Ipsilateral Delayed Endolymphatic Hydrops Research Articles

A 14-year nationwide epidemiological analysis of delayed endolymphatic hydrops in Japan

Background Delayed endolymphatic hydrops (DEH) is an inner ear disease that causes recurrent vertigo in the ipsilateral ear or fluctuating hearing in the contralateral ear due to endolymphatic hydrops secondary to preceding deafness. There are few reports of large, multicentre studies investigating the clinical-epidemiological characteristics of DEH. Objective This study aimed to clarify the characteristics of DEH in Japan. Methods Clinical data on 662 patients with DEH were analysed by nationwide, multicentre surveys conducted by the Peripheral Vestibular Disorders Research Group of Japan. Results The proportion of ipsilateral DEH (IDEH) was slightly higher than that of contralateral DEH (CDEH) at 55.4%. The time delay between onset of precedent deafness and onset of DEH was significantly longer for CDEH than for IDEH. The most common cause of precedent deafness was a disease of unknown cause with onset in early childhood (33.1%). Epidemiological characteristics were not significantly different between CDEH with and without vertigo. Conclusion DEH appearing to be caused by viral labyrinthitis has a high rate of onset within 40 years of precedent deafness. Clinical and epidemiological characteristics of IDEH, CDEH with vertigo, and CDEH without vertigo were very similar. Significance The clinical-epidemiological characteristics of DEH in Japan were clarified.

Anatomical variation of inner ear may be a predisposing factor for unilateral M\xe9ni\xe8re\u2019s disease rather than for ipsilateral delayed endolymphatic hydrops

ObjectiveRadiological anatomical variations, measured by magnetic resonance imaging (MRI), were evaluated in patients with ipsilateral delayed endolymphatic hydrops (DEH) and unilateral Ménière’s disease (MD). The role of anatomical variations in different subtypes of hydropic ear disease was investigated.MethodsTwenty-eight patients with ipsilateral DEH, 76 patients with unilateral MD, and 59 control subjects were enrolled. The radiological indices included the distance between the vertical part of the posterior semicircular canal and the posterior fossa (MRI-PP distance) and the visibility of vestibular aqueduct (MRI-VA). These variations among patients with DEH, MD, and control subjects were compared. The correlation between radiological anatomical variations and clinical features or audio-vestibular findings was also examined.Results(1) MRI-PP distance in the affected side of unilateral MD was shorter than that in ipsilateral DEH (Z = − 2.481, p = 0.013) and control subjects (Z = − 2.983, p = 0.003), while the difference of MRI-PP distance between the affected side of ipsilateral DEH and control subjects was not statistically significant (Z = − 0.859, p = 0.391). (2) There was no significant interaural difference of MRI-PP distance in patients with unilateral MD (Z = − 0.041, p = 0.968) and ipsilateral DEH (t = − 0.107, p = 0.915) respectively. (3) No significant interaural difference of MRI-VA visibility was observed in patients with unilateral MD (χ2 = 0.742, p = 0.389) and ipsilateral DEH (χ2 = 0.327, p = 0.567) respectively. (4) No correlation was found between these anatomical variables and clinical features or audio-vestibular findings in patients with unilateral MD and ipsilateral DEH respectively (p > 0.05).ConclusionsAnatomical variations of inner ear may be a predisposing factor in the pathogenesis of unilateral MD rather than ipsilateral DEH.Key Points• Patients with ipsilateral delayed endolymphatic hydrops showed normal distance between the vertical part of the posterior semicircular canal and the posterior fossa.• Compared to patients with ipsilateral delayed endolymphatic hydrops and control subjects, patients with unilateral Ménière’s disease exhibited shorter distance between the vertical part of the posterior semicircular canal and the posterior fossa.• Anatomical variations of inner ear may be a predisposing factor in the pathogenesis of unilateral Ménière’s disease rather than ipsilateral delayed endolymphatic hydrops.

