The influence of vestibular stimulation on metabolism and body composition

The Effect of Time-Restricted Feeding on Postural Balance: From a Vestibular Perspective

INTRODUCTION

The aims of the present study were to evaluate postural balance performance of the subjects on the time-restricted feeding (TRF) and reveal the effect of TRF on the vestibular system by comparing the results to those of traditional daily dietary (DD) condition.

METHODS

Sixteen adults (3 males, 13 females; mean age: 25.4 ± 4 years) who had experienced at least 1 month of TRF were included in the study. The Sensory Organization Test (SOT) and Head-Shake SOT (HS-SOT) - which evaluate proprioceptive, visual, and vestibular systems - were performed on TRF and DD conditions via the Computerized Dynamic Posturography system.

RESULTS

Significant differences were obtained between TRF and DD situations in SOT-5 (p = 0.008), SOT-6 (p = 0.01), and HS-SOT5 (p = 0.007) conditions in which the vestibular system dominated.

CONCLUSION

We revealed that TRF has an effect on postural balance in the absence of proprioceptive and visual systems. This feeding model is a negative stressor that has a substantial effect on the vestibular system, but this impact is minimal once the proprioceptive and visual systems are intact. To the best of our knowledge, it is the first study to evaluate postural balance utilizing vestibular parameters in TRF.

Histaminergic System and Vestibular Function in Normal and Pathological Conditions

Most neurotransmitter systems are represented in the central and peripheral vestibular system and are thereby involved both in normal vestibular signal processing and the pathophysiology of vestibular disorders. However, there is a special relationship between the vestibular system and the histaminergic system. The purpose of this review is to document how the histaminergic system interferes with normal and pathological vestibular function. In particular, we will discuss neurobiological mechanisms such as neuroinflammation that involve histamine to modulate and allow restoration of balance function in the situation of a vestibular insult. These adaptive mechanisms represent targets of histaminergic pharmacological compounds capable of restoring vestibular function in pathological situations. The clinical use of drugs targeting the histaminergic system in various vestibular disorders is critically discussed.

The Effectiveness of Electrical Vestibular Stimulation (VeNS) on Symptoms of Anxiety: Study Protocol of a Randomized, Double-Blinded, Sham-Controlled Trial

The prevalence of symptoms of anxiety is increasing, especially during the COVID-19 pandemic. A home use transdermal neurostimulation device might help to minimize the severity of anxiety disorder. To the best of our knowledge, there is no clinical trial using transdermal neurostimulation to treat individuals with symptoms of anxiety in Asia. This gives us the impetus to execute the first study which aims at evaluating the efficacy of Electrical Vestibular Stimulation (VeNS) on anxiety in Hong Kong. This study proposes a two-armed, double-blinded, randomized, sham-controlled trial including the active VeNS and sham VeNS group. Both groups will be measured at baseline (T1), immediately after the intervention (T2), and at the 1-month (T3) and 3-month follow-up (T4). A total of 66 community-dwelling adults aged 18 to 60 with anxiety symptoms will be recruited in this study. All subjects will be computer randomised into either the active VeNS group or the sham VeNS group in a 1:1 ratio. All subjects in each group will receive twenty 30 min VeNS sessions during weekdays, which will be completed in a 4-week period. Baseline measurements and post-VeNS evaluation of the psychological outcomes (i.e., anxiety, insomnia, and quality of life) will also be conducted on all participants. The 1-month and 3-month follow-up period will be used to assess the long-term sustainability of the VeNS intervention. For statistical analysis, ANOVA with repeated measures will be used to analyze data. Missing data were managed with multiple mutations. The level of significance will be set to p < 0.05. Results of this study will be used to determine whether this VeNS device can be considered as a self-help technological device to reduce perceived anxiety in the general population in the community setting. This clinical Trial was registered with the Clinical Trial government, identifier: NCT04999709.

Effects of vestibular rehabilitation on body composition and daily-living physical activity in chronic unilateral vestibular hypofunction

BACKGROUND

Unilateral vestibular hypofunction (UVH) may lead to modifications on metabolism and body composition. Vestibular rehabilitation (VR) demonstrated its effectiveness in ameliorating balance function and several other daily-living aspects.

