Publications
429 results found
Minakaran N, Soorma T, Bronstein AM, et al., 2019, Charles Bonnet syndrome and periodic alternating nystagmus Moving visual hallucinations, Neurology, Vol: 92, Pages: E1072-E1075, ISSN: 1526-632X
ObjectiveTo describe and discuss potential mechanisms for modulation of visual hallucinations by nystagmus.MethodsWe present 2 patients with coexistent Charles Bonnet syndrome and periodic alternating nystagmus in the context of acquired visual loss.ResultsThe combination has given rise to a rare phenomenon: visual hallucinations that move in a manner governed by the nystagmus, specifically by the direction and velocity of the slow phase. The perceived modulation of movement is selective for a surface in one case and a landscape in the other but not present for hallucinated individual objects and people separate from the hallucinated background visual scene.ConclusionsThe collision of Charles Bonnet syndrome and periodic alternating nystagmus in these 2 patients has demonstrated that some visual hallucinations can be modulated by, or collaterally with, ocular movements. We propose 2 potential mechanisms based on ocular proprioceptive input from extraocular muscles projecting to either extrastriate processing of visual scene, or to higher-order visual cortical areas involved in analysis of motion signals across the whole visual field.
Bronstein A, Bednarczuk N, Bonsu A, et al., 2019, Abnormal visuo-vestibular interactions in vestibular migraine: a cross sectional study, BRAIN, Vol: 142, Pages: 606-616, ISSN: 1460-2156
Vestibular migraine is among the commonest causes of episodic vertigo. Chronically, patients with vestibular migraine develop abnormal responsiveness to both vestibular and visual stimuli characterized by heightened self-motion sensitivity and visually-induced dizziness. Yet, the neural mechanisms mediating such symptoms remain unknown. We postulate that such symptoms are attributable to impaired visuo-vestibular cortical interactions, which in turn disrupts normal vestibular function. To assess this, we investigated whether prolonged, full-field visual motion exposure, which has been previously shown to modulate visual cortical excitability in both healthy individuals and avestibular patients, could disrupt vestibular ocular reflex and vestibular-perceptual thresholds of self-motion during rotations. Our findings reveal that vestibular migraine patients exhibited abnormally elevated reflexive and perceptual vestibular thresholds at baseline. Following visual motion exposure, both reflex and perceptual thresholds were significantly further increased in vestibular migraine patients relative to healthy controls, migraineurs without vestibular symptoms and patients with episodic vertigo due to a peripheral inner-ear disorder. Our results provide support for the notion of altered visuo-vestibular cortical interactions in vestibular migraine, as evidenced by vestibular threshold elevation following visual motion exposure.
Bronstein AM, Dieterich M, 2019, Long-term clinical outcome in vestibular neuritis., Curr Opin Neurol, Vol: 32, Pages: 174-180
PURPOSE OF REVIEW: To review recent work on clinical and imaging aspects of vestibular neuritis (or acute vestibular syndrome), in particular with a view to identifying factors predicting long-term clinical outcome. RECENT FINDINGS: Evidence for a role of inflammation in the vestibular nerve, and the presence of Gadolinium enhancement acutely in vestibular neuritis, is accruing. Visual dependence, anxiety and somatization traits predict the development of chronic dizziness after acute vestibular neuritis. Adaptation to asymmetric rotation is impaired in vestibular neuritis and this may indicate insufficient central compensation in chronic dizzy patients. Corticosteroids appear ineffective at improving long-term clinical outcome. Functional imaging changes during the central compensation period lead to structural brain changes; both processes correlate with clinical recovery. SUMMARY: Vestibular neuritis appears to be the result of postviral neuroinflammation of the vestibular nerve. However, long-term prognosis is not dependent on the magnitude of the peripheral residual damage (as measured with caloric and video head-impulse test). Instead, a combination of visuovestibular psychophysical factors (visual dependence), psychological traits and dysfunctional vestibular perception are relevant. Several functional and structural neuroimaging changes develop after vestibular neuritis, which reflect and underlie the aforementioned psychophysiological and psychological features.
