Electrical stimulation of the peripheral and central vestibular system.

PURPOSE OF REVIEW: Electrical stimulation of the peripheral and central vestibular system using noninvasive (galvanic vestibular stimulation, GVS) or invasive (intracranial electrical brain stimulation, iEBS) approaches have a long history of use in studying self-motion perception and balance control. The aim of this review is to summarize recent electrophysiological studies of the effects of GVS, and functional mapping of the central vestibular system using iEBS in awake patients. RECENT FINDINGS: The use of GVS has become increasingly common in the assessment and treatment of a wide range of clinical disorders including vestibulopathy and Parkinson's disease. The results of recent single unit recording studies have provided new insight into the neural mechanisms underlying GVS-evoked improvements in perceptual and motor responses. Furthermore, the application of iEBS in patients with epilepsy or during awake brain surgery has provided causal evidence of vestibular information processing in mostly the middle cingulate cortex, posterior insula, inferior parietal lobule, amygdala, precuneus, and superior temporal gyrus. SUMMARY: Recent studies have established that GVS evokes robust and parallel activation of both canal and otolith afferents that is significantly different from that evoked by natural head motion stimulation. Furthermore, there is evidence that GVS can induce beneficial neural plasticity in the central pathways of patients with vestibular loss. In addition, iEBS studies highlighted an underestimated contribution of areas in the medial part of the cerebral hemispheres to the cortical vestibular network.

Neural bases of the bodily self as revealed by electrical brain stimulation: A systematic review.

An increasing amount of recent research has focused on the multisensory and neural bases of the bodily self. This pre-reflective form of self is considered as multifaceted, incorporating phenomenal components, such as self location, body ownership, first-person perspective, agency, and the perceptual body image. Direct electrical brain stimulation (EBS) during presurgical evaluation of epilepsy and brain tumor resection is a unique method to causally relate specific brain areas to the various phenomenal components of the bodily self. We conducted a systematic review of the literature describing altered phenomenal experience of the bodily self evoked by EBS. We included 42 articles and analyzed self reports from 221 patients. Three-dimensional density maps of EBS revealed that stimulation in the middle cingulum, inferior parietal lobule, supplementary motor area, posterior insula, hippocampal complex/amygdala, and precuneus most consistently altered one or several components of the bodily self. In addition, we found that only EBS in the parietal cortex induced disturbances of all five components of the bodily self considered in this review article. These findings inform current neuroscientific models of the bodily self.

Visual perspective, distance, and felt presence of others in dreams.

The peripersonal space, that is, the limited space surrounding the body, involves multisensory coding and representation of the self in space. Previous studies have shown that peripersonal space representation and the visual perspective on the environment can be dramatically altered when neurotypical individuals self-identify with a distant avatar (i.e., in virtual reality) or during clinical conditions (i.e., out-of-body experience, heautoscopy, depersonalization). Despite its role in many cognitive/social functions, the perception of peripersonal space in dreams, and its relationship with the perception of other characters (interpersonal distance in dreams), remain largely uncharted. The present study aimed to explore the visuospatial properties of this space, which is likely to underlie self-location as well as self/other distinction in dreams. 530 healthy volunteers answered a web-based questionnaire to measure their dominant visuo-spatial perspective in dreams, the frequency of recall for felt distances between their dream self and other dream characters, and the dreamers' viewing angle of other dream characters. Most participants reported dream experiences from a first-person perspective (1PP) (82%) compared to a third-person perspective (3PP) (18%). Independent of their dream perspective, participants reported that they generally perceived other dream characters in their close space, that is, at distance of either between 0 and 90 cm, or 90-180 cm, than in further spaces (180-270 cm). Regardless of the perspective (1PP or 3PP), both groups also reported more frequently seeing other dream characters from eye level (0° angle of viewing) than from above (30° and 60°) or below eye level (-30° and -60°). Moreover, the intensity of sensory experiences in dreams, as measured by the Bodily Self-Consciousness in Dreams Questionnaire, was higher in individuals who habitually see other dream characters closer to their personal dream self (i.e., within 0-90 cm and 90-180 cm). These preliminary findings offer a new, phenomenological account of space representation in dreams with regards to the felt presence of others. They might provide insights not only to our understanding of how dreams are formed, but also to the type of neurocomputations involved in self/other distinction.

Prenatal imaging of genital defects: clinical spectrum and predictive factors for severe forms.

