The additive effect of co-occurring anxiety and depression on health status, quality of life and coping strategies in help-seeking tinnitus sufferers.

OBJECTIVE: Evaluating the effect of anxiety and depression on clinical measures of general health, tinnitus-specific quality of life, and coping abilities. DESIGN: Two hundred sixty-five chronic, subjective tinnitus sufferers were divided into four psychological symptom groups according to cut-off scores on anxiety and depression subscales of the Hospital Anxiety and Depression Scale: (1) no-symptoms, (2) anxiety-only, (3) depression-only, and (4) anxiety-plus-depression. General health-related quality of life (SF-36), tinnitus-specific quality of life (tinnitus reaction questionnaire and tinnitus handicap inventory), and coping abilities (tinnitus coping style questionnaire) were assessed and analyzed across these four psychological symptom groups, which did not differ on age, gender, marital, and working status. RESULTS: Statistically significant and clinically relevant differences on general health-related and tinnitus-specific quality of life and coping abilities were identified when comparing anxiety-plus-depression subgroup with the subgroups anxiety-only, depression-only, or no-symptoms. Highest associations were seen between the anxiety-plus-depression subgroup and impaired quality of life and maladaptive coping. CONCLUSIONS: Our results demonstrate the additive effect of both anxiety and depression in impairing general health-related and tinnitus-specific quality of life and application of coping strategies, and reiterate the need for investigating both symptoms in the clinical evaluation of tinnitus patients.

Rupture of Reissner's membrane during acute endolymphatic hydrops in the guinea pig: a model for Ménière's disease?

CONCLUSION: The changes in cochlear function during a destructive acute endolymphatic hydrops were relatively small. This might be consistent with the hypothesis that an endolymphatic hydrops is a marker of disordered inner ear homeostasis rather than the cause of the clinical symptoms of Ménière's disease. OBJECTIVE: Assessment of cochlear function during induction of a destructive acute endolymphatic hydrops. MATERIALS AND METHODS: During repetitive microinjections of 0.5 microl of artificial endolymph at a rate of 50 nl/s the 2f1-f2 and f2-f1 cochlear microphonics distortion products (CMDP) and 2f1-f2 distortion products otoacoustic emissions (DPOAE) were recorded in the guinea pig. RESULTS: A 'catastrophe' occurred in the inner ear when 2.5-3.5 microl of artificial endolymph was injected. A rupture of Reissner's membrane was then found, most often in the apical turn of the cochlea. This rupture had only minor effects on the endocochlear potential, whereas it caused a marked decrease in 2f1-f2 DPOAE amplitude. The 2f1-f2 and f2-f1 CMDP amplitude increased during each injection prior to the rupture. After the rupture the f2-f1 CMDP amplitude decreased during each injection, possibly due to a shift of the cochlear transducer operating point position.

Functional imaging of the central auditory system using PET.

In the last few decades functional neuroimaging tools have emerged to study the function of the human brain in vivo. These techniques have increased the knowledge of how the brain processes stimuli of different sensory modalities, including auditory processing. Positron emission tomography (PET) has been used for nearly 20 years to study changes in cerebral blood flow associated with auditory stimulation in normal and hearing impaired subjects. PET studies gave insight into the neural base of processing basic sound features such as frequency and intensity, but complex stimuli such as speech and music have also been investigated extensively. Knowledge of the normal auditory function of the brain helps us to understand the neural base of hearing deficits and provides ideas for possible treatments. Although functional magnetic resonance imaging (fMRI) is replacing PET in many neuroimaging studies nowadays, PET still holds unique advantages and can give us valuable knowledge about the auditory cortex and auditory perception.

The relationship of the round window membrane to the cochlear aqueduct shown in three-dimensional imaging.

The round window membrane and cochlear aqueduct complex in the guinea pig are reconstructed with 3D-imaging, using orthogonal plane fluorescence optical sectioning (OPFOS). The 3D-images show that the periotic duct and the aqueduct are connected to a pouch-like extension of the round window. The function of this may be regulation of aqueduct flow resistance under the influence of a pressure difference between inner ear fluid and middle ear.

Morphology of the endolymphatic sac in the guinea pig after an acute endolymphatic hydrops.

