Superior canal dehiscence with tegmen defect revealed by otoscopy: Video clip demonstration of pulsatile tympanic membrane.

Superior canal dehiscence is a pathologic condition of the otic capsule acting as aberrant window of the inner ear. It results in reduction of inner ear impedance and in abnormal exposure of the labyrinthine neuroepithelium to the action of the surrounding structures. The sum of these phenomena leads to the onset of typical cochleo-vestibular symptoms and signs. Among them, pulsatile tinnitus has been attributed to a direct transmission of intracranial vascular activities to labyrinthine fluids. We present the first video-otoscopic documentation of spontaneous pulse-synchronous movements of the tympanic membrane in two patients with superior canal dehiscence. Pulsating eardrum may represent an additional sign of third-mobile window lesion.

Dehiscence of the superior semicircular canal: a review of the literature on its possible pathogenic explanations.

The dehiscence of superior semicircular canal is a well-known affection which is able to explain some cases of hearing loss, tinnitus and/or vertigo unexpectedly presenting in adults without previous otologic affections. Although a diagnostic algorithm has been assessed and a surgical therapy has been indicated, the review of the literature shows that a completely satisfactory explanation for the reason why symptoms of a supposed congenital condition only occur in adulthood is still lacking. A pathogenic hypothesis based on the slow metabolism of the bony labyrinth, which could in time result in a prevalence of bone re-absorption on new bone formation leading to a dehiscence, despite some controversial findings could represent a the most reliable explanation for the question.

Relationship between multidetector CT imaging of the vestibular aqueduct and inner ear pathologies.

This study investigated the relationships between morphological changes in the vestibular aqueduct (VA) in different inner ear pathologies. Eighty-eight patients (34 males and 54 females, ranging from seven to 88 years of age; average age 49.2 years) with cochleovestibular disorders underwent temporal bone CT (with a 64-channel helical CT system according to temporal bone protocol parameters; 0.6 mm slice thickness, 0.6 mm collimation, bone reconstruction algorithm). All patients with cochleovestibular disorders who underwent temporal bone CT had been previously divided into six different suspected clinical classes: A) suspected pathology of the third window; B) suspected retrocochlear hearing loss; C) defined Ménière's disease; D) labyrinth lithiasis; E) recurrent vertigo. On CT images we analyzed the length, width and morphology of the VA, contact between the VA and the jugular bulb (JB), the thickness of the osseous capsule covering the semicircular canals, the pneumatization rate of the temporal bone and the diameter of the internal auditory canal. At the end of the diagnostic work-up all patients were grouped into six pathological classes, represented as follow: 1) benign paroxysmal positional vertigo (BPPV), 2) recurrent vertigo (RV), 3) enlarged vestibular aqueduct syndrome (EVAS), 4) sudden or progressive unilateral sensorineural hearing loss (SNHL), 5) superior semicircular canal dehiscence syndrome (SSCD), 6) recurrent vestibulocochlear symptoms in Ménière's disease. We evaluated 176 temporal bones in 88 patients. The VA was clearly visualized in 166/176 temporal bones; in ten ears the VA was not visualized. In 14 ears (11 patients, in three of whom bilaterally) we found an enlarged VA while in 31 ears the VA was significantly narrower. In 16 ears a dehiscence of the JB with the vestibular or cochlear aqueduct was noted. In all six patients with suspected EVAS we found a AV wider than 1.5 mm on CT scans; moreover CT identified four patients with large VA and ill-defined clinical symptoms. Most patients with BPPV (11 patients, Class 1) we did not find any VA abnormalities on CT scans, confirming the clinical diagnosis in ten patients; in the remaining patients we found an enlarged VA, not clinically suspected. In the RV class (eight patients, Class 2) we found three patients with negative CT scans, two patients with narrow aqueduct and subsequently reclassified as Ménière's disease patients, and three patients with ectasic JB dehiscence with the VA. In patients suffering from SNHL we found no statistically significant correlation with the morphological abnormalities. The clinical suspicion of SSCD was confirmed by CT in 11/13 patients (84.6 %); in addition another seven patients showed a thinning or dehiscence of the superior semicircular canals as the prevailing alteration on CT scans, and were reclassified in this group. Ménière's disease symptoms were correlated with a VA alteration in more than half of the cases; the most striking finding in this class was that the VA was significantly narrower (21 patients). Our study demonstrates that alterations of the VA morphology are not only related to EVAS but are also found in other inner ear pathologies such as Ménière's disease. Furthermore, MDCT may confirm the presence of correlations between the morphology of inner ear structures such as VA, semicircular canals or JB dehiscence, and alterations of vestibulocochlear function.

