The balance of sleep: Role of the vestibular sensory system

Does vestibular stimulation modify circadian rhythms and sleep? A systematic review

INTRODUCTION

Circadian rhythms and sleep processes are essential in human and their disruption affect health in many ways. They share anatomical-functional pathways with the vestibular system making vestibular stimulation an interesting tool that has yet to prove its efficacy at reducing such disruptions. This review aims at evaluating the effects of different types of vestibular stimulations on circadian rhythms and sleep.

METHODS

It followed PRISMA recommendations and was registered to PROSPERO (CRD42024492913). The databases PubMed and ScienceDirect were searched until January 2024 for articles published between 1950 and 2023 to collect articles fitting the scope of the review.

RESULTS

Among the ninety-six screened studies, a total of twelve studies were included. A significant beneficial effect of vestibular stimulation was shown on a circadian rhythm and in eight out of eleven studies evaluating sleep. Among the twelve studies, three showed a high risk of bias, two induced some concerns and the seven left showed a low risk of bias.

CONCLUSION

Vestibular stimulation appears as a promising technique to improve both circadian rhythms and sleep.

High prevalence of sleep disorders in Ménière's disease: Interplay between vestibular function and sleep

BackgroundIn Ménière's disease (MD), impaired sleep worsens the quality of life and triggers episodes, perpetuating a vicious cycle. The intricate connection between vestibular function and sleep regulation is poorly understood.ObjectiveWe aimed to investigate this link by studying sleep in confirmed MD patients.MethodsIn a single-center observational study, 26 consecutive patients with MD were enrolled. Sleep characterization included thorough symptom inquiry, questionnaires (PSQI, ESS, PFS, STOP-Bang, and AAO-HNS), and respiratory polygraphy (RP) or polysomnography (PSG).ResultsDespite 42% of patients reporting overall sleep satisfaction, further inquiry revealed 76% experiencing sleep disturbances per PSQI. STOP-Bang indicated 56% with a moderate-to-severe risk of OSAS. OSAS defined by apnea hypopnea index (AHI) ≥ 5/h was present in 75%. OSAS severity was categorized as mild (5/h ≤ AHI < 15/h, 33%), moderate (15/h ≤ AHI < 30/h, 21%), and severe (AHI ≥ 30/h, 21%). In patients with AAO-HNS score >3, migraines and insomnia were more prevalent. Patients with moderate-to-severe OSAS had poorer hearing. All recently diagnosed patients with moderate-to-severe OSAS had undergone more than one medical treatment compared to others (32%).ConclusionsThe high prevalence of sleep disorders in MD patients underscores the need for thorough screening, even without spontaneous complaints. Instrumental sleep exploration via RP or PSG is essential, as OSAS treatment could aid vestibular function.

The Impact of Sleep Deprivation on Video Head Impulse Test Results

OBJECTIVE

To investigate the association between sleep deprivation and vestibular dysfunction by Video Head Impulse Test (vHIT).

METHODS

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).

RESULTS

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.

CONCLUSION

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.

LEVEL OF EVIDENCE

3 Laryngoscope, 135:1177-1182, 2025.

Poor Sleep Quality Worsens Static and Dynamic Balance Control in Individuals With Chronic Low Back Pain: A Cross-Sectional Study

Objective: To investigate the influence of sleep quality and associated factors on balance control in individuals with chronic low back pain (CLBP). Methods: 85 participants (mean age 33.2 ± 12.5 years) with CLBP were recruited. Physical and emotional well-beings were evaluated using a battery of questionnaires. Sleep quality over the last month was assessed using the Pittsburgh Sleep Quality Index (PSQI). Participants were dichotomized into the good sleep quality (GSQ) and poor sleep quality (PSQ) groups if their PSQI scores were ≤ 5 and > 5, respectively. Balance control was measured using the one-leg stance with eyes closed and Y-balance test. Results: The GSQ group included 37 participants, while the PSQ group comprised 48 participants. After controlling for confounds (including gender, age, disability, anxiety, depression, and fear avoidance beliefs), participants with PSQ displayed significantly poorer performance in the one-leg stance with eyes closed and lower normalized posteromedial, posterolateral, and composite scores of the Y-balance test compared with participants with GSQ. Additionally, sleep quality accounted for 16.9%-24.9% of the variance in balance control, while age explained an additional 5.2%-13.2% of the variance. Additionally, higher levels of physical disability and anxiety were associated with poorer balance control. Conclusions: Individuals with concurrent CLBP and PSQ exhibit significantly worse balance control than those with CLBP alone. Future studies should investigate whether improving sleep quality, physical disability, and anxiety can enhance balance in individuals with CLBP.

Ambient chemical and physical approaches for the modulation of sleep and wakefulness

Humans spend a third of their lives asleep. While the sleep-wake behaviors are primarily modulated by homeostasis and circadian rhythm, several ambient chemical and physical factors, including light, sound, odor, vibration, temperature, electromagnetic radiation, and ultrasound, also affect sleep and wakefulness. Light at different wavelengths has different effects on sleep and wakefulness. Sound not only promotes but also suppresses sleep; this effect is mediated by certain nuclei, including the pedunculopontine nucleus and inferior colliculus. Certain sleep-promoting odorants regulate sleep through the involvement of the olfactory bulb and olfactory tubercle. In addition, vibrations may induce sleep through the vestibular system. A modest increase in ambient temperature leads to an increase in sleep duration through the involvement of the preoptic area. Electromagnetic radiation has a dual effect on sleep-wake behaviors. The stimulation produced by the ambient chemical and physical factors activates the peripheral sensory system, which converts the chemical and physical stimuli into nerve impulses. This signal is then transmitted to the central nervous system, including several nuclei associated with the modulation of sleep-wake behaviors. This review summarizes the effects of ambient chemical and physical factors on the regulation of sleep and wakefulness, as well as the underlying neurobiological mechanisms.

Intermittent Vibration Induces Sleep via an Allatostatin A-GABA Signaling Pathway and Provides Broad Benefits in Alzheimer's Disease Models

While animals across species typically experience suppressed consciousness and an increased arousal threshold during sleep, the responsiveness to specific sensory inputs persists. Previous studies have demonstrated that rhythmic and continuous vibration can enhance sleep in both animals and humans. However, the neural circuits underlying vibration-induced sleep (VIS) and its potential therapeutic benefits on neuropathological processes in disease models remain unclear. Here, it is shown that intermittent vibration, such as cycles of 30 s on followed by 30 s off, is more effective in inducing sleep compared to continuous vibration. A clear evidence is further provided that allatostatin A (AstA)-GABA signaling mediates short-term intermittent vibration-induced sleep (iVIS) by inhibiting octopaminergic arousal neurons through activating GABAA receptors. The existence of iVIS in mice is corroborated, implicating the GABAergic system in this process. Finally, intermittent vibration not only enhances sleep but also reduces amyloid-β (Aβ) deposition and reverses memory defects in Alzheimer's disease models. In conclusion, the study defines a central neural circuit involved in mediating short-term iVIS and the potential implications of vibration in treating sleep-related brain disorders.

Association of vertigo with adult obstructive sleep apnea: A systematic review and meta-analysis

BACKGROUND

Several studies have demonstrated a relationship between vertigo and obstructive sleep apnea (OSA) in adults. This review examined the association between vertigo and OSA and investigated the effects of OSA treatment on vestibular function.

METHODS

Searches were conducted in PubMed, MEDLINE, EMBASE, Cochrane, Scopus, and Web of Science databases. Two authors independently searched the databases up to November 2023. Meta-analysis of caloric test, cervical vestibular evoked myogenic potential (cVEMP), and ocular vestibular evoked myogenic potential (oVEMP), between adults with and without OSA was done.

RESULTS

Overall, 28 studies were identified, and most of which focused on vestibular dysfunction in the OSA group. Compared with controls, adults with OSA had an increased risk of abnormal caloric test results (odds ratio [OR] = 4.8), absence of cVEMP (OR = 7.9), absence of oVEMP (OR = 6.2), decreased n1p2 amplitude (standardized mean difference [SMD] = -0.78), decreased p1n1 amplitude (SMD = -0.92), decreased p1n1 interval (SMD = -2.37) in cVEMP testing and prolonged n1 latency (SMD = 0.81) and decreased p1n1 amplitude (SMD = -0.51) in oVEMP testing. Three population-based studies implied a high risk of vertigo in adult OSA, although not statistically significant (OR = 2.53, 95 % confidence interval = 0.97 to 6.61). According to 3 studies, OSA is relatively prevalent among patients with vertigo. Another 3 studies regarding OSA treatment on vestibular functions revealed inconsistent findings.

