Characterizing a Joint Reflection-Distortion OAE Profile in Humans With Endolymphatic Hydrops.

OBJECTIVES: Endolymphatic hydrops (EH), a hallmark of Meniere disease, is an inner-ear disorder where the membranes bounding the scala media are distended outward due to an abnormally increased volume of endolymph. In this study, we characterize the joint-otoacoustic emission (OAE) profile, a results profile including both distortion- and reflection-class emissions from the same ear, in individuals with EH and speculate on its potential utility in clinical assessment and monitoring. DESIGN: Subjects were 16 adults with diagnosed EH and 18 adults with normal hearing (N) matched for age. Both the cubic distortion product (DP) OAE, a distortion-type emission, and the stimulus-frequency (SF) OAE, a reflection-type emission, were measured and analyzed as a joint OAE profile. OAE level, level growth (input/output functions), and phase-gradient delays were measured at frequencies corresponding to the apical half of the human cochlea and compared between groups. RESULTS: Normal hearers and individuals with EH shared some common OAE patterns, such as the reflection emissions being generally higher in level than distortion emissions and showing more linear growth than the more strongly compressed distortion emissions. However, significant differences were noted between the EH and N groups as well. OAE source strength (a metric based on OAE amplitude re: stimulus level) was significantly reduced, as was OAE level, at low frequencies in the EH group. These reductions were more marked for distortion than reflection emissions. Furthermore, two significant changes in the configuration of OAE input/output functions were observed in ears with EH: a steepened growth slope for reflection emissions and an elevated compression knee for distortion emissions. SFOAE phase-gradient delays at 40 dB forward-pressure level were slightly shorter in the group with EH compared with the normal group. CONCLUSIONS: The underlying pathology associated with EH impacts the generation of both emission types, reflection and distortion, as shown by significant group differences in OAE level, growth, and delay. However, hydrops impacts reflection and distortion emissions differently. Most notably, DPOAEs were more reduced by EH than were SFOAEs, suggesting that pathologies associated with the hydropic state do not act identically on the generation of nonlinear distortion at the hair bundle and intracochlear reflection emissions near the peak of the traveling wave. This differential effect underscores the value of applying a joint OAE approach to access both intracochlear generation processes concurrently.

Meniere's disease is a manifestation of migraine.

PURPOSE OF REVIEW: To discuss the theory that Meniere's disease (MD) is a variation of otologic migraine rather than an isolated inner ear condition. RECENT FINDINGS: In contrast to the approximately 12% of the general population suffering from migraine headaches, 51-60% of patients with MD experience migraine headaches. While pathognomonic for MD, endolymphatic hydrops has also been identified in patients with vestibular migraine. Treatment with the integrative neurosensory rehabilitation approach (diet and lifestyle changes, magnesium and riboflavin supplementation, and when needed, prophylactic medication) to treat the underlying migraine process has been highly effective in patients with MD. SUMMARY: MD can be understood as a manifestation of migraine such that patients with MD can be effectively treated with migraine therapies.

The Diagnostic Value of 1.5T Versus 3.0T Magnetic Resonance Imaging Intratympanic Gadolinium Inner Ear Enhancement in Patients with Meniere's Disease.

BACKGROUND: A comparative study of 1.5T and 3.0T magnetic resonance imaging inner ear gadolinium enhancement was carried out to further explore the practicality and universality of 1.5T magnetic resonance imaging in the diagnosis of inner ear labyrinthine hydrops positive imaging. METHODS: This dual case-control study was conducted on 25 patients with Meniere's disease (experimental group), diagnosed by People's Hospital of Ordos Dongsheng District between April 2017 and April 2019 and 51 patients with Meniere's disease (control group), diagnosed by People's Hospital Affiliated to Fujian University of Traditional Chinese Medicine between March 2010 and February 2011 and published on Chinese Medical Journal in 2011. Both groups were injected with gadolinium diluent into bilateral tympanic chambers through the tympanic membrane, and 3 dimensional-Fluid Attenuated Inversion Recovery (FLAIR) magnetic resonance imaging scanning of the inner ear was performed 24 hours later. The results of the 2 groups were observed, calculated, and statistically processed. RESULTS: The positive rate of membranous labyrinthine hydrops was 96% (24/25) in the experimental group and 96.1% (49/51) in the control group. The results are very close. CONCLUSION: In clinical diagnoses of Meniere's disease, 1.5T magnetic resonance imaging and 3.0T magnetic resonance imaging have the same value and significance.