Ocular vestibular evoked myogenic potentials in patients with acoustic neuroma.

To assess the usefulness of vestibular testing in patients with acoustic neuroma, considering two main aspects: to compare diagnostic sensitivity of the current vestibular tests, especially considering ocular vestibular evoked myogenic potentials (OVEMPs) and to identify pre-operative localization of the tumor (inferior vestibular nerve vs. superior vestibular nerve) only with the help of vestibular electrophysiological data. Twenty-six patients with unilateral acoustic neuroma (mainly intracanalicular type) were studied with a full audio-vestibular test battery (pure tone and speech audiometry, caloric bithermal test, vibration-induced nystagmus test (VIN), cervical and OVEMPs). 18 patients (69 %) showed abnormal caloric responses. 12 patients (46.2 %) showed a pattern of VIN test suggestive of vestibular asymmetry. 16 patients (61.5 %) showed abnormal OVEMPs (12 only to AC, 4 both to AC and BC). 10 patients (38.5 %) showed abnormal cervical vestibular evoked myogenic potentials (5 both to AC and BC, 5 only to AC). In one case, results of vestibular evoked potentials and caloric test were confirmed by intra-operative and post-operative findings. Results of electrophysiological tests in AN patients could be helpful for planning the proper surgical approach, considering that sensitivity of every exam is quite low in intracanalicular lesion; clinical data allow a better interpretation of vestibular evoked myogenic potentials.

Management of growing vestibular schwannomas.

Conservative management of small vestibular schwannomas is frequently proposed as most tumours do not grow. Anyway, tumour growth is reported in 30-40 % of the cases, so that surgery is consequently generally proposed. We primarily observed 161 patients affected by unilateral vestibular schwannomas. All patients were examined by means of gadolinium-enhanced magnetic resonance imaging scans. Tumour growth was recorded in 58 cases (35.8 %) and these subjects set up the group of study. Twenty-two (37.9 %) patients were surgically treated; tumour was always completely removed, all patients had normal facial function after surgery and only one patient suffered from a major complication (cerebellar haematoma). Fourteen patients (24.1 %) were submitted to radiotherapy, while one patient was lost at follow-up and another one died because of other medical reasons. Finally, 20 (34.5 %) subjects continued to be observed for different reasons. The mean follow-up period after identification of growth was 6.1 years. Nine tumours continued to grow, nine tumours stopped growing, one tumour grew and then regressed in size and one tumour decreased. Sixty percent of patients with useful hearing at diagnosis preserved it during the entire observation period. In conclusion, most of VS do not grow; in case of tumour growth, a surgical procedure may be suggested and the outcomes are not negatively influenced by the delay of the procedure. But in some cases, patients can still follow the "wait and scan" policy. In fact, only less than half of the growing tumours continued to grow. Moreover, most of the patients continued to retain a useful hearing.

Do signs of natural plugging of superior semicircular canal dehiscence exist?

Our experience with 102 patients having superior semicircular canal dehiscence confirm that the clinical manifestations of the disease are very diverse; we also identified 3 patients who showed Meniere-like symptoms. Clinical examination during an acute vertigo attack of a patient with Meniere disease for several years and whom we subsequently diagnosed as having large superior semicircular canal dehiscence on the affected side allowed us to hypothesize that a natural plugging of the superior semicircular canal by the overhanging dura mater could be responsible for the recurrence of symptoms. Clinical and instrumental data were very similar to those recorded in 7 of 9 patients immediately after surgical plugging. The aim of the study was to understand which semiological and instrumental elements could be clinically useful, first in distinguishing Meniere disease from superior semicircular canal dehiscence and, secondly, in understanding if signs of natural plugging are present.

