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semicircular canal

Richard F Lewis
Damage to the peripheral vestibular system can result in debilitating postural, perceptual, and visual symptoms. A new potential treatment for this clinical problem is to replace some aspects of peripheral vestibular function with an implant that senses head motion and provides this information to the brain by stimulating branches of the vestibular nerve. In this review I consider animal studies performed at our institution over the past fifteen years, which have helped elucidate how the brain processes information provided by a vestibular (semicircular canal) implant and how this information could be used to improve the problems experienced by patients with peripheral vestibular damage...
October 19, 2016: Journal of Neurophysiology
Christian Güldner, Isabell Diogo, Eva Bernd, Stephanie Dräger, Magis Mandapathil, Afshin Teymoortash, Hesham Negm, Thomas Wilhelm
Cone beam computed tomography (CBCT, syn. digital volume tomography = DVT) was introduced into ENT imaging more than 10 years ago. The main focus was on imaging of the paranasal sinuses and traumatology of the mid face. In recent years, it has also been used in imaging of chronic ear diseases (especially in visualizing middle and inner ear implants), but an exact description of the advantages and limitations of visualizing precise anatomy in a relevant number of patients is still missing. The data sets of CBCT imaging of the middle and inner ear of 204 patients were analyzed regarding the visualization of 18 different anatomic structures...
October 17, 2016: European Archives of Oto-rhino-laryngology
Woo Seok Kang, Sang Hun Lee, Chan Joo Yang, Joong Ho Ahn, Jong Woo Chung, Hong Ju Park
Vestibular migraine (VM) is one of the most common causes of episodic vertigo. We reviewed the results of multiple vestibular function tests in a cohort of VM patients who were diagnosed with VM according to the diagnostic criteria of the Barany Society and the International Headache Society and assessed the efficacy of each for predicting the prognosis in VM patients. A retrospective chart analysis was performed on 81 VM patients at a tertiary care center from June 2014 to July 2015. Patients were assessed by the video head impulse test (vHIT), caloric test, vestibular-evoked myogenic potentials (VEMPs), and sensory organization test (SOT) at the initial visit and then evaluated for symptomatic improvement after 6 months...
2016: Frontiers in Neurology
Maristela Mian Ferreira, Maurício Malavasi Ganança, Heloisa Helena Caovilla
INTRODUCTION: Otolith function can be studied by testing the subjective visual vertical, because the tilt of the vertical line beyond the normal range is a sign of vestibular dysfunction. Benign paroxysmal positional vertigo is a disorder of one or more labyrinthine semicircular canals caused by fractions of otoliths derived from the utricular macula. OBJECTIVE: To compare the subjective visual vertical with the bucket test before and immediately after the particle repositioning maneuver in patients with benign paroxysmal positional vertigo...
September 28, 2016: Brazilian Journal of Otorhinolaryngology
A Ernst, I Todt, J Wagner
BACKGROUND: Dehiscence syndromes of the semicircular canals are a relatively new group of neurotological disorders. They have a variety of symptoms with hearing/balance involvement. Younger patients have clinically relevant symptoms in only about one third of cases. In addition to etiology and pathogenesis, the present paper describes diagnostic and therapeutic possibilities using a patient series of the authors. MATERIALS AND METHODS: This nonrandomized prospective study included 52 patients with uni-/bilateral dehiscence syndromes of the superior and/or posterior canal (SCDS/PCDS), diagnosed with high-resolution computed tomography (HR-CT) of the petrous bone...
October 14, 2016: HNO
Neil S Patel, Jacob B Hunter, Brendan P O'Connell, Natalie M Bertrand, George B Wanna, Matthew L Carlson
OBJECTIVE: Patients with incidental or minimally symptomatic superior semicircular canal dehiscence (SSCD) are usually observed, without surgical repair. However, it remains unknown whether a labyrinthine fistula of the superior semicircular canal is associated with progressive conductive or sensorineural hearing loss over time. STUDY DESIGN: Retrospective review at two tertiary care academic referral centers. METHODS: Adults analyzed were diagnosed with SSCD by high-resolution temporal bone computed tomography and vestibular evoked myogenic potential testing and observed with a minimum of two sequential audiograms...