OBJECTIVES: To report the clinical spectrum of genital defects diagnosed before birth, identify predictive factors for severe phenotypes at birth, and determine the rate of associated malformations. PATIENTS AND METHODS: A retrospective study (2008-2017) of 4580 fetuses, identified prenatally with abnormalities evaluated by our Reference Center for Fetal Medicine, included cases with fetal sonographic findings of abnormal genitalia or uncertainty of fetal sex determination. Familial, prenatal and postnatal data were collected via a standardised questionnaire. RESULTS: In all, 61 fetuses were included. The positive predictive value (PPV) of the prenatal diagnosis of genital defects was 90.1%. Most cases were 46,XY-undervirilized boys, 42 cases (68.8%), which included 29 with mid-penile or posterior hypospadias, nine with anterior hypospadias, and epispadias, micropenis, scrotal transposition, and buried penis (one each). In all, 46,XX-virilized girls were identified in seven cases (11.5%), which included four with congenital adrenal hyperplasia, two with isolated clitoromegaly, and one with ovotestis. Other defects included prune belly syndrome and persistent cloaca (six cases). Early detection during the second trimester (58.1% vs 18.8%, P = 0.03), intra-uterine growth restriction (IUGR) (45.2% vs 9.1%, P = 0.06), and curvature of the penis (38.7% vs 0%, P = 0.02), were more frequently related to severe defects in male newborns. Associated malformations (14 cases, 22.9%) and genetic defects (six) were frequent in undervirilized boys. CONCLUSION: Prenatal imaging of genital defects leads to a wide range of phenotypes at birth. Its PPV is high and extra-urinary malformations are frequent. Early diagnosis during the second trimester, associated IUGR, and curvature of the genital tubercle, should raise suspicion of a severe phenotype and may justify delivery near a multidisciplinary disorders/differences of sex development team.

Late surgical correction of hypospadias increases the risk of complications: a series of 501 consecutive patients.

OBJECTIVES: To evaluate the outcomes of hypospadias surgery according to age and to determine if some complications are age-related. PATIENTS AND METHODS: This retrospective study was based on 722 boys with hypospadias undergoing primary repair. A total of 501 boys underwent urethroplasty and were included in the study. Complications requiring an additional procedure (stenosis, fistula, dehiscence, relapse of curvature, urethrocele) were included in the analysis, as well as healing problems, infections, haematomas and detrusor-sphincter dyssynergy. Logistic regression analysis was performed. RESULTS: Hypospadias was anterior in 63.1%, mid-penile in 20.5%, posterior in 8.4% and scrotal in 7.9% of the boys. The median (range) age was 4 (1-16) years. The overall rates of re-intervention and complications were 22.8% and 36.2%, respectively. Age >2 years was a significant predictor of complications (P = 0.002, odds ratio 1.98 [95% confidence interval 1.26-3.13]). Some periods of time appeared to be associated with a specific complication: dyssynergy was more common between the ages of 24 and 36 months (12.5 vs 3.6%; P = 0.01) and healing problems were more common in boys aged >13 years (1.5 vs 28.5%; P = 0.06). CONCLUSION: Delayed surgery may be detrimental for patients. Factors related to age may influence the rate of complications. After the age of 2 years, urethral surgery may interfere with the normal toilet-training process. During puberty, endogenous testosterone may alter healing. Even if no specific data exist for severe hypospadias, it may be prudent to continue to advocate early surgery in patients with disorders of sex development.

Oscillatory neural responses evoked by natural vestibular stimuli in humans.

While there have been numerous studies of the vestibular system in mammals, less is known about the brain mechanisms of vestibular processing in humans. In particular, of the studies that have been carried out in humans over the last 30 years, none has investigated how vestibular stimulation (VS) affects cortical oscillations. Here we recorded high-density electroencephalography (EEG) in healthy human subjects and a group of bilateral vestibular loss patients (BVPs) undergoing transient and constant-velocity passive whole body yaw rotations, focusing our analyses on the modulation of cortical oscillations in response to natural VS. The present approach overcame significant technical challenges associated with combining natural VS with human electrophysiology and reveals that both transient and constant-velocity VS are associated with a prominent suppression of alpha power (8-13 Hz). Alpha band suppression was localized over bilateral temporo-parietal scalp regions, and these alpha modulations were significantly smaller in BVPs. We propose that suppression of oscillations in the alpha band over temporo-parietal scalp regions reflects cortical vestibular processing, potentially comparable with alpha and mu oscillations in the visual and sensorimotor systems, respectively, opening the door to the investigation of human cortical processing under various experimental conditions during natural VS.

