medical histories and lifestyle factors, including obesity, smoking, and alcohol consumption. To our knowledge, this is the first study to explore the reciprocal association between BPPV and osteoporosis. In subgroup analyses, only women showed a reciprocal association between BPPV and osteoporosis.

INTRODUCTION

A previous population cohort study suggested an association between osteoporosis and benign paroxysmal positional vertigo (BPPV). This study aimed to investigate the bidirectional association between BPPV and osteoporosis.

METHODS

The Korean National Health Insurance Service-Health Screening Cohort data from 2002 to 2013 were used. In study I, the 50,897 osteoporosis patients were 1:1 matched with control I participants for age, sex, income, and region of residence. The previous histories of BPPV were analyzed in both groups using conditional logistic regression analysis. In study II, 9621 BPPV patients were 1:4 matched with control II participants. The previous histories of osteoporosis were analyzed in both groups using conditional logistic regression analysis. According to age and sex, subgroup analyses were achieved in both studies I and II.

RESULTS

A total of 1.6% (822/50,897) of osteoporosis patients and 1.3% (644/50,897) of control I participants had BPPV. The osteoporosis patients demonstrated a 1.28 times higher chance of developing BPPV (95% confidence intervals [95% CI] = 1.16-1.42, P < 0.001). In study II, 21.2% (2040/9621) of BPPV patients and 17.6% (6790/38,484) of control II participants had osteoporosis. The BPPV patients showed 1.34 times higher chance of having osteoporosis (95% CI = 1.26-1.43, P < 0.001). In the analysis of the women subgroup, these relations were reliable.

CONCLUSION

Osteoporosis patients had increased odds of having BPPV. On the other hand, BPPV patients had increased odds of having osteoporosis. This bidirectional relation was consistent only in the women subgroup.

Impaired Calcium Metabolism in Benign Paroxysmal Positional Vertigo: A Topical Review

BACKGROUND AND PURPOSE

Although acute attacks of benign paroxysmal positional vertigo (BPPV) may be treated with canalith repositioning maneuvers, there have been no well-designed prospective trials to prevent this highly prevalent and recurrent disorder. This topical review explores the evidence related to the association between deficient calcium metabolism and BPPV. We also describe the development of therapeutic options to prevent recurrences of BPPV and introduce results from a recent randomized controlled trial on the effect of vitamin D and calcium supplementation in preventing BPPV recurrences.

SUMMARY OF KEY POINTS

The literature describes 3 lines of evidence on association of impaired calcium metabolism and development of BPPV: (1) decreased bone mineral density was more frequently observed in persons with BPPV than in healthy controls; (2) estrogen plays a vital role in maintenance of otoconia, and estrogen deficiency appears to precipitate degeneration of otoconia and development of BPPV; and (3) lower serum vitamin D level is associated with development of BPPV, and supplementation of vitamin D and calcium carbonate may reduce further attacks of BPPV in persons with BPPV and subnormal serum vitamin D level.

RECOMMENDATIONS FOR CLINICAL PRACTICE

Restoration of impaired calcium metabolism with supplementation of vitamin D or estrogen should be considered in the treatment of individuals with frequent recurrences of BPPV. Future randomized controlled trials are mandatory to validate these supplementation therapies in individuals with recurrent BPPV.

Causes and treatment of idiopathic benign paroxysmal positional vertigo based on endocrinological and other metabolic factors

The genesis of the Benign Paroxysmal Positional Vertigo (BPPV) seems to be related to some metabolic factors. These factors, such as vitamin D, glucocorticoids, and even thyroid and growth hormones, can affect bone metabolism and the mineralization of otoconia. It also seems to link to factors related to aging or nutritional habits. Besides, since the incidence of BPPV is quantitatively higher in women than in men, female sex steroids could be associated with this process. It could be useful to understand how these factors act in otoconial mineralization if we want to develop treatments aimed at preventing or delaying BPPV recurrences. In this review, we will analyze the role of these metabolic and hormonal factors in otoconial mineralization and in the treatment of BPPV.

Evaluation of the structure of the otoconial layer using micro-computed tomography

OBJECTIVE

Estrogen deficiency caused by bilateral ovariectomy (OVX) has been reported to lead to morphological changes in otoconia. Thus, we examined the morphological changes in the otoconial layer after OVX. We also investigated whether micro-computed tomography (µCT) is useful for the detection of morphological changes in the otoconial layer.

