Search

Malignant leptomeningitis can present as the clinical syndrome of pseudotumor cerebri due to infiltration of arachnoid villi in the superior sagittal sinus. We show that malignant pachymeningitis can also present with pseudotumor cerebri, likely due to cerebral venous hypertension from transverse sinus compression. We present 3 cases of pseudotumor cerebri due to pachymeningeal or leptomeningeal metastases and discuss the mechanism of intracranial hypertension in such cases, its diagnosis and treatment., (Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.)

Susac's syndrome is the clinical triad of encephalopathy, branch retinal artery occlusions and sensorineural hearing loss (Susac 1994) [1]. It occurs predominantly in young females and is believed to be an immune-mediated endotheliopathy of small vessels of the brain, retina and cochlea (Neumayer et al. 2009) [2]. Early, aggressive, and sustained immunosuppressive therapy has been recommended for Susac's syndrome and anecdotal evidence has suggested a therapeutic role for monoclonal antibodies (Rennebohm et al. 2008, Lee and Amezcua 2009) [3,4]. We report a case of Susac's syndrome in which the patient improved immediately after tumour necrosis factor (TNF) inhibition with the monoclonal antibody, infliximab., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Objective: Carotid endarterectomy (CEA) guidelines in symptomatic carotid stenosis are based on NASCET and ECST criteria with 70% or greater carotid stenosis as estimated from a catheter angiogram the major indication. This has several problems: (1) lack of reliable correlation between non-invasive imaging and catheter angiography, which has been largely superseded by non-invasive imaging in investigating carotid stenosis; (2) errors inherent in estimating the degree of stenosis from catheter angiography; (3) disregard for the fact that stroke risk also depends on plaque stability, and number of ischaemic events., Methods: A retrospective review of ischaemic events, imaging results, operative findings, surgical complications and stroke-free follow-up in 31 patients presenting over a 23 year period with TIA/stroke (symptoms lasting > 24 h and/or imaging evidence of infarction) who had 70% or less carotid stenosis (on non-invasive imaging), but nonetheless underwent CEA., Results: Nineteen patients had small strokes, 7 had TIAs and 5 had ocular events; 28 patients had features of unstable plaque on imaging; 19 patients experienced multiple events before CEA. All had haemorrhagic, ruptured plaque at CEA. One patient suffered an intra-operative stroke, only 1 patient suffered a further stroke/TIA (mean follow-up 4.2 years)., Conclusion: To predict the likelihood of major stroke in symptomatic carotid stenosis and the benefit of CEA, plaque stability and the number of ischaemic events might be as important as an estimate of the degree of stenosis., (Copyright © 2010 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.)

Objective: Bone-conducted vibration (BCV) in the midline at the hairline (Fz), results in short latency potentials recorded by surface electrodes beneath the eyes - the ocular vestibular-evoked myogenic potential (oVEMP). The early negative component of the oVEMP, n10, is due to vestibular stimulation, however it is similar to the early R1 component of the blink reflex. Here we seek to dissociate n10 from R1., Methods: Surface potentials were recorded from the infraorbital electromyogram of 10 healthy subjects, 6 patients with bilateral vestibular loss, 2 with unilateral vestibular loss, 4 with facial palsy and 3 with facial and vestibular nerve lesions on the same side. BCV was delivered at Fz, the inion, the glabella or the supraorbital ridge using a tendon hammer or a bone-conduction vibrator., Results: Onset latencies of the n10 evoked by taps at Fz or inion were significantly shorter than the R1 components of blink responses to supraorbital and glabellar stimuli. Upward gaze increased the amplitude of n10 but not R1. The n10 was absent bilaterally in patients with bilateral vestibular loss and beneath the contralesional eye in patients with unilateral vestibular loss, but in both these groups of patients R1 was preserved. In severe facial palsy the R1 component was absent or delayed and attenuated ipsilesionally, but n10 was preserved bilaterally. In subjects with unilateral facial and vestibular nerve lesions (Herpes Zoster of the facial and vestibulocochlear nerves) the dissociation was complete - the ipsilesional R1 was absent or attenuated whereas the ipsilesional n10 was preserved., Conclusions: n10 is distinguished from R1 by its earlier onset, laterality, modulation by gaze position and dissociation in patient groups., Significance: The n10 component evoked by BCV at Fz is not the R1 component of the blink reflex.