The vestibular system: balancing more than just the body.

PURPOSE OF REVIEW: The review presents a selection of recent studies in the field of vestibular neuroscience, including how vestibular stimulation modulates space and body perception. RECENT FINDINGS: Recent neuroimaging studies identified the operculo-insular/retroinsular cortex as the core vestibular cortex and showed how it is reorganized after vestibular dysfunctions. Subliminal galvanic vestibular stimulation (GVS) induces long-term reduction of hemispatial neglect and improves vertical perception in stroke patients, but the underlying mechanisms remain to be identified. Healthy volunteer research suggests that GVS and caloric vestibular stimulation (CVS) modulate visual and somatosensory processing and that beneficial effects of GVS/CVS in stroke patients are not limited to merely rebalancing brain hemispheric activity. Another mechanism would be that GVS/CVS anchors the self to the body, thus promoting an egocentric frame of reference. SUMMARY: In addition to 'balancing the body', the vestibular cortical network contributes to modulate space, body and self-awareness. Emerging evidence suggests that the vestibular network expands into dimensions of emotion processing, mental health, and social cognition. Here, the importance of connecting vestibular physiology, affective neuroscience, and social neuroscience to better understand the psychological aspects of vertigo in otoneurology is discussed.

Vestibular responses to direct stimulation of the human insular cortex.

OBJECTIVE: The present study provides a functional mapping of vestibular responses in the human insular cortex. METHODS: A total of 642 electrical stimulations of the insula were performed in 219 patients, using stereotactically implanted depth electrodes, during the presurgical evaluation of drug-refractory partial epilepsy. We retrospectively identified 41 contacts where stimulation elicited vestibular sensations (VSs) and analyzed their location with respect to (1) their stereotactic coordinates (for all contacts), (2) the anatomy of insula gyri (for 20 vestibular sites), and (3) the probabilistic cytoarchitectonic maps of the insula (for 9 vestibular sites). RESULTS: VSs occurred in 7.6% of the 541 evoked sensations after electrical stimulations of the insula. VSs were mostly obtained after stimulation of the posterior insula, that is, in the granular insular cortex and the postcentral insular gyrus. The data also suggest a spatial segregation of the responses in the insula, with the rotatory and translational VSs being evoked at more posterior stimulation sites than other less definable VSs. No left-right differences were observed. INTERPRETATION: These results demonstrate vestibular sensory processing in the insula that is centered on its posterior part. The present data add to the understanding of the multiple sensory functions of the insular cortex and of the cortical processing of vestibular signals. The data also indicate that lesion or dysfunction in the posterior insula should be considered during the evaluation of vestibular epileptic seizures.

Bodily ownership and self-location: components of bodily self-consciousness.

Recent research on bodily self-consciousness has assumed that it consists of three distinct components: the experience of owning a body (body ownership); the experience of being a body with a given location within the environment (self-location); and the experience of taking a first-person, body-centered, perspective on that environment (perspective). Here we review recent neuroimaging studies suggesting that at least two of these components-body ownership and self-location-are implemented in rather distinct neural substrates, located, respectively, in the premotor cortex and in the temporo-parietal junction. We examine these results and consider them in relation to clinical evidence from patients with altered body perception and work on a variety of multisensory, body-related illusions, such as the rubber hand illusion, the full body illusion, the body swap illusion and the enfacement illusion. We conclude by providing a preliminary synthesis of the data on bodily self-consciousness and its neural correlates.

Understanding the neural bases of bodily self-consciousness: recent achievements and main challenges.

The last two decades have seen a surge of interest in the mechanisms underpinning bodily self-consciousness (BSC). Studies showed that BSC relies on several bodily experiences (i.e., self-location, body ownership, agency, first-person perspective) and multisensory integration. The aim of this literature review is to summarize new insights and novel developments into the understanding of the neural bases of BSC, such as the contribution of the interoceptive signals to the neural mechanisms of BSC, and the overlap with the neural bases of conscious experience in general and of higher-level forms of self (i.e., the cognitive self). We also identify the main challenges and propose future perspectives that need to be conducted to progress into the understanding of the neural mechanisms of BSC. In particular, we point the lack of crosstalk and cross-fertilization between subdisciplines of integrative neuroscience to better understand BSC, especially the lack of research in animal models to decipher the neural networks and systems of neurotransmitters underpinning BSC. We highlight the need for more causal evidence that specific brain areas are instrumental in generating BSC and the need for studies tapping into interindividual differences in the phenomenal experience of BSC and their underlying mechanisms.

