Imperial College London

DrMiteshPatel

Faculty of MedicineDepartment of Brain Sciences

Honorary Research Associate
 
 
 
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mitesh.patel1

 
 
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Neuro-Otology (10L)Charing Cross HospitalCharing Cross Campus

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Summary

 

Publications

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64 results found

Patel M, Nilsson MH, Rehncrona S, Tjernstrom F, Magnusson M, Johansson R, Fransson P-Aet al., 2020, Effects of Deep Brain Stimulation on Postural Control in Parkinson's Disease, COMPUTERS IN BIOLOGY AND MEDICINE, Vol: 122, ISSN: 0010-4825

Journal article

Patel M, Roberts E, Arshad Q, Bunday K, Golding JF, Kaski D, Bronstein AMet al., 2020, The "broken escalator" phenomenon: vestibular dizziness interferes with locomotor adaptation, Journal of Vestibular Research: Equilibrium and Orientation: an international journal of experimental and clinical vestibular science, Vol: 30, Pages: 81-94, ISSN: 0957-4271

BACKGROUND: Although vestibular lesions degrade postural control we do not know the relative contributions of the magnitude of the vestibular loss and subjective vestibular symptoms to locomotor adaptation. OBJECTIVE: To study how dizzy symptoms interfere with adaptive locomotor learning. METHODS: We examined patients with contrasting peripheral vestibular deficits, vestibular neuritis in the chronic stable phase (n = 20) and strongly symptomatic unilateral Meniere's disease (n = 15), compared to age-matched healthy controls (n = 15). We measured locomotor adaptive learning using the "broken escalator" aftereffect, simulated on a motorised moving sled. RESULTS: Patients with Meniere's disease had an enhanced "broken escalator" postural aftereffect. More generally, the size of the locomotor aftereffect was related to how symptomatic patients were across both groups. Contrastingly, the degree of peripheral vestibular loss was not correlated with symptom load or locomotor aftereffect size. During the MOVING trials, both patient groups had larger levels of instability (trunk sway) and reduced adaptation than normal controls. CONCLUSION: Dizziness symptoms influence locomotor adaptation and its subsequent expression through motor aftereffects. Given that the unsteadiness experienced during the "broken escalator" paradigm is internally driven, the enhanced aftereffect found represents a new type of self-generated postural challenge for vestibular/unsteady patients.

Journal article

Fransson P-A, Nilsson MH, Niehorster DC, Nystrom M, Rehncrona S, Tjernstrom F, Magnusson M, Johansson R, Patel Met al., 2020, Exploring the effects of deep brain stimulation and vision on tremor in Parkinson's disease-benefits from objective methods, JOURNAL OF NEUROENGINEERING AND REHABILITATION, Vol: 17

Journal article

Harcourt JP, Lambert A, Wong PY, Patel M, Agarwal K, Golding JF, Bronstein AM, Harcourt JP, Lambert A, Wong PY, Patel M, Agarwal K, Golding JF, Bronstein AMet al., 2019, Long-term follow-up of intratympanic methylprednisolone versus gentamicin in patients with unilateral Menière's disease, Otology and Neurotology, Vol: 40, Pages: 491-496, ISSN: 1531-7129

OBJECTIVES: To determine whether long term (>48 months) symptomatic vertigo control is sustained in patients with Menière's disease from a previous comparative trial of intratympanic methylprednisolone versus gentamicin, and if the two treatments remain nonsignificantly different at long-term follow-up. STUDY DESIGN: Mail survey recording vertigo frequency in the previous one and six months, further intratympanic treatment received, and validated symptom questionnaires. SETTING: Outpatient hospital clinic setting. PATIENTS: Adult patients with definite unilateral refractory Menière's disease, who previously received intratympanic treatment in a comparative trial. INTERVENTION: A survey of trial participants who received intratympanic gentamicin (40 mg/mL) or methylprednisolone (62.5 mg/mL). OUTCOME MEASURES: Primary: number of vertigo attacks in the 6 months prior to receiving this survey compared with the 6 months before the first trial injection. Secondary number of vertigo attacks over the previous 1 month; validated symptom questionnaire scores of tinnitus, dizziness, vertigo, aural fullness, and functional disability. RESULTS: Forty six of the 60 original trial patients (77%) completed the survey, 24 from the gentamicin and 22 from the methylprednisolone group. Average follow-up was 70.8 months (standard deviation 17.0) from the first treatment injection. Vertigo attacks in the 6 months prior to receiving the current survey reduced by 95% compared to baseline in both drug groups (intention-to-treat analysis, both p < 0.001). No significant difference between drugs was found for the primary and secondary outcomes. Eight participants (methylprednisolone = 5 and gentamicin = 3) required further injections for relapse after completing the original trial. CONCLUSION: Intratympanic methylprednisolone treatment provides effective long-lasting relief of vertigo, without the known inner-ear toxicity associated with gentamicin. There are no significan