CONCLUSION

Adults with OSA exhibit abnormalities in caloric, cVEMP, and oVEMP test results, indicating impairments in the semicircular canal, saccule, and utricle.

12-week melatonin supplementation improved dynamic postural stability and walking performance in persons living with multiple sclerosis: A randomized controlled trial

BACKGROUND

Persons with multiple sclerosis (PwMS) suffer from sleep disturbances, fatigue and pain, which can be due, at least in part, to decreased levels of endogenous melatonin. These alterations could exacerbate postural instability, gait disorders and fall risk. Acute effects of exogenous melatonin on physical disorders have been studied in PwMS but its long-term effects on these parameters have not been explored yet in this population. This study aimed to determine the impact of chronic melatonin intake on dynamic postural stability, walking performance and fall risk in PwMS.

METHODS

This randomized placebo-controlled study included 27 PwMS who were assigned to either melatonin group (MG, n=15) or placebo group (PG, n=12) (3 mg/night for 12 weeks). Dynamic postural balance (force platform), walking performance (locometer) and fall risk (Four Square Step Test) were evaluated pre (T0)- and post (T1)-intervention. Sleep quality (Pittsburgh Sleep Quality Index (PSQI)), fatigue perception (Fatigue Severity Scale (FSS)), neuropathic pain (Neuropathic Pain Questionnaire 4 (DN4)) and quality of life (International Multiple Sclerosis (MS) Quality of Life Questionnaire) were also assessed at T0 and T1.

RESULTS

The center of pressure mean velocity decreased in MG compared with PG in the frontal plane (22.98 %, p=0.028). Stride length and walking speed increased in MG comparatively with PG (18.09 %, p=0.036; 9.65 %, p=0.025, respectively). The PSQI (55.89 %, p<0.001), FSS (32.38 %, p=0.003) and DN4 (32.41 %, p=0.035) scores decreased in MG compared with PG.

CONCLUSION

12-week melatonin supplementation can be recommended for managing MS-related gait disorders and dynamic postural imbalance. This therapy may also be prescribed for PwMS due to its anti-fatigue and analgesic effects as well as its benefits on sleep quality.

CLINICAL REGISTRATION

This study was prospectively recorded in the Pan African Clinical Trial Registry database (PACTR202007465309582) (https://pactr.samrc.ac.za/.).

Development and verification of a nomogram for recurrence risk of Benign Paroxysmal Positional Vertigo in middle-aged and older populations

Background

Benign Paroxysmal Positional Vertigo (BPPV) is the most common cause of peripheral vertigo, with frequent recurrence, particularly pronounced among middle-aged and elderly populations, significantly affecting patients' quality of life. This study aimed to identify predictive factors for recurrence in middle-aged and older patients with BPPV and to develop a nomogram prediction model based on these predictors.

Methods

This retrospective study included 582 participants aged ≥45 years who were selected from the electronic medical records system of the First Hospital of Changsha between March 2021 and March 2024. Randomly chosen participants (n = 407, 70%) constituted the training group, whereas the remaining participants (n = 175, 30%) formed the validation group. This study used LASSO binomial regression to select the most predictive variables. A predictor-based nomogram was developed to calculate the risk of BPPV recurrence. The performance of the nomogram was evaluated using the area under the receiver operating characteristic curve (AUC) and calibration curves with 1,000 bootstrap resampling validations. Decision curve analysis (DCA) was conducted to assess the clinical usefulness of the nomogram.

Results

According to findings from least absolute shrinkage and selection operator (LASSO) binomial regression and logistic regression screening, older age, higher levels of uric acid (UA) and homocysteine (HCY), diabetes, migraine, anxiety, and insomnia were identified as independent factors associated with an increased recurrence risk of BPPV. A nomogram model for predicting recurrence risk was developed based on these predictors. The nomogram achieved an AUC (C-statistic) of 0.8974 (95% CI: 0.8603-0.9345) in the training group and 0.8829 (95% CI: 0.8253-0.9406) in the validation group. Calibration curves, after 1,000 bootstrap resamples, demonstrated good agreement between the predicted and actual probabilities in the development and validation cohorts. DCA indicated that the nomogram had clinical utility.

Conclusion

The nomogram model incorporating age, UA, HCY, diabetes, migraine, anxiety status, and insomnia demonstrated a strong predictive capability for estimating the probability of BPPV recurrence in middle-aged and elderly patients. This tool is valuable for identifying individuals at high risk of BPPV recurrence and can aid physicians in making informed treatment decisions aimed at reducing recurrence rates.

Is the Otolithic Function Affected in Patients with Obstructive Sleep Apnea Syndrome?

BACKGROUND

 While cardiovascular and neurological diseases induced by obstructive sleep apnea syndrome (OSAS) hypoxia are well established, the association between neuro-otological diseases and OSAS is not entirely understood. Vestibular and audiological tests have been used to evaluate the degeneration of neurons in the brainstem caused by recurrent hypoxia.

PURPOSE

 Evaluation of the vestibular-evoked myogenic potential (VEMP) test findings applied to detect the possible influence on the vestibular reflex arc due to hypoxia in patients diagnosed with OSAS using Activity-Specific Balance Confidence (ABC) and Berg Balance Scale (BBS) scales determination of scores.

RESEARCH DESIGN

 This was a cross-sectional study.

STUDY SAMPLE

 Participants aged 18 to 60 who underwent polysomnography due to snoring/sleep apnea were divided into an OSAS, and a control group of subjects were also included. Each group consisted of 20 participants.

DATA COLLECTION AND ANALYSIS

 All participants were evaluated with cervical VEMP (cVEMP) and ocular VEMP (oVEMP) tests. The groups were compared regarding variables such as the rate of oVEMP and cVEMP waves obtained, the interval between the waves, and the latency and amplitude. Also, BBS and ABC scales were applied to all participants.

RESULTS

 The cVEMP (50%) and oVEMP (45%) response rates and amplitudes were significantly lower in the OSAS group. No significant difference was found between the groups when comparing other VEMP parameters. However, a statistically significant decrease was observed in the ABC and BBS scores in the OSAS group.

CONCLUSION

 The identification of VEMP alterations in the OSAS group is a clear indication that the vestibular reflex pathways may be adversely affected by hypoxia. Personal rehabilitation programs can be created by evaluating activities of daily living with the ABC and static and dynamic balances with BBS in patients with OSAS.

Advanced progress of vestibular compensation in vestibular neural networks

Vestibular compensation is the natural process of recovery that occurs with acute peripheral vestibular lesion. Here, we summarize the current understanding of the mechanisms underlying vestibular compensation, focusing on the role of the medial vestibular nucleus (MVN), the central hub of the vestibular system, and its associated neural networks. The disruption of neural activity balance between the bilateral MVNs underlies the vestibular symptoms after unilateral vestibular damage, and this balance disruption can be partially reversed by the mutual inhibitory projections between the bilateral MVNs, and their top-down regulation by other brain regions via different neurotransmitters. However, the detailed mechanism of how MVN is involved in vestibular compensation and regulated remains largely unknown. A deeper understanding of the vestibular neural network and the neurotransmitter systems involved in vestibular compensation holds promise for improving treatment outcomes and developing more effective interventions for vestibular disorders.

Exploration of effects of galvanic vestibular stimulation on circadian rhythms and its associations with sleep and spatial memory in patients with breast cancer: The ICANSLEEP-2 protocol

BACKGROUND

Patients with breast cancer (BC) exhibit circadian rhythm disruptions, mainly of rest-activity rhythm (RAR), of which sleep is an essential component, and cortisol rhythm. Sleep complaints such as insomnia and cognitive impairments are prevalent in BC. In general population, sleep is known to contribute greatly to cognition. Thus, improving RAR (and particularly sleep) could help limiting cognitive impairments in BC patients. It has recently been suggested that, in addition to its essential role in spatial memory, the vestibular system contributes to RAR synchronization. Its stimulation could therefore limit both sleep disturbances and spatial memory deficits in BC.

OBJECTIVES

The main aim of the ICANSLEEP-2 study is to assess the effects of galvanic vestibular stimulation (GVS) on circadian rhythms. The secondary aim is to assess whether GVS improves sleep and spatial memory in BC patients.