Superior semicircular canal dehiscence and enlarged vestibular aqueduct.

Superior semicircular canal dehiscence is a well described labyrinthine defect, detect in pediatric population too. We report a case of superior semicircular canal dehiscence, which radiological diagnosis was confirmed by multiplanar reformatted CT images, associated to omolateral enlarged vestibular aqueduct in a 16-year-old female who presented with congenital hearing loss without vestibular symptoms. Both inner ear malformations act as a third mobile window into the labyrinth and cochleo-vestibular symptoms can result from loud sounds or pressure changes. An early diagnosis should be strived for preserve inner ear functions.

Meniere's disease and the use of proton pump inhibitors.

PRINCIPLES: On the basis of previous observations we examined the possibility of a favourable effect of proton pump inhibitors (PPI) on Meniere's disease (MD). A preliminary step was made by retrospectively analysing the number of menieric crisis in group of patients suffering from MD and using PPI for other reasons as compared to a group of menieric subjects who had never used PPI. METHODS: Between January 2001 and December 2006, 42 patients affected by MD were examined in the tertiary referral centre at the University Hospital of Bologna, Italy and in the private office of an ENT specialist in Cassino, Italy. Within the study group, 18 patients had used PPI for various reasons for at least 12 consecutive months, whilst 24 patients had never been prescribed them. We recorded the number of menieric crises reported in the observation period. The mean follow-up period was 21.9 months. Statistical analysis was performed by means of the x2 test and significance was defined when p<0.05. RESULTS: Most of MD patients (72%) using PPI suffered less than one episode of menieric crisis/year. On the other hand patients who had never used a PPI, experienced considerably more episodes only 16.7% having less than one crisis per year. This difference was statistically significant (p<0, 001). CONCLUSIONS: Even taking the limitations of this retrospective study into account the reported data nevertheless strongly suggest a possible role for proton pumps in the pathogenesis of MD. This could lead to interesting developments and contribute to a better definition of MD and the therapeutic possibilities.

Hearing loss in vestibular schwannomas: analysis of cochlear function by means of distortion-product otoacoustic emissions.

OBJECTIVE: We investigated cochlear function in a group of patients affected by vestibular schwannoma (VS), by means of recording distortion-product otoacoustic emissions (DPOAEs). METHODS: Between January 1996 and January 2007, we observed 183 patients affected by unilateral VS. DPOAEs, compared to the corresponding hearing thresholds, were subjectively classified into three categories: "compatible" with hearing function, "cochlear" and "retro-cochlear". We also related the responses to some clinical variables (tumor size, intracanalicular tumor and radiologic appearance of the internal auditory canal). Statistical analysis was performed. RESULTS: In 137 cases (74.9%), DPOAEs were as expected based on audiometry responses, while in 11 patients (6%) a "cochlear" DP-gram was recorded and in 35 patients (19.1%) DPOAEs evidenced a "retro-cochlear" pattern. In eight cases we detected acoustic responses despite a profound hearing loss. No statistically significant data merged from the comparison between "cochlear" and "retro-cochlear" responses and the clinical variables. CONCLUSION: Our results confirm that sensorineural hearing loss due to VS can be of sensory and/or neural origin. DPOAEs still remain just a complementary auditory test; nevertheless, in case of severe or profound unilateral hearing loss, recorded acoustic responses may be suspicious for the presence of a vestibular schwannoma.

Possible influence on heart rate on tinnitus.

Assuming the possibility of the inner ear damage due to a hemodynamic imbalance essentially due to an abnormal vasomotor regulatory response, the possibility that heart rate (HR) has a correlation with the onset and/or the enhancement of tinnitus is hypothesized. In fact, recent studies have drawn the influence of other factors than blood pressure, in normotensive subjects, in taking part to the regulation of peripheral resistance, outlining the importance of both cardiac output (CO) - which is a function of heart rate (HR) and stroke volume (SV) and SV itself as a dynamic component to baroreflex control of muscle sympathetic nerve activity (MSNA). From this point of view, it could be possible that a condition of bradycardia can enhance tinnitus regardless of its cause, and conversely that a more elevated HR can be related to a relief of this symptom.