Vestibular rehabilitation improves spontaneous nystagmus normalization in patients with acute unilateral vestibulopathy.

Introduction: Spontaneous nystagmus (SN) can be observed after acute unilateral vestibulopathy (AUVP). The slow phase eye velocity of the SN progressively decreases in darkness as the result of rebalanced neurophysiological activity between both vestibular nuclei, a process that can take several months. Although this compensatory process can occur spontaneously, there is poor evidence that vestibular rehabilitation (VR) can facilitate the process. Methods: We documented the natural time course of SN reduction in patients with AUVP, as well as the effects of VR by means of a unilateral rotation paradigm. In a retrospective study (Study 1: n = 126 AUVP patients), we compared the time course of the SN reduction in patients with VR (n = 33) and without VR (n = 93). In a prospective study (Study 2: n = 42 AUVP patients), we compared the effects of early VR (n = 22; initiated within the first two weeks of symptoms onset) or late VR (n = 20; initiated after the second week of symptoms onset) on the time course of the SN reduction. Results: Study 1 showed shorter median time of SN normalization in patients with VR compared to patients without VR (14 days and 90 days, respectively). Study 2 showed that AUVP patients with early and late VR had a similar median time of SN normalization. The SN slow phase eye velocity was significantly decreased as early as the end of the first VR session in both groups, and kept decreasing at each subsequent VR session. In the early VR group, 38% of the patients had slow phase eye velocity below 2°/s after the first VR session, 100% after the fifth session. Similar findings were observed in the late VR group. Discussion: Taken together, these results indicate that VR with a unidirectional rotation paradigm speeds up the normalization of SN. This effect seems independent of the time between symptoms onset and commencement of VR, but early intervention is recommended to speed up the SN reduction.

The origin of pleasant sensations: Insight from direct electrical brain stimulation.

Research into the neuroanatomical basis of emotions has resulted in a plethora of studies over the last twenty years. However, studies about positive emotions and pleasant sensations remain rare and their anatomical-functional bases are less understood than that of negative emotions. Pleasant sensations can be evoked by electrical brain stimulations (EBS) during stereotactic electroencephalography (SEEG) performed for pre-surgical exploration in patients with drug-resistant epilepsy. We conducted a retrospective analysis of 10 106 EBS performed in 329 patients implanted with SEEG in our epileptology department. We found that 13 EBS in 9 different patients evoked pleasant sensations (.60% of all responses). By contrast we collected 111 emotional responses of negative valence (i.e., 5.13% of all responses). EBS evoking pleasant sensations were applied at 50 Hz with an average intensity of 1.4 ± .55 mA (range .5-2 mA). Pleasant sensations were reported by nine patients of which three patients presented responses to several EBS. We found a male predominance among the patients reporting pleasant sensations and a prominent role of the right cerebral hemisphere. Results show the preponderant role of the dorsal anterior insula and amygdala in the occurrence of pleasant sensations.

Navigation strategies in patients with vestibular loss tested in a virtual reality T-maze.

During navigation, humans mainly rely on egocentric and allocentric spatial strategies, two different frames of reference working together to build a coherent representation of the environment. Spatial memory deficits during navigation have been repeatedly reported in patients with vestibular disorders. However, little is known about how vestibular disorders can change the use of spatial navigation strategies. Here, we used a new reverse T-maze paradigm in virtual reality to explore whether vestibular loss specifically modifies the use of egocentric or allocentric spatial strategies in patients with unilateral (n = 23) and bilateral (n = 23) vestibular loss compared to healthy volunteers (n = 23) matched for age, sex and education level. Results showed that the odds of selecting and using a specific strategy in the T-maze were significantly reduced in both unilateral and bilateral vestibular loss. An exploratory analysis suggests that only right vestibular loss decreased the odds of adopting a spatial strategy, indicating an asymmetry of vestibular functions. When considering patients who used strategies to navigate, we observed that a bilateral vestibular loss reduced the odds to use an allocentric strategy, whereas a unilateral vestibular loss decreased the odds to use an egocentric strategy. Age was significantly associated with an overall lower chance to adopt a navigation strategy and, more specifically, with a decrease in the odds of using an allocentric strategy. We did not observe any sex difference in the ability to select and use a specific navigation strategy. Findings are discussed in light of previous studies on visuo-spatial abilities and studies of vestibulo-hippocampal interactions in peripheral vestibular disorders. We discuss the potential impact of the history of the disease (chronic stage in patients with a bilateral vestibulopathy vs. subacute stage in patients with a unilateral vestibular loss), of hearing impairment and non-specific attentional deficits in patients with vestibular disorders.