METHODS

Two groups with insomnia complaints (Insomnia Severity Index > 7) will be included: a patients' group with BC (n = 50) and a healthy control group without history of cancer (n = 25). There will be two assessment sessions, before and after 2 weeks of GVS. Patients will be randomly assigned to either a GVS group or a sham group (noneffective stimulation). Controls will receive GVS. GVS effects will be quantified and compared between groups. Assessments will include actigraphy, salivary cortisol, polysomnography, a cognitive test battery (including a computer-based task for spatial memory) and validated questionnaires (for psychological functioning and sleep complaints).

DISCUSSION

Current methods for improving sleep in BC have had controversial outcomes regarding sleep structure. We expect GVS to offer a new mean of directly targeting RAR disruptions in BC patients, with beneficial effects on sleep structure. Given the crucial impact of sleep on cognitive functioning, notably spatial memory, improving sleep of BC patients should enhance their cognitive functioning.

ETHICS AND DISSEMINATION

This study received ethical approval from the Ile de France IV institutional review board on 19 April 2022 (no. ID-RCB: 2022-A00437-36). The findings yielded by this protocol will be presented at various conferences and in peer-reviewed journals.

CLINICALTRIALS.GOV REGISTRATION NUMBER

NCT05414357.

Repeated electrical vestibular nerve stimulation (VeNS) reduces severity in moderate to severe insomnia; a randomised, sham-controlled trial; the modius sleep study

BACKGROUND

Insomnia is a prevalent health concern in the general population associated with a range of adverse health effects. New, effective, safe and low-cost treatments, suitable for long-term use, are urgently required. Previous studies have shown the potential of electrical vestibular nerve stimulation (VeNS) in improving insomnia symptoms, however only one sham-controlled trial has been conducted on people with chronic insomnia.

OBJECTIVES/HYPOTHESIS

Repeated VeNS delivered by the Modius Sleep device prior to sleep onset will show superior improvement in Insomnia Severity Index (ISI) scores over a 4-week period compared to sham stimulation.

METHODS

In this double-blinded, multi-site, randomised, sham-controlled study, 147 participants with moderate to severe insomnia (ISI≥15) were recruited and allocated a VeNS or a sham device (1:1 ratio) which they were asked to use at home for 30 min daily (minimum 5 days per week) for 4 weeks.

RESULTS

After 4 weeks, mean ISI score reduction was 2.26 greater in the VeNS treatment group than the sham group (p = 0.002). In the per protocol analysis, the treatment group had a mean ISI score decrease of 5.8 (95 % CI [-6.8, -4.81], approaching the clinically meaningful threshold of a 6-point reduction, with over half achieving a clinically significant decrease. Furthermore, the treatment group showed superior improvement to the sham group in the SF-36 (Quality of Life) energy/fatigue component (PP p = 0.004, effect size 0.26; ITT p = 0.006, effect size 0.22).

CONCLUSIONS

Modius sleep has the potential to provide a viable, non-invasive and safe clinically meaningful alternative treatment option for insomnia.

Does sleep quality affect balance? The perspective from the somatosensory, vestibular, and visual systems

OBJECTIVE

Previous studies have focused on the balance system's involvement in sleep deprivation or disorders. This study investigated how daily routine sleep quality affects the balance system of people without sleep deprivation or diagnosed sleep disorders.

METHODS

The study included 45 participants with a BMI score of <25. The PSQI was used to determine sleep quality. The SOT, HS-SOT, and ADT evaluated the vestibular system's functionality.

RESULTS

In SOT, condition 3, 4, 5, and 6 composite scores, VIS and VEST composite balance scores, and HS-SOT 5 scores were lower in the HPSQI group. At the same time, there is a statistically significant negative correlation between these scores and PSQI scores.

CONCLUSION

Poor sleep quality may be a factor influencing the balance system. Sleep quality affects the visual and vestibular systems rather than the somatosensory system. The population should be made aware of this issue, and clinicians should consider the potential impact of sleep quality when evaluating the balance system.

Spatial anxiety contributes to the dizziness-related handicap of adults with peripheral vestibular disease

In subjects with peripheral vestibular disease and controls, we assessed: 1. The relationship between spatial anxiety and perceived stress, and 2. The combined contribution of spatial anxiety, spatial perspective-taking, and individual cofactors to dizziness-related handicap. 309 adults participated in the study (153 with and 156 without peripheral vestibular disease), including patients with bilateral vestibular deficiency, unilateral deficiency (evolution <3 or ≥3 months), Meniere's disease, and Benign Paroxysmal Positional Vertigo. Assessments included: general health, personal habits, spatial anxiety (3-domains), perceived stress, spatial perspective-taking, dizziness-related handicap (3-domains), unsteadiness, sleep quality, motion sickness susceptibility, trait anxiety/depression, state anxiety, depersonalization/derealization. After bivariate analyses, analysis of covariance was performed (p ≤ 0.05). Spatial anxiety was related to unsteadiness and perceived stress, with an inverse relationship with trait anxiety (ANCoVA, adjusted R2 = 0.27-0.30, F = 17.945-20.086, p < 0.00001). Variability on perspective-taking was related to vestibular disease, trait and state anxiety, motion sickness susceptibility, and age (ANCoVA, adjusted R2 = 0.18, F = 5.834, p < 0.00001). All domains of spatial anxiety contributed to the Physical domain of dizziness-related handicap, while the Navigation domain contributed to the Functional domain of handicap. Handicap variability was also related to unsteadiness, spatial perspective-taking, quality of sleep, and trait anxiety/depression (ANCoVA, adjusted R2 = 0.66, F = 39.07, p < 0.00001). Spatial anxiety is related to perceived stress in adults both with and without vestibular disease, subjects with trait anxiety rated lower on spatial anxiety. State anxiety and acute stress could be helpful for recovery after peripheral vestibular lesion. Spatial anxiety and perspective-taking contribute to the Physical and Functional domains of dizziness-related handicap, possibly because it discourages behavior beneficial to adaptation.

Effect of Vestibular Rehabilitation on Sleep Quality and Depression in the Elderly With Chronic Dizziness: A Prospective Study

BACKGROUND AND OBJECTIVES

Dizziness and the accompanying complaints, including sleep disorders and depression, are common among the elderly. This study investigated the effect of vestibular rehabilitation on complaints of dizziness, sleep problems, and the severity of depression in older people with chronic dizziness.

SUBJECTS AND METHODS

The study included 25 participants with chronic dizziness accompanied by comorbid sleep disturbance (Pittsburgh Sleep Quality Index [PSQI] global score >5). Participants completed the Dizziness Handicap Inventory (three sub-scales: physical, emotional, and functional), the PSQI, and the Persian version of the shortened Beck Depression Inventory (BDI-13) before and after the vestibular rehabilitation.

RESULTS

The findings showed that the handicap caused by dizziness, the severity of depression, and the quality of sleep in the study participants improved significantly after the intervention (p<0.05).

CONCLUSIONS

Vestibular rehabilitation is an effective intervention to reduce dizziness handicap, comorbid sleep disturbance, and depression.

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.

Psychosocial Factors Associated with dizziness and chronic dizziness: a nationwide cross-sectional study

BACKGROUND

Dizziness is a common symptom in adults, and chronic dizziness, such as persistent postural-perceptual dizziness, is also frequently reported and affects the quality of life of patients. This study aimed to identify psychosocial factors related to dizziness and chronic dizziness in a large-scale nationwide cohort.

METHODS

This population-based cross-sectional study used the database of the Eighth Korea National Health and Nutrition Examination Survey in 2020. Data from 4,147 adults over 40 years old were analyzed, and 1,102 adults who experienced dizziness were included in the dizziness cohort. Demographic data, medical conditions, comorbidities, functional status variables, nutritional variables and psychological variables were collected. The pattern of depressive symptoms according to the severity of dizziness was analyzed by network analysis.

RESULTS

The prevalence rate of dizziness was 24.6% in the general population, and chronic dizziness (≥ 3 months) developed in 210 of 1,102 (17.1%) individuals who experienced dizziness. Multiple logistic regression analysis revealed that female sex, stress, and depression were associated with dizziness. Chronic dizziness was related to tympanic abnormalities, diabetes, short sleep duration, and higher levels of stress and depression. Psychomotor retardation/agitation was a central symptom of depression in patients with chronic dizziness.