Objective: The n10 component (n10) of the ocular vestibular evoked myogenic potential (oVEMP) to brief bone conducted vibration (BCV) of the forehead at Fz is probably caused by the vibration selectively activating vestibular otolithic receptors. If the n10 is due primarily to utricular activation then diseases which affect only the superior division of the vestibular nerve (SVN) should reduce or eliminate n10., Methods: The n10 component of the oVEMP was measured in 13 patients with unilateral SVN but with inferior vestibular nerve function preserved., Results: We compared the n10 to BCV of these 13 SVN patients to previously published data for healthy subjects and patients after complete unilateral vestibular loss. We found that in 12 out of the 13 patients with SVN, n10 was markedly reduced or absent under the contralesional eye., Conclusion: Since all utricular afferents course in the superior vestibular nerve and in 12/13 of these patients the n10 was reduced we conclude that the n10 component of the oVEMP to BCV is probably mediated by the superior vestibular nerve and probably due to activation of mainly utricular receptors., Significance: The n10 appears to be a simple new test of superior vestibular nerve and probably mainly utricular function.

The mitochondrial 12S rRNA is considered a hotspot for mutations associated with nonsyndromic (NSHL) and aminoglycoside-induced hearing loss (AIHL). Although aminoglycoside ototoxicity is the most common cause of bilateral vestibular dysfunction, the conceivable role of 12S rRNA mutations has never been systematically investigated. We sequenced the 12S rRNA of 66 patients with bilateral vestibulopathy (BV) with (n=15) or without (n=51) prior exposure to aminoglycosides, as well as 155 healthy controls with intact vestibular function (sport pilots), and compared these to 2704 published sequences (Human Mitochondrial Genome Database). No mutations with a confirmed pathogenicity were found (A1555G, C1494T), but four mutations with a hitherto tentative status were detected (T669C, C960del, C960ins, T961G). Due to their predominant occurrence in patients without aminoglycoside exposure, their detection in controls and a weak evolutionary conservation, their pathogenic role in vestibulocochlear dysfunction remains provisional.

Objective: To provide the empirical basis for using ocular vestibular evoked myogenic potentials (oVEMPS) in response to Fz bone conducted vibration (BCV) stimulation to indicate vestibular function in human subjects. To show the generality of the response by testing a large number of unselected healthy subjects across a wide age range and the repeatability of the response within subjects. To provide evidence that the response depends on otolithic function., Methods: The early negative component (n10) of the oVEMP to brief BCV of the forehead, in the midline at the hairline (Fz) is recorded by surface EMG electrodes just beneath the eyes. We used a Bruel and Kjaer 4810 Mini-Shaker or a light tap with a tendon hammer to provide adequate BCV stimuli to test a large number (67) of unselected healthy people to quantify the individual differences in n10 magnitude, latency and symmetry to Fz BCV. A Radioear B-71 bone oscillator at Fz is not adequate to elicit a reliable n10 response., Results: The n10 oVEMP response showed substantial differences in amplitude between subjects, but is repeatable within subjects. n10 is of equal magnitude in both eyes with an average asymmetry around 11%. The average n10 amplitude for Mini Tone Burst BCV is 8.47microV+/-4.02 (sd), the average latency is 10.35ms+/-0.63 (sd). The amplitude of n10 decreases and its latency increases with age., Conclusions: oVEMPs are a new reliable, repeatable test to indicate vestibular and probably otolithic function., Significance: This study shows the optimum conditions for recording oVEMPs and provides baseline values for individual differences and asymmetry. oVEMPs can be measured in senior subjects without difficulty.

Objective: Patients with superior canal dehiscence (SCD) typically have enhanced sound-evoked vestibular reflexes, such as vestibulo-collic and vestibulo-ocular reflexes. We wished to investigate whether sound-evoked lower limb EMG responses and postural sway are also enhanced in this condition., Methods: Eight patients with CT confirmed SCD (11 affected ears) and 8 age-matched normal controls participated. Three sound-evoked responses were measured; vestibulo-collic reflexes (i.e. vestibular-evoked myogenic potentials, VEMPs), lower limb vestibulo-spinal reflexes and body sway (centre of pressure in mm). Sound stimuli were 500 Hz air-conducted tone bursts of varying lengths (VEMPs: 2 ms; vestibulo-spinal: 20 ms; sway: 1s and 200 ms) set at fixed levels above each subject's VEMP threshold., Results: SCD patients had very large VEMP and vestibulo-spinal responses following high intensity stimulation, but at the matched intensity of 15 dB above threshold amplitudes were similar in both SCD patients and controls. The amplitude of both responses increased linearly with increasing stimulus intensity in both groups. Large ( approximately 20mm), stereotyped sway responses were present in only one (atypical) patient with high intensity stimulation. Small ( approximately 2mm) sway responses were present in the remaining patients, and began immediately following the vestibulo-spinal responses., Conclusions: Despite the presence of large vestibular reflexes, there is usually very little body sway in response to loud sounds in SCD patients., Significance: Large short-latency vestibulo-spinal reflexes in SCD do not necessarily evoke large sway responses.