Long-term effect of transtympanic intermittent pressure therapy using a tympanic membrane massage device for intractable meniere's disease and delayed endolymphatic hydrops.

BACKGROUND: A 12-month follow-up study showed that middle ear pressure treatment with a transtympanic membrane massage (TMM) device had a similar effect to a Meniett device. OBJECTIVES: The effects of pressure treatment with a TMM device were retrospectively compared to the effects of treatment with a Meniett device in patients with Meniere's disease (MD) and delayed endolymphatic hydrops (DEH) who were followed for a minimum of 24 months. MATERIALS AND METHODS: Twenty-seven patients were treated with the TMM device and 14 patients were treated with a Meniett device. The insertion of a transtympanic ventilation tube was necessary for the Meniett device but not for the TMM device. RESULTS: In patients treated with the TMM and Meniett devices, the frequency of vertigo significantly improved at 19-24 months after treatment. The distribution of vertigo at 19-24 months after treatment did not differ between the patients treated with the two types of devices. Pressure treatment for 8 months or more was suitable to achieve remission. CONCLUSIONS AND SIGNIFICANCE: Middle ear pressure treatment for 8 months or more with a TMM or Meniett device was equally effective and provided minimally invasive treatment options for intractable MD and DEH.

Effects of transtympanic intermittent pressure therapy using a new tympanic membrane massage device for intractable Meniere's disease and delayed endolymphatic hydrops: a prospective study.

BACKGROUND: The retrospective study showed that the effect of the middle ear pressure treatment by the tramstympanic membrane massage (TMM) device was similar to that of the Meniett device. OBJECTIVES: The new TMM device named EFET device was prospectively evaluated in patients with Meniere's disease (MD) and delayed endolymphatic hydrops (DEH) and we compared the effects to the Meniett device. MATERIALS AND METHODS: 23 ears of 19 patients were treated with an EFET device, and 17 ears of 15 patients were treated with the Meniett device. All patients suffering from intractable MD and DEH were treated for 4 months. The insertion of a transtympanic ventilation tube was necessary for the Meniett device, but not the EFET device. RESULTS: In patients treated by the EFET and Meniett devices, the frequency of vertigo significantly improved after treatment. The distribution of vertigo outcomes at 4 months after treatment did not differ between patients treated with the both devices. CONCLUSIONS AND SIGNIFICANCE: Middle ear pressure treatment by the EFET device is effective and provides minimally invasive options for intractable MD and DEH like the Meniett device.

Long-term efficacy of triple semicircular canal plugging in the treatment of patients with ipsilateral delayed endolymphatic hydrops.

This study aims to explore the long-term efficacy of triple semicircular canal plugging (TSCP) in the treatment of intractable ipsilateral delayed endolymphatic hydrops (DEH), so as to provide an alternative therapy for this disease. Forty-eight patients diagnosed with ipsilateral DEH referred to vertigo clinic of our hospital between Dec. 2010 and Dec. 2017, were included in this study for retrospective analysis. All patients were followed up for 2 years. Vertigo control and auditory functions were measured and analyzed. Pure tone audiometry, caloric test, and vestibular evoked myogenic potential (VEMP) were performed in two-year follow-up. Forty-five patients who accepted intratympanic gentamicin (26.7 mg/mL) twice given one week apart were selected as a control group. The total control rate of vertigo in TSCP group was 97.9% (47/48) in the two-year follow-up, with complete control rate of 83.3% (40/48) and substantial control rate of 14.6% (7/48). The rate of hearing loss was 22.9% (11/48). The total control rate of vertigo in intratympanic gentamicin group was 80.0% (36/45), with complete control rate of 57.8% (26/45) and substantial control rate of 22.2% (10/45), and the rate of hearing loss was 20.0% (9/45). The vertigo control rate of TSCP was significantly higher than that of intratympanic gentamicin (χ2 = 6.01, p < 0.05). There was no significant difference of hearing loss rate between two groups. (χ2 = 0.12, p > 0.05). TSCP, which can reduce vertiginous symptoms in patients with intractable ipsilateral DEH, represents an effective therapy for this disorder.