Partial and full own-body illusions of epileptic origin in a child with right temporoparietal epilepsy.

Partial and full own-body illusions of neurological origin have been claimed crucial to understand the contribution of bodily experience and perception to self-consciousness. Whereas partial body illusions are relatively common and well defined, much less is known about full own-body illusions, and even less is known about these illusions in children. Here we describe a 10-year-old patient with the association of partial and full own-body illusions (somatoparaphrenia and out-of-body experience) that occurred sequentially during an epileptic seizure caused by right temporoparietal epilepsy. This report shows that partial and full own-body illusions share functional and neuroanatomical properties and highlights the importance of the right temporoparietal junction for bodily self-consciousness. This is the first report of out-of-body experiences in a child with focal epilepsy.

Vestibular-Evoked Cerebral Potentials.

The human vestibular cortex has mostly been approached using functional magnetic resonance imaging and positron emission tomography combined with artificial stimulation of the vestibular receptors or nerve. Few studies have used electroencephalography and benefited from its high temporal resolution to describe the spatiotemporal dynamics of vestibular information processing from the first milliseconds following vestibular stimulation. Evoked potentials (EPs) are largely used to describe neural processing of other sensory signals, but they remain poorly developed and standardized in vestibular neuroscience and neuro-otology. Yet, vestibular EPs of brainstem, cerebellar, and cortical origin have been reported as early as the 1960s. This review article summarizes and compares results from studies that have used a large range of vestibular stimulation, including natural vestibular stimulation on rotating chairs and motion platforms, as well as artificial vestibular stimulation (e.g., sounds, impulsive acceleration stimulation, galvanic stimulation). These studies identified vestibular EPs with short latency (<20 ms), middle latency (from 20 to 50 ms), and late latency (>50 ms). Analysis of the generators (source analysis) of these responses offers new insights into the neuroimaging of the vestibular system. Generators were consistently found in the parieto-insular and temporo-parietal junction-the core of the vestibular cortex-as well as in the prefrontal and frontal areas, superior parietal, and temporal areas. We discuss the relevance of vestibular EPs for basic research and clinical neuroscience and highlight their limitations.

Abnormal self-location and vestibular vertigo in a patient with right frontal lobe epilepsy.

We describe the case of a 33-year-old man with complex partial seizures characterized by the feeling of being projected outside his body, including dissociation of "mind and self from body" (disembodiment), followed by vestibular vertigo due to right frontal lobe epilepsy caused by an oligodendroglioma. We distinguish the patient's ictal symptoms with respect to autoscopic phenomena (out-of-body experience, heautoscopy, autoscopic hallucinations) and vestibular phenomena of epileptic origin, and we discuss their neural origin with respect to vestibular and multisensory cortical mechanisms of bodily self-consciousness in temporoparietal and frontal cortex.

How vestibular stimulation interacts with illusory hand ownership.

Artificial stimulation of the peripheral vestibular system has been shown to improve ownership of body parts in neurological patients, suggesting vestibular contributions to bodily self-consciousness. Here, we investigated whether galvanic vestibular stimulation (GVS) interferes with the mechanisms underlying ownership, touch, and the localization of one's own hand in healthy participants by using the "rubber hand illusion" paradigm. Our results show that left anodal GVS increases illusory ownership of the fake hand and illusory location of touch. We propose that these changes are due to vestibular interference with spatial and/or temporal mechanisms of visual-tactile integration leading to an enhancement of visual capture. As only left anodal GVS lead to such changes, and based on neurological data on body part ownership, we suggest that this vestibular interference is mediated by the right temporo-parietal junction and the posterior insula.

Measuring perceived self-location in virtual reality.