OBJECTIVES

The aim of this study was to evaluate metabolic composition, by means of bioelectrical impedance analysis (BIA) and daily activity, with the use of a wrist-worn movement tracker, in UVH participants before and after VR, and to compare data with a healthy control group (CG) of adults.

METHODS

46 UVH and 60 CG participants underwent otoneurological testing, self-report and performance questionnaires, BIA, and wore a device tracking daily movement and energy expenditure for one full day; this was performed before and after VR.

RESULTS

UVH participants demonstrated a significant (p = 0.008) increase in muscle mass after VR, and, when compared to CG, no differences were present with respect to visceral fat and muscle mass. UVH adults reported a significant increase in energy expenditure spent in movement (p = 0.008) and during the day (p = 0.009), daily number of strides (p = 0.009) and calories spent in sweeping (p = 0.009) and stairing (p = 0.008).

CONCLUSIONS

Results from this study show that VR provided an improvement of metabolic function and body composition of people with UVH, possibly by contrasting structural modifications in neural pathways stemming from the vestibular nuclei and connected to autonomous function.

One-year prevalence and clinical characteristics in chronic dizziness: The 2019-2020 Korean National Health and Nutrition Examination Survey

INTRODUCTION

In this cross-sectional study, we investigated the 1-year prevalence and related factors in the general population with an experience of chronic dizziness.

METHODS

This study analyzed persons (n = 5,163) who respond to dizziness and nutrition questionnaire from participant of Korean National Health and Nutrition Examination Survey (KNHANES, 2019-2020).

RESULTS

Of individuals over 40 years, 25.3% of the general population (61.6% females) reported either dizziness or imbalance for the past year. Moreover, 4.8% of the patients reported they suffered from chronic dizziness or imbalance for more than 3 months. In multiple regression analysis, patients with chronic dizziness were older, females, had lower body mass index (BMI), had stress awareness, and had a history of tinnitus within 1 year (>5 min per episode). Relative to normal body weight, both overweight and mild obesity (obesity stages 1 and 2) were associated with a significantly lower risk of chronic dizziness. Overweight, obesity stage 1, and obesity stage 2 had odds ratios of 0.549 [95% confidence interval (CI), 0.332-0.910], 0.445 (95% CI, 0.273-0.727), and 0.234 (95% CI, 0.070-0.779), respectively.

CONCLUSIONS

In this study, the prevalence of chronic dizziness in the general population was 4.8%. Our study demonstrated that overweight and mild obesity were independently associated with a lower risk of chronic dizziness in adults for the past year. Therefore, the optimal BMI for patients with dizziness should be defined and managed according to an integrated care pathway.

Electrical vestibular nerve stimulation (VeNS): a follow-up safety assessment of long-term usage

OBJECTIVES

This retrospective, open-label study was undertaken to assess the safety of repeated, long-term electrical vestibular nerve stimulation (VeNS). The primary outcome for this study was assessment of hearing function as reported by formal audiometry testing.

METHODS

Assessments were conducted on n=25 long-term users of daily 1.5 mA VeNS. Skin inspection of the mastoid area, otoscope examination of the inner ear, and formal audiometry testing was conducted on n=18 users. All participants completed a survey-based assessment to determine usage of the device, adverse events, and long-term outcomes.

RESULTS

Mean duration of use was 22 months, with approximately 80% of users reporting 1 h of daily, or 1 h of regular (2-3 times per week) VeNS usage. No adverse events were reported. There were no significant findings during examination of the mastoid areas, ear canal, or tympanic membranes. There were no significant findings reported from the formal audiogram assessments.

CONCLUSIONS

This appears to be the first study to provide formal assessment to show that repeated, long-term VeNS usage has not generated any significant side effects or adverse events. Results from this study further support previous literature that electrical vestibular stimulation is both safe and well-tolerated.