The role of the endolymphatic sac (ES) in endolymph volume homeostasis is speculative. The present study investigates changes of the ES's epithelia and luminal filling after induction of an acute endolymphatic hydrops. After microinjection of 1.1 mul artificial endolymph into scala media of the cochlea, guinea pigs were terminated immediately (n = 6) or after different time intervals ; 1/2 h (n = 3), 1 h (n = 4) and 2 h (n = 4). Inner ear specimens were processed for light and/or transmission electron microscopy. The non-injected contralateral ear served as a histological control. Correct injection was confirmed by detection of microspheres in the endolymphatic compartment after the same microinjection procedure. In all specimens, ribosome rich cells and intraluminal macrophages appeared to be actively involved in degradation of homogeneous substance (HS) by secreting lytic enzymes and digestion, respectively. Amazingly, in our study no ES differences were found between injected and non-injected ears and no distinct changes were observed in guinea pigs terminated after different time intervals. The ES's luminal HS was always present and often to a large extent. This is in contrast with [Hear. Res. 138, 81] dramatic changes were observed. Endolymph volume homeostasis is a complex mechanism, in which the role of HS remains obscure.

Neurostimulation as a new treatment for severe tinnitus: a pilot study.

BACKGROUND: Tinnitus is an uncomfortable symptom for the patient and an embarrassing one for the consulted physician. So far, there is no treatment that can be considered well established in terms of providing long-term reduction of tinnitus in excess of placebo effects. There is considerable evidence of pathophysiological similarity between tinnitus and chronic pain. Some forms of chronic pain can be treated by neurostimulation. OBJECTIVE: This study was designed to investigate the feasibility of neurostimulation of the cochlear nerve in order to reduce tinnitus. STUDY DESIGN: Pilot study. SETTING: Tertiary referral center. PATIENTS: Five patients with therapeutically refractory tinnitus were selected for this study. INTERVENTION: Placing a stimulation lead around the cochlear nerve through the suboccipital approach and connecting the stimulation lead to a pulse generator. MAIN OUTCOME MEASURES: The patients experienced 1) an absence of major or minor complications, such as death, meningitis, cranial nerve deficit, and vestibular problems; 2) tolerance of the procedure as considered by the patient; 3) relief of tinnitus in at least one patient. RESULTS: Implantation of the neurostimulation system was accomplished in each patient without any difficulty. None of the patients considered the treatment unbearable. No major or minor complications occurred in this study. Subjective tinnitus reduction was accomplished in four patients. CONCLUSION: Our preliminary data show that neurostimulation of the cochlear nerve is feasible, is bearable for the patient, and is a safe treatment modality without major complications. The effects on tinnitus are promising.

Cochlear aqueduct flow resistance depends on round window membrane position in guinea pigs.

The resistance for fluid flow of the cochlear aqueduct was measured in guinea pigs for different positions of the round window membrane. These different positions were obtained by applying different constant pressures to the middle ear cavity. Fluid flow through the aqueduct was induced by small pressure steps superimposed on these constant pressures. It was found that the resistance for fluid flow through the aqueduct depended on the round window position but not on flow direction. The results can be explained by special fibrous structures that connect the round window with the entrance of the aqueduct. It was also found that the equilibrium inner ear pressure depends on middle ear pressure, indicating that the aqueduct does not connect the inner ear with a cavity with constant pressure.

Effect of probiotic bacteria on prevalence of yeasts in oropharyngeal biofilms on silicone rubber voice prostheses in vitro.

The proliferation of yeasts in the mixed bacterial and fungal biofilms colonising silicone rubber voice prostheses in laryngectomised patients is the main cause of malfunctioning of the valve mechanism on the oesophageal side of the prostheses. Indwelling voice prostheses usually have to be replaced every 3-4 months. The consumption of probiotic bacteria is largely motivated by health claims related to the urogenital and lower digestive tract, but not to the upper digestive tract. The present study examined the influence of probiotic bacteria on the prevalence of yeasts in oropharyngeal biofilms on silicone rubber voice prostheses, as formed in a modified Robbins device. Exposure of oropharyngeal biofilms on voice prostheses to suspensions of Bifidobacterium infantis 420 or Enterococcus faecium 603 did not significantly reduce the number of yeasts in the biofilm. However, suspensions of Lactobacillus fermentum B54, L. rhamnosus 744 or L. lactis cremoris SK11 led to a reduction in the number of yeasts harvested from the voice prostheses. Suspensions of L. casei Shirota and Streptococcus thermophilus B significantly reduced the number of yeasts in the biofilm to 39% and 33%, respectively. The reduction brought about in yeast prevalence in the mixed biofilm was greatest by exposure to a suspension of L. lactis 53, with yeast prevalence only 4% of the control. In conclusion, the study demonstrated that the prevalence of yeasts in oropharyngeal biofilms on silicone rubber voice prostheses might be controlled by consumption of probiotic bacteria.

