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The surgical results in 78 recent cases of total removal of unilateral acoustic neuroma in which an attempt was made to preserve cochlear function have been added to the authors' previous series of 66 cases to evaluate the factors influencing the ability to preserve useful hearing. Useful hearing was defined by speech reception threshold no poorer than 70 dB and a discrimination score of at least 15%. Analysis using a logistic regression model showed that certain preoperative clinical parameters such as tumor size, speech discrimination score, and gender were significantly correlated with hearing outcome. Favorable outcome was significantly correlated with smaller tumor size, higher preoperative speech discrimination score, and male sex. From this data, an explicit formula was devised for predicting hearing outcome for an individual patient. In four cases with useful hearing preserved, there was improvement of greater than 15 percentage points in speech discrimination scores. While preoperative auditory brainstem responses were not predictive of hearing preservation, monitoring of intraoperative auditory evoked potentials was predictive of hearing outcome in selected cases. Specifically, when wave V was unchanged at the end of the operation, even if it may have been transiently lost during surgery, useful hearing was invariably preserved.

A case report of bilateral acoustic neurofibromatosis (NF-2) is presented with temporal bone histopathology. The distinct clinical and genetic features of NF-2 are reviewed in the context of recent data that show it to be a disorder distinct from classic von Recklinghausen's disease (NF-1).

Our aim was to assess whether "idiopathic" bilateral progressive sensorineural hearing loss (BPSHL) has an immunological cause in some patients; antibodies to native type II collagen were sought by an ELISA in eighteen patients with BPSHL, before and after corticosteroid treatment, and in twelve patients with Meniere's disease, fifteen with otosclerosis, eighteen with rheumatoid arthritis, nine with fibrositis, and nine healthy controls. A positive result was defined as a mean dilution titre of 2 or more. Eight of eighteen BPSHL patients had positive titres--significantly (p less than 0.005) more than in any other group (one Meniere's disease, two otosclerosis, and no others). The mean antibody titre was higher in the BPSHL group than in any other group (2.02 [SEM 0.62] vs 0.17 [0.17]) Meniere's disease, 0.44 [0.32] otosclerosis, 0 all others; p less than 0.005). The nine BPSHL patients who showed a clinical response to corticosteroids (improvement in at least one tone by audiogram or 25 db in speech discrimination score) had the highest mean antibody titre (3.46 [0.88] vs 0.59 [0.59] for the nine non-responsive patients; p less than 0.04). We suggest that in some patients with BPSHL, immunity to type II collagen, a major constituent of the inner ear, may be important in the pathogenesis of the disorder.

Despite the localization implied by the term "chronic otitis media," little attention has been paid to the role of the hypotympanum in chronic active otitis media. Most authors have emphasized the role of recurrent cholesteatoma or unexenterated cells in the mastoid cell system as causes of recurrent disease. Seven cases are reported in which clinical evidence indicated that recurrent chronic otitis media was limited to the hypotympanum and infralabyrinthine cell system. In the five cases in which revision surgery was done, exenteration of this area resulted in an asymptomatic ear. The anatomy, radiographic evaluation, and surgical approach to the hypotympanum are reviewed. Careful inspection of the hypotympanum in primary surgery for chronic ear disease and exenteration of the hypotympanic and proximal infralabyrinthine cell tract are advocated when these regions contain cholesteatoma or extensive granulomatous disease.

Although the cause of idiopathic sudden sensorineural hearing loss remains uncertain, a viral origin has been suggested in many cases on the basis of anamnestic microbiologic and pathologic data. Twenty-two temporal bone specimens from 18 patients who during life suffered a sudden partial or complete sensorineural hearing loss were studied. On the basis of clinical data, these cases were assigned to one of three diagnostic categories, and the temporal bones were studied by light microscopy and serial section analysis. The implications of the histopathologic findings for the pathogenesis of idiopathic sudden sensorineural hearing loss are discussed.