METHODS

The otic capsules of C57BL/6 J mice were removed and evaluated using histological techniques and µCT at 2, 4, and 8 weeks after OVX or sham surgery. The volume of the utricle otoconial layer was measured and compared between the OVX and sham groups. The µCT scan and histological study results were also compared.

RESULTS

The volume of the utricle otoconial layer was significantly increased 4 weeks after OVX compared to the sham group in both histological and µCT studies (p < 0.05). The volume of the otoconial layer measured using µCT was significantly correlated with the histological study results (p < 0.05).

CONCLUSION

The volume of the utricle otoconial layer increased after OVX. These morphological changes could be detected by µCT.

Auditory function and dysfunction: estrogen makes a difference

Estrogen is the major female hormone involved in reproductive functions, but it also exerts a variety of additional roles in non-reproductive organs. In this review, we highlight the preclinical and clinical studies that have pointed out sex differences and estrogenic influence on audition. We also describe the experimental evidences supporting a protective role of estrogen towards acquired forms of hearing loss. Although a high level of endogenous estrogen is associated with a better hearing function, hormonal treatments at menopause have provided contradictory outcomes. The various factors that are likely to explain these discrepancies include the treatment regimen as well as the hormonal status and responsiveness of the patients. The complexity of estrogen signaling is being untangled and many downstream effectors of its genomic and non-genomic actions have been identified in other systems. Based on these advances and on the common physio-pathological events that underlie age-related, drug or noise-induced hearing loss, we discuss potential mechanisms for their protective actions in the cochlea.

[The impairment of bone-mineral metabolism in the development of benign paroxysmal positional vertigo]

Benign paroxysmal positional vertigo (BPPV) is one of the most common causes of systemic vertigo in clinical practice. The results of recent research demonstrated the decrease of bone mineral density, level of vitamin D and estrogen in blood serum in patients with BPPV. In summary these data points at the relationship between osteoporosis/osteopenia and BPPV. This association is most obvious in menopausal women and in those with recurrent BPPV. Patients with recurrent BPPV should undergo investigation for osteoporosis/osteopenia. Treatment of bone-mineral metabolism allows decreasing the frequency of BPPV recurrence, however more research is needed in this area.

Review of the pathology underlying benign paroxysmal positional vertigo

The pathophysiological mechanism underlying benign paroxysmal positional vertigo (BPPV) is related to free-floating debris/otoliths in the semicircular canal (canalolithiasis) or debris/otoliths attached to the cupula (cupulolithiasis). These debris/otoliths are considered to originally accumulate after detachment from the neuroepithelium of the utricular macula secondary to a type of degeneration. An idiopathic form, which is assumed to occur spontaneously, is diagnosed when the causative pathology is obscure. However, an association between various other systemic or inner ear conditions and BPPV has been reported, indicating the existence of secondary BPPV. This study was performed to present the first review of the pathology underlying BPPV following a complete PubMed/Medline search. In total, 1932 articles published from 1975 to 2018 were reviewed. The articles were classified according to 17 potentially causative factors (aging; migraine; Meniere's disease; infection; trauma; idiopathic sudden sensorineural hearing loss; sleeping habits; osteoporosis and vitamin D insufficiency; hyperglycemia and diabetes mellitus; chronic head and neck pain; vestibule or semicircular canal pathology; pigmentation disorders; estrogen deficiency; neurological disorders; autoimmune, inflammatory, or rheumatologic disorders; familial or genetic predisposition; and allergy). A discussion of the underlying cause of BPPV for each factor is presented.

Otopetrin-2 Immunolocalization in the Human Macula Utricle

BACKGROUND

In the present study, we investigated the localization of otopetrin-2-a member of the otopetrin family that encodes proton-selective ion channels-in the human macula utricle using immunohistochemistry.

METHODS

Macula utricle were acquired at surgery from patients who required transmastoid labyrinthectomy for intractable vertigo due to Meniere's disease (MD; n = 3) and/or vestibular drops attacks (VDA; n = 2) and from temporal bones (n = 2) acquired at autopsy from individuals with no balance disorders. Immunofluorescence staining with otopetrin-2 (rabbit affinity purified polyclonal antibody) and GFAP (mouse monoclonal antibody) to identify vestibular supporting cells was made in formalin fixed cryostat sections or whole microdissected utricle (for flat mount preparations). Secondary antibodies against rabbit and mouse were used for the identification of both proteins. Digital fluorescent images were obtained using a high-resolution laser confocal microscope.