Journal article

Fransson P-A, Patel M, Jensen H, Lundberg M, Tjernstrom F, Magnusson M, Hansson EEet al., 2019, Postural instability in an immersive Virtual Reality adapts with repetition and includes directional and gender specific effects, Scientific Reports, Vol: 9, Pages: 1-10, ISSN: 2045-2322

The ability to handle sensory conflicts and use the most appropriate sensory information is vital for successful recovery of human postural control after injury. The objective was to determine if virtual reality (VR) could provide a vehicle for sensory training, and determine the temporal and spatial nature of such adaptive changes. Twenty healthy subjects participated in the study (10 females). The subjects watched a 90-second VR simulation of railroad (rollercoaster) motion in mountainous terrain during five repeated simulations, while standing on a force platform that recorded their stability. The immediate response to watching the VR movie was an increased level of postural instability. Repeatedly watching the same VR movie significantly reduced both the anteroposterior (62%, p < 0.001) and lateral (47%, p = 0.001) energy used. However, females adapted more slowly to the VR stimuli as reflected by higher use of total (p = 0.007), low frequency (p = 0.027) and high frequency (p = 0.026) energy. Healthy subjects can significantly adapt to a multidirectional, provocative, visual environment after 4–5 repeated sessions of VR. Consequently, VR technology might be an effective tool for rehabilitation involving visual desensitisation. However, some females may require more training sessions to achieve effects with VR.

Journal article

Roberts R, Ahmad H, Patel M, Danai D, Ibitoye R, Sharif M, Leech R, Arshad Q, Bronstein A, Bronstein A, Arshad Q, Roberts R, Ahmad HENA, Ibitoye RICHARD, Patel M, Danai Dima, Sharif M, Leech R, Bronstein A, Arshad Q, Ahmad H, Roberts R, Ibitoye R, Sharif M, Patel M, Danai Dima, Leech Ret 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.

Journal article

Patel M, Arshad Q, Seemungal BM, Harcourt JP, Golding JF, Bronstein AMet 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

Journal article

Einarsson E-J, Patel M, Petersen H, Wiebe T, Fransson P-A, Magnusson M, Moell Cet al., 2018, Elevated visual dependency in young adults after chemotherapy in childhood, PLoS ONE, Vol: 13, ISSN: 1932-6203

Chemotherapy in childhood can result in long-term neurophysiological side-effects, which could extend to visual processing, specifically the degree to which a person relies on vision to determine vertical and horizontal (visual dependency). We investigated whether adults treated with chemotherapy in childhood experience elevated visual dependency compared to controls and whether any difference is associated with the age at which subjects were treated. Visual dependency was measured in 23 subjects (mean age 25.3 years) treated in childhood with chemotherapy (CTS) for malignant, solid, non-CNS tumors. We also stratified CTS into two groups: those treated before 12 years of age and those treated from 12 years of age and older. Results were compared to 25 healthy, age-matched controls. The subjective visual horizontal (SVH) and vertical (SVV) orientations was recorded by having subjects position an illuminated rod to their perceived horizontal and vertical with and without a surrounding frame tilted clockwise and counter-clockwise 20° from vertical. There was no significant difference in rod accuracy between any CTS groups and controls without a frame. However, when assessing visual dependency using a frame, CTS in general (p = 0.006) and especially CTS treated before 12 years of age (p = 0.001) tilted the rod significantly further in the direction of the frame compared to controls. Our findings suggest that chemotherapy treatment before 12 years of age is associated with elevated visual dependency compared to controls, implying a visual bias during spatial activities. Clinicians should be aware of symptoms such as visual vertigo in adults treated with chemotherapy in childhood.