Castro P, Kaskia D, Schieppati M, et al., 2019, Subjective stability perception is related to postural anxiety in older subjects, GAIT & POSTURE, Vol: 68, Pages: 538-544, ISSN: 0966-6362
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- Citations: 15
Kaski D, Rust HM, Ibitoye R, et al., 2019, Theoretical framework for "unexplained" dizziness in the elderly: The role of small vessel disease, Editors: Ramat, Shaikh, Publisher: ELSEVIER SCIENCE BV, Pages: 225-240
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- Citations: 8
Castro P, Sena Esteves S, Lerchundi F, et al., 2018, Viewing target distance influences the vestibulo-ocular reflex gain when assessed using the video head impulse test, Audiology and Neurotology, Vol: 23, Pages: 285-289, ISSN: 1420-3030
Gaze stabilization during head movements is provided by the vestibulo-ocular reflex (VOR). Clinical assessment of this reflex is performed using the video Head Impulse Test (vHIT). To date, the influence of different fixation distances on VOR gain using the vHIT has not been explored. We assessed the effect of target proximity on the horizontal VOR using the vHIT. Firstly, we assessed the VOR gain in 18 healthy subjects with 5 viewing target distances (150, 40, 30, 20, and 10 cm). The gain increased significantly as the viewing target distance decreased. A second experiment on 10 subjects was performed in darkness whilst the subjects were imagining targets at different distances. There were significant inverse relationships between gain and distance for both the real and the imaginary targets. There was a statistically significant difference between light and dark gains for the 20- and 40-cm distances, but not for the 150-cm distance. Theoretical VOR gains for different target distances were calculated and compared with those found in light and darkness. The increase in gain observed for near targets was lower than predicted by geometrical calculations, implying a physiological ceiling effect on the VOR. The VOR gain in the dark, as assessed with the vHIT, demonstrates an enhancement associated with a reduced target distance.
Edwards A, Guven O, Furman M, et al., 2018, Electroencephalographic correlates of continuous postural tasks of increasing difficulty, Neuroscience, Vol: 395, Pages: 35-48, ISSN: 0306-4522
Cortical involvement in postural control is well recognized, however the role of non-visual afferents remains unclear. Parietal cortical areas are strongly implicated in vestibulo-spatial functions, but topographical localization during balance tasks remains limited. Here, we use electroencephalography (EEG) during continuous balance tasks of increasing difficulty at single electrode positions. Twenty-four healthy, right-handed individuals performed four balance tasks of increasing difficulty (bipedal and unipedal) and a seated control condition with eyes closed. Subjective ratings of task difficulty were obtained. EEG was recorded from 32 electrodes; 5 overlying sensory and motor regions of interest (ROIs) were chosen for further investigation: C3, Cz, C4, P3, P4. Spectral power and coherence during balance tasks were analyzed in theta (4–8 Hz) and alpha (8–12 Hz) bands. Alpha power reduced as task difficulty increased and this reduction correlated with subjective difficulty ratings. Alpha coherence increased with task difficulty between C3–Cz–C4 electrode pairs. Differential changes in power were observed in Cz, suggestive of a distinct role at this electrode location, which captures lower limb cortical representation. Hemispheric asymmetry was observed, as reflected by greater reductions in theta and alpha power in right-sided areas. Our results demonstrate the functional importance of bilateral central and parietal cortices in continuous balance control. The hemispheric asymmetry observed implies that the non-dominant hemisphere is involved with online monitoring of postural control. Although the posterior parietal asymmetry found may relate to vestibular, somatosensory or multisensory feedback processing, we argue that the finding relates to active balance control rather than simple sensory-intake or reflex circuit activation.
Roberts R, Ahmad H, Patel M, et al., 2018, An fMRI study of visuo-vestibular interaction in Vestibular Neuritis, NeuroImage: Clinical, Vol: 20, Pages: 1010-1017, ISSN: 2213-1582
Vestibular neuritis (VN) is characterised by acute vertigo due to a sudden loss of unilateral vestibular function. A considerable proportion of VN patients proceed to develop chronic symptoms of dizziness, including visually induced dizziness, specifically during head turns. Here we investigated whether the development of such poor clinical outcomes following VN, is associated with abnormal visuo-vestibular cortical processing. Accordingly, we applied functional magnetic resonance imaging to assess brain responses of chronic VN patients and compared these to controls during both congruent (co-directional) and incongruent (opposite directions) visuo-vestibular stimulation (i.e. emulating situations that provoke symptoms in patients). We observed a focal significant difference in BOLD signal in the primary visual cortex V1 between patients and controls in the congruent condition (small volume corrected level of p < .05 FWE). Importantly, this reduced BOLD signal in V1 was negatively correlated with functional status measured with validated clinical questionnaires. Our findings suggest that central compensation and in turn clinical outcomes in VN are partly mediated by adaptive mechanisms associated with the early visual cortex.