CONCLUSIONS

This study found sex differences in factors associated with dizziness and identified psychosocial factors linked to chronic dizziness. Focusing on somatic factors rather than depressive symptoms may benefit patients with chronic dizziness.

The impacts of exercise training programs on balance in children with hearing loss: A systematic review and meta-analysis

INTRODUCTION AND PURPOSE

According to the prevalence of balance disorders among children with hearing loss (HL), researchers used exercise programs to improve balance in children with HL. So, the present systematic review and meta-analysis briefly summarize findings regarding the impacts of exercise training programs on balance in children with HL.

METHODS

Science Direct, MEDLINE/PubMed, SCOPUS, LILACS, CINAHL, CENTRAL, Web of Science, PEDro, and Google Scholar were searched from inception until November 11th, 2023. Two independent researchers analyzed and extracted the data from potential papers whose eligibility was confirmed. Then, the PEDro scale was used to obtain quality assessment scores. The total PEDro score is 11 and incorporates the presentation of statistical analysis and evaluation criteria of internal validity. Studies that scored 7-11 were considered methodologically "high", 5 to 6 were "fair", and ≤4 were considered "poor".

RESULTS

10 studies involving a total of 304 participations were included in the systematic review. Our results demonstrate that exercise training programs positively impact static balance (p = 0.001) with level 1a evidence, the postural sway (p = 0.001) with level 1a evidence, and dynamic balance (p = 0.001) with level 1a evidence in children with HL.

CONCLUSION

The findings of this systematic review and meta-analysis related to studies with excellent methodological quality revealed that the intended training programs significantly impact postural sway along with static and dynamic balance in children with HL. It is recommended that future exercise training programs be paired with rehabilitation programs for children with HL.

Sleep related rhythmic movement disorder: phenotypic characteristics and treatment response in a paediatric cohort

OBJECTIVE

To describe phenotypic, polysomnographic characteristics, impact, and treatment response in children with sleep related rhythmic movement disorder (SR-RMD).

BACKGROUND

There is limited research on SR-RMD. We have developed a systematic clinical evaluation of children with SR-RMD to improve understanding and treatment.

METHODS

A retrospective chart review of 66 children at a UK tertiary hospital. Baseline assessment included validated screening questionnaires to study autism spectrum characteristics, general behaviour and sensory profile. A standardised questionnaire assessed impact on sleep quality and daytime wellbeing of child and family. Polysomnography data were collated.

RESULTS

Children were aged 0.9-16.3 years (78.8% male). 51.5% had a neurodevelopmental disorder, most commonly autism spectrum disorder. High rates of behavioural disturbance and sensory processing differences were reported, not confined to children with neurodevelopmental disorders. Parents reported concerns about risk of injury, loss of sleep and persistence into adulthood. Daytime wellbeing was affected in 72% of children and 75% of other family members. Only 31/48 children demonstrated rhythmic movements during video-polysomnography, occupying on average 6.1% of time in bed. Most clusters occurred in the settling period but also arose from N1, N2 and REM sleep and wake after sleep onset. Melatonin was prescribed to 52 children, all but one were extended-release preparations. 24/27 children with available data were reported to improve with melatonin.

CONCLUSIONS

SR-RMD places a significant burden on child and family wellbeing. Our novel findings of sensory processing differences in this population and parent reported therapeutic response to extended-release melatonin offer potential avenues for future research.

Changes in sleep performance and chronotype behaviour after vestibular rehabilitation in unilateral vestibular hypofunction

OBJECTIVE

This study aimed to investigate changes in sleep parameters and self-perceived sleep quality in unilateral vestibular hypofunction participants after vestibular rehabilitation.

METHOD

Forty-six unilateral vestibular hypofunction participants (before and after vestibular rehabilitation) along with a control group of 60 healthy patients underwent otoneurological examination, a one-week actigraphy sleep analysis and a series of self-report and performance measures.

RESULTS

After vestibular rehabilitation, unilateral vestibular hypofunction participants showed a significant score decrease in the Pittsburgh Sleep Quality Index, a self-rated reliable questionnaire depicting sleep quality during the last month, as well as a reduction in sleep onset latency and an increase in total sleep time, indicating an objective improvement in sleep quality as measured by actigraphy analysis. However, after vestibular rehabilitation, unilateral vestibular hypofunction participants still showed statistically significant differences with respect to the control group in both self-rated and objective measurements of sleep quality.

CONCLUSION

Vestibular rehabilitation may impact on sleep performance and chronotype behaviour, possibly by opposing long-term structural changes along neural pathways entangled in sleep activity because of the deafferentation of the vestibular nuclei.

Exploring the relationship between sleep apnea and vestibular symptoms following traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a complex health problem in military veterans and service members (V/SM) that often involves comorbid vestibular impairment. Sleep apnea is another comorbidity that may exacerbate, and/or be exacerbated by, vestibular dysfunction.

OBJECTIVE

To examine the relationship between sleep apnea and vestibular symptoms in V/SM diagnosed with TBI of any severity.

DESIGN

Multicenter cohort study; cross-sectional sample.

SETTING

In-patient TBI rehabilitation units within five Veterans Affairs (VA) Polytrauma Rehabilitation Centers.

PARTICIPANTS

V/SM with a diagnosis of TBI (N = 630) enrolled in the VA TBI Model Systems study.

INTERVENTION

Not applicable.

METHODS

A multivariable regression model was used to evaluate the association between sleep apnea and vestibular symptom severity while controlling for relevant covariates, for example, posttraumatic stress disorder (PTSD).

MAIN OUTCOME MEASURES

Lifetime history of sleep apnea was determined via best source reporting. Vestibular disturbances were measured with the 3-item Vestibular subscale of the Neurobehavioral Symptom Inventory (NSI).

RESULTS

One third (30.6%) of the sample had a self-reported sleep apnea diagnosis. Initial analysis showed that participants who had sleep apnea had more severe vestibular symptoms (M = 3.84, SD = 2.86) than those without sleep apnea (M = 2.88, SD = 2.67, p < .001). However, when the data was analyzed via a multiple regression model, sleep apnea no longer reached the threshold of significance as a factor associated with vestibular symptoms. PTSD severity was shown to be significantly associated with vestibular symptoms within this sample (p < .001).

CONCLUSION

Analysis of these data revealed a relationship between sleep apnea and vestibular symptoms in V/SM with TBI. The significance of this relationship was affected when PTSD symptoms were factored into a multivariable regression model. However, given that the mechanisms and directionality of these relationships are not yet well understood, we assert that in terms of clinical relevance, providers should emphasize screening for each of the three studied comorbidities (sleep apnea, vestibular symptoms, and PTSD).

Evaluation of cellular activity in response to sleep deprivation by a comprehensive analysis of the whole mouse brain

Sleep deprivation (SD) causes several adverse functional outcomes, and understanding the associated processes can improve quality of life. Although the effects of SD on neuronal activity in several brain regions have been identified, a comprehensive evaluation of the whole brain is still lacking. Hence, we performed SD using two different methods, gentle handling and a dedicated chamber, in targeted recombination in active populations 2 (TRAP2) mice crossed with Rosa-ZsGreen reporter mice and visualized cellular activity in the whole brain. Using the semi-automated post-imaging analysis tool Slice Histology Alignment, Registration, and Cell Quantification (SHARCQ), the number of activated cells was quantified. From the analysis of 14 brain regions, cellular activity was significantly increased in the olfactory areas and decreased in the medulla by the two SD methods. From the analysis of the further subdivided 348 regions, cellular activity was significantly increased in the vascular organ of the lamina terminalis, lateral hypothalamic area, parabigeminal nucleus, ventral tegmental area, and magnocellular reticular nucleus, and decreased in the anterior part of the basolateral amygdalar nucleus, nucleus accumbens, septohippocampal nucleus, reticular nucleus of the thalamus, preoptic part of the periventricular hypothalamic nucleus, ventromedial preoptic nucleus, rostral linear nucleus raphe, facial motor nucleus, vestibular nuclei, and some fiber tracts (oculomotor nerve, genu of corpus callosum, and rubrospinal tract) by the two SD methods. Two subdivided regions of the striatum (caudoputamen and other striatum), epithalamus, vascular organ of the lamina terminalis, anteroventral preoptic nucleus, superior colliculus optic layer, medial terminal nucleus of the accessory optic tract, pontine gray, and fiber tracts (medial lemniscus, columns of the fornix, brachium of the inferior colliculus, and mammillary peduncle) were differentially affected by the two SD methods. Most brain regions detected from these analyses have been reported to be involved in regulating sleep/wake regulatory circuits. Moreover, the results from the connectivity analysis indicated that the connectivity of cellular activity among brain regions was altered by SD. Together, such a comprehensive analysis of the whole brain is useful for understanding the mechanisms by which SD and/or sleep disruption affects brain function.