Frequency-specific Electrocochleography and Traveling Wave Time as a Clinical Test for Menière's Disease.

INTRODUCTION: Menière's disease is a clinical entity with no definitive objective testing. It has been hypothesized that underlying endolymphatic hydrops stiffens the basilar membrane leading to increased speed of the acoustic stimulus, therefore traveling wave velocity has been proposed as an objective test to aid in the diagnosis. The objective of this study is to compare electrocochleography frequency-specific action potential latency, basilar membrane traveling wave time, and summation to action potential (SP/AP) ratio in Menière's and non-Menière's patients. METHODS: Tympanic electrocochleography was performed with frequency-specific action potential latency time and SP/AP ratio recorded. Patient demographics, symptoms, audiogram data, AAO-HNS classification of Menière's disease, management interventions, and follow-up were recorded. Statistical analysis was performed to compare outcome measures across patient groups, demographics, and clinical data. RESULTS: Ninety-one patients (182 ears) were included. There was a significant difference between a "definite" Menière's diagnosis and an "unlikely" or "probable" diagnosis by an average of 13 dB HL for the pure-tone thresholds at 250 Hz on the affected side (p = 0.006). There was no significant difference in pure-tone thresholds at any other frequency, AP latency at any frequency, or AP/SP ratio between the different Menière's classification groups. CONCLUSIONS: Our study fails to show significance of the traveling wave velocity as an objective test for Menière's disease. A significant correlation was found with low-frequency hearing loss between AAO-HNS Menière's classification groups.

Arginine Vasopressin-Aquaporin-2 Pathway-Mediated Dehydration Effects of Electroacupuncture in Guinea Pig Model of AVP-Induced Eendolymphatic Hydrops.

OBJECTIVE: To investigate the effects of electroacupuncture (EA) on endolymphatic hydrops (EH) and the regulation of arginine vasopressin (AVP)-aquaporin-2 (AQP2) pathway in guinea pigs. METHODS: EH was induced in male guinea pigs by an intraperitoneal injection of AVP. For the treatment, EA was delivered to Baihui (GV 20) and Tinggong (SI 19) acupoints, once per day for 10 consecutive days. In histomorphological studies, cochlear hydrops degree was evaluated by hematoxylin-eosin (HE) staining, and then the ratio of scala media (SM) area to SM + scala vestibuli (SV) area (R value) was calculated. In mechanical studies, a comparison of plasma AVP (p-AVP) concentrations, cyclic adenosine monophosphate (cAMP) levels, vasopressin type 2 receptor (V2R) and AQP2 mRNA expressions in the cochlea were compared among groups. RESULTS: EA significantly reduced cochlear hydrops in guinea pigs (P=0.001). EA significantly attenuated the AVPinduced up-regulation of p-AVP concentrations (P=0.006), cochlear cAMP levels (P=0.003) and AQP2 mRNA expression (P=0.016), and up-regulated the expression of V2R mRNA (P=0.004) in the cochlea. CONCLUSIONS: The dehydrating effect of EA might be associated with its inhibition of AVP-AQP2 pathway activation.

Effect of electroacupuncture on arginine vasopressin-induced endolymphatic hydrops.

OBJECTIVE: To investigate the influence of electroacupuncture (EA) on experimentally induced endolymphatic hydrops (EH) in guinea pigs, and elucidate the association between the dehydrating effect of EA and changes in stria vascularis ultrastructure and expression of vasopressin type 2 receptor (V2R), cyclic adenosine monophosphate (cAMP), and aquaporin 2 (AQP2) in the endolymphatic sac (ES). METHODS: The EH model was established by intraperitoneal injection of arginine vasopressin (AVP). As a treatment, EA was delivered to Baihui (GV 20) and Tinggong (SI 19) acupoints, once daily for 10 consecutive days. For histomorphological studies, degree of cochlear hydrops was evaluated by hematoxylin-eosin staining, and the ratio of scala media (SM) area to SM + scala vestibuli area was calculated. In mechanical studies, ultrastructural changes in stria vascularis tissue were examined by transmission electron microscopy. In addition, cAMP levels and mRNA expression levels of V2R and AQP2 in the ES were compared among groups. RESULTS: EA treatment significantly reduced cochlear hydrops compared with hydropic guinea pigs (P = 0.015). Furthermore, EA attenuated ultrastructural changes in the stria vascularis tissue following EH, significantly upregulated the expression of V2R (P = 0.016), and attenuated AVP-induced upregulation of both cAMP (P = 0.038) and AQP2 expression (P = 0.017) in the ES. CONCLUSION: Collectively, the results of the present study suggest that the dehydrating effect of EA is associated with improvement of stria vascularis ultrastructure and V2R-cAMP-AQP2 signaling pathway regulation in the ES.