Acceptability and feasibility of a vestibular nerve stimulation headset protocol in children with cerebral palsy

Background

Research suggests electrical Vestibular Nerve Stimulation (VeNS) may improve balance for people with neurological impairments. This study aimed to assess the feasibility and acceptability of a VeNS headset protocol in children with cerebral palsy (CP).

Methods

Children aged 5–18 years with ambulant CP, their parents, and healthcare professionals were recruited via social media. Children completed a battery of balance tests and wore a sham VeNS headset one hour per day for four weeks. Perspectives on the balance tests and headset were ascertained from children, parents and healthcare professionals using semi-structured interviews. Interview data were analysed thematically.

Results

Two families and four healthcare professionals participated. Balance outcome measures were fully completed and deemed acceptable. Adherence with wearing the headset was 89–100% but discomfort with self-adhesive electrodes was reported. Four themes emerged from interview data: headset issues, perceptions about VeNS, the importance of balance, and modifications for future study.

Conclusions

Although the VeNS headset had high acceptability, the volunteer sample was small, potentially suggesting limited interest in VeNS as a treatment for children with CP, or reluctance to trial a ‘non-active’ headset. Recruitment via clinicians known to the family and use of an ‘active’ headset may increase participation in future research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-03093-1.

Changes in daily energy expenditure and movement behavior in unilateral vestibular hypofunction: Relationships with neuro-otological parameters

The vestibular system has been found to affect energy homeostasis and body composition, due to its extensive connections to the brainstem and melanocortin nuclei involved in regulating the metabolism and feeding behavior. The aim of this study was to evaluate - by means of a wrist-worn physical activity tracker and bioelectrical impedance analysis (BIA) - the energy expenditure (EE) in resting (REE) and free-living conditions and movement behavior in a group of chronic unilateral vestibular hypofunction (UVH) patients when compared with a control group (CG) of healthy participants. Forty-six chronic UVH and 60 CG participants underwent otoneurological (including video-Head Impulse Test [vHIT] for studying vestibulo-ocular reflex [VOR] and static posturography testing [SPT]), and EE and movement measurements and self-report (SRM) andperformance measures (PM). As well as significant (p < 0.001) changes in SPT variables (area and path length) and SRM/PM, UVH participants also demonstrated significantly (p < 0.001) lower values in REE, movement EE, hours/day spent upright, number of strides and distance covered and total daily EE (p = 0.007) compared to the CG. UVH patients consumed significantly lower Kcal/min in sweeping (p = 0.001) and walking upstairs and downstairs (p < 0.001) compared to the CG. Multiple correlations were found between free-living and resting EE and neuro-otological parameters in UVH participants. Since the melanocortin system could be affected along the central vestibular pathways as a consequence of chronic vestibular deafferentation, data collected by reliable wearables could reflect the phenomena that constitute an increased risk of falls and sedentary lifestyle for patients affected by UVH, and could improve rehabilitation stages.

Changes in body composition in unilateral vestibular hypofunction: relationships between bioelectrical impedance analysis and neuro-otological parameters

PURPOSE

Experimental works have indicated the potential of the vestibular system to affect body composition to be mediated by its extensive connections to brainstem nuclei involved in regulating metabolism and feeding behavior. The aim of this study was to evaluate-by means of bioelectrical impedance analysis (BIA)-the body composition in a group of chronic UVH normal-weighted patients when compared with an equally balanced group of healthy participants, serving as a control group (CG).

METHODS

Forty-six chronic UVH and 60 CG participants underwent otoneurological (including video Head Impulse Test [vHIT] and static posturography testing [SPT]), BIA measurements and self-report (SRM) and performance measures (PM).

RESULTS

Beyond significant (p < 0.001) changes in SPT variables (surface and length) and SRM/PM (including Dizziness Handicap Inventory, Dynamic Gait Index and Activity Balance Confidence scales), UVH participants demonstrated significant (p < 0.001) higher values of fat mass and visceral fat and lower values of muscle mass (p = 0.004), when compared to CG. Significant correlations were found in UVH participants between otoneurological and BIA measurements.