Chronic Vestibular Hypofunction Is Associated with Impaired Sleep: Results from the DizzyReg Patient Registry

Temporary or permanent vestibular hypofunction has been hypothesized to affect circadian rhythm, sleep, and thermoregulation. Chronic or long-term vestibular disorders such as unilateral vestibular hypofunction may have an even greater negative impact on sleep quality than acute vestibular problems. This study examines self-reported sleep quality, as assessed by the Pittsburgh Sleep Quality Index (PSQI), and its association with vestibular symptom duration in a group of patients with vestibular disorders. We used data from the cross-sectional DizzyReg patient registry of the German Center for Vertigo and Balance Disorders outpatient clinic. Vestibular diagnoses were ascertained based on the International Classification of Vestibular Disorders. A total of 137 patients were included (60% female, mean age 55.4 years, standard deviation, SD, 16.7). The mean PSQI total score was 6.3 (SD = 3.2), with 51% reporting overall poor sleep quality. Patients who had vertigo for two years or longer reported significantly poorer global sleep quality (63% vs. 37%, p = 0.021) and significantly more difficulties with sleep latency (79% vs. 56%, p = 0.013) and sleep efficiency (56% vs. 34%, p = 0.022). The association of poor sleep quality with a longer duration of vertigo remained significant after multivariable adjustment. Further research should investigate the interaction of vestibular disorders, sleep, and their potential mechanisms.

Tackling Insomnia Symptoms through Vestibular Stimulation in Patients with Breast Cancer: A Perspective Paper

Insomnia symptoms are common among patients with breast cancer (BC; 20-70%) and are predictors of cancer progression and quality of life. Studies have highlighted sleep structure modifications, including increased awakenings and reduced sleep efficiency and total sleep time. Such modifications may result from circadian rhythm alterations consistently reported in this pathology and known as carcinogenic factors, including lower melatonin levels, a flattened diurnal cortisol pattern, and lower rest-activity rhythm amplitude and robustness. Cognitive behavioral therapy and physical activity are the most commonly used non-pharmacological interventions to counter insomnia difficulties in patients with BC. However, their effects on sleep structure remain unclear. Moreover, such approaches may be difficult to implement shortly after chemotherapy. Innovatively, vestibular stimulation would be particularly suited to tackling insomnia symptoms. Indeed, recent reports have shown that vestibular stimulation could resynchronize circadian rhythms and improve deep sleep in healthy volunteers. Moreover, vestibular dysfunction has been reported following chemotherapy. This perspective paper aims to support the evidence of using galvanic vestibular stimulation to resynchronize circadian rhythms and reduce insomnia symptoms in patients with BC, with beneficial effects on quality of life and, potentially, survival.

A randomized controlled trial to evaluate the efficacy of electrical vestibular nerve stimulation (VeNS), compared to a sham control for the management of sleep in young adults

OBJECTIVES

Preliminary research suggests that electrical vestibular nerve stimulation (VeNS) may improve sleep outcomes by influencing the hypothalamus and brainstem nuclei involved in regulating the circadian rhythm and wakefulness. This randomised, sham-controlled trial aimed to assess the effectiveness of VeNS on insomnia in young adults.

METHODS

Eighty adults aged 18-24 years were randomly allocated to the intervention (n=40) and control groups (n=40). The intervention group was provided with 30 min per day of VeNS with five sessions weekly for four weeks, while the control group received sham stimulation for the same period. Baseline Insomnia Sleep Index (ISI) scores were recorded weekly. At baseline and at day 28, questionnaires to evaluate emotional states of depression, anxiety and stress, and quality of life (QoL) were completed. The primary outcome was change in ISI with comparison between baseline and day 28.

RESULTS

The VeNS group significantly reduced their mean ISI score after 7 days usage (p<0.001). At day 28 it was found that mean ISI scores had reduced from 19 to 11 in the VeNS group, and from 19 to 18 in the sham group, and the difference between the groups was significant (p<0.001). Moreover, application of VeNS appeared to significantly improve emotional state and QoL outcomes.

CONCLUSIONS

This trial demonstrates that regular VeNS usage over four weeks leads to a clinically meaningful decrease in ISI scores in young adults with insomnia. VeNS may have potential as a drug-free and non-invasive therapy to improve sleep outcomes by positively influencing the hypothalamic and brainstem nuclei.

Relationships between the Pittsburgh Sleep Quality Index (PSQI) and vertigo outcome

OBJECTIVE

This retrospective cohort study aimed to investigate the association of sleep characteristics measured by the Pittsburgh Sleep Quality Index (PSQI) with the vertigo outcome in vertiginous patients with comorbid cardiometabolic diseases.

METHODS

Four hundred and thirteen patients with comorbid cardiometabolic diseases who consecutively visiting vertigo and dizziness clinic were enrolled between October 2018 and January 2020 in a tertiary teaching medical center. Regression analyses and stratified analyses were used to explore the relationship between PSQI and vertigo outcome, which was measured by the visual analogue scale (VAS) score.

RESULTS

In the study sample, 73.8% (305/413) were defined as 'poor sleep' (PSQI>5). Participants with better recovery tended to have better baseline PSQI global score, PSQI sleep quality, PSQI sleep onset latency, PSQI daytime dysfunction, less severe baseline vertigo symptoms indicated by VAS, Vertigo Symptom Scale (VSS) and Dizziness Handicap Inventory (DHI) scores. Moreover, baseline PSQI global score and PSQI daytime dysfunction score were independently associated with the vertigo VAS scores at the last follow-up.

CONCLUSION

The present results clearly indicated that poor sleep is common and inversely associated with vertigo outcome in vertiginous patients with co-morbid cardiometabolic diseases. Therefore, sleep deserves greater attention in the total medical care in specific subgroup of vertiginous patients.

The relationship between psychological conditions and recurrence of benign paroxysmal positional vertigo: a retrospective cohort study

BACKGROUND

Psychological conditions have been found to be associated with an increased risk of incident benign paroxysmal positional vertigo (BPPV). However, much less is known on whether and how psychological conditions such as anxiety, insomnia and obsessive-compulsive disorder (OCD) affect the recurrence of BPPV.

METHODS

A retrospective cohort study of 2,612 outpatients and inpatients diagnosed with BPPV between September 2012 and August 2020. BPPV recurrence was followed up until February 2021. The Cox proportional hazard regression was used to analyze the association between psychological conditions and the risk of the first recurrence. Poisson regression was applied to analyze the association between psychological conditions and the number of recurrences in patients with at least one relapse.

RESULTS

During the follow-up, 391 patients had at least one BPPV recurrence. Female BPPV patients were more likely than male patients to experience relapses than male patients, but the characteristics of BPPV recurrence (number of recurrences and duration between recurrences) did not differ between men and women. After adjustment for sex, age and comorbidities, a heightened risk of first BPPV recurrence was found to be associated with anxiety (hazard ratio [HR]: 1.30, 95% confidence interval [CI]: 1.01, 1.68) and OCD (HR: 2.15, 95% CI: 1.31, 3.52). An increased risk of first BPPV recurrence associated with insomnia was only observed in male patients (HR: 2.22, 95% CI: 1.24, 3.98) but not in female patients (HR: 0.91, 95% CI: 0.63, 1.31). None of these psychological conditions were associated with the number of recurrences in patients who experienced recurrence.

CONCLUSIONS

The presence of anxiety and OCD increased the risk of first BPPV recurrence, as well as insomnia for male patients. These psychological conditions were not associated with the number of BPPV recurrences. Diagnosis and treatment of these psychological conditions could be a useful strategy to prevent the recurrence of BPPV.

Prevalence and risk factors for abnormal tandem gait in patients with essential tremor syndrome: A cross-sectional study in Southwest China

Objectives

Patients with essential tremor (ET) syndrome have more prevalent and more serious gait and balance impairments than healthy controls. In this cross-sectional study, we explored whether balance impairments are associated with falls as well as more pronounced non-motor symptoms in patients with ET syndrome.