Delayed Effect of Active Pressure Treatment on Endolymphatic Hydrops.

OBJECTIVE: To identify eventual correlations between the effect of low-pressure treatment and endolymphatic hydrops in Ménière patients. MATERIAL AND METHODS: The study group consisted of subjects affected by definite Ménière disease (2015) and a severe degree of disability, who received a ventilation tube with or without a low-pressure treatment before undergoing a surgical procedure (vestibular neurectomy). After the placement of the ventilation tube, the subjects were either left alone with the tube or received 1 month of self-administered low-pressure therapy with a portable device. In all subjects, an electrocochleography (ECochG) was performed and specific questionnaires - Dizziness Handicap Inventory (DHI) and Functional Scale Level (FSL) - were completed before starting either arm of treatment, at the end of treatment, and then 3 and 6 months later. RESULTS: All selected subjects presented with an ECochG pattern that was indicative of endolymphatic hydrops before starting either treatment. At the end of pressure treatment, 80% showed symptomatic improvement while maintaining the hydropic ECochG pattern. At the 3-month control stage, the hydropic pattern resulted normalized (<0.5) in all the improved subjects. CONCLUSIONS: Although 1 month of low-pressure treatment provided a positive symptomatological outcome, normalization of the hydropic ECochG parameters occurred only at a later time. Therefore, it is possible to assume that endolymphatic hydrops could be concurrent with a non-symptomatic stage of Ménière disease, and that the anti-hydropic effect of the low-pressure treatment, if any, would present with a certain delay after its completion.

Treatment of ear and bone disease in the Phex mouse mutant with dietary supplementation.

HYPOTHESIS: Phosphorus and vitamin D (calcitriol) supplementation in the Phex mouse, a murine model for endolymphatic hydrops (ELH), will improve otic capsule mineralization and secondarily ameliorate the postnatal development of ELH and sensorineural hearing loss (SNHL). BACKGROUND: Male Phex mice have X-linked hypophosphatemic rickets (XLH), which includes osteomalacia of the otic capsule. The treatment for XLH is supplementation with phosphorus and calcitriol. The effect of this treatment has never been studied on otic capsule bone and it is unclear if improving the otic capsule bone could impact the mice's postnatal development of ELH and SNHL. METHODS: Four cohorts were studied: 1) wild-type control, 2) Phex control, 3) Phex prevention, and 4) Phex rescue. The control groups were not given any dietary supplementation. The Phex prevention group was supplemented with phosphorus added to its drinking water and intraperitoneal calcitriol from postnatal day (P) 7-P40. The Phex rescue group was also supplemented with phosphorus and calcium but only from P20 to P40. At P40, all mice underwent auditory brainstem response (ABR) testing, serum analysis, and temporal bone histologic analysis. Primary outcome was otic capsule mineralization. Secondary outcomes were degree of SNHL and presence ELH. RESULTS: Both treatment groups had markedly improved otic capsule mineralization with less osteoid deposition. The improved otic capsule mineralized did not prevent the development of ELH or SNHL. CONCLUSION: Supplementation with phosphorus and calcitriol improves otic capsule bone morphology in the Phex male mouse but does not alter development of ELH or SNHL.

Diagnostic value of vestibular-evoked myogenic potentials in Ménière's disease and vestibular migraine.