MR of the inner ear in patients with Cogan syndrome.

PURPOSE: To determine whether the bony and soft-tissue obliterations of the intralabyrinthine fluid spaces reported in pathologic studies of patients with Cogan syndrome can be detected with MR or CT. METHODS: The inner ears of six patients with Cogan syndrome were studied. High-resolution CT was performed in five patients; all six patients were studied with MR, including T1-weighted spin-echo images with and without gadolinium administration, T2-weighted spin-echo images, and three-dimensional Fourier transform constructive interference in steady state images. RESULTS: In two patients, small calcified obliterations were detected on CT but the three-dimensional Fourier transform constructive interference in steady state images revealed more extensive soft-tissue obliteration in five of the six patients. High signal inside the membranous labyrinth on precontrast T1-weighted images and contrast enhancement inside the membranous labyrinth on the postcontrast T1-weighted images were seen in one patient. CONCLUSIONS: The study showed that calcific obliteration and soft-tissue obliteration of the intralabyrinthine fluid spaces in patients with Cogan syndrome can be demonstrated radiologically and that soft-tissue obliteration is more frequent than calcified obliteration. MR detected the intralabyrinthine disease far more frequently than did CT. The three-dimensional Fourier transform constructive interference in steady state sequence proved to be the most sensitive MR sequence. Hyperintensity inside the membranous labyrinth on the precontrast T1-weighted images and enhancement on the contrast-enhanced T1 images were less frequent and probably represent leakage through the abnormal labyrinthine membrane from active disease.

Clinical characteristics and diagnostic delay of head and neck cancer: results from a prospective study in Belgium.

A prospective study of head and neck cancer patients was started to gather information about topographic and clinical characteristics of head and neck cancer, alcohol and nicotine abuse and the delay in diagnosis. More than half of the patients consulted our institution with an advanced stage of disease. As was expected, we found a positive association between the size of the tumour and the clinical stage of the neck. Concerning nicotine and alcohol abuse, our results support the hypothesis that tobacco smoking is more strongly associated with lesions in sites heavily exposed to inhaled smoke, whereas alcohol consumption has a stronger effect on structures belonging to the 'food channel' and reservoir systems. We found no association between delay and tumour stage at diagnosis, but a statistically significant correlation was found between the delay and the tumour site. This leads us to conclude that the tumour stage is determined mostly by the biology of the tumour.

Dynamics of inner ear pressure release, measured with a double-barreled micropipette in the guinea pig.

The inner ear fluid pressure was measured in scala media of the guinea pig through one barrel of a double-barreled micropipette after a sudden volume increase or decrease, caused by injection or withdrawal of artificial endolymph through the other barrel. During injection or withdrawal, the inner ear pressure changed in the order of 1-10 cm water, but it returned to its initial value within a few seconds. The time constant for the pressure recovery depended on the flow direction. It was on average 1.1 s after a short overpressure and 2.8 s after underpressure. The obtained results could be fitted with a simple physical model, when it was assumed that inner ear pressure recovery is a non-linear process, governed by a pressure-dependent flow resistance and/or membrane compliance.

Measurement of the mechanical compliance of the endolymphatic compartments in the guinea pig.

During injection of artificial endolymph into scala media of the guinea pig, fluid pressure was simultaneously measured in endolymph and perilymph with micropipettes. Pressure differences in the order of 10 Pa could reproducibly be measured upon injection of 2-4 microl of artificial endolymph with a rate of 50 nl/s. Injection of larger volumes damaged the endolymphatic system. From the results, values were derived for the compliances of the membranes surrounding scala media and the vestibular part of the endolymphatic system. The shape of the pressure-time curve during and between repetitive injections of fluid could well be described with a two-component model for the endolymphatic system, consisting of two compartments with compliant walls, connected through a flow resistance. With this model, a larger compliance was found for the second compartment (vestibular part of endolymphatic system) than for the first compartment, into which fluid was injected (scala media).