The possible role of proton pump inhibitors of the homeostasis of the inner ear.

The possibility of a benefit in some cases of inner ear sufferance by using proton pump inhibitors has been considered after a casual observation. The hypothesis is advanced considering the adverse effect of reflux on the eustachian tube function, the possible influence of the latter on inner ear symptoms and, from a more general point of view, the trigger effect which a gastric dysfunction requiring proton pump inhibitors could exert on the sympathetic system. These considerations, deserving a further study, seem to be based on logical assessment and therefore in our opinion deserve to be kept in mind in trying to define inner ear disorders of uncertain origin.

Inner ear dysfunction of uncertain origin: a multidisciplinary approach could give something more.

In order to find out any possible cause of an alteration of the vasomotor reactivity which can be responsible for a more or less severe sufferance of the inner ear, announced by the onset or the enhancement of sensorineural hearing loss, tinnitus, and some kind of dizziness and vertigo, a multidisciplinary approach should be considered. The possibility of an influence of hemodynamic imbalance due to hypotensive changes followed by vasomotor changes affecting the microcirculation of the inner ear has already been widely discussed; moreover, an increase in prevalence of tinnitus (which in many cases can be considered as a symptom of sufferance of the inner ear) has been found in subjects submitted to an "aggressive" antihypertensive therapy as well as in patients with severe heart failure, thus demonstrating a relationship between hemodynamic changes and inner ear dysfunction. For the same reason, the research for this mechanism of imbalance could concern other conditions possibly activating an abnormal response of the autonomic nervous system, which could in turn lead to a circulatory impairment of the labyrinth: among these, affections concerning central nervous system, endocrine system, metabolism, renal apparatus and even gastroenteric diseases with a functional component and any other factor which could interfere with vasomotor regulation should be considered. Thus, the absence of reliable causes for a sufferance of the inner ear should not lead to catalogue it as a disorder of "idiopathic" nature, but should represent a reason for a multidisciplinary investigation on all the possible causes of hemodynamic imbalance and/or autonomic dysregulation.

Nystagmus induced by bone (mastoid) vibration in otosclerosis: a new perspective in the study of vestibular function in otosclerosis.

BACKGROUND: The aim was to explore vestibular responses to bone vibration-induced nystagmus (BVIN) during bed-side examination in patients with otosclerosis and conductive hearing loss. It is assumed that vibration of the mastoid (at 100 Hz) stimulates all vestibular end organs (semicircular canals and otolith structures). Previous studies described oculomotor responses to vestibular activation by vibratory stimulus. Stimulation of individual semicircular canals produces eye movement in the plane of the stimulated canal. Vibratory stimulation of otolith structures (utricular macula) produces changes in ocular torsional position. Otosclerosis is responsible for conductive hearing loss and symptoms such as dizziness and vertigo. Diagnosis is usually by a combination of family medical history, conductive hearing loss pattern, absence of air-VEMP, and CT scan of the temporal bone. MATERIAL/METHODS: Eye movements of patients diagnosed with otosclerosis and conductive hearing loss were recorded in complete darkness. These oculomotor responses to long-lasting unilateral vibratory stimulation applied to the mastoid surface were evaluated and the patterns of vertical, torsional, and horizontal eye velocity and eye position were measured by three-dimensional computerized infrared video oculography. RESULTS: Mastoid vibration evoked responses in all cases, mostly demonstrating excitation of the affected side. In all cases, three-dimensional infrared video oculography showed mostly horizontal nystagmus directed with the slow phase to the healthy side. CONCLUSIONS: Three-dimensional analysis of BVIN in patients with otosclerosis and conductive hearing loss may be appropriate in evaluating the vestibular function and altered immittance related with this clinical entity. This promises to be an interesting new field of research.

Bone vibration-induced nystagmus is useful in diagnosing superior semicircular canal dehiscence.

