113 results found
Rust HM, Smith RM, Mahmud M, et al., 2022, Force-dependency of benign paroxysmal positional vertigo in acute traumatic brain injury: a prospective study, Journal of Neurology, Neurosurgery and Psychiatry, ISSN: 0022-3050
Mahmud M, Hadi Z, Prendergast M, et al., 2022, The effect of galvanic vestibular stimulation on postural balance in Parkinson’s Disease: A systematic review and meta-analysis
<jats:title>Abstract</jats:title><jats:p>People with Parkinson’s disease (PD) experience postural imbalance, leading to considerably increased risk of falls. Galvanic Vestibular Stimulation (GVS) is postulated to modulate postural balance in humans and improve it in PD. This systematic review and meta-analysis investigate the effects of GVS on postural balance in PD.</jats:p><jats:p>Six separate databases and research registers were searched for cross-over design trials that evaluated the effects of GVS on postural balance in PD. We used standardized mean difference (Hedges’ g) as a measure of effect size in all studies.</jats:p><jats:p>We screened 223 studies, evaluated 14, of which five qualified for the meta-analysis. Among n = 40 patients in five studies (range n= 5 to 13), using a fixed effects model we found an effect size estimate of g = 0.43 (p < 0.001, 95% CI [0.29,0.57]). However, the test for residual heterogeneity was significant (p < 0.001), thus we used a random effects model and found a pooled effect size estimate of 0.62 (p > 0.05, 95% CI [– 0.17, 1.41], I2 = 96.21%). Egger’s test was not significant and thus trim and funnel plot indicated no bias. To reduce heterogeneity, we performed sensitivity analysis and by removing one outlier study (n = 7 patients), we found an effect size estimate of 0.16 (p < 0.05, 95% CI [0.01, 0.31], I2 = 0%).</jats:p><jats:p>Our meta-analysis found GVS has a favourable effect on postural balance in PD patients, but due to limited literature and inconsistent methodologies, this favourable effect must be interpreted with caution.</jats:p>
Hadi Z, Pondeca Y, Calzolari E, et al., 2022, The human brain networks mediating the vestibular sensation of self-motion, BIORXIV
<jats:title>Abstract</jats:title><jats:p>Vestibular Agnosia - where peripheral vestibular activation triggers the usual reflex nystagmus response but with attenuated or no self-motion perception - is found in brain disease with disrupted cortical network functioning, e.g. traumatic brain injury (TBI) or neurodegeneration (Parkinson’s Disease). Patients with acute focal hemispheric lesions (e.g. stroke) do not manifest vestibular agnosia. Thus brain network mapping techniques, e.g. resting state functional MRI (rsfMRI), are needed to interrogate functional brain networks mediating vestibular agnosia. Whole-brain rsfMRI was acquired from 39 prospectively recruited acute TBI patients with preserved peripheral vestibular function, along with self-motion perceptual thresholds during passive yaw rotations in the dark. Following quality-control checks, 25 patient scans were analyzed. TBI patients were classified as having vestibular agnosia (n = 11) or not (n = 14) via laboratory testing of self-motion perception. Using independent component analysis, we found altered functional connectivity in the right superior longitudinal fasciculus and left rostral prefrontal cortex in vestibular agnosia. Moreover, regions of interest analyses showed both inter-hemispheric and intra-hemispheric network disruption in vestibular agnosia. In conclusion, our results show that vestibular agnosia is mediated by bilateral anterior and posterior network dysfunction and reveal the distributed brain mechanisms mediating vestibular self-motion perception.</jats:p>
Smith R, Burgess C, Marsden J, et al., 2021, Benign paroxysmal positional vertigo in acute traumatic brain injury patients - data from a multi-centre prospective randomised feasibility study, 25th World Congress of Neurology (WCN), Publisher: ELSEVIER, ISSN: 0022-510X
Hadi Z, Pondeca YJ, Calzolari E, et al., 2021, Vestibular Agnosia Linked to Widespread Abnormality of Functional Brain Networks, BNA 2021, Publisher: SAGE Publications, ISSN: 2398-2128
Calzolari E, Chepisheva M, Smith RM, et al., 2021, Vestibular agnosia in traumatic brain injury and its link to imbalance., Brain, Vol: 144, Pages: 128-143
Vestibular dysfunction, causing dizziness and imbalance, is a common yet poorly understood feature in patients with TBI. Damage to the inner ear, nerve, brainstem, cerebellum and cerebral hemispheres may all affect vestibular functioning, hence, a multi-level assessment-from reflex to perception-is required. In a previous report, postural instability was the commonest neurological feature in ambulating acute patients with TBI. During ward assessment, we also frequently observe a loss of vertigo sensation in patients with acute TBI, common inner ear conditions and a related vigorous vestibular-ocular reflex nystagmus, suggesting a 'vestibular agnosia'. Patients with vestibular agnosia were also more unbalanced; however, the link between vestibular agnosia and imbalance was confounded by the presence of inner ear