Clinical features of vestibular syncope associated with tumarkin attacks in delayed endolymphatic hydrops

Objective: To analyze the clinical characteristics of vestibular syncope (VS) associated with drop attacks (DA) in delayed endolymphatic hydrops (DEH). Methods: DEH cases with complete data were retrospectively analyzed, including three DEH cases with DA and VS (VS group), and six DEH cases without DA or VS (control group). The clinical profile, the results of neurotological examinations [such as pure tone audiometry, electrocochleography (EcochG), caloric test, vestibular evoked myogenic potentials (VEMP), and video head impulse test (vHIT)] and treatment outcomes were analyzed. Results: (1) In the VS group, there were three cases of ipsilateral DEH; in the control group, there were six cases of ipsilateral type. One case in each group had a history of migraine. (2) The prevalence of abnormal results in caloric test, vHIT, cervical VEMP, and ocular VEMP in the VS group was 3/3, 1/3, 2/2, and 2/2, respectively, and in the control group was 3/6, 0/3, 1/6, and 4/6, respectively. Two cases in each group underwent EcochG, and no identifiable waveform was elicited on the affected side, and-SP/AP ratio of unaffected side was less than 0.4. (3) Patients in both groups were initially treated with conservative medication. Two cases in the VS group subsequently received intratympanic injections of dexamethasone. No DA or VS occurred during a follow-up period lasting over one year. All patients achieved good control of vertigo during the follow-up period. Conclusions: VS may occur in the patients with DEH. The differential diagnosis of syncope in patients with otogenic vertiginous disease can help improve clinical diagnosis and treatment.

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.

Dissociation of Caloric and Video Head Impulse Tests in Patients With Delayed Endolymphatic Hydrops.

Delayed endolymphatic hydrops (DEH) represents a rare clinical entity characterized by intermittent vertigo attacks mimicking those of Ménière's disease (MD) in a patient with a prior sensorineural hearing loss. Some vestibular tests have been employed in patients with DEH. These tests provide useful diagnostic information and facilitate clinical decision-making. Here, we retrospectively studied the features of video head impulse test (vHIT) and examined its relationship with caloric test used in DEH patients. Included in this study were 17 patients with ipsilateral DEH and 2 with contralateral DEH. Among them, 73.7% (14/19) showed abnormal caloric test response (76.5% in ipsilateral DEH and 50% in contralateral DEH). Meanwhile, only 15.8% (3/19) of patients yielded abnormal horizontal vHIT results (11.8% in ipsilateral DEH and 50% in contralateral DEH). Abnormal caloric response in the presence of a preserved vHIT was common in DEH patients, especially those with ipsilateral DEH. This dissociation might be a distinctive pattern of vestibular deficit in DEH.

Bilateral delayed endolymphatic hydrops evaluated by bilateral intratympanic injection of gadodiamide with 3T-MRI.

The purpose of this study was to assess the diagnostic performance of 3T MRI after intratympanic injection of gadodiamide for delayed endolymphatic hydrops (DEH), and assess the relationship between endolymphatic hydrops (ELH) and vestibular function in patients diagnosed with DEH and confirmed by 3T MRI. Nineteen patients clinically diagnosed with DEH (11 ipsilateral DEH, 8 contralateral DEH) participated in this study. Diluted gadodiamide was administered to the bilateral tympanic cavity by injection through the tympanic membrane. At 24 hours post-injection, the ELH was evaluated by MRI. Patient vestibular functions were evaluated by caloric testing and cVEMP. ELH was observed in all patients (19/19: positive rate 100%). The distribution patterns of ELH varied between the cochlear or vestibular region. Vestibular ELH was observed in the affected ear in all ipsilateral DEH patients. In the contralateral DEH patients, however, there were individual differences in the distribution patterns of ELH. Six patients (1 ipsilateral DEH, 5 contralateral DEH) had bilateral ELH. No obvious relationships were observed between ELH and vestibular function. ELH distribution was complicated, particularly in the contralateral DEH cases. It was difficult to identify the existence of ELH by vestibular functional testing alone; therefore, 3T MRI is thought to be useful for identifying the affected ear. A significant number of cases had “bilateral” DEH, particularly among the contralateral DEH cases, indicating that we should pay careful attention to this pathology when treating DEH.