Journal article

Patel M, 2017, CSMD1 gene mutations can lead to familial Parkinson disease, Nature Reviews Neurology, Vol: 13, Pages: 641-641, ISSN: 1759-4758

Journal article

Patel M, 2017, Prolonged neural stem cell maturation restores motor function in spinal cord-lesioned rats, Nature Reviews Neurology, Vol: 13, Pages: 641-641, ISSN: 1759-4758

Journal article

Patel M, 2017, Intrathecal inflammation mediates mood in relapsing–remitting multiple sclerosis, Nature Reviews Neurology, Vol: 13, Pages: 641-641, ISSN: 1759-4758

Journal article

Patel M, 2017, Action observation in the modification of postural sway and gait: Theory and use in rehabilitation, GAIT & POSTURE, Vol: 58, Pages: 115-120, ISSN: 0966-6362

Journal article

Patel M, 2017, Stroke: Twist in artery linked to stroke in young adults., Nat Rev Neurol, Vol: 13

Journal article

Patel M, 2017, Alzheimer disease: Revising the risk of Alzheimer disease in women., Nat Rev Neurol, Vol: 13

Journal article

Patel M, 2017, Multiple sclerosis: Microstructural pathology imaged in MS., Nat Rev Neurol, Vol: 13

Journal article

Ahmad H, Roberts E, Patel M, Lobo R, Seemungal B, Arshad Q, Bronstein Aet 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.

Journal article

Patel M, 2017, Intratympanic corticosteroids in Ménière's disease: A mini-review, Journal of Otology, Vol: 12, Pages: 117-124, ISSN: 1672-2930

This article reviews the effectiveness of intratympanic corticosteroids for vertigo control in Ménière's disease at 2-years follow-up according to the guidelines expressed by the American Academy of Otolaryngology-Head & Neck Surgery. Despite the increased use of intratympanic corticosteroids for vertigo control in Ménière's disease there is debate as to their effectiveness, particularly compared to gentamicin. Even so, after just a single course of injections, corticosteroids can reliably provide complete vertigo control (Class A) at 2-years in about 50% of cases as indicated in a recent double-blind randomized controlled clinical trial (Patel et al., 2016). But the effectiveness of intratympanic corticosteroids truly increases when treatment is provided ‘as-needed’, whereby complete vertigo control is established in up to 91% of cases. On the basis of available literature, there is good evidence to recommend the use of intratympanic steroid treatment for vertigo control in Ménière's disease, but patients must be monitored for non-response. The rationale for treating patients as-needed and the possible reasons for corticosteroid non-response are discussed.

Journal article

Arshad Q, Roberts RE, Ahmad H, Lobo R, Patel M, Ham T, Sharp DJ, Seemungal BMet 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

Journal article

Roberts RE, Arshad Q, Patel M, Dima D, Leech R, Seemungal BM, Sharp DS, Bronstein AMet 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.

Journal article

Golding JF, Patel M, 2016, Meniere's, migraine, and motion sickness, Acta Oto-Laryngologica, Vol: 137, Pages: 495-502, ISSN: 0001-6489

Conclusion:Elevated Motion Sickness Susceptibility (MSS) in Meniere’s disease (MD) is likely to be aconsequence of the onset of MD and not migraineperse.Objectives:Pathologies of the vestibular system influence MSS. Bilateral vestibular deficits lower MSS,vestibular neuritis or benign paroxysmal positional vertigo have little overall effect, whereas vestibularmigraine elevates MSS. However, less is known about MSS in MD, a condition in which many patientsexperience vestibular loss and migraine symptoms.Methods:The authors conducted an online survey that posed diagnostic and disease questions beforeaddressing frequency of headaches, migraines, visual display dizziness (VDD), syncope, social life, andwork impact of dizziness (SWID4) and motion sickness susceptibility (MSSQ). The two groups were:diagnosed MD individuals with hearing loss (n¼751) and non-MD individuals in the control group(n¼400).Results:The MD group showed significantly elevated MSS, more headache and migraine, increasedVDD, higher SWID4 scores, and increased syncope. MSS was higher in MD than controls only after thedevelopment of MD, but not before, nor in childhood. Although elevated in MD compared with con-trols, MSS was lower than migraine patients from past data. Multivariate analysis revealed VDD, SWID4,and MSS in adulthood as the strongest predictors of MD, but not headache nor migraine.