Ahmad H, Requena T, Frejo L, et al., 2018, A novel variant in ELF2 gene in cerebellar ataxia, neuropathy and vestibular areflexia syndrome (CANVAS) upregulates ataxin-2 translation in BE(2)-M17 cells, 50th European-Society-of-Human-Genetics (ESHG) Conference, Publisher: NATURE PUBLISHING GROUP, Pages: 376-377, ISSN: 1018-4813
Balint B, Antelmi E, Mencacci NE, et al., 2018, Oculomotor apraxia and disrupted sleep with nocturnal ballistic bouts in ADCY5-related disease, PARKINSONISM & RELATED DISORDERS, Vol: 54, Pages: 103-106, ISSN: 1353-8020
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- Citations: 10
Kaski DN, Haider S, Male A, et al., 2018, Adult periodic alternating nystagmus masked by involuntary head movements: a case report, Frontiers in Neurology, Vol: 9, ISSN: 1664-2295
A 20-year-old previously well female presented with a history of abrupt onset recurrent episodic (seconds) “dizziness” characterized by a shimmering of the world in front of her. By day 3 she began to experience a constant sensation of vertigo, oscillopsia, mild headache, and prominent vomiting. She was afebrile, had no neck stiffness, but described photophobia. She had gradually developed an involuntary mild side-to-side continuous head movement by day 3. On day 6 there was a constant “no-no” head movement with variable frequency (circa. 2–4 Hz) and amplitude (circa. 15° peak-to-peak) and initially had a fast phase component to the right, with occasional oblique movements (Video S1 in Supplementary Material). The family reported that the movement disappeared during sleep. On admission to hospital, there was right-beating nystagmus (RBN) in the primary position intensifying on right gaze and also apparent on upgaze (Video S1 in Supplementary Material). The intensity of the nystagmus was enhanced during positional maneuvers, without a change in nystagmus direction. Oculographic recordings were not available acutely. The gait was unsteady, with asymmetric step length, inconsistent foot placement, and variable left foot intorsion, sug-gesting a functional (psychogenic) etiology (Video S2 in Supplementary Material). There was no limb ataxia, and no myoclonus. Ten days after the original assessment the head movements worsened dramatically, rendering interpretation of the eye movements difficult (Figure 1A; Video S3 in Supplementary Material), but the patient continued to complain of oscillopsia, even when the examiner attempted to restrain the head manually (the patient did not consent to the use of a bite bar). The head tremor resolved immediately on day 21 after symptom onset with subtherapeutic 50 mouse units of abobotulinumtoxin A applied to the levator sc
Ahmad H, Requena T, Frejo L, et al., 2018, Clinical and functional characterization of a missense ELF2 variant in a CANVAS Family, Frontiers in Genetics, Vol: 9, ISSN: 1664-8021
Cerebellar ataxia with neuropathy and bilateral vestibular areflexia syndrome (CANVAS) is a rare disorder with an unknown etiology. We present a British family with presumed autosomal dominant CANVAS with incomplete penetrance and variable expressivity. Exome sequencing identified a rare missense variant in the ELF2 gene at chr4:g.140058846 C > T, c.10G > A, p.A4T which segregated in all affected patients. By using transduced BE (2)-M17 cells, we found that the mutated ELF2 (mt-ELF2) gene increased ATXN2 and reduced ELOVL5 gene expression, the causal genes of type 2 and type 38 spinocerebellar ataxias. Both, western blot and confocal microscopy confirmed an increase of ataxin-2 in BE(2)-M17 cells transduced with lentivirus expressing mt-ELF2 (CEE-mt-ELF2), which was not observed in cells transduced with lentivirus expressing wt-ELF2 (CEE-wt-ELF2). Moreover, we observed a significant decrease in the number and size of lipid droplets in the CEE-mt-ELF2-transduced BE (2)-M17 cells, but not in the CEE-wt-ELF2-transduced BE (2)-M17. Furthermore, changes in the expression of ELOVL5 could be related with the reduction of lipid droplets in BE (2)-M17 cells. This work supports that ELF2 gene regulates the expression of ATXN2 and ELOVL5 genes, and defines new molecular links in the pathophysiology of cerebellar ataxias.