Methods

We assessed the tandem gait (TG) test, as well as falls or near-falls that occurred over the previous year. Non-motor symptoms-including cognitive deficits, psychological and sleep disorders-were evaluated. In univariate analyses, statistical significance was corrected for multiple comparisons using the Benjamini-Hochberg method. Multiple logistic regression was utilized to evaluate the risk factors of poor TG performance in patients with ET syndrome.

Results

A total of 358 patients with ET syndrome were divided into the abnormal TG (a-TG) and normal TG (n-TG) groups based on their performances in the TG test. We revealed that 47.2% of patients with ET syndrome had a-TG. The patients with a-TG were older, were more likely female, and were more likely present with cranial tremors and falls or near-falls (all adjusted P < 0.01). The patients with a-TG had significantly lower Mini-Mental Status Examination scores, as well as significantly higher Hamilton Depression/Anxiety Rating Scale and Pittsburgh Sleep Quality Index scores. Multiple logistic regression analysis demonstrated that female sex (OR 1.913, 95% CI: 1.180-3.103), age (OR 1.050, 95% CI: 1.032-1.068), cranial tremor scores (OR 1.299, 95% CI: 1.095-1.542), a history of falls or near-falls (OR 2.952, 95% CI: 1.558-5.594), and the presence of depressive symptoms (OR 1.679, 95% CI: 1.034-2.726) were associated with the occurrence of a-TG in patients with ET syndrome.

Conclusion

TG abnormalities may be a predictor of fall risk in patients with ET syndrome and are associated with non-motor symptoms, especially depression.

Detrimental effects of sleep deprivation on the regulatory mechanisms of postural balance: a comprehensive review

This review addresses the effects of sleep deprivation on postural balance based on a comprehensive search of articles dealing with this relationship in the electronic databases PubMed, Google Scholar, and ScienceDirect. Evidence suggests that postural balance is sensitive to acute and chronic sleep deprivation for everyone, including young and healthy subjects. Pathologies, aging and the circadian pattern aggravate and/or accentuate the effects of sleep deprivation on postural balance. It turns out that the different systems of information taking, decision making, and motor execution of the postural balance function are negatively affected by sleep deprivation. For example, regarding the information taking system, the sensitivity of visual perception and visuo-spatial performance and the oculomotricity are disrupted and the vestibulo-ocular reflex and the sensory reweighting are altered. Regarding the decision making system, the different brain areas activated for the regulation of postural balance are less active after sleep deprivation and the executive function and perception of verticality are impaired. Regarding the motor execution system, the agonist-antagonist muscle coordination can be modified. However, the different detrimental effects induced for each system of the postural balance function are not yet fully known and deserve further exploration in order to better understand them.

Vestibular symptoms are related to the proportion of REM sleep in people with sleep complaints: A preliminary report

OBJECTIVE/BACKGROUND

Though sleep problems (apnea, insomnia) and related daytime symptoms (fatigue, anxiety, depression) have been associated with vestibular problems (falls, dizziness), it is not well known which particular sleep features relate to vestibular problems. We thus assessed symptoms of vestibular problems in patients visiting a sleep clinic and evaluated how they were associated with objective sleep parameters derived from polysomnography and relevant daytime symptoms.

PATIENTS/METHODS

The polysomnography data of thirty-one patients (61% female, between 20 and 79 years of age) who were referred for clinical sleep assessment was collated with subjective measures of symptoms linked to vestibular problems (rated on the Situational Characteristics Questionnaire), as well as fatigue, anxiety and depression symptoms. Multiple linear regression was used to identify factors associated with vestibular symptoms, including analyses adjusted for age, sex, medication use and total sleep time.

RESULTS

A higher percentage of REM sleep and more severe anxiety symptoms were independently associated with more severe vestibular symptoms, which survived adjusted analyses. Other sleep stages, as well as as sleep efficiency, apnea-hypopnea index and oxygen saturation were not significantly related to vestibular symptoms.

CONCLUSIONS

These results point at vestibular symptoms as possible important and overlooked correlates of variations in sleep architecture in individuals with sleep complaints. Though replication is needed to confirm findings from this limited sample, the results highlight the importance of assessing vestibular symptoms in people with sleep complaints. In particular, further investigations will need to address the potential implication of REM sleep for vestibular functions and the directionality of this relation.

Effects of 15-Days −6° Head-Down Bed Rest on the Attention Bias of Threatening Stimulus

Previous researchers have found that head-down bed rest (HDBR) will affect the emotional state of individuals, and negative emotions such as anxiety are closely related to attention bias. The present study adopted the dot-probe task to evaluate the effects of 15-days of −6° HDBR on the attention bias of threatening stimulus in 17 young men, which was completed before (Pre-HDBR), during (HDBR-1, HDBR-8, HDBR-15), after (Post-HDBR) the bed rest. In addition, self-report inventories (State Anxiety Inventory, SAI; Positive Affect and Negative Affect Scale, PANAS) were conducted to record emotional changes. The results showed that the participants’ negative affect scores on HDBR-8 were significantly lower than the HDBR-1 in PANAS while there was no significant difference on positive affect scores and anxiety scores in SAI. And the results showed that at the Pre-HDBR, HDBT-1, HDBR-15, Post-HDBR, the response speed to threatening stimulus was faster than neutral stimulus, but no statistical significance. However, reaction time of threatening stimulus is significantly longer than neutral stimulus in the HDBR-8, indicating that HDBR may have an effect on the participants’ attention bias, and this effect is manifested as attention avoidance.

Investigation of the Relationship between Vestibular Disorders and Sleep Disturbance

Introduction  Vestibular pathologies cause physical and psychological symptoms, as well as cognitive problems.

Objective  To evaluate the deterioration in sleep quality associated with vestibular pathologies.

Methods  The Dizziness Handicap Inventory (DHI), the Beck Depression Inventory (BDI), the Pittsburgh Sleep Quality Index (PSQI), and the Limits of Stability test (LOS) were applied to the participants.

Results  We included 25 patients with Meniere's disease (MD), 22 patients with benign paroxysmal positional vertigo (BPPV), 21 patients with unilateral peripheral vestibular loss (UPVL), 23 patients with vestibular migraine (VM), and 43 controls. The total PSQI scores of the controls were better than those of the MD ( p  = 0.014), VM ( p < 0.001), BPPV ( p  = 0.003), and UPVL ( p  = 0.001) groups. The proportion of poor sleepers in the MD ( p  = 0.005), BPPV ( p  = 0.018), and UPVL ( p < 0.001) groups was significantly higher than that of the controls. The highest total DHI score (45.68 ± 25.76) was found among the MD group, and it was significantly higher than the scores of the BPPV ( p  = 0.007) and control ( p < 0.001) groups. The highest BDI score was obtained in the VM group, and it was significantly higher than the scores of the BPPV ( p  = 0.046) and control ( p < 0.001) groups. Moreover, the BDI scores of the MD ( p = 0.001) and UPVL groups were also significantly worse than the score of the controls ( p = 0.001).

Conclusion  The present study showed thatpatients with vestibular symptoms have physical and functional complaints, as well as increased psychosocial stress and decreased sleep quality. Evaluating multiple parameters of quality of life may contribute to a better understanding of vestibular physiology and symptoms, and may help establish a more effective therapeutic approach.

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.

Vestibular Deficits in Deafness: Clinical Presentation, Animal Modeling, and Treatment Solutions

The inner ear is responsible for both hearing and balance. These functions are dependent on the correct functioning of mechanosensitive hair cells, which convert sound- and motion-induced stimuli into electrical signals conveyed to the brain. During evolution of the inner ear, the major changes occurred in the hearing organ, whereas the structure of the vestibular organs remained constant in all vertebrates over the same period. Vestibular deficits are highly prevalent in humans, due to multiple intersecting causes: genetics, environmental factors, ototoxic drugs, infections and aging. Studies of deafness genes associated with balance deficits and their corresponding animal models have shed light on the development and function of these two sensory systems. Bilateral vestibular deficits often impair individual postural control, gaze stabilization, locomotion and spatial orientation. The resulting dizziness, vertigo, and/or falls (frequent in elderly populations) greatly affect patient quality of life. In the absence of treatment, prosthetic devices, such as vestibular implants, providing information about the direction, amplitude and velocity of body movements, are being developed and have given promising results in animal models and humans. Novel methods and techniques have led to major progress in gene therapies targeting the inner ear (gene supplementation and gene editing), 3D inner ear organoids and reprograming protocols for generating hair cell-like cells. These rapid advances in multiscale approaches covering basic research, clinical diagnostics and therapies are fostering interdisciplinary research to develop personalized treatments for vestibular disorders.