conditions. We investigated the brain mechanisms of imbalance in acute TBI, its link with vestibular agnosia, and potential clinical impact, by prospective laboratory assessment of vestibular function, from reflex to perception, in patients with preserved peripheral vestibular function. Assessment included: vestibular reflex function, vestibular perception by participants' report of their passive yaw rotations in the dark, objective balance via posturography, subjective symptoms via questionnaires, and structural neuroimaging. We prospectively screened 918 acute admissions, assessed 146 and recruited 37. Compared to 37 matched controls, patients showed elevated vestibular-perceptual thresholds (patients 12.92°/s versus 3.87°/s) but normal vestibular-ocular reflex thresholds (patients 2.52°/s versus 1.78°/s). Patients with elevated vestibular-perceptual thresholds [3 standard deviations (SD) above controls' average], were designated as having vestibular agnosia, and displayed worse posturography than non-vestibular-agnosia patients, despite no difference in vestibular symptom scores. Only in patients with impaired postural control (3 SD above c
Smith R, Marroney N, Beattie J, et al., 2020, A mixed methods randomised feasibility trial investigating the management of benign paroxysmal positional vertigo in acute traumatic brain injury, Pilot and Feasibility Studies, Vol: 6, Pages: 1-10, ISSN: 2055-5784
BackgroundTraumatic brain injury (TBI) is the leading cause of long-term disability in working age adults. Recent studies show that most acute TBI patients demonstrate vestibular features of dizziness and imbalance, often from combined peripheral and central vestibular dysfunction. Effective treatment for vestibular impairments post-TBI is important given its significant adverse impact upon quality of life and employment prospects. The most frequent peripheral vestibular disorder in acute TBI is benign paroxysmal positional vertigo (BPPV), affecting approximately half of acute cases. Although there is effective treatment for idiopathic BPPV, there are no high quality clinical data for post-TBI BPPV regarding its prevalence, natural history, which treatment is most effective and when is the best time to treat. In particular, observational studies suggest post-TBI BPPV may be recurrent indicating that hyperacute treatment of BPPV may be futile. Given the potential hurdles and the lack of accurate post-TBI BPPV data, the current study was designed to provide information regarding the feasibility and the optimal design of future large-scale prospective treatment studies that would compare different interventions and their timing for post-TBI BPPV. MethodA multi-centre randomised mixed methods feasibility study design was employed. We aim to recruit approximately 75 acute TBI patients across a range of clinical severities, from three major trauma centres in London. Patients will be randomised to one of three treatment arms: (1) therapist-led manoeuvres; (2) patient-led exercises; and (3) advice. Participants will be re-assessed by blinded outcome assessors at 4 and 12 weeks. Acceptability of the intervention will be obtained by patient interviews at the end of their treatment, and therapist interviews at the end of the study. Primary outcomes relate to feasibility parameters including recruitment and retention rates, adverse events, and intervention fidelity. We will al
Shaikh AG, Bronstein A, Carmona S, et al., 2020, Consensus on virtual management of vestibular disorders: urgent versus expedited care, The Cerebellum: an international journal from neurosciences to clinical perspectives, Pages: 1-5, ISSN: 1473-4222
The virtual practice has made major advances in the way that we care for patients in the modern era. The culture of virtual practice, consulting, and telemedicine, which had started several years ago, took an accelerated leap as humankind was challenged by the novel coronavirus pandemic (COVID19). The social distancing measures and lockdowns imposed in many countries left medical care providers with limited options in evaluating ambulatory patients, pushing the rapid transition to assessments via virtual platforms. In this novel arena of medical practice, which may form new norms beyond the current pandemic crisis, we found it critical to define guidelines on the recommended practice in neurotology, including remote methods in examining the vestibular and eye movement function. The proposed remote examination methods aim to reliably diagnose acute and subacute diseases of the inner-ear, brainstem, and the cerebellum. A key aim was to triage patients into those requiring urgent emergency room assessment versus non-urgent but expedited outpatient management. Physicians who had expertise in managing patients with vestibular disorders were invited to participate in the taskforce. The focus was on two topics: (1) an adequate eye movement and vestibular examination strategy using virtual platforms and (2) a decision pathway providing guidance about which patient should seek urgent medical care and which patient should have non-urgent but expedited outpatient management.