CONCLUSION

These study findings represent the first clinical in-field attempt at depicting, with the use of BIA parameters, changes in body composition related to chronic UVH. Since such alterations in metabolic parameters could be considered both the consequences and/or the cause of vestibular-related quality of life deficit, BIA parameters could be considered as cheap, easy to use, noninvasive assessments in case of chronic UVH.

Prolonged functional cerebral asymmetry as a consequence of dysfunctional parvocellular paraventricular hypothalamic nucleus signaling: An integrative model for the pathophysiology of bipolar disorder

Approximately 45 million people worldwide are diagnosed with bipolar disorder (BD). While there are many known risk factors and models of the pathologic processes influencing BD, the exact neurologic underpinnings of BD are unknown. We attempt to integrate the existing literature and create a unifying hypothesis regarding the pathophysiology of BD with the hope that a concrete model may potentially facilitate more specific diagnosis, prevention, and treatment of BD in the future. We hypothesize that dysfunctional signaling from the parvocellular neurons of the paraventricular hypothalamic nucleus (PVN) results in the clinical presentation of BD. Functional damage to this nucleus and its signaling pathways may be mediated by myriad factors (e.g. immune dysregulation and auto-immune processes, polygenetic variation, dysfunctional interhemispheric connections, and impaired or overactivated hypothalamic axes) which could help explain the wide variety of clinical presentations along the BD spectrum. The neurons of the PVN regulate ultradian rhythms, which are observed in cyclic variations in healthy individuals, and mediate changes in functional hemispheric lateralization. Theoretically, dysfunctional PVN signaling results in prolonged functional hemispheric dominance. In this model, prolonged right hemispheric dominance leads to depressive symptoms, whereas left hemispheric dominance correlated to the clinical picture of mania. Subsequently, physiologic processes that increase signaling through the PVN (hypothalamic-pituitaryadrenal axis, hypothalamic- pituitary-gonadal axis, and hypothalamic-pituitary-thyroid axis activity, suprachiasmatic nucleus pathways) as well as, neuro-endocrine induced excito-toxicity, auto-immune and inflammatory flairs may induce mood episodes in susceptible individuals. Potentially, ultradian rhythms slowing with age, in combination with changes in hypothalamic axes and maturation of neural circuitry, accounts for BD clinically presenting more frequently in young adulthood than later in life.

Electrical vestibular nerve stimulation as an adjunctive therapy in the management of type 2 diabetes

OBJECTIVES

Vestibular nerve stimulation using the portable battery-operated vestibular nerve stimulator is a sophisticated method noninvasive, safe, and easy to operate. It was hypothesized that vestibular nerve stimulation is effective in the management of type 2 diabetes. Hence, the present study was undertaken to determine the effectiveness of vestibular nerve stimulation using portable battery-operated vestibular nerve stimulator in the management of diabetes.

METHODS

The present study was a double-blind randomized controlled trial with 1:1 split between the control and experimental groups. A total of 30 participants with type 2 diabetes were part of the study after obtaining the written informed consent. After recording the baseline values, the vestibular nerve stimulation was administered to the participants in the intervention group for 90 days. Sham stimulation was administered to the control group for 90 days. Outcome measures were recorded after 30 days and after 90 days of the intervention in both the groups.

RESULTS

There was significant decrease in the total body weight, fasting, postprandial blood glucose, glycosylated hemoglobin levels, leptin, very low density lipoproteins levels followed by the intervention. There was significant improvement in both spatial and verbal memory scores. Depression and stress scores and systolic blood pressure decreased and remained in normal limits.

CONCLUSIONS

The study results have proven multimodal action of vestibular stimulation. It not only acts on regulation of the glucose metabolism but also can regulate the autonomic activity and improve cognition and relieve stress. This is the interesting finding of our study, which needs detailed further research to support implementation of vestibular nerve stimulation as an adjunctive therapy in the management of diabetes.