Low-voltage field-emission scanning electron microscopy of non-coated guinea-pig hair cell stereocilia.

The stereociliar structures of the guinea-pig cochlear organ of Corti were studied at low-voltage (1-5 kV) with field-emission scanning electron microscope (SEM) using various pre- and post-fixation methods, such as OTOTO (OsO4/thiocrbohydrazide/OsO4/thiocarbohydrazide/OsO4) and TAO (tannic acid/arginine/OsO4), and different dissection procedures of the cochlea. A perfusion and immersion pre-fixation with glutaraldehyde, in combination with removal of the bony wall and stria vascularis from the cochlea, followed by the TAO non-coating treatment gave the best result at 2 kV acceleration voltage. Due to these new technique, several interesting delicate structures of the stereocilia, in particular fine surface structures, were detected for the first time using SEM. These findings include the different types of cross-links and tip links, i.e., the fine surface morphology of the stereocilia and their attachments and imprints in the tectorial membrane (TM). One of the most interesting findings in this study is a network of long filamentous structures, which has been identified mainly at the top of the longest stereocilia and the undersurface of the TM and which may represent the glycocalyx. These findings and their possible implications in the process of mechanoelectrical transduction will be discussed.

The effect of nimodipine on cochlear potentials and Na+/K(+)-ATPase activity in normal and hydropic cochleas of the albino guinea pig.

In experimental endolymphatic hydrops (EEH) a decrease in the endocochlear potential (EP) has been reported and is thought to be due to decreased activity of the enzyme Na+/K(+)-ATPase in the stria vascularis. By stimulating Na+/K(+)-ATPase, the EP, and thereby cochlear function as a whole, might be restored. On the other hand, stimulation of stria vascularis Na+/K(+)-ATPase might result in excessive production of endolymph and thus produce or augment hydrops. In this study we have investigated the effect of intraperitoneally applied nimodipine on cochlear potentials and on Na+/K(+)-ATPase activity in the stria vascularis, both in normal cochleas (control) and in cochleas with EEH. Nimodipine is an L-type Ca(2+)-channel blocking agent with Na+/K(+)-ATPase stimulating properties at concentrations as low as 1.5 nM. The compound action potential (CAP), evoked by 2,4 and 8 kHz tone bursts was found to be depressed in the EEH ears with and without nimodipine treatment, and in the nimodipine treated control ears. Statistical analysis (ANOVA) showed that the effects of EEH and nimodipine on the CAP were additive. The negative summating potential (SP), measured extracochlearly at the apex, in response to 4 and 8 kHz tone bursts was significantly enhanced in the EEH ears. Nimodipine treatment did not affect the SP, neither in the control, nor in the EEH ears. Cytochemically, Na+/K(+)-ATPase activity appeared to be decreased in the oedematous stria vascularis of hydropic cochleas. No effect of nimodipine on Na+/K(+)-ATPase activity could be established ultracytochemically, neither in the controls nor in the EEH ears. In the lower turns of some of the nimodipine treated control cochleas a mild hydrops was seen during light-microscopic evaluation. Although it was not possible to prove a stimulatory effect of nimodipine on the enzyme Na+/K(+)-ATPase cytochemically, the finding of mild endolymphatic hydrops in nimodipine treated control ears suggests (a history of) increased endolymph production. This hydrops might be responsible for the depression of the CAP in the nimodipine treated ears.

Antimicrobial activity of synthetic salivary peptides against voice prosthetic microorganisms.

OBJECTIVES: To investigate whether synthetic salivary antimicrobial peptides have an inhibitory effect on the growth of bacteria and yeasts isolated from used silicone rubber voice prostheses. METHODS: The antimicrobial activities of six synthetic salivary peptides (histatin 5, dhvarl, dhvar4, dhvar5, lactoferrin b 1730 [LFb 17-30], and cystatin S1-15) at concentrations of 2 and 4 mg/mL were determined against different oropharyngeal yeast (four) and bacterial (eight) strains and against a "total microflora" isolated from explanted voice prostheses using agar diffusion tests. The spectrum of susceptible microorganisms was determined qualitatively. RESULTS: Histatin 5 and cystatin S1-15 did not show any antimicrobial activity against the microorganisms involved in this study. Dhvar1 was active against some of the oropharyngeal microorganisms tested, including the yeast strains, but not against Rothia dentocariosa, Staphylococcus aureus, Escherichia coli, and the total microflora Dhvar4 was active against all microorganisms tested, including the total microflora. Dhvar5 lacked activity against E coli and the total microflora LFb 1730 did not inhibit the growth of any of the yeast strains involved and showed only minor activity against some of the bacterial strains. LFb 1730 slightly inhibited the growth of the total microflora from an explanted prosthesis. CONCLUSIONS: The synthetic salivary peptide dhvar4 has a broad antimicrobial activity against all microorganisms that are commonly isolated from explanted voice prostheses, including yeasts. Therewith, it may represent a useful drug, as an alternative for antibiotics and antimycotics employed in various ways to prolong the lifetime of voice prostheses in laryngectomees.