Murdin L, Seemungal BM, Bronstein AM, 2020, Assessment of dizziness in neurology, Medicine, ISSN: 1357-3039
Dizziness and vertigo are common symptoms. Because there are effective treatments for vestibular disorders, it is always important to make an accurate diagnosis. In acute vertigo, expert clinical assessment is critically important in discerning stroke from non-stroke causes because results of stroke-protocol brain magnetic resonance imaging, including diffusion-weighted imaging, can be falsely negative in the first 24 hours. It follows that acute medical services must have access to clinicians expert in assessing acute vertigo. Expertise in clinical examination and interpretation of findings requires appropriate training, but here we outline the basic diagnostic and therapeutic approach to patients with dizziness. Appropriate early management of these conditions is part of prevention of disabling chronic functional dizziness.
Harris L, Hateley S, Tsang KT, et al., 2020, Impact of anti-epileptic drug choice on discharge in acute traumatic brain injury patients, JOURNAL OF NEUROLOGY, Vol: 267, Pages: 1774-1779, ISSN: 0340-5354
Lempert T, Seemungal BM, 2020, How to define migraine with brainstem aura?, Brain, ISSN: 1460-2156
Marcus HJ, Paine H, Sargeant M, et al., 2019, Vestibular dysfunction in acute traumatic brain injury, Journal of Neurology, Vol: 266, Pages: 2430-2433, ISSN: 0340-5354
Traumatic brain injury (TBI) is the commonest cause of disability in under-40-year-olds. Vestibular features of dizziness (illusory self-motion) or imbalance which affects 50% of TBI patients at 5 years, increases unemployment threefold in TBI survivors. Unfortunately, vestibular diagnoses are cryptogenic in 25% of chronic TBI cases, impeding therapy. We hypothesized that chronic adaptive brain mechanisms uncouple vestibular symptoms from signs. This predicts a masking of vestibular diagnoses chronically but not acutely. Hence, defining the spectrum of vestibular diagnoses in acute TBI should clarify vestibular diagnoses in chronic TBI. There are, however, no relevant acute TBI data. Of 111 Major Trauma Ward adult admissions screened (median 38-years-old), 96 patients (87%) had subjective dizziness (illusory self-motion) and/or objective imbalance were referred to the senior author (BMS). Symptoms included: feeling unbalanced (58%), headache (50%) and dizziness (40%). In the 47 cases assessed by BMS, gait ataxia was the commonest sign (62%) with half of these cases denying imbalance when asked. Diagnoses included BPPV (38%), acute peripheral unilateral vestibular loss (19%), and migraine phenotype headache (34%), another potential source of vestibular symptoms. In acute TBI, vestibular signs are common, with gait ataxia being the most frequent one. However, patients underreport symptoms. The uncoupling of symptoms from signs likely arises from TBI affecting perceptual mechanisms. Hence, the cryptogenic nature of vestibular symptoms in TBI (acute or chronic) relates to a complex interaction between injury (to peripheral and central vestibular structures and perceptual mechanisms) and brain-adaptation, emphasizing the need for acute prospective, mechanistic studies.
