Three-Dimensional Visualization of Vertebrobasilar System Aneurysms in a Vertigo Patient

Cerebral artery fenestration refers to a division in the lumen of an artery leading to two distinct endothelium-lined channels. At the site of turbulent flow, fenestration may predispose to an aneurysm formation. In this study, a 45- year-old woman suffered an acute vertiginous attack after cervical manipulation. The MRI scan demonstrated basilar artery duplication and tortuous left distal vertebral artery impinging on the cisternal segment of the cochleovestibular nerve. Subsequent three- dimensional (3D) reconstruction by MR imaging showed vertebrobasilar artery fenestrations with aneurysms. Unfortunately, subarachnoid hemorrhage occurred 6 days later, and the patient became comatose one year after presentation. In summary, subarachnoid hemorrhage caused by vertebrobasilar system aneurysms is a life-threatening event . Delineating the configuration by 3D-reconstruction of MR images allows more accurate diagnosis and more effective management

Multiple System Atrophy Manifested as Dizziness and Imbalance: A Report of Two Cases

Multiple system atrophy (MSA) is a progressive neurodegenerative disease of undetermined origin that occasionally manifests as dizziness and imbalance. It is not often considered in clinical situations, especially not by neuro-otological consultants. Hence, we report our recent experience with two cases of MSA. One is that of a 62-year- old man with MSA with a predominant cerebellar feature, and the other is that of a 72- year-old man with MSA with a predominant parkinsonian feature. The results of the syncopic study correlated with orthostatic hypotension. The neuro- otological study in both patients revealed an abnormal eye tracking test, abnormal optokinetic nystagmus test and loss of visual suppression in the caloric nystagmus. These indicate that the central vestibular system, e.g. , the cerebellum or brain stem, is affected by MSA, contributing to dizziness and imbalance. Therefore, diagnosis of MSA should be kept in mind by neuro-otological consultants when dealing with patients with dizziness and imbalance, especially when this is accompanied by orthostatic hypotension

Consistent Latencies of Vestibular Evoked Myogenic Potentials

OBJECTIVES: This study investigated the association between neck length and vestibular evoked myogenic potential (VEMP) latencies in healthy children, adolescents, and adults to elucidate when VEMP latencies reach consistent levels. DESIGN: Findings of VEMP tests in 14 healthy children, seven healthy adolescents, and 14 healthy adults were analyzed for correlations with neck length, which was measured as the distance of a line dropping vertically from the mastoid tip to the horizontal plane passing through the clavicle. RESULTS: All healthy children, adolescents, and adults exhibited present VEMP responses. Children, adolescents, and adults significantly differed in p13 latency, n23 latency, and p13-n23 interval. According to receiver operating characteristic curve analysis, the optimal cutoff values of p13 and n23 latencies between children and adults were 12.6 and 19.8 msec, respectively. Because the odds ratio of p 13 latency was less than that of n23 latency, n23 latency was used to discriminate VEMP latencies between children and adults. Accordingly, a cutoff value of 15.3 cm for neck length was proposed as a criterion for predicting VEMP latency within the adult range. Consequently, a positive correlation between neck length and VEMP latency was observed when neck length was 15.3 cm

Vestibular Evoked Myogenic Potentials Using Simultaneous Binaural Acoustic Stimulation

The aim of this study is to investigate the feasibility of recording vestibular evoked myogenic potential (VEMP) using simultaneous binaural acoustic stimulation (B-VEMP), and compare it with that using monaural acoustic stimulation (M- VEMP). Seven healthy volunteers were evoked by initial B- VEMP test and subsequent M-VEMP test, whereas vice versa in another 7 volunteers. All 14 subjects demonstrated both B- VEMPs and M- VEMPs, without significant difference in the latencies of p13 and n23. When using interaural amplitude difference (IAD) ratio for interpreting amplitude, B-VEMPs did not differ significantly from that of M-VEMPs. Hence, B- VEMPs can produce information equivalent to M-VEMPs in terms of response rate, latencies, and IAD ratio in healthy subjects. Likewise, similar results were also shown in the patients with unilateral Meniere's disease. In conclusion, B -VEMPs provide neither different information nor less variability, as compared with M-VEMPs. In addition, B-VEMPs can offer information on unilateral inner ear (saccular) pathology similar to that by M-VEMPs. Furthermore, recording from binaural stimulation can be used as a possibly more convenient mode compared with two monaural recordings, especially when testing young or old or disabled patients, since a continuous muscular effort is required during recording. (C) 2003 Elsevier B.V. All rights reserved

Reversible Cochleo-Vestibular Deficits in Two Cases of Jugular Foramen Tumor after Surgery

Primary jugular foramen (JF) tumor, such as glomus jugular tumor or JF schwannoma, may manifest as a lower cranial nerve deficit; in addition, it can be accompanied by deafness or vertigo if it affects the cranial nerve (CN) VIII. Recently, we encountered JF schwannoma 1 and glomus jugulare tumor 1. Both cases invaded the adjacent cerebellopontine angle, leading to cochleo-vestibular deficits prior to the operation. After surgery, recovery of the audiovestibular function, including hearing, auditory brainstem response and caloric response, was anticipated in both patients. Therefore, cochleo-vestibular deficits in JF tumors can be attributed to compression neuropathy, rather than tumor infiltration

Ocular Vestibular-Evoked Myogenic Potentials in Children Using Air Conducted Sound Stimulation