Sensory cell damage in two-phase endolymphatic hydrops: a morphologic evaluation of a new experimental model by low-voltage scanning techniques.

HYPOTHESIS: The aim of this study was to create a more dynamic animal model of Ménière's disease combining multiple causes, such as the role of endocrine factors and endolymphatic sac dysfunction, that may mimic the fluctuant characteristics of Ménière's disease. BACKGROUND: Endolymphatic hydrops remains to be considered a pathologic substrate in the etiology of Ménière's disease. The classic guinea pig model of inducing hydrops by total destruction of the endolymphatic sac is a nonphysiologic rigid model of Ménière's disease. METHODS: The authors developed the two-phase endolymphatic hydrops model by inducing hydrops by mild chronic endolymphatic sac dysfunction, in combination with increased endolymph production by aldosterone. Sensory cell damage was evaluated by low-voltage field emission scanning microscopy. RESULTS: This study describes a wide spectrum of morphologic effects of the outer hair cells in radial gradients, in which most effects were observed in the third to second row of outer hair cells, and longitudinal gradients in which the most severe effects were observed in the apical turns. Most affected were the ears that underwent distal endolymphatic sac dissection followed by the administration of aldosterone. Damaging effects proceeded from degeneration and absence of short stereocilia of outer hair cells and even some inner hair cells in the apical turns, to stereociliary disarrangement and atrophy, followed by degeneration and absence of outer hair cells, which were replaced by supporting cells. CONCLUSION: The two-phase endolymphatic hydrops model seems to represent a functional model that may mimic the fluctuant characteristics of Ménière's disease and emphasizes the influence of multiple and coexisting hydrops-inducing influences.

Perilymphatic and endolymphatic pressure in the guinea pig after distal dissection of the endolymphatic sac.

HYPOTHESIS: The study was designed to investigate whether endolymphatic pressure exceeds perilymphatic pressure in an endolymphatic hydrops model with a partially functioning endolymphatic sac. BACKGROUND: Previous investigations of perilymphatic and endolymphatic pressure measurements during endolymphatic hydrops were done in a classic endolymphatic hydrops model, with a surgically blocked endolymphatic duct and sac. This model, in contrast to the clinical situation of Meniere's patients, totally lacks the functional contribution of the endolymphatic sac. METHODS: In the guinea pig, a partially functioning endolymphatic sac was created via dissection of the distal portion of the sac from the sigmoid sinus. Three (n = 5) and 6 months (n = 3) later, perilymphatic and endolymphatic pressures were measured consecutively using a WPI 900A micropressure system. RESULTS: It was observed that damage to the distal part of the endolymphatic sac caused endolymphatic hydrops in 58% of the cases. The hydrostatic pressure in hydropic ears did not differ from that of control ears. There was no pressure difference between the perilymphatic and endolymphatic compartments in ears with endolymphatic hydrops. The endocochlear potential in ears with hydrops was statistically significantly decreased (p < 0.002). CONCLUSION: In a hydrops model developed to be more comparable to the histopathologic appearance of Meniere's disease in the inner ear, no hydrostatic pressure difference was measured between the perilymphatic and endolymphatic spaces. The only functional difference from control ears we found was a decreased endocochlear potential.

Three-dimensional Fourier transformation constructive interference in steady state magnetic resonance imaging of the inner ear in patients with unilateral and bilateral Menière's disease.

