Because inner ear organs are interconnected through the endolymph and surrounding endolymphatic membrane, the patients with sudden sensorineural hearing loss (SSNHL) often complain of vertigo. In this study, we report a patient with SSNHL accompanied by persistent positional vertigo, and serial findings of head-roll tests are described. At acute stage, head-roll test showed persistent geotropic direction-changing positional nystagmus (DCPN), which led to a diagnosis of SSNHL and ipsilateral light cupula. Although vertigo symptom gradually improved, positional vertigo lasted for more than 3 weeks. At this chronic stage, persistent apogeotropic DCPN was observed in a head roll test, which led to a diagnosis of the heavy cupula. Although the mechanism for the conversion of nystagmus direction from geotropic to apogeotropic persistent DCPN is unclear, the change of specific gravity of the endolymph might be one of the plausible hypothetical explanations.
Diagnosis ; Ear, Inner ; Endolymph ; Head ; Hearing Loss, Sensorineural* ; Humans ; Membranes ; Nystagmus, Physiologic ; Specific Gravity ; Vertigo*

BACKGROUND AND OBJECTIVES: The plasma stress-related hormonal [cortisol, growth hormone, prolactin, antidiuretic hormone (ADH), adrenocorticotropic hormone (ACTH)] levels have been reported to be elevated in sudden sensorineural hearing loss (SSNHL) patients. However, little is known regarding the mechanisms related with the elevation of stress-related hormonal levels in SSNHL. Therefore, we measured the level of plasma stress-related hormones in SSNHL patients and in normal persons to demonstrate the association between the stress-related hormones and SSNHL. SUBJECTS AND METHOD: Stress-related hormonal levels were measured from 68 patients who were diagnosed with SSNHL. These values were compared with the stress-related hormonal levels of 24 healthy control subjects. RESULTS: The plasma ADH levels was significantly higher in SSNHL group compared with that in their normal control group, as shown by their respective values, 4.46 [95% confidence interval (CI): 3.80-5.24 pg/mL] and 3.05 (95% CI: 2.34-3.98 pg/mL). The values for plasma cortisol, growth hormone, and ACTH levels whose values were 2.07 (95% CI: 1.65-2.61 microg/L), 0.20 (95% CI: 0.14-0.29 microg/L), and 12.79 (95% CI: 11.16-14.66 pg/mL), respectively, were significantly lower in the SSNHL group than those in the normal control group whose values were 7.86 (95% CI: 5.33-5.24 microg/L), 0.61 (95% CI: 0.36-1.04 microg/L), 18.48 (95% CI: 14.99-22.78 pg/mL), respectively. But there was no significant difference in prolactin between the two groups. CONCLUSION: This study demonstrates a possible role of stress-related hormones in the pathogenesis of SSNHL. However, only ADH level was higher than the control group. Furthermore, ACTH, growth hormone and cortisol levels were lower than the control groups. This means ADH, growth hormone, cortisol, ACTH levels are related with SSNHL. However, the impact of this hormone on the inner ear and endolymph homeostasis is still unknown. Further investigation is necessary to identify the action mechanism of these hormones in the inner ear.
Adrenocorticotropic Hormone ; Ear, Inner ; Endolymph ; Growth Hormone ; Hearing Loss, Sensorineural* ; Homeostasis ; Humans ; Hydrocortisone ; Plasma ; Prolactin

Benign paroxysmal positional vertigo (BPPV) is a common inner ear cause of vertigo, most of which can be treated by particle repositioning maneuver (PRM). However, in rare cases, positional vertigo could persist or frequently recur after several PRM. In these intractable cases, surgical treatments including singular neurectomy and semicircular canal occlusion have been used. Posterior semicircular canal occlusion has some advantages over singular neurectomy in hearing preservation and feasible surgical technique. Also free-floating endolymph particles causing intractable BPPV are known to occur in about 20% of the cases during canal occlusion surgery. Nevertheless, to the best of our knowledge, there has not been any report on the identification of those particles in the Korean literature. In this paper, we report a case of free-floating endolymph particle found during transmastoid posterior semicircular canal occlusion for intractable posterior canal BPPV.
Benign Paroxysmal Positional Vertigo* ; Ear, Inner ; Endolymph* ; Hearing ; Semicircular Canals* ; Vertigo