Patel M, Arshad Q, Seemungal BM, et al., 2018, Steroid injections through the eardrum reduce dizziness in Meniere’s disease, study finds - REPLY TO ADRION ET AL. ON PATEL ET AL., British Medical Journal, Vol: 355, ISSN: 0959-8138
Staab JP, Eckhardt-Henn A, Horii A, et al., 2018, Diagnostic criteria for persistent postural-perceptual dizziness (PPPD): Consensus document of the committee for the Classification of Vestibular Disorders of the Barany Society, Journal of Vestibular Research, Vol: 27, Pages: 191-208, ISSN: 0957-4271
This paper presents diagnostic criteria for persistent postural-perceptual dizziness (PPPD) to be included in the International Classification of Vestibular Disorders (ICVD). The term PPPD is new, but the disorder is not. Its diagnostic criteria were derived by expert consensus from an exhaustive review of 30 years of research on phobic postural vertigo, space-motion discomfort, visual vertigo, and chronic subjective dizziness. PPPD manifests with one or more symptoms of dizziness, unsteadiness, or non-spinning vertigo that are present on most days for three months or more and are exacerbated by upright posture, active or passive movement, and exposure to moving or complex visual stimuli. PPPD may be precipitated by conditions that disrupt balance or cause vertigo, unsteadiness, or dizziness, including peripheral or central vestibular disorders, other medical illnesses, or psychological distress. PPPD may be present alone or co-exist with other conditions. Possible subtypes await future identification and validation. The pathophysiologic processes underlying PPPD are not fully known. Emerging research suggests that it may arise from functional changes in postural control mechanisms, multi-sensory information processing, or cortical integration of spatial orientation and threat assessment. Thus, PPPD is classified as a chronic functional vestibular disorder. It is not a structural or psychiatric condition.
Arshad Q, Nigmatullina Y, Siddiqui S, et al., 2017, Influence of biases in numerical magnitude allocation on human prosocial decision making, JOURNAL OF NEUROPHYSIOLOGY, Vol: 118, Pages: 3007-3013, ISSN: 0022-3077
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- Citations: 1
Bronstein A, 2017, Clinical neuro-otology of spatial orientation, 23rd World Congress of Neurology (WCN), Publisher: ELSEVIER SCIENCE BV, Pages: 15-15, ISSN: 0022-510X
Arshad Q, Bonsu A, Lobo R, et al., 2017, Biased numerical cognition impairs economic decision-making in Parkinson’s disease, Annals of Clinical and Translational Neurology, Vol: 4, Pages: 739-748, ISSN: 2328-9503
ObjectivePrevious findings suggest a context-dependent bihemispheric allocation of numerical magnitude. Accordingly, we predicted that lateralized motor symptoms in Parkinson's disease (PD), which reflect hemispheric asymmetries, would induce systematic lateralized biases in numerical cognition and have a subsequent influence on decision-making.MethodsIn 20 PD patients and matched healthy controls we assessed numerical cognition using a number-pair bisection and random number generation task. Decision-making was assessed using both the dictator game and a validated questionnaire.ResultsPD patients with predominant right-sided motor symptoms exhibited pathological biases toward smaller numerical magnitudes and formulated less favorable prosocial choices during a neuroeconomics task (i.e., dictator game). Conversely, patients with left-sided motor symptoms exhibited pathological biases toward larger numerical magnitudes and formulated more generous prosocial choices. Our account of context-dependent hemispheric allocation of numerical magnitude in PD was corroborated by applying our data to a pre-existing computational model and observing significant concordance. Notably, both numerical biasing and impaired decision-making were correlated with motor asymmetry.InterpretationAccordingly, motor asymmetry and functional impairment of cognitive processes in PD can be functionally intertwined. To conclude, our findings demonstrate context-dependent hemispheric allocation and encoding of numerical magnitude in PD and how biases in numerical magnitude allocation in Parkinsonian patients can correspondingly impair economic decision-making.