Connor TA, Clark JM, Jayamohan J, et al., 2019, Do equestrian helmets prevent concussion? A retrospective analysis of head injuries and helmet damage from real-world equestrian accidents, Sports Medicine - Open, Vol: 5, Pages: 19-19, ISSN: 2198-9761
OBJECTIVES: To collect and analyse helmets from real-world equestrian accidents. To record reported head injuries associated with those accidents. To compare damage to helmets certified to different standards and the injuries associated with them. METHODS: Two hundred sixteen equestrian helmets were collected in total. One hundred seventy-six helmets from amateur jockeys were collected via accident helmet return schemes in the UK and USA, while 40 helmets from professional jockeys were collected by The Irish Turf Club. All helmet damage was measured, and associated head injury was recorded. RESULTS: Eighty-eight percent (189) of equestrian fall accidents returned an injury report of which 70% (139) reported a head injury. Fifty-four percent (75) of head injury cases had associated helmet damage while 46% had no helmet damage. Reported head injuries consisted of 91% (126) concussion, 4% (6) skull fractures, 1 (0.7%) subdural hematoma, 1 (0.7%) cerebral edema and 5 (3.6%) diffuse axonal injury (DAI). It is also shown that helmets certified to the most severe standard are overrepresented in this undamaged group (p <0.001). CONCLUSIONS: It is clear that despite jockeys wearing a helmet, large proportions of concussion injuries still occur in the event of a jockey sustaining a fall. However, the data suggest it is likely that helmets reduce the severity of head injury as the occurrence of skull fracture is low. The proportion of undamaged helmets with an associated head injury suggests that many helmets may be too stiff relative to the surface they are impacting to reduce the risk of traumatic brain injury (TBI). It may be possible to improve helmet designs and certification tests to reduce the risk of head injury in low-severity impacts.
Harris L, Hateley S, Seemungal B, 2019, PHENYTOIN VERSUS LEVETIRACETAM FOR POST TRAUMATIC BRAIN INJURY SEIZURE PROPHYLAXIS; A RETROSPECTIVE STUDY AT A UK MAJOR TRAUMA CENTRE, Joint Autumn Meeting of the Society-of-British-Neurological-Surgeons (SBNS)/Association-of-British-Neurologists (ABN), Publisher: BMJ PUBLISHING GROUP, Pages: E31-E31, ISSN: 0022-3050
Smith R, Chepisheva M, Cronin T, et al., 2019, Diagnostic approaches techniques in concussion/mild traumatic brain injury: Where are we?, Neurosensory Disorders in Mild Traumatic Brain Injury, Pages: 247-277, ISBN: 9780128125489
Currently, sporting body consensus criteria consider concussion to be a mild traumatic brain injury (mTBI), which is indicated by a transient mental obtundation. Acute concussion diagnosis, thus, relies upon first-hand observation of the impact and the effect upon the patient (or recorded video), and clinical assessment including clinical history and examination. The diagnosis of a concussion can be difficult if there are no witnesses. Additionally, the inability of the patient to provide a clear account of the circumstances of the injury can make the diagnostic process more challenging, and on the other hand, is suggestive of a retrospective amnesia and, hence, supportive of a concussion. However, the converse may not be true, since some patients may provide a clear history of no concussion, but display objective signs of momentary mental obtundation, not recalled by the patient. Thus, since a concussion diagnosis by patient history is problematic, diagnosis should rely upon objective measures, including third-person witness account, clinical examination, and laboratory testing. We review the different means to make a diagnosis of concussion.
Rust HM, Seemungal BM, Kheradmand A, 2019, Vestibular Perception: From Bench to Bedside, Contemporary Clinical Neuroscience, Pages: 43-71
Classic experiments over several decades examined the physiology and pathophysiology of a critical brainstem function called vestibulo-ocular reflex. These studies provided a wealth of information on how the brain, particularly the cerebellum and brainstem, computes the representation of our own motion in order to generate compensatory movements. Contemporary literature over last two decades started focusing on an equally important aspects of vestibular function – the motion perception and spatial orientation. From both physiological and computational standpoints, these studies further extended the application of cerebellar principles (for the control of vestibulo-ocular reflex) to thalamic and cortical function, emphasising on cerebello-cerebral connections. This chapter provides a concise review of the physiology and pathophysiology of vestibular perception and discusses seminal work from our laboratories.