BACKGROUND AND OBJECTIVES: Strial marginal cells are known to secrete K(+) into endolymph. Slowly activating, voltagede-pendent K(+) channels (I(sK) channels) have been identified in the apical membrane of these cells. Although antidiuretic hormone (vasopressin) has been known to play an important role in the various tissues, its physiological and phamacological roles in the inner ear are still unknown. The purpose of this study is to to investigate the hypothesis that vasopressin increases apical K(+) secretion. MATERIALS AND METHODS: On-cell macro-patch recordings were made on the apical membrane of strial marginal cells dissected from neonate rat. The effect of vasopressin was compared to the one of raising the bath K(+) concentration. RESULTS: We observed I(sK) channels in 21 patches (9%) of 235 high resistance seals. When the pipette contained NaCl-pipette solution, raising the bath K(+) concentration from 3.6 mM to 25 mM led to a statistically significant increase in apical outward K(+) current from 0.44+/-0.04 pA to 3.31+/-0.40 pA (n=10). When the bath K(+) concentration was returned to 3.6 mM, the outward current declined to 0.45+/-0.04 pA, which was not statistically different from the original level. Arginine vasopressin (AVP, 10-7 M) increased apical current from 0.43+/-0.04 pA to 2.20+/-0.30 pA (n=10). The current stimulated by elevated AVP was carried by the apical I(sK) channel. CONCLUSION: Our results demonstrate that AVP receptor is present in marginal cells and that AVP increases transepithelial K(+) secretion by activation of I(sK) channel in neonate rat.
Animals ; Arginine Vasopressin ; Baths ; Ear, Inner ; Endolymph ; Humans ; Infant, Newborn* ; Membranes ; Rats ; Vasopressins

OBJECTIVETo attempt to visualize the endolymph in patients with Meniere's disease by applying non-invasive intratympanic gadolinium through eustachian tube and three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging (3D-FLAIR MRI).

METHODSWith a 3 Tesla magnetic resonance imaging (MRI) unit, 3D-FLAIR imaging was performed 24 hours after intratympanic gadolinium through eustachian tube in two patients with medically active and intractable Meniere's disease. Pure tone test and tympanometry were performed 24 hours before and after the administration of gadolinium.

RESULTSThe gadolinium appeared in almost all parts of the perilymph inside the inner ear; moreover, the border between the perilymph and the endolymph was visible so endolymphatic space was clearly shown on 3D-FLAIR. No change in pure tone test and tympanometry was noted.

CONCLUSIONS3D-FLAIR MRI with intratympanic gadolinium through eustachian tube can clearly reveal the visualization of endolymph in patients with Meniere's disease. Intratympanic gadolinium therapy through eustachian tube is a safe and effective.

Adult ; Endolymph ; diagnostic imaging ; Female ; Humans ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging ; Male ; Meniere Disease ; diagnostic imaging ; Middle Aged ; Radiography

In order to know the effects of caloric stimulation on neuronal firing in medial vestibular nuclei (MVN) by middle ear irrigation, the middle ear was irrigated with ice (4 degrees C), hot (44 degrees C), and warm (37 degrees C) water, and the firing rate of MVN neuron was extracellularly recorded. The results showed that the firing rate of MVN neuron was changed by caloric stimulation, and the majority of MVN neurons showed excitation by irrigation with hot water and inhibition by ice water (type A). The neuronal firing was recovered immediately after the cessation of the stimulation. I It was concluded that the neuronal firing rate in MVN was changed by caloric stimulation in middle ear cavity. The response was different in various neurons.
Cold ; Ear, Middle ; Electrophysiology ; Endolymph/physiology ; Heat ; Irrigation ; Neurons/classification ; Neurons/physiology ; Rats, Wistar ; Vestibular Nerve/*physiology ; Vestibular Nuclei/*physiology

Pendred syndrome is an autosomal recessive condition classically characterized by congenital deafness and goiter, and is the most common cause of hereditary deafness in Korea. It is caused by mutations in the PDS gene (SLC26A4) located in 7q31. The PDS gene encodes a chloride-iodide transport protein called pendrin, which plays a role in the reabsorption of endolymph and the maintenance of the endolymph homeostasis in the inner ear and in the uptake and organification of iodide in the thyroid gland. A mutation in PDS also causes non-syndromic recessive deafness (DFNB4) and therefore securing the diagnosis is important for genetic counseling purposes. The perchlorate discharge test and radiological conformation of the inner ear anomaly are useful diagnostic aids but have limited diagnostic value. However, because PDS mutations are widely distributed along the gene, it consumes too much time and money to perform molecular studies in clinics. We present a case of congenital sensorineural hearing loss with multinodular goiter, which shows definite findings of Pendred syndrome.
Deafness ; Diagnosis ; Ear, Inner ; Endolymph ; Genetic Counseling ; Goiter* ; Hearing Loss, Sensorineural* ; Homeostasis ; Korea ; Thyroid Gland ; Vestibular Aqueduct

OBJECTIVETo investigate the prophylactic effect of low calcium concentration perilymph on noise-induced hearing loss.