Delayed endolymphatic hydrops. Special emphasis on nystagmus associated with episodes and contribution of chemical labyrinthectomy

ObjectivesThe main objective was to describe spontaneous nystagmus characteristics during an episode of delayed endolymphatic hydrops (DEH), including an initial vertical upbeating nystagmus in one patient. The secondary objective was to highlight the contribution of chemical labyrinthectomy. MethodsEpisodic vertigo after a prolonged period of time of sensorineural hearing loss (profound or total) in one ear characterized ipsilateral DEH and was associated with the development of hearing loss in the opposite ear in contralateral DEH. ResultsTen patients met the criteria for DEH: 7 ipsilateral and 3 contralateral. Three (all ipsilateral DEH) were examined during a vertigo episode. Two patients had a typical horizontal-torsional nystagmus beating contralaterally to the hearing loss. One patient showed atypic initial vertical upbeating nystagmus with a slight torsional component, which secondarily became horizontal-torsional beating contralaterally to the hearing loss. Four patients had disabling vertigo with unilateral total deafness (ipsilateral DEH), successfully treated by 1-3 transtympanic gentamycin (Gentalline®) injections. ConclusionNystagmus direction during vertigo episodes varies, and may initially present as vertical upbeating nystagmus, which, to our knowledge, has not been previously reported in DEH or Menière's disease. This nystagmus might reflect an inhibition of the superior semicircular canal (on the hearing-impaired side), suggesting incipient hydrops in this canal. Chemical labyrinthectomy is a simple and effective procedure in unilateral DEH, especially as the patient often suffers from total deafness.

Intratympanic Injections of Dexamethasone in Delayed Endolymphatic Hydrops: A Prospective Clinical Study

Objective: This study was designed to evaluate the effectiveness of intratympanic dexamethazone (ITD) for the treatment of ipsilateral delayed endolymphatic hydrops (DEH). Methods: Forty-one patients were diagnosed with ipsilateral DEH. Only 37 patients completed this study. Patients were randomly divided into 2 groups. Group A (n = 16) received oral medication, and group B (n = 21) received ITD once weekly for 4 consecutive weeks. Results: In group A, 6 patients showed improvement in their vertigo. Four patients (25%) showed complete vertigo control, and 2 patients (12.5%) showed substantial vertigo control. In group B, 21 patients showed improvement in their vertigo, 11 patients (52%) showed complete vertigo control, and 10 patients (47%) showed substantial vertigo control. Only 1 case did not show any improvement in their vertigo. Conclusion: ITD is proven to be a valuable and promising alternative modality for the management of ipsilateral DEH.

Contralateral type of delayed endolymphatic hydrops may consist of two phenotypes based on a magnetic resonance imaging preliminary study

Objective: This study was performed to determine the volume distribution of EH in contralateral DEH.Patients and methods: Five contralateral DEH patients (age range = 21–77 years) and one ipsilateral DEH patient. Visualization of in vivo EH using 3T magnetic resonance (MR) imaging was performed by intravenous administration of gadolinium. The EH volume was determined quantitatively by adding the area of EH in consecutive MR images.Results: The total EH volume of the patients with contralateral DEH varied from 24.2 to 56.6 μL in the first ear and 20.2 to 35.7 μL in the contralateral ear. EH was dominantly developed in the first ear for Patient no. 3 and 4, and not dominantly developed in the first ear for Patient no. 1, 2, and 5.Conclusions: The volume distribution of endolymphatic hydrops (EH) in contralateral delayed endolymphatic hydrops (DEH) was classified into two phenotypes. This suggests that contralateral DEH may consist of two etiologies.

Gadolinium-enhanced inner ear magnetic resonance imaging for evaluation of delayed endolymphatic hydrops, including a bilateral case

Conclusion The data suggests that gadolinium-enhanced inner ear MR imaging is useful for diagnosis of delayed endolymphatic hydrops (DEH) because it is independent of inner ear function, and the size of the affected endolymphatic space is clearly enlarged. Objective This study was performed to semi-quantitatively evaluate the endolymphatic space in patients with all types of DEH using gadolinium-enhanced inner ear magnetic resonance (MR) imaging. Patients and methods Seven patients (age range = 21–77 years; five female, two male) with ipsilateral DEH (n = 5), contralateral DEH (n = 1), and bilateral DEH (n = 1). All patients underwent 3T MR imaging 4 h after intravenous injection of gadolinium. Software was used to determine the size of the endolymphatic space. Pure tone audiometry and caloric testing using an electronystagmogram were carried out. Results One side of the endolymphatic space was dominantly extended in patients with ipsilateral DEH, and both sides of the space were extended in patients with contralateral and bilateral DEH. In patients with ipsilateral DEH, the volume ratio of endolymph to vestibule was 2.5–4.3-times that in the unaffected ear. The volume ratio of endolymph to vestibule was nearly equal in patients with contralateral and bilateral DEH.