Papathanasiou ES, Cronin T, Seemungal B, et al., 2018, Electrophysiological testing in concussion: A guide to clinical applications, Journal of Concussion, Vol: 2, ISSN: 2059-7002
The diagnosis of mild traumatic brain injury in concussion is difficult since it is often unwitnessed, the patient’s recall is unreliable and initial clinical examination is often unrevealing, correlating poorly with the extent of brain injury. At present, there are no objective biomarkers of mild traumatic brain injury in concussion. Thus, a sensitive gold standard test is required to enable the effective and safe triage of patients who present to the acute services. As well as triage, objective monitoring of patients’ recovery over time and separate from clinical features that patients may develop following the injury (e.g. depression and migraine) is also needed. In contrast to neuroimaging, which is widely used to investigate traumatic brain injury patients, electrophysiology is readily available, is cheap and there are internationally recognized standardised methodologies. Herein, we review the existing literature on electrophysiological testing in concussion and mild traumatic brain injury; specifically, electroencephalogram, polysomnography, brainstem auditory evoked potentials, electro- and videonystagmography, vestibular evoked myogenic potentials, visually evoked potentials, somatosensory evoked potentials and transcranial magnetic stimulation.
Sargeant M, Sykes E, Saviour M, et al., 2018, The utility of the Sports Concussion Assessment Tool in hospitalized traumatic brain injury patients, Journal of Concussion, Vol: 2, ISSN: 2059-7002
The Sports Concussion Assessment Tool 3rd version is a sports screening tool that is often used to support return to play decisions following a head injury. The Sports Concussion Assessment Tool 3rd version is presumed to identify brain dysfunction (implying a degree of brain injury); however, the Sports Concussion Assessment Tool has never been validated with patients with definite acute brain injury. In this study, we found that all three Sports Concussion Assessment Tool 3rd version domains – symptoms, cognitive and balance assessments – were sensitive in discriminating traumatic brain injury patients (all with abnormal acute neuroimaging) from healthy controls. Through a correlation matrix (Bonferroni corrected), we found no correlation between the subjective (symptoms) and objective (examination) Sports Concussion Assessment Tool 3rd version assessments, e.g. complaints of imbalance and memory dysfunction were not correlated, respectively, with performance on testing balance and memory function. When relaxing the correction for multiple comparisons we found that of all Sports Concussion Assessment Tool 3rd version symptoms, a feeling of ‘pressure in the head’ had the largest number of co-correlations (including affective symptoms) and overwhelmingly in a pattern indicative of migraine. Taken together, that objective and subjective assessments in the Sports Concussion Assessment Tool 3rd version are poorly correlated, could suggest that symptoms in the Sports Concussion Assessment Tool 3rd version poorly reflect brain injury but rather indicate non-brain injury processes such as migraine. It follows that the current prominent orthodoxy of resting athletes following a head injury until their symptoms settle for fear of exacerbating brain injury may be unfavourable for their recovery – at least in some cases. Prospective clinical studies would be required to assess patient recovery from concussion with early active investigation and t
Xiang M, Glasauer S, Seemungal BM, 2018, Quantitative postural models as biomarkers of balance in Parkinson’s disease, Brain, Vol: 141, Pages: 2824-2827, ISSN: 1460-2156
Seemungal BM, Passamonti L, 2018, Persistent postural-perceptual dizziness: a useful new syndrome, Practical Neurology, Vol: 18, Pages: 3-4, ISSN: 1474-7766
Cronin T, Arshad Q, Seemungal BM, 2017, Vestibular deficits in neurodegenerative disorders: balance, dizziness, and spatial disorientation, Frontiers in Neurology, Vol: 8, ISSN: 1664-2295
The vestibular system consists of the peripheral vestibular organs in the inner ear and the associated extensive central nervous system projections—from the cerebellum and brainstem to the thalamic relays to cortical projections. This system is important for spatial orientation and balance, both of critical ecological importance, particularly for successful navigation in our environment. Balance disorders and spatial disorientation are common presenting features of neurodegenerative diseases; however, little is known regarding central vestibular processing in these diseases. A ubiquitous aspect of central vestibular processing is its promiscuity given that vestibular signals are commonly found in combination with other sensory signals. This review discusses how impaired central processing of vestibular signals—typically in combination with other sensory and motor systems—may account for the impaired balance and spatial disorientation in common neurodegenerative conditions. Such an understanding may provide for new diagnostic tests, potentially useful in detecting early disease while a mechanistic understanding of imbalance and spatial disorientation in these patients may enable a vestibular-targeted therapy for such problems in neurodegenerative diseases. Studies with state of the art central vestibular testing are now much needed to tackle this important topic.
