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Bristol, United Kingdom

Manzari L.,Academy Center | Burgess A.M.,University of Sydney | McGarvie L.A.,Institute of Clinical Neurosciences | Curthoys I.S.,University of Sydney
Ear and Hearing | Year: 2012

Objective: The aim of this study was to investigate the effect of superior semicircular canal dehiscence (SSCD) on the n10 component of the ocular vestibular evoked myogenic potential (oVEMP n10) and the p13-n23 component of the cervical vestibular evoked myogenic potential (cVEMP p13-n23) evoked by 500 Hz bone-conducted vibration (BCV) at the midline forehead at the hairline (Fz) in 26 patients with computed tomography-verified SSCD. Previous evidence has led to the proposal that the oVEMP n10 is of utricular origin whereas the cVEMP p13-n23 is of saccular origin. The question is can the oVEMP n10 to 500 Hz BCV indicate SSCD? Design: A hand-held Bruel & Kjaer 4810 Minishaker was used to provide BCV stimulation using surface electromyography electrodes to record oVEMP n10 and cVEMP p13-n23. The stimulus was 7 msec bursts of 500 Hz BCV at either Fz or at the vertex of the skull (Cz). Twenty-seven healthy subjects were tested in the same paradigm. Results: In response to 500 Hz Fz BCV in SSCD patients the oVEMP n10 amplitude beneath the contraSSCD eye was substantially and significantly larger than the oVEMP n10 beneath the ipsiSSCD eye, whereas in these same patients the cVEMP p13-n23 amplitude over the ipsiSSCD sternocleidomastoid muscle to Fz BCV was slightly but significantly larger than the cVEMP p13-n23 amplitude over the contraSSCD sternocleidomastoid muscle. In SSCD patients there was a significant relationship between the size of the dehiscence and the amplitude of the contralateral oVEMP n10 potential. The oVEMP n10 to Cz stimulation was still present in SSCD patients, but small or absent in healthy subjects. Conclusions: In response to 500 Hz Fz BCV an asymmetrical oVEMP n10 with a significantly increased amplitude of contralesional oVEMP n10 (compared with population values of healthy subjects) is a simple useful indicator of SSCD, confirmed by the Cz response. oVEMP testing with 500 Hz Fz BCV allows very simple, very fast identification of a probable unilateral SSCD. Copyright © 2012 by Lippincott Williams & Wilkins.

Fraser T.,University of Bristol | Tayler H.,University of Bristol | Love S.,Institute of Clinical Neurosciences
Neurochemical Research | Year: 2010

Dietary ω3-polyunsaturated fatty acids are thought to influence the risk of Alzheimer's disease (AD), and supplemental docosahexaenoic acid (DHA; 22:6n-3) has been reported to reduce neurodegeneration in mouse models of AD. We have analysed the fatty acid composition of frontal, temporal and parietal neocortex in 58 normal and 114 AD brains. Significant reductions were found for stearic acid (18:0) in frontal and temporal cortex and arachidonic acid (20:4n-6) in temporal cortex in AD, and increases in oleic acid in frontal and temporal cortex (18:1n-9) and palmitic acid (16:0) in parietal cortex. DHA level varied more in AD than controls but the mean values were not significantly different. Fatty acid composition was not related to APOE genotype, age, gender or post-mortem delay. Further research is needed to distinguish between alterations that are secondary to AD and those that contribute to the disease process. © 2009 Springer Science+Business Media, LLC.