Intratympanic injection in delayed endolymphatic hydrops

Conclusions: The present study showed that intratympanic dexamethasone injection (ITD) is a promising approach for the treatment of contralateral and ipsilateral delayed endolymphatic hydrops (DEH). Moreover, intratympanic gentamicin injection (ITG), as a chemical labyrinthectomy, is a simple alternative for controlling vertigo in patients with ipsilateral DEH. Objective: This study examined the effect of ITD or ITG on DEH. Methods: Fourteen patients with DEH completed the clinical and audio-vestibular evaluation. Among them, 10 cases (ipsilateral type: nine cases, contralateral type: one case) were treated with intratympanic injection. Four patients with ipsilateral DEH underwent ITG, five patients with ipsilateral type and one patient with contralateral type received ITD. All 10 cases were followed up for 8–48 months. Results: Complete and substantial vertigo control was achieved in four of nine ipsilateral DEH patients treated with ITG. In the other five ipsilateral cases who received ITD, two accomplished complete vertigo control and two had substantial control. In one case, the vertigo was not effectively controlled. One case of contralateral DEH underwent ITD and this case had complete vertigo control. The vertigo intensity, vertigo frequency, vertigo duration and the functional level scale after intratympanic injection was decreased significantly.

Evidence for bilateral endolymphatic hydrops in ipsilateral delayed endolymphatic hydrops: preliminary results from examination of five cases

Conclusion: After the administration of a standard dose of gadodiamide, an intravenous gadolinium-based contrast agent (GBCA), magnetic resonance imaging (MRI) evaluation of endolymphatic hydrops (EH) became possible in patients with ipsilateral delayed endolymphatic hydrops (DEH). We found that patients with ipsilateral DEH may also have bilateral EH. Objective: MRI evaluation contributes to understanding of the pathological conditions in patients with EH. However, double or triple the standard dose of GBCA is often required to obtain images of high quality. We attempted to examine EH bilaterally in patients with ipsilateral DEH after routine administration of an intravenous GBCA. Methods: GBCA (gadodiamide, 0.2 ml/kg) was administered intravenously to five patients with ipsilateral DEH. Three-dimensional fluid attenuated inversion recovery (3D-FLAIR) MRI was performed with a 3-T MRI scanner 4 h after GBCA administration. Results: In all five patients, EH was observed in the affected vestibules. Moreover, EH was observed bilaterally in four (80%) of five patients with ipsilateral DEH. The region of the deaf ear affected by EH was considerably larger compared with the normal ear in three patients. However, observed regions of EH were of approximately the same size in both ears in patients 4 and 5.

Long-term effects of the Meniett device in Japanese patients with Meniere's disease and delayed endolymphatic hydrops reported by the Middle Ear Pressure Treatment Research Group of Japan

Conclusion: The Meniett device is a minimally invasive and safe treatment that may be used to provide longer-term reduction of vestibular symptoms in patients with delayed endolymphatic hydrops (DEH) as well as those with Meniere's disease (MD). Objective: The effects of the Meniett device were evaluated in patients with a diagnosis of definite MD or DEH according to the 1995 AAO-HNS criteria. Methods: Twenty-nine ears of 28 patients with MD and 5 ears of 5 patients with DEH (ipsilateral type 4, contralateral type 1) were treated with the Meniett device by the Middle Ear Pressure Treatment Research Group of Japan. All of the patients had failed to respond to medical treatment including diuretics before the pressure treatment. Results: Sixteen (57%) patients with MD and all five (100%) patients with DEH remained entirely free from vertigo spells; nine (32%) patients with MD responded with a significant decrease in the frequency of vertigo spells. In regard to hearing, 25 ears (74%: MD, n = 21; ipsilateral DEH, n = 4) had stable hearing levels; only 4 ears (12%: MD, n = 3; contralateral DEH, n = 1) showed a significant hearing improvement. No complications were attributable to the Meniett device.