Bronstein AM, Panichi R, Faralli M, et al., 2017, Asymmetric vestibular stimulation reveals persistent disruption of motion perception in unilateral vestibular lesions, American Journal of Physiology, Vol: 118, Pages: 2819-2832, ISSN: 0002-9513
Self-motion perception was studied in patients with unilateral vestibular lesions (UVL) due to acute vestibular neuritis at 1 week, 4, 8 and 12 months after the acute episode. We assessed vestibularly-mediated self-motion perception by measuring the error in reproducing the position of a remembered visual target at the end of 4 cycles of asymmetric whole-body rotation. The oscillatory stimulus consists of a slow (0.09Hz) and a fast (0.38Hz) half cycle. A large error was present in UVL patients when the slow half cycle was delivered towards the lesion side, but minimal towards the healthy side. This asymmetry diminished over time, but it remained abnormally large at 12 months. In contrast, vestibulo-ocular reflex responses showed a large direction-dependent error only initially, then they normalized. Normalization also occurred for conventional reflex vestibular measures (caloric tests, subjective visual vertical and head shaking nystagmus) and for perceptual function during symmetric rotation. Vestibular-related handicap, measured with the Dizziness Handicap Inventory (DHI) at 12 months, correlated with self-motion perception asymmetry but not with abnormalities in vestibulo-ocular function. We conclude that 1) a persistent self-motion perceptual bias is revealed by asymmetric rotation in UVLs despite vestibulo-ocular function becoming symmetric over time 2) this dissociation is caused by differential perceptual-reflex adaptation to high and low frequency rotations when these are combined as with our asymmetric stimulus 3) the findings imply differential central compensation for vestibulo-perceptual and vestibulo-ocular reflex functions 4) self-motion perception disruption may mediate long-term vestibular-related handicap in UVL patients.
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.
Bednarczuk NF, Ortega MC, Fluri A-S, et al., 2017, Inter-hemispheric control of vestibular thresholds, BRAIN STIMULATION, Vol: 10, Pages: 988-991, ISSN: 1935-861X
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- Citations: 9
Geraghty AWA, Essery R, Kirby S, et al., 2017, Internet-based Vestibular Rehabilitation for older adults with chronic dizziness: a randomized controlled trial in primary care, Annals of Family Medicine, Vol: 15, Pages: 209-216, ISSN: 1544-1709
PURPOSE Vestibular rehabilitation is an effective intervention for dizziness due to vestibular dysfunction, but is seldom provided. We aimed to determine the effectiveness of an Internet-based vestibular rehabilitation program for older adults experiencing dizziness in primary care.METHODS We undertook a single-center, single-blind randomized controlled trial comparing an Internet-based vestibular rehabilitation intervention (Balance Retraining, freely available from https://balance.lifeguidehealth.org) with usual primary care in patients from 54 primary care practices in southern England. Patients aged 50 years and older with current dizziness exacerbated by head movements were enrolled. Those in the intervention group accessed an automated Internet-based program that taught vestibular rehabilitation exercises and suggested cognitive behavioral management strategies. Dizziness was measured by the Vertigo Symptom Scale–Short Form (VSS-SF) at baseline, 3 months, and 6 months. The primary outcome was VSS-SF score at 6 months.RESULTS A total of 296 patients were randomized in the trial; 66% were female, and the median age was 67 years. The VSS-SF was completed by 250 patients (84%) at 3 months and 230 patients (78%) at 6 months. Compared with the usual care group, the Internet-based vestibular rehabilitation group had less dizziness on the VSS-SF at 3 months (difference, 2.75 points; 95% CI, 1.39–4.12; P <.001) and at 6 months (difference, 2.26 points; 95% CI, 0.39–4.12; P = .02, respectively). Dizziness-related disability was also lower in the Internet-based vestibular rehabilitation group at 3 months (difference, 6.15 points; 95% CI, 2.81–9.49; P <.001) and 6 months (difference, 5.58 points; 95% CI, 1.19–10.0; P = .01).CONCLUSIONS Internet-based vestibular rehabilitation reduces dizziness and dizziness-related disability in older primary care patients without requiring clinical support. This intervention has potential for wide appl
Kaski D, Bronstein AM, 2017, Ocular tremor in Parkinson’s disease: discussion, debate, and controversy, Frontiers in Neurology, Vol: 8, ISSN: 1664-2295
The identification of ocular tremor in a small cohort of patients with Parkinson’s disease (PD) had lay somewhat dormant until the recent report of a pervasive ocular tremor as a universal finding in a large PD cohort that was, however, generally absent from a cohort of age-matched healthy subjects. The reported tremor had frequency characteristics similar to those of PD limb tremor, but the amplitude and frequency of the tremor did not correlate with clinical tremor ratings. Much controversy ensued as to the origin of such a tremor, and specifically as to whether a pervasive ocular tremor was a fundamental feature of PD, or rather a compensatory eye oscillation secondary to a transmitted head tremor, and thus a measure of a normal vestibulo-ocular reflex. In this mini review, we summarize some of the evidence for and against the case for a pervasive ocular tremor in PD and suggest future experiments that may help resolve these conflicting opinions.