Love S.,Institute of Clinical Neurosciences
Histopathology | Year: 2011

Love S (2011) Histopathology58, 333ndash;351 Autopsy approach to stroke Stroke is a major cause of morbidity and mortality but the brain and other relevant tissues are often examined only cursorily when stroke patients come to autopsy. The pathological findings and clinical implications vary according to the type of stroke and its location and cause. Large ischaemic strokes are usually associated with atherosclerosis of extracranial or major intracranial arteries but can be caused by dissection. Most small cerebral infarcts are caused by arteriosclerosis or, in the elderly, cerebral amyloid angiopathy (CAA). However, vasculitides and coagulopathies can cause a range of different patterns of ischaemic (and, occasionally, haemorrhagic) stroke. Global brain ischaemia, caused by severe hypotension or raised intracranial pressure, produces damage that is accentuated in certain regions and neuronal populations and may be confused with hypoglycaemic injury. The main cause of subarachnoid haemorrhage is a ruptured berry aneurysm but CAA, arteriovenous malformations and infective aneurysms are occasionally responsible. These can also cause parenchymal brain haemorrhage, although this most often complicates hypertensive small vessel disease. Sometimes the haemorrhage arises from a neoplasm. Performing an adequate autopsy in stroke requires proper preparation, awareness of the likely pathological processes, familiarity with intracranial vascular anatomy, careful gross examination and dissection, and appropriate use of histology. © 2010 Blackwell Publishing Limited.

Nguyen K.D.,Johns Hopkins University | Welgampola M.S.,Institute of Clinical Neurosciences | Carey J.P.,Johns Hopkins University
Otology and Neurotology | Year: 2010

OBJECTIVE:: To determine the test-retest reliability and age-related trends of the cervical and ocular vestibular evoked myogenic potential (cVEMP and oVEMP, respectively) responses to air-conducted sound and bone-conducted vibration stimulation. STUDY DESIGN:: Prospective study. SETTING:: Tertiary referral center. PATIENTS:: Fifty-three healthy adults with no hearing or vestibular deficits. INTERVENTION(S):: All subjects underwent cVEMP and oVEMP testing in response to sounds (0.1-ms clicks and 500-Hz tone bursts) and vibration (midline forehead taps at the hairline, Fz, with a reflex hammer and a Brüel & Kjær Mini-Shaker Type 4810). Twelve subjects underwent an additional testing session that was conducted at a mean of 10 weeks after the first one. MAIN OUTCOME MEASURE(S):: Test-retest reliability for VEMP response parameters (latency, peak-to-peak amplitude, and asymmetry ratio) were assessed using the intraclass correlation coefficient (ICC). RESULTS:: oVEMP amplitudes had excellent test-retest reliability (ICC > 0.75) for all 4 stimuli; cVEMP amplitudes had excellent reliability for hammer taps and fair-to-good reliability for other stimuli. oVEMP asymmetry ratios had excellent reliability for clicks and fair-to-good reliability (ICC = 0.4-0.75) for other stimuli; cVEMP asymmetry ratios had fair-to-good reliability for clicks and hammer taps. Older subjects (>50 years old) were found to have significantly decreased cVEMP amplitudes in response to clicks, tones, and taps with a Mini-Shaker and significantly decreased oVEMP amplitudes in response to clicks, tones, and taps with a reflex hammer. No age-related changes were found for latencies or asymmetry ratios. CONCLUSION:: Overall, oVEMP response parameters demonstrated better test-retest reliability than cVEMP response parameters, but oVEMPs and cVEMPs had similar age-related changes. Copyright © 2010 Otology & Neurotology, Inc.

Santos E.,Hospital Geral Santo Antonio | Shaunak S.,Royal Preston Hospital | Renowden S.,Frenchay Hospital | Scolding N.J.,Institute of Clinical Neurosciences
Journal of Neurology, Neurosurgery and Psychiatry | Year: 2010

Background: Neurological involvement in sarcoidosis is serious and often aggressive. Many patients respond to steroids but some show a progressive course despite treatment with steroids and even more potent immunosuppressive drugs. Objective: The aim of this study was to describe our experience in the treatment of refractory neurosarcoidosis with Infliximab - its effect on the course of the disease and side effects. Methods: A series of four patients are reported with neurosarcoidosis refractory to treatment with steroids combined with various immunosuppressive drugs in whom Infliximab was used. Results: A good response, with improvement or stabilisation of the neurological condition, was seen in all cases, without significant side effects. Infliximab is a chimeric monoclonal antibody that neutralises the biological activity of tumour necrosis factor α, a cytokine thought to play an important role in the pathophysiology of sarcoidosis. Conclusion: Our experience using Infliximab adds to the growing evidence that it may fulfil a useful role in cases of refractory neurosarcoidosis.

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