Journal article

Patel M, Agarwal K, Arshad Q, Hariri M, Rea P, Seemungal BM, Golding JF, Harcourt JP, Bronstein AMet 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)

Journal article

Ahmad H, Arshad Q, Roberts R, Patel M, Ham T, Sharp D, Seemungal Bet al., 2016, CHRONIC DIZZINESS POST TRAUMATIC BRAIN INJURY: A CROSS-SECTIONAL STUDY, Annual Meeting of the Association-of-British-Neurologists (ABN), Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050

Conference paper

Einarsson E-J, Patel M, Petersen H, Wiebe T, Fransson P-A, Magnusson M, Moell Cet al., 2016, Decreased postural control in adult survivors of childhood cancer treated with chemotherapy, Scientific Reports, Vol: 6, ISSN: 2045-2322

The objective of cancer treatment is to secure survival. However, as chemotherapeutic agents can affect the central and peripheral nervous systems, patients must undergo a process of central compensation. We explored the effectiveness of this compensation process by measuring postural behaviour in adult survivors of childhood cancer treated with chemotherapy (CTS). We recruited sixteen adults treated with chemotherapy in childhood for malignant solid (non-CNS) tumours and 25 healthy age-matched controls. Subjects performed posturography with eyes open and closed during quiet and perturbed standing. Repeated balance perturbations through calf vibrations were used to study postural adaptation. Subjects were stratified into two groups (treatment before or from 12 years of age) to determine age at treatment effects. Both quiet (p = 0.040) and perturbed standing (p ≤ 0.009) were significantly poorer in CTS compared to controls, particularly with eyes open and among those treated younger. Moreover, CTS had reduced levels of adaptation compared to controls, both with eyes closed and open. Hence, adults treated with chemotherapy for childhood cancer may suffer late effects of poorer postural control manifested as reduced contribution of vision and as reduced adaptation skills. These findings advocate development of chemotherapeutic agents that cause fewer long-term side effects when used for treating children.

Journal article

Roberts RE, Da Silva Melo M, Siddiqui AA, Arshad Q, Patel Met al., 2016, Vestibular and oculomotor influences on visual dependency., Journal of Neurophysiology, Vol: 116, Pages: 1480-1487, ISSN: 1522-1598

The degree to which a person relies on visual stimuli for spatial orientation is termed visual dependency (VD). VD is considered a perceptual trait or cognitive style influenced by psychological factors and mediated by central re-weighting of the sensory inputs involved in spatial orientation. VD is often measured using the rod-and-disk test, wherein participants align a central rod to the subjective visual vertical (SVV) in the presence of a background that is either stationary or rotating around the line of sight - dynamic SVV. Although this task has been employed to assess VD in health and vestibular disease, it is unknown what effect torsional nystagmic eye movements may have on individual performance. Using caloric ear irrigation, 3D video-oculography and the rod-and-disk test, we show that caloric torsional nystagmus modulates measures of visual dependency and demonstrate that increases in tilt after irrigation are positively correlated with changes in ocular torsional eye movements. When the direction of the slow phase of the torsional eye movement induced by the caloric is congruent with that induced by the rotating visual stimulus, there is a significant increase in tilt. When these two torsional components are in opposition there is a decrease. These findings show that measures of visual dependence can be influenced by oculomotor responses induced by caloric stimulation. The findings are of significance for clinical studies as they indicate that VD, which often increases in vestibular disorders, is not only modulated by changes in cognitive style but also by eye movements, in particular nystagmus.

Journal article

Patel M, Arshad Q, Roberts RE, Ahmad H, Bronstein AMet al., 2016, Chronic Symptoms After Vestibular Neuritis and the High-Velocity Vestibulo-Ocular Reflex, OTOLOGY & NEUROTOLOGY, Vol: 37, Pages: 179-184, ISSN: 1531-7129

Journal article

Einarsson E-J, Patel M, Petersen H, Wiebe T, Magnusson M, Moell C, Fransson P-Aet al., 2016, Oculomotor Deficits after Chemotherapy in Childhood, PLOS One, Vol: 11, ISSN: 1932-6203