RESULTS

Using cryostat sections and flat mount preparations otopetrin-2 immunofluorescence was seen as punctated signal throughout the supporting cells cytoplasm. GFAP immunofluorescence was present in the supporting cell cytoplasm. The distribution of otopetrin-2 was similar in the macula utricle obtained from MD, VDA, or autopsy normative patients.

CONCLUSIONS

Otopetrin-2 was localized in supporting cells in a similar fashion that otopetrin-1 previously reported in the mouse macula utricle. The differential expression of otopetrin-2 in the supporting cells of the human macula utricle suggest an important role in the vestibular sensory periphery homeostasis and otolith maintenance.

Dizziness in peri- and postmenopausal women is associated with anxiety: a cross-sectional study

Background

Although dizziness is one of the most common symptoms of menopause, the underlying mechanism is not precisely known. Therefore, this study aimed to investigate the prevalence of, and the factors associated with, dizziness in peri- and postmenopausal women.

Methods

We conducted a cross-sectional study in which we analyzed the first-visit records of 471 Japanese women aged 40 to 65 years who enrolled in a health and nutrition education program at a menopause clinic. The prevalence of dizziness was estimated according to the participants’ responses to the Menopausal Health-Related Quality of Life Questionnaire. The background characteristics of age, menopause status, body composition, cardiovascular parameters, basal metabolism, and physical fitness; other menopausal symptoms, including vasomotor, insomnia, depression, and anxiety symptoms; and lifestyle characteristics were assessed for their associations with dizziness.

Results

The percentage of women who suffered from dizziness once a week or more frequently was 35.7%. Compared to the women without dizziness, those with the symptom were younger; had a higher body weight, body mass index, body fat percentage, muscle mass, and waist-to-hip ratio; had higher systolic pressure; were slower in reaction time; had higher physical and psychological symptom scores of menopause; exercised less regularly; and consumed less alcohol. A multivariate logistic regression analysis revealed that the anxiety symptom, which was evaluated by the Hospital Anxiety and Depression Scale, was the sole factor that was independently associated with dizziness (adjusted odds ratio 1.14; 95% confidence interval 1.08–1.20).

Conclusions

Dizziness is highly prevalent in Japanese peri- and postmenopausal women and it is associated with anxiety. The treatment of anxiety in this population might improve the symptom.

Assessment of Bone Metabolism in Male Patients With Benign Paroxysmal Positional Vertigo

Objective: Several studies have suggested a probable association between benign paroxysmal positional vertigo (BPPV) and both reduction of bone mineral density (BMD) and serum vitamin D levels, but none of these studies have explored their findings by examining bone turnover markers (BTM) in male idiopathic BPPV patients. This study aimed to evaluate the relationship between BMD and serum 25-hydroxyvitamin D (25(OH) D), with the occurrence of BPPV along with the characteristics of bone metabolism in male idiopathic BPPV patients. Methods: This retrospective study comprised 60 male idiopathic BPPV patients and 92 age-matched healthy controls referred to Ningbo No.2 Hospital during the period of February 2016 to February 2018. All subjects' serum levels of 25(OH) D, bone formation marker amino-terminal propeptide of type I procollagen (PINP), and bone resorption marker β-isomerized carboxy-terminal telopeptide of type I collagen (β-CTX) were measured. BMD was determined by dual energy X-ray absorption at the lumbar spine and hip. Results: Among male patients with BPPV, the prevalence of BMD reduction was 35.0%, which was similar to that of 27.2% in healthy controls. There were significant differences in the mean serum 25(OH) D level and prevalence of vitamin D deficiency between the two groups, with p-values of 0.049 and 0.009, respectively. The bone turnover markers of PINP and β-CTX in BPPV patients were lower than those in healthy controls. Logistic regression showed that vitamin D deficiency were associated with BPPV with an odds ratio of 3.8 (95% confidence interval = 1.25-11.73). Conclusion: Our study found that decreased serum vitamin D may be a risk factor for BPPV in male patients. The level of bone turnover among male patients with BPPV was lower than that among healthy controls.