Overlaps can be seen between vestibular migraine (VM) Ménière's Disease (MD) and diagnosis is difficult if hearing is normal. We aimed to investigate the sacculo-collic pathway in VM patients, MD patients, and healthy controls to define the diagnostic role of cervical VEMP (cVEMP). VEMP testing in response to 500 Hz and 1000 Hz air-conducted tone burst (TB) stimulation was studied prospectively in 22 subjects with definite VM (according to Bárány nomenclature), 30 subjects with unilateral definite MD, and 18 volunteers matched healthy controls. In VM subjects, response rate, p13 and n23 latencies were similar to healthy controls, but peak-to-peak amplitudes were bilaterally reduced at 500 Hz TBs (p= 0.005). cVEMP differentiated MD patients from VM and healthy controls with asymmetrically reduced amplitudes on affected ears with low response rates at 500 Hz TBs, and alteration of frequency dependent responses at 500 and 1000 Hz TBs. These findings suggest that cVEMP can be used as a diagnostic test to differentiate MD from VM. On the other hand, VEMP responses are symmetrically reduced on both sides in VM patients, suggesting that otolith organs might be affected by migraine-induced ischemia.

[Effects of electroacupuncture on cochlea morphology and expression of aquaporins in guinea pigs with endolymphatic hydrops].

OBJECTIVE: To observe the effects of electroacupuncture (EA) on cochlea morphology and expression of aquaporin 1 (AQP1) in guinea pigs with endolymphatic hydrops, so as to explore the possible mechanism of EA on endolymphatic hydrops. METHODS: Forty guinea pigs were randomly divided into a blank group, a model group, a medication group and an EA group, 10 guinea pigs in each one. Model of endolymphatic hydrops was established by using intraperitoneal injection of aldosterone. Guinea pigs in the blank group and model group were treated with identical immobilization as EA group but no treatment was given; guinea pigs in the medication group were treated with intragastric administration of hydrochlorothiazide at a dose of 5 mg/kg, once a day for consecutive 10 days; guinea pigs in the EA group were treated with' EA at "Baihui" (GV 20) and "Tinggong"(SI 19), once a day for consecutive 10 days. The serum ionic concentration in each group was tested by turbidimetric method; hematoxylin-eosin staining was used to measure the severity of cochlea hydrops; immunohistochemical method was used to observe the expression of AQP1 in the cochlea. RESULTS: (1) There was no endolymphatic hydrops in the blank group, moderate-severe endolymphatic hydrops in the model group and slight endolymphatic hydrops in the EA group and medication group. (2) The concentration of K+ and Ca2+ in the EA group was higher than that in the model group and medication group (all P<0. 01); the concentration of Na+ was lower than that in the model group (P< 0. 01) but higher than that in the medication group (P<0. 01); the concentration of Cl- was higher than that in the medication group (P<0. 01), but not significantly different from the model group (P>0. 05). (3) The ratio of expression area of AQP1 in the model group was lower than that in the blank group (P<0. 01); the ratio of expression area of AQP1 in the EA group was higher than that in the model group (P<0. 01), and lower than that in the medication group without significant difference (P>0. 05). CONCLUSION: EA could relieve the endolymphatic hydrops in guinea pigs; the mechanism is likely to be related with up-regulating the expression of AQP1 in cochlea and ion concentration might be an important factor involved.

Abnormal fast fluctuations of electrocochleography and otoacoustic emissions in Menière's disease.

The responses of cochlear hair cells to sound stimuli depend on the resting position of their stereocilia bundles, which is sensitive to the chemical and mechanical environment. Cochlear hydrops, a hallmark of Menière's disease (MD), which is likely to come with disruption of this environment, results in hearing symptoms and electrophysiological signs, such as excessive changes in the cochlear summating potential (SP) and in the postural shifts of distortion-product otoacoustic emissions (DPOAEs). Here, SP from the basal part of the cochlea and DPOAEs from the apical part of the cochlea were recorded concomitantly in 73 patients with a definite MD, near an attack (n = 40) or between attacks with no clinical symptoms (n = 33), to compare their sensitivities to posture and evaluate their stability. The phase of the 2f1-f2 DPOAEs was monitored during body tilt, with stimuli f1 = 1 kHz and f2 = 1.2 kHz at 72 dB SPL. Extratympanic electrocochleography was performed in response to 95-dBnHL clicks. The normal limits of the DPOAE phase shift with body tilt, [-18°, +38°], and of the SP to action-potential (AP) ratio, <0.40, were exceeded in 75% and 60% of patients, respectively, near an attack. In these patients, but not in the asymptomatic ones, both tests reveal fluctuating cochlear responses from one data sample to the next. They emphasize how hydrops hinders normal hair-cell operation and may generate fast fluctuations in inner-ear functioning. If these fluctuations also occur on shorter time scales, it might explain the imperfect diagnostic sensitivity of SP and DPOAE tests, as averaging procedures would tend to level out transient fluctuations characteristic of hydrops.