Advances in the diagnosis and treatment of pediatric malignancies have substantially increased the number of childhood cancer survivors. However, reports suggest that some of the chemotherapy agents used for treatment can cross the blood brain barrier which may lead to a host of neurological symptoms including oculomotor dysfunction. Whether chemotherapy at young age causes oculomotor dysfunction later in life is unknown. Oculomotor performance was assessed with traditional and novel methods in 23 adults (mean age 25.3 years, treatment age 10.2 years) treated with chemotherapy for a solid malignant tumor not affecting the central nervous system. Their results were compared to those from 25 healthy, age-matched controls (mean age 25.1 years). Correlation analysis was performed between the subjective symptoms reported by the chemotherapy treated subjects (CTS) and oculomotor performance. In CTS, the temporal control of the smooth pursuit velocity (velocity accuracy) was markedly poorer (p<0.001) and the saccades had disproportionally shorter amplitude than normal for the associated saccade peak velocity (main sequence) (p = 0.004), whereas smooth pursuit and saccade onset times were shorter (p = 0.004) in CTS compared with controls. The CTS treated before 12 years of age manifested more severe oculomotor deficits. CTS frequently reported subjective symptoms of visual disturbances (70%), unsteadiness, light-headedness and that things around them were spinning or moving (87%). Several subjective symptoms were significantly related to deficits in oculomotor performance. To conclude, chemotherapy in childhood or adolescence can result in severe oculomotor dysfunctions in adulthood. The revealed oculomotor dysfunctions were significantly related to the subjects’ self-perception of visual disturbances, dizziness, light-headedness and sensing unsteadiness. Assessments of oculomotor function may, thus, offer an objective method to track and rate the level of neurolog

Journal article

Ahmad H, Roberts R, Arshad QA, Patel M, Bronstein Aet al., 2015, USING TRANSCRANIAL MAGNETIC STIMULATION (TMS) TO PROBE EFFECTS OF VISUAL MOTION ADAPTATION ON PRIMARY VISUAL CORTEX (V1) EXCITABILITY IN BILATERAL VESTIBULAR FAILURE (BVF) PATIENTS, Annual Meeting of the Association-of-British-Neurologists (ABN), Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050

Conference paper

Ahmad H, Arshad Q, Patel M, Roberts R, Bronstein Aet al., 2015, ACQUIRED PENDULAR NYSTAGMUS IN STARGARDT'S SYNDROME SUPPRESSED BY ALCOHOL, Annual Meeting of the Association-of-British-Neurologists (ABN), Publisher: BMJ PUBLISHING GROUP, ISSN: 0022-3050

Conference paper

Bronstein AM, Arshad Q, Siddiqui S, Ramachandran S, Goga U, Bonsu A, Patel M, Roberts RE, Nigmatullina Y, Malhotra Pet al., 2015, Right hemisphere dominance directly predicts both baseline V1 cortical excitability and the degree of top-down modulation exerted over low-level brain structures, Neuroscience, Vol: 311, Pages: 484-489, ISSN: 0306-4522

Right hemisphere dominance for visuo-spatial attention is characteristically observed in most right-handed individuals. This dominance has been attributed to both an anatomically larger right fronto-parietal network and the existence of asymmetric parietal interhemispheric connections. Previously it has been demonstrated that interhemispheric conflict, which induces left hemisphere inhibition, results in the modulation of both (i) the excitability of the early visual cortex (V1) and (ii) the brainstem-mediated vestibular–ocular reflex (VOR) via top-down control mechanisms. However to date, it remains unknown whether the degree of an individual’s right hemisphere dominance for visuospatial function can influence, (i) the baseline excitability of the visual cortex and (ii) the extent to which the right hemisphere can exert top-down modulation. We directly tested this by correlating line bisection error (or pseudoneglect), taken as a measure of right hemisphere dominance, with both (i) visual cortical excitability measured using phosphene perception elicited via single-pulse occipital trans-cranial magnetic stimulation (TMS) and (ii) the degree of trans-cranial direct current stimulation (tDCS)-mediated VOR suppression, following left hemisphere inhibition. We found that those individuals with greater right hemisphere dominance had a less excitable early visual cortex at baseline and demonstrated a greater degree of vestibular nystagmus suppression following left hemisphere cathodal tDCS. To conclude, our results provide the first demonstration that individual differences in right hemisphere dominance can directly predict both the baseline excitability of low-level brain structures and the degree of top-down modulation exerted over them.

Journal article

Ahmad H, Roberts RE, Arshad Q, Patel M, Bronstein AMet al., 2015, Probing effects of visual motion adaptation on primary visual cortex (V1) excitability using Tms in Bilateral Vestibular Failure (Bvf) patients, JOURNAL OF THE NEUROLOGICAL SCIENCES, Vol: 357, Pages: E172-E172, ISSN: 0022-510X

Journal article

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