OBJECTIVE: To explore vestibular integrity by bone vibration-induced nystagmus (VIN) during bedside examination. Disease or dysfunction of vestibular end organs would reduce or eliminate their contribution to total eye movement response to VIN. BACKGROUND: It is assumed that vibration of the mastoid (at a frequency of 100 Hz) stimulates all vestibular end organs (semicircular canals and otolith structures). Previous studies have described oculomotor responses to vestibular activation by vibratory stimulus. Stimulation of individual semicircular canals produces eye movement in the plane of the stimulated canal. Vibratory stimulation of otolith structures (utricular macula) produces changes in ocular torsional position. Superior semicircular canal dehiscence (SCD) is responsible for nontypical cochleovestibular symptoms. Diagnosis is difficult without resorting to imaging, high-resolution computed tomography (HRCT) being the only tool providing reliable assessment. To avoid unnecessary referral for expensive imaging, it would be useful to have a simple screening test to select cases for HRCT. METHODS: Video eye movements were recorded in complete darkness in patients diagnosed with SCD. The eye movement responses to long-lasting unilateral vibratory stimulation applied to the mastoid surface were evaluated. RESULTS: VIN evoked a response in all cases, mostly demonstrating excitation of the affected side. The pattern of vertical, torsional and horizontal eye velocity and eye position was evaluated with three-dimensional infrared video-oculography (50 Hz sampling). CONCLUSION: Analysis of VIN, recently proposed to study transmission of excitatory stimuli by bone conduction, may be appropriate for altered immittance caused by dehiscence. This promises to be an interesting new field of research.

Conservative management of vestibular schwannomas: an effective strategy.

OBJECTIVES: Stimulated by the availability of a larger sample of patients and a longer follow-up period, we update our experience with conservative management of vestibular schwannomas. STUDY DESIGN: Patients with intracanalicular and small/medium-sized tumors have been followed prospectively at a tertiary referral center. METHODS: One hundred twenty-three patients affected by sporadic vestibular schwannoma were primarily observed by means of magnetic resonance imaging scans. In case of significant tumor growth (> or =2 mm), patients were either surgically treated or submitted to radiotherapy, but, not rarely, they continued to follow the "wait-and-scan" policy. Tumor-size changes over time were also evaluated with hearing function. Statistical analysis with predictive growth factors was performed. RESULTS: Almost two thirds (64.5%) of the cases did not show tumor growth during the entire period of observation (mean follow-up period, 4.8 yrs). Among growing tumors, 16 patients were surgically treated with no complications or facial nerve palsy. Less than half (45.5%) of the patients presented useful hearing (classes A and B of the American Academy of Otolaryngology-Head and Neck Surgery classification) at diagnosis, and 41 (73.2%) patients had preserved hearing during follow-up independently from the tumor growth rate. CONCLUSIONS: Conservative management of vestibular schwannoma appears to be a safe procedure because most tumors do not grow and surgical outcomes are not affected by possible delays. In the great majority of cases, useful hearing is maintained over time. Because of the irregular behavior of the tumor, periodic neuroradiologic scans are mandatory to limit late surgical risks.

Could echocardiography yield a cardiovascular profile of the tinnitus prone subject?

The possible genesis of some damage of the inner ear from a hemodynamic imbalance of functional origin, possibly linked to hypotension followed by an abnormal vasomotor regulatory activity, has been pointed out by our group over the years. As tinnitus, which is often referable to an inner ear origin, can represent a signal of incoming sufferance of the organ of Corti and may not necessarily be linked to hearing impairment, it seemed of some utility to investigate on the prevalence of tinnitus under various well monitored hemodynamic conditions. This led to observe that the prevalence of this symptom, regardless of audiological features, was increased under "aggressive" antihypertensive therapy as well as in particularly severe degree of heart decompensation. These data represent a first step and encourage in searching for a profile of subject who could be more prone to the development of tinnitus with respect to the normal population, even in absence of pathological conditions. With this aim, echocardiography is thought to be able to yield useful informations in addition to standard and ambulatory blood pressure monitoring, in order to obtain a better definition of the correlations between cardiovascular function (and related changes) and inner ear insufficient perfusion.