MRI Inner Ear Imaging and Tone Burst Electrocochleography in the Diagnosis of Ménière's Disease.

OBJECTIVE: To compare the sensitivity of gadolinium MRI inner imaging with tone burst electrocochleography (EcochG) for diagnosing endolymphatic hydrops. STUDY DESIGN: A prospective study on patients who were to have an MRI scan to exclude retrocochlear pathology. SETTING: Tertiary care center. PATIENTS: One hundred and two patients: 57 patients with Possible, Probable, or Definite Ménière's Disease, 25 with asymmetrical hearing loss, 18 with sudden sensorineural hearing loss, and 2 with unilateral tinnitus had additional MRI inner ear imaging and click and tone burst stimulus EcochG testing. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURE: To compare the sensitivity of the two techniques. RESULTS: In 30 patients with symptom-based Definite Ménière's Disease, tone burst EcochG was positive in 25 (83%) and the click EcochG was positive in 9/30 (30%), and gadolinium MRI imaging diagnosed hydrops in 14 (47%). A positive result for either MRI imaging or tone burst EcochG was seen in 26 patients (87%). In 14 subjects with symptom-based Probable Ménière's Disease, 10 (71%) had either a positive EcochG or MRI. In 13 with Possible Ménière's Disease, four (31%) had a positive EcochG or MRI. CONCLUSION: This study confirms the greatly enhanced diagnostic sensitivity of tone burst EcochG over click response in diagnosing endolymphatic hydrops in Ménière's disease. Even though adequate MRI imaging was achieved in 90%, tone burst EcochG was a more sensitive test.

Frequency preference in cervical vestibular evoked myogenic potential of idiopathic otolithic vertigo patients. Does it reflect otolithic endolymphatic hydrops?

CONCLUSION: Idiopathic otolithic vertigo (IOV) with relatively long duration of attacks might be caused by endolymphatic hydrops in the otolith organ. OBJECTIVES: To clarify the pathophysiology underlying IOV, episodic tilting or translational sensation attacks by unknown causes, especially the possibility of endolymphatic hydrops in the otolith organ. METHODS: Sixteen patients (6 men and 10 women) diagnosed with having IOV were enrolled. In these subjects, frequency preference in cervical vestibular evoked myogenic potential (cVEMP) was studied. The subjects underwent cVEMP testing using 500 Hz and 1000 Hz short tone bursts (STB) (125 dB SPL, air-conducted sound). The 500-1000 Hz cVEMP slope was calculated and assessed in comparison with data from healthy subjects in the preceding study. RESULTS: Twelve of the 16 examined patients had a significant preference of 1000 Hz to 500 Hz, which was suggestive of endolymphatic hydrops in the saccule. Patients with frequency preference of 1000 Hz to 500 Hz showed a tendency for longer vertigo attacks than patients without preference of 1000 Hz.

Endolymphatic hydrops is prevalent in the first weeks following cochlear implantation.

AIM: To explore morphological or electrophysiological evidence for the presence of endolymphatic hydrops (EH) in guinea pig cochleae in the first 3 months after cochlear implantation. METHODS: Dummy silastic electrodes were implanted atraumatically into the basal turn of scala tympani via a cochleostomy. Round window electrocochleography (ECochG) was undertaken prior to and after implantation. Animals survived for 1, 7, 28 or 72 days prior to a terminal experiment, when ECochG was repeated. The cochleae were imaged using micro-CT after post-fixing with osmium tetroxide to reveal the inner ear soft tissue structure. EH was assessed by visual inspection at a series of frequency specific places along the length of the cochlea, and the extent to which Reissner's membrane departed from its neutral position was quantified. Tissue response volumes were calculated. Using ECochG, the ratio of the summating potential to the action potential (SP/AP ratio) was calculated in response to frequencies between 2 and 32 kHz. RESULTS: There was minimal evidence of electrode trauma from cochlear implantation on micro-CT imaging. Tissue response volumes did not change over time. EH was most prevalent 7 days after surgery in implanted ears, as determined by visual inspection. Scala media areas were increased, as expected in cases of EH, over the first month after cochlear implantation. SP/AP ratios decreased immediately after surgery, but were elevated 1 and 7 days after implantation. CONCLUSIONS: EH is prevalent in the first weeks after implant surgery, even in the absence of significant electrode insertion trauma.