Third-person perspective full-body illusions (3PP-FBI) enable the manipulation, through multisensory stimulation, of perceived self-location. Perceived self-location is classically measured by a locomotion task. Yet, as locomotion modulates various sensory signals, we developed in immersive virtual reality a measure of self-location without locomotion. Tactile stimulation was applied on the back of twenty-five participants and displayed synchronously or asynchronously on an avatar's back seen from behind. Participants completed the locomotion task and a novel mental imagery task, in which they self-located in relation to a virtual ball approaching them. Participants self-identified with the avatar more during synchronous than asynchronous visuo-tactile stimulation in both tasks. This was accentuated for the mental imagery task, showing a larger self-relocation toward the avatar, together with higher reports of presence, bi-location and disembodiment in the synchronous condition only for the mental imagery task. In conclusion, the results suggest that avoiding multisensory updating during walking, and using a perceptual rather than a motor task, can improve measures of illusory self-location.

Interoception and embodiment in patients with bilateral vestibulopathy.

There are tight functional and anatomical links between the vestibular and interoceptive systems, and both systems have shown to fundamentally underlie emotional processes and our sense of a bodily self. Yet, nothing is known about how long-term bilateral vestibulopathy (BVP) influences interoception and its relation to embodiment and the sense of self. We thus compared cardiac interoceptive accuracy, confidence in the performance, and general body awareness in 25 BVP patients and healthy controls using a heartbeat tracking task, self-reports about interoceptive awareness, as well as measures of self-localization and of self-body closeness. Results showed no difference between patients and controls regarding interoceptive accuracy, confidence and body awareness, suggesting that long-term BVP does not influence cardiac interoception. Patients and controls did not differ either regarding self-location and self-body closeness. However, in our overall sample of patients and controls, we found that interoceptive accuracy increased with perceived self-body closeness, suggesting that anchoring the self to the body is generally linked with better cardiac interoception. This result is in line with previous suggestions of an important contribution of interoception to the sense of embodiment.

Vestibular rehabilitation in Europe: a survey of clinical and research practice.

Vestibular rehabilitation (VR) is practiced across Europe but little in this area has been quantified. The aim of this study was to investigate current VR assessment, treatment, education, and research practices. This was an online, cross-sectional survey with 39 VR specific questions and four sections: demographics, current practice, education, and research. The survey was disseminated through the Dizzynet network to individual therapists through country-specific VR special interest groups. Results were analysed descriptively. A thematic approach was taken to analyse open questions. A total of 471 individuals (median age 41, range 23 - 68 years, 73.4% women), predominately physiotherapists (89.4%) from 20 European countries responded to the survey. They had worked for a median of 4 years (range < 1 - 35) in VR. The majority (58.7%) worked in hospital in-patient or out-patient settings and 21.4% in dedicated VR services. Most respondents specialized in neurology, care of the elderly (geriatrics), or otorhinolaryngology. VR was reported as hard/very hard to access by 48%, with the main barriers to access identified as lack of knowledge of health care professionals (particularly family physicians), lack of trained therapists, and lack of local services. Most respondents reported to know and treat benign paroxysmal positional vertigo (BPPV 87.5%), unilateral vestibular hypofunction (75.6%), and cervicogenic dizziness (63%). The use of vestibular assessment equipment varied widely. Over 70% used high-density foam and objective gait speed testing. Over 50% used dynamic visual acuity equipment. Infrared systems, Frenzel lenses, and dynamic posturography were not commonly employed (< 20%). The most frequently used physical outcome measures were the Clinical Test of the Sensory Interaction of Balance, Functional Gait Assessment/Dynamic Gait Index, and Romberg/Tandem Romberg. The Dizziness Handicap Inventory, Visual Analogue Scale, Falls Efficacy Scale, and the Vertigo Symptom Scale were the most commonly used patient reported outcome measures. Adaptation, balance, and habituation exercises were most frequently used (> 80%), with virtual reality used by 15.6%. Over 70% reported knowledge/use of Semont, Epley and Barbeque-Roll manoeuvres for the treatment of BPPV. Most education regarding VR was obtained at post-registration level (89.5%) with only 19% reporting pre-registration education. There was strong (78%) agreement that therapists should have professionally accredited postgraduate certification in VR, with blended learning the most popular mode. Three major research questions were identified for priority: management of specific conditions, effectiveness of VR, and mechanisms/factors influencing vestibular compensation and VR. In summary, the survey quantified current clinical practice in VR across Europe. Knowledge and treatment of common vestibular diseases was high, but use of published subjective and objective outcome measures as well as vestibular assessment varied widely. The results stress the need of improving both training of therapists and standards of care. A European approach, taking advantage of best practices in some countries, seems a reasonable approach.