METHODSForty guinea pigs with normal hearing weighing 250-350 g were assigned to five groups (8 in each group): (1) Ca(2+)-deficient perilymph perfusion (CDP) for 2 h; (2) white noise (120 dB SPL) exposure (WNE) only for 1 h, (3) combination of calcium-deficient perilymph perfusion and white noise (120 dB SPL) exposure (WNE + CDP); (4) normal artificial perilymph (NAP) perfusion for 2 h; and (5) white noise exposure + normal artificial perilymph perfusion (WNE + NAP) for 2 h. Compound action potentials (CAP) evoked by click was recorded from round window every 15 min. The cochleae from 5 animals in each group were examined with scanning electron microscope.

RESULTSThe CAP for group 1 experienced a threshold shift (TS) of 15-26 dB, while group 2 yielded a 46-59 dB TS and group 3 a 37-45 dB TS; no threshold shift occurred in group 4. The CAP TS in group 5 was 33-64 dB. The CAP TS of group 3 was less than that of group 2. After one hour of noise exposure, the CAP TS of group 3 were 45.92 +/- 2.90 dB and 59.30 +/- 3.95 dB in group 2. There were significant differences (P < 0.05) between groups 3 and 2. The CAP TS of group 3 was less than that of group 5 at the points of 1, 1.5 and 2 h after noise exposure. There was a significant difference between groups 3 and 5 (P < 0.01). Stereocilia of 89 OHC(3) were in disarray in five cochleae after noise exposure in group 2. The cuticular plates of 8 OHC(2),3 sank and the stereocilia became fused in only one animal cochlea after noise exposure in group 3 combined with low calcium perilymph perfusion.

CONCLUSIONSLow calcium concentration appears to participate in preventing noise-induced hearing loss and the rising of calcium concentrations in inner hair cells after noise exposure, which may have been due to the opening of calcium channels in inner hair cells during noise exposure. The mechanism of the prophylactic effect might be caused by a lower calcium concentration in inner hair cells in the cochlea attenuating the influence of noise exposure on hearing loss; calcium deficient perilymph perfusion prevented calcium accumulation in inner hair cells of the cochlea. The motility of the OHCs might be partially inhibited by low calcium concentration that reduced noise-induced hearing loss in turn.

Action Potentials ; Animals ; Calcium ; analysis ; physiology ; Cochlea ; pathology ; physiology ; Endolymph ; metabolism ; Guinea Pigs ; Hair Cells, Auditory ; metabolism ; Hearing Loss, Noise-Induced ; prevention & control ; Perilymph ; physiology

In order to know the effects of caloric stimulation on neuronal firing in medial vestibular nuclei (MVN) by middle ear irrigation, the middle ear was irrigated with ice (4 degrees C), hot (44 degrees C), and warm (37 degrees C) water, and the firing rate of MVN neuron was extracellularly recorded. The results showed that the firing rate of MVN neuron was changed by caloric stimulation, and the majority of MVN neurons showed excitation by irrigation with hot water and inhibition by ice water (type A). The neuronal firing was recovered immediately after the cessation of the stimulation. I It was concluded that the neuronal firing rate in MVN was changed by caloric stimulation in middle ear cavity. The response was different in various neurons.
Animals ; Cold Temperature ; Ear, Middle ; Electrophysiology ; Endolymph ; physiology ; Female ; Hot Temperature ; Male ; Neurons ; classification ; physiology ; Rats ; Rats, Wistar ; Therapeutic Irrigation ; Vestibular Nerve ; physiology ; Vestibular Nuclei ; physiology

Hydrops of the endolymphatic space in the inner ear deteriorates hearing and balance function. This idiopathic syndrome of endolymphatic hydrops is Meniere's disease and is characterized by episodic vertigo, fluctuating hearing loss, tinnitus and ear fullness. For the pathophysiologic mechanisms of the episode, the progression of the hydrops leads to ruptures in the membranes separating endolymph from perilymph, producing a sudden increase in potassium concentration in the perilymph. Recurrent episodes may interfere with routine daily activities and sometimes accompany sudden drop attacks, so called Tumarkin's otolithic crisis, which may lead to serious injuries. Life style modification, low salt diet and prescription of diuretics have been traditionally tried in order to relieve endolymphatic hydrops. Surgical and destructive treatment options are necessary in selected intractable patients depending on the frequency of vertigo, severity of hearing loss and the possibility of bilateral involvement. However, a large proportion of these patients shows a spontaneous cure of vertigo with the aggravation of hearing loss (burnt out stage) over time. The goal of treatment is trying not to make the patient worse than this natural course of disease.
Diet ; Diuretics ; Dizziness ; Ear ; Ear, Inner ; Edema ; Endolymph ; Endolymphatic Hydrops ; Hearing ; Hearing Loss ; Humans ; Life Style ; Membranes ; Meniere Disease ; Otolithic Membrane ; Perilymph ; Potassium ; Prescriptions ; Rupture ; Syncope ; Tinnitus ; Vertigo