OBJECTIVE: In this study, three-dimensional Fourier transformation constructive interference in steady state (3DFT-CISS) magnetic resonance imaging was used to quantify the distance between the vertical part of the posterior semicircular canal and the posterior fossa as a measure of the endolymphatic sac and duct in patients with Menière's disease. Differences in this distance between affected and unaffected ears, as well as differences between unilaterally and bilaterally affected patients, were studied and compared with a control group. Also, possible correlations between the measured distance and the duration and severity of symptoms, patient age, and average hearing loss were investigated in the group of patients with Menière's disease. STUDY DESIGN: Retrospective clinical study. SETTING: Tertiary referral center (University Hospital) as part of a large, diagnostic research project on Menière's disease. PATIENTS: Of the 111 patients with Menière's disease initially included, 90 patients underwent 3DFT-CISS MRI. Eighty-six of these patients were analyzed in this MRI study. Fifty-six patients had unilateral Menière's disease, and 30 patients had bilateral Menière's disease (116 affected and 56 unaffected ears). Sixty-two ears in patients without Menière's disease were studied as controls. INTERVENTION: The distance between the vertical part of the posterior semicircular canal and the posterior fossa was determined by 3DFT-CISS MRI. MAIN OUTCOME MEASURES: Contiguous axial 3DFT-CISS MRI slices of 0.7 to 1.0 mm were made by a radiologist according to a strict protocol. Measurements of the distance between the vertical part of the posterior semicircular canal and the posterior fossa were taken by two professionals-a radiologist and an otolaryngologist-using a ruler and the original scan. RESULTS: A significantly smaller distance (2.9 mm) between the vertical part of the posterior semicircular canal and the posterior fossa as visualized on MRI scans was found in the ears of patients with Menière's disease than in the ears of patients in the control group (3.8 mm, p < 0.001). In both uni- and bilaterally affected patients (n = 56 and n = 30, respectively), no significant difference between ears was found (p = 0.44 and p = 0.19, respectively). In bilaterally affected patients, however, this distance (3.2 mm) was significantly greater than the distance in unilaterally affected patients (2.7 mm, p = 0.004). There was no relationship between the MRI-visualized distance between the vertical part of the posterior semicircular canal and the posterior fossa and the duration of disease, average hearing loss, or severity of symptoms in uni- and bilaterally affected patients. CONCLUSION: The difference in MRI-visualized distances between the vertical part of the posterior semicircular canal and the posterior fossa of uni- and bilaterally affected patients strongly suggests that unilateral and bilateral hearing loss are two different entities in patients with Menière's disease. The size of the endolymphatic sac seems not to be the only factor in the pathogenesis of Menière's disease. That the MRI-visualized distance between the vertical part of the posterior semicircular canal and the posterior fossa does not have any relationship to the duration of the disease or to patient age indicates that this distance is a congenital feature.

Therapy of idiopathic sudden sensorineural hearing loss: antiviral treatment of experimental herpes simplex virus infection of the inner ear.

Experimental herpes simplex virus type 1 (HSV-1) labyrinthitis provides a model of idiopathic sudden sensorineural hearing loss (ISSHL). Corticosteroids improve the prognosis for hearing recovery in ISSHL, but the effects of acyclovir are unknown. To establish the therapeutic efficacy of acyclovir (Zovirax) and prednisolone in experimental HSV-1 viral labyrinthitis, we induced HSV-1 labyrinthitis in 12 guinea pigs. Three animals received no treatment, 3 received prednisolone, 3 received acyclovir, and 3 received both. Four other animals served as controls, receiving culture medium only. Hearing, HSV-1 antibody titers, and cochlear damage were evaluated. The HSV-1 labyrinthitis caused hearing loss within 24 hours. Combination treatment consisting of prednisolone and acyclovir resulted in earlier hearing recovery and less extensive cochlear destruction compared to prednisolone or acyclovir as a monotherapy. The beneficial effect of this treatment modality remains to be demonstrated in ISSHL.

Early hair cell loss in experimental hydrops.

One, 2, and 4 months after surgical obliteration of the endolymphatic sac, the sequence of degenerative changes in the organ of Corti of the guinea pig was studied. The block surface technique with interference differential (Nomarski) microscopy was used for this investigation to study the morphological changes in the organ of Corti. The hair cell loss was calculated and mapped in cytocochleograms. One month postoperatively a minimal loss of only outer hair cells was observed in the apical cochlear turn. At 2 months a progression of outer hair cell loss was seen, which proceeded in the 4-month group. At 4 months the inner hair cells showed a slight tendency to degenerate, again beginning in the most apical part of the cochlea.