Effects of electroacupuncture on cochlea morphology and expression of aquaporins in guinea pigs with endolymphatic hydrops / 中国针灸

<p><b>OBJECTIVE</b>To observe the effects of electroacupuncture (EA) on cochlea morphology and expression of aquaporin 1 (AQP1) in guinea pigs with endolymphatic hydrops, so as to explore the possible mechanism of EA on endolymphatic hydrops.</p><p><b>METHODS</b>Forty guinea pigs were randomly divided into a blank group, a model group, a medication group and an EA group, 10 guinea pigs in each one. Model of endolymphatic hydrops was established by using intraperitoneal injection of aldosterone. Guinea pigs in the blank group and model group were treated with identical immobilization as EA group but no treatment was given; guinea pigs in the medication group were treated with intragastric administration of hydrochlorothiazide at a dose of 5 mg/kg, once a day for consecutive 10 days; guinea pigs in the EA group were treated with' EA at "Baihui" (GV 20) and "Tinggong"(SI 19), once a day for consecutive 10 days. The serum ionic concentration in each group was tested by turbidimetric method; hematoxylin-eosin staining was used to measure the severity of cochlea hydrops; immunohistochemical method was used to observe the expression of AQP1 in the cochlea.</p><p><b>RESULTS</b>(1) There was no endolymphatic hydrops in the blank group, moderate-severe endolymphatic hydrops in the model group and slight endolymphatic hydrops in the EA group and medication group. (2) The concentration of K+ and Ca2+ in the EA group was higher than that in the model group and medication group (all P<0. 01); the concentration of Na+ was lower than that in the model group (P< 0. 01) but higher than that in the medication group (P<0. 01); the concentration of Cl- was higher than that in the medication group (P<0. 01), but not significantly different from the model group (P>0. 05). (3) The ratio of expression area of AQP1 in the model group was lower than that in the blank group (P<0. 01); the ratio of expression area of AQP1 in the EA group was higher than that in the model group (P<0. 01), and lower than that in the medication group without significant difference (P>0. 05).</p><p><b>CONCLUSION</b>EA could relieve the endolymphatic hydrops in guinea pigs; the mechanism is likely to be related with up-regulating the expression of AQP1 in cochlea and ion concentration might be an important factor involved.</p>

The diagnostic value of vestibular evoked myogenic potentials in patients with Meniere's disease.

OBJECTIVE: To estimate the sensitivity and specificity of vestibular evoked myogenic potentials (VEMPs) in comparison with caloric test in diagnosing Meniere's disease (MD) among patients with dizziness. METHODS: Data were retrospectively collected from 1,170 consecutive patients who underwent vestibular tests. Among them, 114 patients were diagnosed as having unilateral definite MD. VEMPs in response to clicks and short tone burst stimulation as well as caloric tests were performed. The sensitivity and specificity of each test were evaluated. The results of each test were compared with hearing level and staging of MD. RESULTS: The sensitivity and specificity of VEMPs were 50.0% and 48.9%, while those of the caloric test were 37.7% and 51.2%, respectively. There was no significant difference in hearing level between patients appropriately or inappropriately identified by VEMPs, whereas there was a significant difference in those of the caloric test. Combined use of VEMP and caloric test increased the sensitivity to 65.8%. CONCLUSION: Although the sensitivity and specificity of VEMPs in diagnosing MD were not high, they were comparable to those of caloric test. VEMPs as well as caloric testing may give additional information as part of a diagnostic test battery for detecting vestibular abnormalities in MD.