Objective: This study compared Ocular vestibular-evoked myogenic potentials (oVEMPs) in children and adults using air conducted sound stimulation to determine when oVEMP characteristic parameters in children reach adult levels. The relationships between oVEMP characteristics and structural factors were also investigated. Methods: In total , 15 healthy children (aged 3-13 years) and 15 healthy adults (aged 24-33 years) underwent a combined oVEMP and cVEMP test under 105 dBnHL acoustic stimulation. Results: Mean nl latency, pl latency, nl-pl interval and amplitude of oVEMPs of children did not differ significantly from those of adults. In contrast to oVEMPs, a significant difference in p13 cVEMP latency existed between children and adults. Correlating the structural factors with the characteristic parameters of oVEMPs did not show significant relationship. However, p13 and n23 latencies of cVEMPs in children were significantly related to the age, head girth, body height and body weight. Conclusions: The non-invasive oVEMP test can quantitatively measure the vestibulo-ocular reflex (VOR) system, which has similar characteristic parameters in children aged >3 years and adults. For children aged 3 years old

Ocular Vestibular-Evoked Myogenic Potentials Elicited from Monaural Versus Binaural Acoustic Stimulations

Objective: This study compared the ocular vestibular-evoked myogenic potentials (oVEMPs) that are elicited (recorded) in response to monaural and separately, simultaneous binaural acoustic stimulations. The optimal stimulation mode for oVEMPs was also determined. Methods: Twenty healthy volunteers (14 men and 6 women, aged from 22 to 33 years, mean 28 years) without any previous ear disorders were enrolled in this study. Each subject underwent oVEMP testing using monaural acoustic stimulation (Men- oVEMP) with different stimulus intensities, and with bilateral recording . On another day, the same volunteers underwent oVEMP testing using simultaneous binaural acoustic stimulation and bilateral recording (Bin- oVEMP). Results: With 95 dB nHL tone burst stimulation, the biphasic nl-pl waveforms were recorded with maximal amplitudes from the electrodes located below the eyes contralateral to the side of acoustic stimulation while the subject was gazing upward. Significant correlations were identified between Mon-oVEMPs and Bin- oVEMPs with respect to threshold, latencies and amplitude. However, no significant difference existed between Mon- oVEMPs and Bin-oVEMPs in terms of the response rate, threshold, latency or amplitude. Conclusions: The Bin-oVEMP test yields the same information as the Mon-oVEMP test, but the duration of recording in the former is shorter than the latter. Significance: The Bin-oVEMP test may be a more convenient screening tool for evaluating the crossed vestibulo-ocular reflex

Development of Vestibular Evoked Myogenic Potentials in Preterm Neonates

Our recent study successfully recorded vestibular evoked myogenic potential (VEMP) responses in full-term newborns. However, when VEMP responses are elicited in preterm neonates remains unclear. This study employed the VEMP test in 27 low-risk preterm and 25 healthy full-term neonates without sedation to investigate the development of VEMP response after birth. Fourteen (26%) of 54 ears in preterm neonates exhibited VEMP responses, a response rate significantly lower than that of full-term neonates (72%). The mean latencies of peaks p13 and n23 in the preterm group were significantly longer than those in the full-term group . Analysis of variable parameters for present VEMPs in pre- and fullterm neonates revealed that the cutoff values of body weight were 2.26 and 2.82 kg, and that those of postmenstrual age were 37.1 and 38.4 weeks, respectively. Both body weight and postmenstrual age were significantly negatively correlated with p13 and n23 latencies but not with p13-n23 amplitude. In conclusion, present VEMPs can be anticipated when the body weight of pre-and full-term neonates reaches > 2.26 and 2.82 kg, respectively. It indicates that the sacculocollic reflex develops in the same manner, but the difference in response rate between full- and pre- term neonates may, at least in part, correlate with muscle bulk and strength, relative to the body weight adequate for the VEMP response

Localization and Prevalence of Hydrops Formation in Menieres Disease Using a Test Battery

This study investigated the localization and prevalence of hydrops formation in 20 patients with unilateral Menieres disease using a battery of tests, including audiometry, caloric, ocular vestibular evoked myogenic potential oVEMP and cervical VEMP cVEMP tests. The latter two tests used air -conducted sound ACS and bone-conducted vibration BCV as stimuli. Thirteen patients 65% had abnormal hearing with a 4 -tone average >26 dBHL . In the caloric test, 4 patients 20% had abnormal responses, including canal paresis in 3 and caloric areflexia in 1 patient. The percentages of patients with abnormal ACS-oVEMP, BCV-oVEMP, ACS-cVEMP, and BCV-cVEMP tests were 65, 25, 45, and 25% in affected ears, and 40, 0, 15, and 0% in unaffected ears, respectively. Although ACS- and BCV-oVEMP results differed significantly, ACS- and BCV- cVEMP results did not, regardless of the affected or unaffected ears. Thus, the abnormal rates for hearing, ACS- cVEMP, BCV-oVEMP, and caloric tests in affected ears were 65 , 45, 25 , and 20%, respectively. This decreasing order of abnormal percentages in function of the cochlea, saccule, utricle, and semicircular canals mimics the declining sequence of hydrops formation in temporal bone studies. In conclusion, an inner ear test battery comprising audiometry, caloric, oVEMP, and cVEMP tests may provide further insight into the localization and prevalence of hydrops formation in Menieres disease