Plasma Vasopressin and V2 Receptor in the Endolymphatic Sac in Patients With Delayed Endolymphatic Hydrops

There are some kinds of sicknesses provoked by inadequate adaptation to physical and/or psychogenic stress in daily life. Delayed endolymphatic hydrops (DEH) is an inner ear disease like Ménière's disease (MD) characterized by episodic vertigo in the setting of preexisting unilateral deafness that especially occurs in civilized people with a stressful lifestyle. Its otopathologic finding was demonstrated to be inner ear endolymphatic hydrops through a temporal bone study in 1976, as in the case with MD in 1938. To elucidate the relationship between stress and the inner ear, we examined the plasma antidiuretic stress hormone vasopressin (pAVP) and its type 2 receptor (V2R) expression in the endolymphatic sac in patients with DEH. A prospective molecular biological study. Between 1998 and 2007, we enrolled 20 patients with ipsilateral DEH to examine their pAVP during remission from vertigo attacks. Plasma vasopressin was also examined in 87 patients with unilateral MD and 30 control patients with chronic otitis media. Using the real-time polymerase chain reaction method with tissue samples obtained during surgery, we examined V2R mRNA expression in the endolymphatic sac in 6 patients with ipsilateral DEH, 9 patients with unilateral MD, and 6 control patients with acoustic neuroma. Plasma vasopressin (1.5 times versus controls; unpaired t test, p = 0.140) and V2R mRNA expression in the endolymphatic sac (35.8 times versus controls; unpaired t test, p = 0.002) were higher in patients with DEH compared with those with acoustic neuroma. There were no significant differences in pAVP or V2R expression in the endolymphatic sac between DEH and MD. Patients with DEH showed a significantly negative correlation between pAVP and V2R (Pearson test, r = -0.92, p = 0.009) as in those with MD (Pearson test, r = -0.68, p = 0.043). Civilized people are frequently exposed to stress in their daily life, and pAVP can easily become elevated at any time. Therefore, a negative feedback system between pAVP and V2R in the endolymphatic sac may function for inner ear fluid homeostasis against stress-induced increases in pAVP. For the pathogenesis of endolymphatic hydrops resulting in vertigo attacks in patients with DEH as well as MD, pAVP may represent a matter of consequence, but V2R overexpression in the endolymphatic sac could be much more essential as a basis for these diseases.

遅発性内リンパ水腫について―ことにメニエール病との比較において―

Delayed endolymphatic hydrops (DEH) is a Meniere’s syndrome that typically occurs in patients suffering from longstanding unilateral profound inner-ear hearing loss. Approximately 55 to 65% of the hearing loss preceding DEH is due to juvenile unilateral profound deafness (early childhood unilateral profound sensorineural hearing loss of unknown etiology). The incidence of ipsilateral DEH (approximately 60%), in which the ear with profound hearing loss suffers progressive endolymphatic hydrops, is higher than that of the contralateral type of DEH (about 40%), in which the formation of progressive endolymphatic hydrops takes place in the ear opposite to the previously deafened ear. The prevalence of DEH in the general population (23 or less per 100,000) is similar to that of definitive Meniere’s disease, and the distribution of age at onset of DEH closely resembles that of Meniere’s disease except for some patients with childhood onset of DEH. Further, the rate of patients with the contralateral type of DEH (about 40%, although the rate is about 15% if the contralateral type is restricted to patients showing typical Meniere’s symptoms) is similar to that of patients with bilateral Meniere’s disease (about 40%, with a rate of about 14% if Meniere’s disease in the second ear is restricted to definitive Meniere’s disease). Since DEH is closely similar to Meniere’s disease not only in symptoms, but also in many clinical-statistical characteristics, the diseases may be identical in pathogenesis and the pathophysiology of progressive endolymphatic hydrops, although the two conditions have different etiologies.