Anti-diabetic effect of vestibular stimulation is mediated via AMP-activated protein kinase

There is abundant animal evidence that vestibular stimulation, particularly of the otolith organs, can trigger a shift in body mass composition towards a leaner physique. One way of non-invasively stimulating the otolith organs is via a small electrical current applied to the skin behind the ears. This technique is called vestibular nerve stimulation, or VeNS, and is believed to have a good safety profile. Thus, it has previously been argued that VeNS could be used in human health as a means of treating the complications of metabolic syndrome, such as obesity and type 2 diabetes mellitus. Weight loss itself is known to improve diabetic control, however, tantalizing evidence is now emerging that the improvements seen in the glycemic control of type 2 diabetics who undergo repeated vestibular stimulation are significantly better than would be expected on the basis of weight loss alone. As vestibular stimulation has been shown to increase levels of an anti-inflammatory protein, called sirtuin 1, we hypothesize here that VeNS will increase levels of an associated enzyme called AMP-activated protein kinase (AMPK). AMPK plays an important role in glucose and fat metabolism and is activated by exercise, as well as being a known target for certain anti-diabetic drugs. This hypothesis is readily amenable to clinical testing as specific assays for testing human AMPK are available. If substantiated, then this hypothesis could prove an important clinical insight and potentially offer a new treatment avenue for patients with type 2 diabetes; a condition which remains a major cause of morbidity and premature mortality worldwide.

A systematic review of vestibular stimulation in cerebral palsy

PURPOSE

Identify the types and dosage of vestibular stimulation interventions in persons with cerebral palsy (CP), and establish the efficacy of these interventions on balance and function.

MATERIALS AND METHODS

This systematic review followed Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols to search for studies evaluating vestibular stimulation interventions in persons with CP. Information sources included MEDLINE, Embase, CINAHL, Cochrane Central Register of Controlled Trials, clinicaltrials.gov and the World Health Organisation registry. Methodological quality was assessed by two independent reviewers using the Methodological Index of Non-Randomised Studies (MINORS) and Cochrane Risk of Bias Tool.

RESULTS

Five articles were included. Three randomised studies were judged to have high risk of bias in at least one domain of the Cochrane Risk of Bias Tool. Two non-randomised studies were rated as low methodological quality using the MINORS tool. All studies used exercise-based vestibular stimulation, but there was little homogeneity regarding dosage. Findings related to efficacy of vestibular stimulation were inconsistent.

CONCLUSIONS

Clinical practice recommendations cannot be made due to lack of high quality studies and heterogeneity of treatment protocols. Future research should address theory-driven selection of intervention, establish dosage, use psychometrically robust tools and include all ages of persons with CP.IMPLICATIONS FOR REHABILITATIONOptimal intervention parameters for vestibular stimulation cannot be determined from existing literature.Further studies to describe vestibular stimulation intervention components and duration are warranted.In practice, use of valid and reliable balance and gross motor function outcome measures are essential if using vestibular stimulation techniques with people with CP, as the efficacy of these interventions has not been clearly demonstrated.Investigation of electrical Vestibular Nerve Stimulation in people with CP is warranted.

Roles of the vestibular system in obesity and impaired glucose metabolism in high-fat diet-fed mice

The vestibular system controls balance, posture, blood pressure, and gaze. However, the roles of the vestibular system in energy and glucose metabolism remain unknown. We herein examined the roles of the vestibular system in obesity and impaired glucose metabolism using mice with vestibular lesions (VL) fed a high-sucrose/high-fat diet (HSHFD). VL was induced by surgery or arsenic. VL significantly suppressed body fat enhanced by HSHFD in mice. Glucose intolerance was improved by VL in mice fed HSHFD. VL blunted the levels of adipogenic factors and pro-inflammatory adipokines elevated by HSHFD in the epididymal white adipose tissue of mice. A β-blocker antagonized body fat and glucose intolerance enhanced by HSHFD in mice. The results of an RNA sequencing analysis showed that HSHFD induced alterations in genes, such as insulin-like growth factor-2 and glial fibrillary acidic protein, in the vestibular nuclei of mice through the vestibular system. In conclusion, we herein demonstrated that the dysregulation of the vestibular system influences an obese state and impaired glucose metabolism induced by HSHFD in mice. The vestibular system may contribute to the regulation of set points under excess energy conditions.