October 14, 2016: Laryngoscope
Jorge Rey-Martinez, Leigh McGarvie, Nicolás Pérez-Fernández
CONCLUSION: The obtained simulations support the underlying hypothesis that the hydrostatic caloric drive is dissipated by local convective flow in a hydropic duct. OBJECTIVE: To develop a computerized model to simulate and predict the internal fluid thermodynamic behavior within both normal and hydropic horizontal ducts. METHODS: This study used a computational fluid dynamics software to simulate the effects of cooling and warming of two geometrical models representing normal and hydropic ducts of one semicircular horizontal canal during 120 s...
October 14, 2016: Acta Oto-laryngologica
Wee Tin K Kao, Lorne S Parnes, Richard A Chole
OBJECTIVES/HYPOTHESIS: Benign paroxysmal positional vertigo (BPPV) is the most common vestibular disorder with an incidence between 10.7 and 17.3 per 100,000 persons per year. The mechanism for BPPV has been postulated to involve displaced otoconia resulting in canalithiasis. Although particulate matter has been observed in the endolymph of affected patients undergoing posterior canal occlusion surgery, an otoconial origin for the disease is still questioned. STUDY DESIGN: In this study, particulate matter was extracted from the posterior semicircular canal of two patients and examined with scanning electron microscopy...
October 11, 2016: Laryngoscope
Hitomi Matsuno, Moeko Kudoh, Akiya Watakabe, Tetsuo Yamamori, Ryuichi Shigemoto, Soichi Nagao
Adaptations of vestibulo-ocular and optokinetic response eye movements have been studied as an experimental model of cerebellum-dependent motor learning. Several previous physiological and pharmacological studies have consistently suggested that the cerebellar flocculus (FL) Purkinje cells (P-cells) and the medial vestibular nucleus (MVN) neurons targeted by FL (FL-targeted MVN neurons) may respectively maintain the memory traces of short- and long-term adaptation. To study the basic structures of the FL-MVN synapses by light microscopy (LM) and electron microscopy (EM), we injected green florescence protein (GFP)-expressing lentivirus into FL to anterogradely label the FL P-cell axons in C57BL/6J mice...
2016: PloS One
Dominik Obrist, Andrea Nienhaus, Ewa Zamaro, Roger Kalla, Georgios Mantokoudis, Michael Strupp
OBJECTIVE: To evaluate the effect of time between the movements/steps, angle of body movements as well as the angular velocity of the maneuvers in an in vitro model of a semicircular canal (SCC) to improve the efficacy of the Sémont maneuver (SM) in benign paroxysmal positional vertigo. MATERIALS AND METHODS: Sémont maneuvers were performed on an in vitro SCC model. Otoconia trajectories were captured by a video camera. The effects of time between the movements, angles of motion (0°, 10°, 20°, and 30° below the horizontal line), different angular velocities (90, 135, 180°/s), and otoconia size (36 and 50 μm) on the final position of the otoconia in the SCC were tested...
2016: Frontiers in Neurology
Rachael L Taylor, Leigh A McGarvie, Nicole Reid, Allison S Young, G Michael Halmagyi, Miriam S Welgampola
OBJECTIVE: To characterize the profiles of afferent dysfunction in a cross section of patients with acute vestibular neuritis using tests of otolith and semicircular canal function sensitive to each of the 5 vestibular end organs. METHODS: Forty-three patients fulfilling clinical criteria for acute vestibular neuritis were recruited between 2010 and 2016 and studied within 10 days of symptom onset. Otolith function was evaluated with air-conducted cervical and bone-conducted ocular/vestibular evoked myogenic potentials and the subjective visual horizontal test...
September 30, 2016: Neurology
Berta Alsina, Tanya T Whitfield
The vertebrate inner ear is a precision sensory organ, acting as both a microphone to receive sound and an accelerometer to detect gravity and motion. It consists of a series of interlinked, fluid-filled chambers containing patches of sensory epithelia, each with a specialised function. The ear contains many different differentiated cell types with distinct morphologies, from the flask-shaped hair cells found in thickened sensory epithelium, to the thin squamous cells that contribute to non-sensory structures, such as the semicircular canal ducts...
September 26, 2016: Seminars in Cell & Developmental Biology
Akihide Ichimura, Koji Otsuka
A 16-year-old boy with rotatory positional vertigo and nausea, particularly when lying down, visited our clinic. Initially, we observed vertical/torsional (downward/leftward) nystagmus in the supine position, and it did not diminish. In the sitting position, nystagmus was not provoked. Neurological examinations were normal. We speculated that persistent torsional down-beating nystagmus was caused by the light cupula of the posterior semicircular canal. This case provides novel insights into the light cupula pathophysiology...