Lyon S, Goodkin DA, Bronstein AM, et al., 2017, Clinical News., Br J Hosp Med (Lond), Vol: 78, Pages: 8-11, ISSN: 1750-8460
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)
Kaski D, Pradhan V, Bronstein AM, 2016, Clinical features of functional (psychogenic) eye movement disorders., J Neurol Neurosurg Psychiatry, Vol: 87, Pages: 1389-1392
Lubeck AJA, Van Ombergen A, Ahmad H, et al., 2016, Differential effect of visual motion adaption upon visual cortical excitability, Journal of Neurophysiology, Vol: 117, Pages: 903-909, ISSN: 0022-3077
The objectives of this study were 1) to probe the effects of visual motion adaptation on early visual and V5/MT cortical excitability and 2) to investigate whether changes in cortical excitability following visual motion adaptation are related to the degree of visual dependency, i.e., an overreliance on visual cues compared with vestibular or proprioceptive cues. Participants were exposed to a roll motion visual stimulus before, during, and after visual motion adaptation. At these stages, 20 transcranial magnetic stimulation (TMS) pulses at phosphene threshold values were applied over early visual and V5/MT cortical areas from which the probability of eliciting a phosphene was calculated. Before and after adaptation, participants aligned the subjective visual vertical in front of the roll motion stimulus as a marker of visual dependency. During adaptation, early visual cortex excitability decreased whereas V5/MT excitability increased. After adaptation, both early visual and V5/MT excitability were increased. The roll motion-induced tilt of the subjective visual vertical (visual dependence) was not influenced by visual motion adaptation and did not correlate with phosphene threshold or visual cortex excitability. We conclude that early visual and V5/MT cortical excitability is differentially affected by visual motion adaptation. Furthermore, excitability in the early or late visual cortex is not associated with an increase in visual reliance during spatial orientation. Our findings complement earlier studies that have probed visual cortical excitability following motion adaptation and highlight the differential role of the early visual cortex and V5/MT in visual motion processing.
Kaski D, Pradhan V, Bronstein A, 2016, The clinical features of functional (psychogenic) eye movements, Annual Meeting of the Association-of-British-Neurologists (ABN), Publisher: BMJ Publishing Group, ISSN: 1468-330X
Functional (psychogenic) eye movements include convergence spasm, functional limitation of gaze, functional (or “voluntary” nystagmus), and functional convergence paralysis. Despite an increasing awareness of the high prevalence of functional neurological disorders, there has been no systematic clinical evaluation of functional eye movement disorders, or appreciation of the scale of the problem. We performed a retrospective review of patient case records attending two specialist neuro-otology outpatient clinics to determine the prevalence and clinical phenotype of functional eye movement disorders. Our results have confirmed that functional eye movements are a common presentation to neuro-otology clinics, with a prevalence of upto 4%. Convergence spasm and functional limitation of gaze are the commonest types seen in our clinics. Almost half the patients with a functional eye movement disorder had an associated functional non-ocular movement disorder, most commonly affecting gait. Early identification of functional eye movements may contribute to a positive diagnosis of a functional movement disorder, and prevent unnecessary – and potentially harmful – invasive investigations and treatments.
Kaski D, Bronstein AM, 2016, Functional eye movement disorders., Handbook of Clinical Neurology, Vol: 139, Pages: 343-351, ISSN: 0072-9752
Functional (psychogenic) eye movement disorders are perhaps less established in the medical literature than other types of functional movement disorders. Patients may present with ocular symptoms (e.g., blurred vision or oscillopsia) or functional eye movements may be identified during the formal examination of the eyes in patients with other functional disorders. Convergence spasm is the most common functional eye movement disorder, but functional gaze limitation, functional eye oscillations (also termed "voluntary nystagmus"), and functional convergence paralysis may be underreported. This chapter reviews the different types of functional eye movement abnormalities and provides a practical framework for their diagnosis and management.
Kaski D, Pradhan V, Bronstein AM, 2016, Clinical features of functional (psychogenic) eye movement disorders, Journal of Neurology Neurosurgery and Psychiatry, Vol: 87, Pages: 1389-1392, ISSN: 1468-330X
Despite increasing awareness of the high prevalence of functional neurological symptoms, there has been only one recent clinical evaluation of functional eye movement disorders, but this study reported only functional (psychogenic) oculogyric crises, opsoclonus and flutter. The aim of this retrospective study was to examine the clinical phenotype and range of functional eye movement disorders, and to report their prevalence across two neuro-otology outpatient clinics.
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