Vestibular-autonomic interactions: beyond orthostatic dizziness

PURPOSE OF REVIEW

This review aims to summarize the current literature describing vestibular-autonomic interactions and to describe their putative role in various disorders' clinical presentations, including orthostatic dizziness and motion sensitivity.

RECENT FINDINGS

The vestibular-autonomic reflexes have long been described as they relate to cardiovascular and respiratory function. Although orthostatic dizziness may be in part related to impaired vestibulo-sympathetic reflex (orthostatic hypotension), there are various conditions that may present similarly. A recent clinical classification aims to improve identification of individuals with hemodynamic orthostatic dizziness so that appropriate recommendations and management can be efficiently addressed. Researchers continue to improve understanding of the underlying vestibular-autonomic reflexes with recent studies noting the insular cortex as a cortical site for vestibular sensation and autonomic integration and modulation. Work has further expanded our understanding of the clinical presentation of abnormal vestibular-autonomic interactions that may occur in various conditions, such as aging, peripheral vestibular hypofunction, traumatic brain injury, and motion sensitivity.

SUMMARY

The vestibular-autonomic reflexes affect various sympathetic and parasympathetic functions. Understanding these relationships will provide improved identification of underlying etiology and drive improved patient management.

Evaluation of Vestibular Function in Patients Affected by Obstructive Sleep Apnea Performing Functional Head Impulse Test (fHIT)

PURPOSE

Obstructive sleep apnoea (OSA) is a common disease with significantly related complications. Since a connection between the vestibular nucleus and sleep regulator pathways has been demonstrated, vestibular evaluation in OSA patients was partially studied and none used functional head impulse test (fHIT) for this purpose. This paper aimed at evaluating the vestibular function in patients affected by OSA using fHIT, selecting patients who did not present any other related to cardiovascular, neurological, or metabolic diseases.

PATIENTS AND METHODS

Patients enrolled had a diagnosis of OSA by polysomnography type III and were cataloged according to American Association of Sleep Medicine criteria. Each patient underwent fHIT. Statistical significance was set at 0.05.

RESULTS

A total of 85 patients were enrolled in the study of which 50 had a diagnosis of OSA and were included in the case group, while 35 belonged to the control group. In 88.6% of subjects of the case group was evidenced a vestibular impairment with a substantial difference between the two study groups (p<0.05).

CONCLUSION

The results show that the incidence of vestibular lesions in patients with obstructive sleep apnoea is underestimated and that fHIT can identify these lesions early.

Drug-Drug Interactions in Vestibular Diseases, Clinical Problems, and Medico-Legal Implications

Peripheral vestibular disease can be treated with several approaches (e.g., maneuvers, surgery, or medical approach). Comorbidity is common in elderly patients, so polytherapy is used, but it can generate the development of drug-drug interactions (DDIs) that play a role in both adverse drug reactions and reduced adherence. For this reason, they need a complex kind of approach, considering all their individual characteristics. Physicians must be able to prescribe and deprescribe drugs based on a solid knowledge of pharmacokinetics, pharmacodynamics, and clinical indications. Moreover, full information is required to reach a real therapeutic alliance, to improve the safety of care and reduce possible malpractice claims related to drug-drug interactions. In this review, using PubMed, Embase, and Cochrane library, we searched articles published until 30 August 2021, and described both pharmacokinetic and pharmacodynamic DDIs in patients with vestibular disorders, focusing the interest on their clinical implications and on risk management strategies.

Low Frequency Transcranial Alternating Current Stimulation Accelerates Sleep Onset Process

GOAL

The aim of this study is to find a kind of low frequency oscillation transcranial alternating current stimulation, which is directly applied to the scalp epidermal, to stimulate the cerebral cortex with a large spatial range of electric field oscillation across the brain hemisphere, and then trigger the start of the Top-Down processing of sleep homeostasis, in the daytime nap.

METHODS

Thirty healthy subjects, to take naps, underwent an intervention of electrical stimulation at 5 Hz, applied to the dorsal lateral prefrontal cortex. The subjects in the experiments were strictly controlled, and opened their eyes when stimulation was transmitted. Subsequently, after 15 min transcranial alternating current stimulation, subjects entered the experimental procedure of sleep. Electroencephalograph was taken at baseline and during sleep. Behavioral indicators were also added to the experiment.

RESULTS

We found that the total power of Electroencephalograph activity in the theta band, as well as low-frequency power at 1-7 Hz, was significantly entrained and increased, and that alpha activity was attenuated faster and spindle activity active earlier. Even more, the transition from awake to Non-rapid eye movement stages occurs earlier. Alertness also decreased when the subjects woke up after brief sleep.

CONCLUSION

The intervention of low frequency brain rhythmic transcranial alternating current stimulation may induce accelerated effect on sleep onset process, thereby possibly alleviating the problems related to sleep disorders such as difficulty to reach the real sleep state quickly after lying down.

Cross-Cultural Adaptation, Reliability, and Psychophysical Validation of the Pain and Sleep Questionnaire Three-Item Index in Finnish

Reciprocal relationships between chronic musculoskeletal pain and various sleep disturbances are well established. The Pain and Sleep Questionnaire three-item index (PSQ-3) is a concise, valid, and reliable patient-reported outcome measure (PROM) that directly evaluates how sleep is affected by chronic low back pain (CLBP). Translation and cross-cultural validation of The Pain and Sleep Questionnaire three-item index Finnish version (PSQ-3-FI) were conducted according to established guidelines. The validation sample was 229 subjects, including 42 pain-free controls and 187 subjects with chronic musculoskeletal pain. Our aims were to evaluate internal consistency, test-retest reliability, measurement error, structural validity, convergent validity, and discriminative validity and, furthermore, to study the relationships between dizziness, postural control on a force plate, and objective sleep quality metrics and total PSQ-3-FI score. The PSQ-3-FI demonstrated good internal consistency, excellent test-retest reliability, and small measurement error. Confirmatory factor analysis confirmed acceptable fit indices to a one-factor model. Convergent validity indicated fair to good correlation with pain history and well-established pain-related PROMs. The PSQ-3-FI total score successfully distinguished between the groups with no pain, single-site pain, and multisite pain. A higher prevalence of dizziness, more impaired postural control, and a general trend towards poorer sleep quality were observed among subjects with higher PSQ-3-FI scores. Postural control instability was more evident in eyes-open tests. The Finnish PSQ-3 translation was successfully cross-culturally adapted and validated. The PSQ-3-FI appears to be a valid and reliable PROM for the Finnish-speaking CLBP population. More widespread implementation of PSQ-3 would lead to better understanding of the direct effects of pain on sleep.

Post-Concussion Dizziness, Sleep Quality, and Postural Instability: A Cross-Sectional Investigation

CONTEXT

Dizziness, postural instability, and poor sleep quality are all commonly reported post-concussion and individually relate to poor outcomes.

OBJECTIVE

To examine sleep quality and postural stability among adolescents who did and did not report dizziness within two weeks of concussion.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

PATIENTS OR OTHER PARTICIPANTS

Participants ages 12-18 years within 14 days of concussion (n=58, 15.2±1.8 years; 50% female; 7.1±3.1 days post-injury) and uninjured controls (n=73; 15.8±1.3 years; 42% female).

MAIN OUTCOME MEASURES

Participants completed pre-injury and current dizziness ratings on the Post-Concussion Symptom Inventory (PCSI) and current sleep quality on the Pittsburgh Sleep Quality Index (PSQI). Participants also completed postural stability assessments (single/dual-task tandem gait and modified Balance Error Scoring System [mBESS]).

RESULTS

We grouped concussion patients into dizzy (n=21) or not dizzy (n=37) groups based on PCSI dizziness ratings: difference between current and pre-injury dizziness rating >3=dizzy; difference <3=not dizzy. The dizzy and not dizzy groups both reported significantly worse sleep quality than the control group (PSQI score: mean=9.6±3.7 vs 7.2±3.5 vs 4.3±2.6; p<0.001) upon univariable comparison. Similarly, the dizzy group performed slowest on single and dual-task tandem gait, followed by the not dizzy group, then the control group (single-task TG: mean= 27.2±11.7 sec vs 21.2±6.3 vs 14.7±3.6; p<0.001); (dual-task TG: mean=38.4±16.2 sec vs 29.9±7.2 vs 21.6±7.5; p<0.001). Both concussion groups demonstrated significantly more errors than the control group on the mBESS (mean=9.8±5.1 vs 6.9±5.8 vs 3.8±3.5; p<0.001). After controlling for total symptom severity in the multivariable model, tandem gait, but not mBESS or sleep quality, was associated with dizziness.