2016: Case Reports in Otolaryngology
Cathrin Pfaff, Doris Nagel, Gregg Gunnell, Gerhard W Weber, Jürgen Kriwet, Michael Morlo, Katharina Bastl
Species of the extinct genus Hyaenodon were among the largest carnivorous mammals from the Late Eocene through Early Miocene in North America, Europe and Asia. The origin, phylogeny and palaeobiology of Hyaenodonta are still ambiguous. Most previous studies focused on teeth and dental function in these highly adapted species, which might be influenced by convergent morphologies. The anatomy of the bony labyrinth in vertebrates is generally quite conservative and, additionally, was used in functional-morphological studies...
September 25, 2016: Journal of Anatomy
Arne Tribukait, Eddie Bergsten, Ola Eiken
BACKGROUND: During hovering with a helicopter, an involuntary change in attitude (during brownout) results in reduced lifting force and a horizontal acceleration component. This movement pattern is difficult to perceive via the otolith organs. If the angular displacement occurs rapidly, it will, however, activate the semicircular canals. The major aim of this study was to establish to what extent pitch-plane angular displacements can be perceived based on canal information when there is no tilt stimulus to the otoliths...
2016: Aerospace Medicine and Human Performance
T Linder, S Mulazimoglu, T El Hadi, V Darrouzet, D Ayache, T Somers, S Schmerber, C Vincent, M Mondain, E Lescanne, D Bonnard
OBJECTIVES: To give an insight into why, when and where iatrogenic facial nerve (FN) injuries may occur and to explain how to deal with them in an emergency setting. DESIGN AND SETTING: Multicentre retrospective study in eight tertiary referral hospitals over 17 years. PARTICIPANTS: Twenty patients with partial or total FN injury during surgery for chronic otitis media (COM) were revised. MAIN OUTCOME MEASURES: Indication and type of surgery, experience of the surgeon, intra- and postoperative findings, value of CT scanning, patient management and final FN outcome were recorded...
September 23, 2016: Clinical Otolaryngology
Ahmad M Aldhafeeri, Abdulrahman A Alsanosi
OBJECTIVES: To determine the prevalence of inner ear anomalies and the frequency of different anomaly types among cochlear implant recipients. METHODS: This study included a retrospective chart review of all patients who received cochlear implants between January 2009 and January 2013 in King Abdulaziz University Hospital cochlear implant program in Riyadh, Saudi Arabia. All subjects underwent thin-cut CT of the temporal bone and MRI. The collected data included age, gender, and CT and MRI findings regarding temporal bone anomalies...
October 2016: Saudi Medical Journal
P Bertholon, A Karkas
This chapter will focus on vertigo/dizziness due to inner-ear malformations, labyrinthine fistula, otosclerosis, infectious processes, and autoimmune inner-ear disorders. Inner-ear malformation due to dehiscence of the superior semicircular canal is the most recently described inner-ear malformation. Vertigo/dizziness is typically induced by sound and pressure stimuli and can be associated with auditory symptoms (conductive or mixed hearing loss). Labyrinthine fistula, except after surgery for otosclerosis, in the context of trauma or chronic otitis media with cholesteatoma, still remains a challenging disorder due to multiple uncertainties regarding diagnostic and management strategies...
2016: Handbook of Clinical Neurology
D Nuti, M Masini, M Mandalà
Benign paroxysmal positional vertigo is a common labyrinthine disorder caused by a mechanic stimulation of the vestibular receptors within the semicircular canals. It is characterized by positional vertigo and positional nystagmus, both provoked by changes in the position of the head with respect to gravity. The social impact of the disease and its direct and indirect costs to healthcare systems are significant owing to impairment of daily activities and increased risk of falls. The first description of a patient with benign paroxysmal positional vertigo is from Robert Bárány in 1921, but the features of the syndrome and the diagnostic maneuver were well described by Dix and Hallpike in 1952...
2016: Handbook of Clinical Neurology
M Fetter
Sudden unilateral loss of vestibular function is the most severe condition that can occur in the vestibular system. The clinical syndrome is caused by the physiologic properties of the vestibulo-ocular reflex (VOR) arc. In the normal situation, the two peripheral vestibular end organs are connected to a functional unit in coplanar pairs of semicircular canals working in a push-pull mode. "Push-pull" mode means that, when one side is excited, the other side is inhibited, and vice versa due to two mechanisms...
2016: Handbook of Clinical Neurology
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