Allen D, Ribeiro L, Arshad Q, et al., 2017, Age-Related Vestibular Loss: Current Understanding and Future Research Directions, Frontiers in Neurology, Vol: 8, ISSN: 1664-2295
The vestibular system sub-serves a number of reflex and perceptual functions, comprisingthe peripheral apparatus, the vestibular nerve, the brainstem and cerebellarprocessing circuits, the thalamic relays, and the vestibular cerebral cortical network.This system provides signals of self-motion, important for gaze and postural control,and signals of traveled distance, for spatial orientation, especially in the dark. Currentevidence suggests that certain aspects of this multi-faceted system may deteriorate withage and sometimes with severe consequences, such as falls. Often the deterioration investibular functioning relates to how the signal is processed by brain circuits rather thanan impairment in the sensory transduction process. We review current data concerningage-related changes in the vestibular system, and how this may be important for cliniciansdealing with balance disorders.
Allen D, Ribeiro L, Arshad Q, et al., 2017, Age-Related Vestibular Loss: Current Understanding and Future Research Directions (vol 7, 231, 2016), FRONTIERS IN NEUROLOGY, Vol: 8, ISSN: 1664-2295
Ahmad H, Roberts E, Patel M, et al., 2017, Downregulation of early visual cortex excitability mediates oscillopsia, Neurology, Vol: 89, Pages: 1179-1185, ISSN: 0028-3878
Objective; Identifying the neurophysiological mechanisms that mediate adaptation to oscillopsia in patients with bilateral-vestibular failure (BVF); an observational study. Methods; We directly probe the hypothesis that adaptive changes which mediate oscillopsia suppression implicate the early visual-cortex (V1/V2). Accordingly, we investigated (V1/V2) excitability using transcranial magnetic stimulation (TMS) in 12 avestibular patients and 12 healthy controls. Specifically, we assessed TMS-induced phosphene thresholds at baseline and cortical excitability changes whilst performing a visual-motion adaptation paradigm during the following conditions: (i) BASELINE measures (i.e. static), (ii) during visual-motion (i.e. MOTION PRE ADAPTATION) and, (iii) during visual-motion following 5 minutes of unidirectional visual-motion adaptation (i.e. MOTION ADAPTED). Results: Patients had significantly higher baseline phosphene-thresholds, reflecting an underlying adaptive mechanism. Individual thresholds were correlated with oscillopsia symptom load. During the visual-motion adaptation condition, no differences in excitability at BASELINE were observed but, during both MOTION PRE ADAPTATION and MOTION ADAPTED conditions, we observed significantly attenuated cortical excitability in patients. Again this attenuation in excitability was stronger in less symptomatic patients.Conclusion; Our findings provide neurophysiological evidence that cortically-mediated adaptive mechanisms in V1/V2 play a critical role in suppressing oscillopsia in patients with bilateral vestibular failure.
Cousins S, Kaski D, Cutfield N, et al., 2017, Predictors of clinical recovery from vestibular neuritis: a prospective study, Annals of Clinical and Translational Neurology, Vol: 4, Pages: 340-346, ISSN: 2328-9503
We sought to identify predictors of symptomatic recovery in vestibular neuritis. Forty VN patients were prospectively studied in the acute phase (median = 2 days) and 32 in the recovery phase (median = 10 weeks) with vestibulo-ocular reflex, vestibular-perceptual, and visual dependence tests and psychological questionnaires. Clinical outcome was Dizziness Handicap Inventory score at recovery phase. Acute visual dependency and autonomic arousal predicted outcome. Worse recovery was associated with a combination of increased visual dependence, autonomic arousal, anxiety/depression, and fear of bodily sensations, but not with vestibular variables. Findings highlight the importance of early identification of abnormal visual dependency and concurrent anxiety.