CONCLUSION

Individuals with post-concussion dizziness also demonstrated impaired tandem gait performance, while poor sleep quality was associated with total symptom severity. Identifying and treating the underlying dysfunction contributing to dizziness and postural instability may guide individualized rehabilitation strategies and facilitate recovery.

Gaze stability in young adults with previous concussion history

BACKGROUND

Disruption of visual-vestibular interaction after concussion can cause gaze instability with head movements. The long-term impact of concussion on gaze stability is unknown.

OBJECTIVE

This cross-sectional comparative pilot study examined gaze stability in the chronic stage after concussion (greater than one year). A secondary objective was to examine the relationship between gaze stability and sleep.

METHODS

Outcome measures included: 1. Gaze stability in logMAR (mean loss of dynamic visual acuity (DVA) in the yaw and pitch planes); 2. Pittsburgh Sleep Quality Index (PSQI); 3. Epworth Sleepiness Scale (ESS). Post-Concussion Symptom Scale (PCSS), time since injury, and number of concussions were collected for the people with concussion.

RESULTS

The study sample included thirty-four adults (mean age 23.35±1.3 years). Seventeen had a history of 1-9 concussions, with a mean duration of 4.4±1.9 years since last concussion; and 17 were age and sex-matched controls. Mean pitch plane DVA loss was greater in the concussion group compared to the control group (p = 0.04). Participants with previous concussion had lower sleep quality based on the PSQI (p = 0.01) and increased daytime sleepiness based on the ESS (p = 0.01) compared to healthy controls. Mean DVA loss in the pitch plane was significantly correlated with the PSQI (r = 0.43, p = 0.01) and the ESS (r = 0.41, p = 0.02).

CONCLUSION

Significant differences in dynamic visual acuity may be found in young adults long after a concussion, compared with those who have no concussion history. Furthermore, loss of dynamic visual acuity was associated with poorer sleep quality and higher daytime sleepiness.

Oscillopsia in Bilateral Vestibular Hypofunction: Not Only Gain But Saccades Too

OBJECTIVES

Oscillopsia is a disabling condition for patients with bilateral vestibular hypofunction (BVH). When the vestibulo-ocular reflex is bilaterally impaired, its ability to compensate for rapid head movements must be supported by refixation saccades. The objective of this study is to assess the relationship between saccadic strategies and perceived oscillopsia.

DESIGN

To avoid the possibility of bias due to remaining vestibular function, we classified patients into two groups according to their gain values in the video head impulse test. One group comprised patients with extremely low gain (0.2 or below) in both sides, and a control group contained BVH patients with gain between 0.2 and 0.6 bilaterally. Binary logistic regression (BLR) was used to determine the variables predicting oscillopsia.

RESULTS

Twenty-nine patients were assigned to the extremely low gain group and 23 to the control group. The BLR model revealed the PR score (saccades synchrony measurement) to be the best predictor of oscillopsia. Receiver operating characteristic analysis determined that the most efficient cutoff point for the probabilities saved with the BLR was 0.518, yielding a sensitivity of 86.6% and specificity of 84.2%.

CONCLUSIONS

BVH patients with higher PR values (nonsynchronized saccades) were more prone to oscillopsia independent of their gain values. We suggest that the PR score can be considered a useful measurement of compensation.

Sleep Performance and Chronotype Behavior in Unilateral Vestibular Hypofunction

OBJECTIVE

To evaluate sleep behavior and its relation to otoneurological parameters in a group of patients with chronic unilateral vestibular hypofunction (UVH) without self-reported sleep disturbances when compared with healthy subjects serving as a control group (CG).

METHODS

Fifty-one patients affected by UVH underwent a retrospective clinical and instrumental otoneurological examination, a 1-week actigraphy sleep analysis, and a series of self-report and performance measures (SRM/PM). A CG of 60 gender- and age-matched healthy subjects was also enrolled. A between-group analysis of variance was performed for each variable, while correlation analysis was performed in UVH patients between otoneurological, SRM/PM, and actigraphy measure scores.

RESULTS

When compared with CG subjects, UVH patients were found to be spending less time sleeping and taking more time to go from being fully awake to asleep, based on actigraphy-based sleep analysis. Also, SRM/PM depicted UVH patients to have poor sleep quality and to be more prone to an evening-type behavior. Correlations were found between vestibular-related functionality indexes and subjective sleep quality, as well as between longer disease duration and reduced sleep time.

CONCLUSION

For the first time, a multiparametric sleep analysis was performed on a large population-based sample of chronic UVH patients. While a different pattern in sleep behavior was found, the cause is still unclear. Further research is needed to expand the extent of knowledge about sleep disruption in vestibular disorders.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 2021.

REM-related obstructive sleep apnea and vertigo: A retrospective case-control study

BACKGROUND

In recent population-based case-control studies, sleep apnea was significantly associated with a higher incidence (hazard ratio, 1.71) of vertigo and the risk of tinnitus was found to increase 1.36 times in patients with sleep apnea. The possibility that obstructive sleep apnea (OSA) might affect neurotological consequences was not noticed, until studies using polysomnography (PSG) for these patients.

OBJECTIVES

The purpose of this study was to investigate the relationship between vertigo and OSA.

METHODS

The collected data among patients from May 1st, 2018 to October 31th, 2018 at Shuang Ho Hospital. Eligibility criteria included an age older than 20 years, a diagnosis of obstructive sleep apnea. The diagnosis of OSA was defined as an oxygen desaturation index of at least 5, was established with the use of polysomnographic examination at hospital. Patients were excluded from the study if they had head injury, brain tumour, headache history and hearing loss. Patients who had vertigo were labeled as Vertigo group. In the other hand, patients who had no dizziness were labeled as control group. 58 patients were in the Vertigo group, and 113 were in the control group.

RESULTS

After PSG examination, 58 patients who had vertigo, were diagnosed OSA (29 males, average age = 57.07 years old, BMI = 26.64, RDI = 24.69, ESS = 8.65), and 24 patients of them (41.3%) were REM-related OSA. Meanwhile, in the control group, 113 patients had OSA (92male, average age = 49.66 years old, BMI = 26.06, RDI = 35.19, ESS = 11.43), and 18 patients of them (15.9%) were REM-related OSA (Table 1). Therefore, patient who had vertigo, would have higher proportion of REM OSA (P<0.001).

CONCLUSIONS

The vertigo patients have a higher rate of REM-related OSA, and the acceptance rate to CPAP use is low. Further research is needed to explore novel therapeutic approaches, or combination of currently available non-CPAP therapies, in patients with REM OSA.

Association between obstructive sleep apnea and persistent-postural perceptual dizziness

BACKGROUND

Obstructive sleep apnea (OSA) has been linked to vestibular dysfunction, but no prior studies have investigated the relationship between Persistent Postural Perceptual Dizziness (PPPD), a common cause of chronic dizziness, and OSA.

OBJECTIVE AND METHODS

We determined the frequency of OSA in an uncontrolled group of PPPD patients from a tertiary dizziness clinic based on polysomnogram (PSG). We then assessed the sensitivity and specificity of common OSA questionnaires in this population.

RESULTS

Twenty-five patients with PPPD underwent PSG (mean age 47, 60% female, mean BMI 29.5). A majority, or 56%, of patients were diagnosed with OSA, and in most, the OSA was severe. OSA patients were older (56 years versus 40 years, p = 0.0006) and had higher BMI (32 versus 26, p = 0.0078), but there was no clear gender bias (56% versus 64% female, p = 1.00). The mean sensitivity and specificity of the STOP BANG questionnaire for detecting OSA was 86% and 55%, respectively. Sensitivity and specificity of the Berlin Questionnaire was 79% and 45%, respectively.

CONCLUSIONS

The prevalence of OSA was much higher in our small PPPD group than in the general population. Screening questionnaires appear to demonstrate good sensitivity to detect PPPD patients at risk of OSA in this small study. Future studies should confirm these findings and determine whether treatment of OSA improves symptoms in PPPD.