Vestibular Evoked Myogenic Potentials in Ipsilateral Delayed Endolymphatic Hydrops

We recorded vestibular evoked myogenic potentials (VEMPs) in 12 patients diagnosed as having ipsilateral delayed endolymphatic hydrops (DEH). Seventy-five percent (9/12) of the patients showed decreased or absent VEMPs in the affected ears. Almost all patients had normal VEMPs in the unaffected ears. In addition, in 4 patients, VEMPs were recorded before and 3 h after oral glycerol administration (1.3 g/kg body weight). VEMPs improved after glycerol administration in 2 of the 3 patients whose VEMPs had been abnormal in the affected ears before glycerol administration. None of the 4 patients presented significant changes in VEMPs in the unaffected ears after glycerol administration. Improvement of VEMPs after glycerol administration confirmed the existence of endolymphatic hydrops in patients with ipsilateral DEH. In conclusion, VEMPs are useful to evaluate the function of otolith organs in patients with ipsilateral DEH, and the glycerol test using VEMPs may be useful to detect endolymphatic hydrops in ipsilateral DEH.

Delayed Endolymphatic Hydrops: Study and Review of Clinical Implications and Surgical Treatment

Delayed endolymphatic hydrops (DEH) differs from Ménière's disease in that it occurs in pre-existing ear pathology in patients who have a profound unilateral or total deafness that was caused by infection, trauma, or unknown causes during childhood or adulthood. We performed a retrospective review of 160 patients with ipsilateral, contralateral, or bilateral DEH. Eighty-seven patients who did not respond to medical therapy underwent surgical treatment. Our findings indicate that the more conservative surgical procedures--endolymphatic sac surgery, cochleosacculotomy, and streptomycin perfusion--are all as effective as and less destructive than labyrinthectomy for controlling vertigo. The clinical results of this study would seem to support the observations of others that DEH and Ménière's disease are related disorders caused predominantly by cases of viral labyrinthitis with unknown etiology.

Clinical features in patients with delayed endolymphatic hydrops

We report clinical features in patients with delayed endolymphatic hydrops (DEH) with juvenile unilateral deafness. Among 23 patients with DEH, 15 cases were diagnosed as ipsilateral DEH and 8 cases as contralateral DEH. The distribution of onset age showed two peaks at ages of < 30 years and > 40 years. In 80% of the ipsilateral DEH cases, the onset of episodic vertigo was at younger ages. On the other hand, in 75% of the contralateral DEH cases, the onset of fluctuation hearing loss of the contralateral ear was at older ages. Ispilateral DEH and Meniere's disease may show different pathophysiologies. The incidence of dominant negative summating potential in the better-hearing ear was 20% in the ispilateral DEH cases and 60% in the contralateral DEH cases. It is suggested that endolymphatic hydrops is in the better-hearing ear of contralateral DEH.

Electrocochleography in the Diagnosis of Delayed Endolymphatic Hydrops

It is known that delayed endolymphatic hydrops (DEH) occurs in patients with unilateral and/or bilateral profound hearing loss. In the ipsilateral and bilateral types of DEH, no audiological tests can be performed on the affected ear because of profound deafness, although these tests can be done in the contralateral type. Electrocochleography (ECochG) was recorded on better hearing ears in both types of DEH. The results showed an increased negative summating potential (SP) in 6 out of 10 contralateral DEH patients whereas it could be measured in only one of 10 ipsilateral DEH patients. The mean SP/AP ratio of the contralateral type was 0.42 which was significantly larger than that of the ipsilateral type. The results suggest that contralateral-type DEH has the same pathology in the cochlea as Meniere's disease, and that ECochG can distinguish between these two types of DEH.

Intratympanic Injection of Gentamicin for the Treatment of Delayed Endolymphatic Hydrops

In three patients with ipsilateral delayed endolymphatic hydrops (DEH), ototoxic gentamicin sulfate was injected through the tympanic membrane for the ablative treatment of frequent attacks of vertigo. Two patients received six injections and one patient received two. Treatment produced complete control of vertigo attacks in one patient who received six injections, and substantial control in the other two patients. The present results showed that there was a delayed onset of the ototoxic effect of gentamicin in the treatment of ipsilateral DEH.