Arshad Q, Roberts RE, Ahmad H, et al., 2017, Patients with chronic dizziness following traumatic head injury typically have multiple diagnoses involving combined peripheral and central vestibular dysfunction, CLINICAL NEUROLOGY AND NEUROSURGERY, Vol: 155, Pages: 17-19, ISSN: 0303-8467
, 2017, The Components of Vestibular Cognition — Motion Versus Spatial Perception, Vestibular Cognition, Publisher: BRILL, Pages: 25-42
Roberts RE, Arshad Q, Patel M, et al., 2016, Functional neuroimaging of visuo-vestibular interaction, Brain Structure & Function, Vol: 222, Pages: 2329-2343, ISSN: 1863-2661
The brain combines visual, vestibular and proprioceptive information to distinguish between self-and world-motion. Often these signals are complementary and indicate that the individual is moving or stationary with respect to the surroundings. However, conflicting visual motion and vestibular cues can lead to ambiguous or false sensations of motion. In this study, we used functional magnetic resonance imaging to explore human brain activation when visual and vestibular cues were either complementary or in conflict. We combined a horizontally moving optokinetic stimulus with caloric irrigation of the right ear to produce conditions where the vestibular activation and visual motion indicatedthe same (congruent) or opposite directions of self-motion (incongruent). Visuo-vestibular conflict was associated with increased activation in a network of brain regions including posterior insular and transverse temporal areas, cerebellar tonsil, cingulate and medial frontal gyri. In the congruent condition there was increased activation in primary and secondary visual cortex. These findings suggest that when sensory information regarding self-motion is contradictory, there is preferential activation of multisensoryvestibular areas to resolve this ambiguity. When cues are congruent there is a bias towards visual cortical activation. The data support the view thata network of brain areas including the posterior insular cortex may play animportant role in integrating and disambiguating visual and vestibular cues.
Patel M, Agarwal K, Arshad Q, et al., 2016, Intratympanic methylprednisolone versus gentamicin in patients with unilateral Ménière's disease: a randomised, double-blind, comparative effectiveness trial, The Lancet, Vol: 388, Pages: 2753-2762, ISSN: 0140-6736
BACKGROUND: Ménière's disease is characterised by severe vertigo attacks and hearing loss. Intratympanic gentamicin, the standard treatment for refractory Ménière's disease, reduces vertigo, but damages vestibular function and can worsen hearing. We aimed to assess whether intratympanic administration of the corticosteroid methylprednisolone reduces vertigo compared with gentamicin. METHODS: In this double-blind comparative effectiveness trial, patients aged 18-70 years with refractory unilateral Ménière's disease were enrolled at Charing Cross Hospital (London, UK) and Leicester Royal Infirmary (Leicester, UK). Patients were randomly assigned (1:1) by a block design to two intratympanic methylprednisolone (62·5 mg/mL) or gentamicin (40 mg/mL) injections given 2 weeks apart, and were followed up for 2 years. All investigators and patients were masked to treatment allocation. The primary outcome was vertigo frequency over the final 6 months (18-24 months after injection) compared with the 6 months before the first injection. Analyses were done in the intention-to-treat population, and then per protocol. This trial is registered with ClinicalTrials.gov, number NCT00802529. FINDINGS: Between June 19, 2009, and April 15, 2013, 256 patients with Ménière's disease were screened, 60 of whom were enrolled and randomly assigned: 30 to gentamicin and 30 to methylprednisolone. In the intention-to-treat analysis (ie, all 60 patients), the mean number of vertigo attacks in the final 6 months compared with the 6 months before the first injection (primary outcome) decreased from 19·9 (SD 16·7) to 2·5 (5·8) in the gentamicin group (87% reduction) and from 16·4 (12·5) to 1·6 (3·4) in the methylprednisolone group (90% reduction; mean difference -0·9, 95% CI -3·4 to 1·6). Patients whose vertigo did not improve after injection (ie, non-responders)
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