A morphometric analysis of the human spiral ganglion was performed at an ultrastructural level. Cells of the basal, middle, and upper middle turns were evaluated by serial section. The following parameters were evaluated: Myelinization, area, diameter, circumference, and degree of roundness of the cell body and nucleus; diameter of the axon and dendrite in their initial segments; and process configuration. Analysis of variance suggested there were at least two types of cell bodies within the human spiral ganglion, best delineated by the dimensions of the cell body and nucleus and the ratio of diameter of the initial segments of axonic and dendritic processes. Myelinization and degree of roundness were relatively unimportant differential parameters. Cluster (multivariate) analysis of the six most important differential parameters suggested the possibility of five subgroups among the groups of large and small cells. For the middle and upper middle turns, cluster analysis suggested that there may be as many as three groups of cells based on morphometric analysis. These results are discussed in relation to other morphologic and physiologic data in the mammalian spiral ganglion.

This invention relates to surgical methods and prosthetic devices for ameliorating hearing loss in patients having ailments of the middle ear. The implant of the invention includes a gas-filled balloon (26) having a pliant membrane (26a) of biocompatible material. The balloon (26) is made such that the acoustic impedance presented by the balloon (26) to the eardrum is low enough to permit the eardrum to vibrate freely in response to sound waves. Because the balloon membrane (26a) is substantially impermeable to gases and water, the implant can function effectively within the middle-ear chamber for an extended period.

The diagnosis and treatment of vestibular schwannoma (formerly known as acoustic neuroma) in patients with neurofibromatosis 2 (NF2) has been improved in recent years by advances in several clinical and scientific areas. Advances in imaging techniques have allowed high-resolution preoperative assessment of size, shape, and anatomic relationships of vestibular schwannomas. Advances in surgical techniques have decreased the risks of postoperative complications especially seventh and eighth nerve dysfunction. 1 Finally, advances in molecular biological techniques have made possible the presymptomatic diagnosis of affected individuals in approximately two-thirds of affected families. 2 The last development raises the issue of whether children with vestibular schwannomas should be identified before they develop symptoms from their tumors. If no treatment exists for a genetic disease that primarily presents in adulthood, there is little rationale for testing children for that disease. In the case of NF2, however, not only does an effective therapy exist, but also

For treatment of conductive hearing loss due, for example, to serous otitis media, a synthetic bubble is implanted in the hypotympanic cavity to displace fluid allowing free motion of the round window. A thin membrane provides the required degree of compliance, and is substantially impermeable to gases and water vapor, resulting in an extended lifetime. A large molecule inert filler gas may be used, either alone, or with normal gases to provide certain partial inflation states wherein osmotic ingress of smaller molecular gases causes sustained self-inflation of the bubble for a substantial time.

Cogan's syndrome (CS) presents typical and atypical types. Typically, there are episodes of non-syphilitic keratitis and audiovestibular dysfunction. Atypically, there are inflammatory changes in other eye structures and other organ systems, particularly the cardiovascular system. The temporal bone pathology in a case of CS shows changes that are similar to those observed in other autoimmune disorders associated with audiovestibular dysfunction. The following pathologic features characterize autoimmune inner ear disease: 1. acute labyrinthitis resulting in atrophy of inner ear tissues including the sense organs and their supporting structures; 2. endolymphatic hydrops; 3. focal and diffuse proliferation of fibrous tissue and bone; and 4. retrograde neuronal degeneration. These pathologic findings are consistent with an inflammatory (and possibly ischemic) attack on the membranous labyrinth.

Objective. —To test whether detection of serum antibody to a 68-kd inner ear protein distinguishes among different causes of sensorineural hearing loss, and identifies patients with active disease and those likely to respond to corticosteroid therapy. Design. —Serum samples were tested by Western blot using bovine inner ear extract as antigen, and results were correlated with patient information obtained by chart review. Setting. —Referral center. Subjects of Study. —Serum samples were obtained from patients with idiopathic, progressive, bilateral sensorineural hearing loss (IPBSNHL) (n=72) otosclerosis (n=11), Cogan's syndrome (n=8), patients with positive tests for antinuclear antibodies (n=10), and normal controls (n=53). Main Outcome Measure. —Detection of serum antibody to a 68-kd inner ear protein. Results. —Serum from 42 of 72 patients with IPBSNHL reacted with a 68-kd protein constituent of inner ear extract. This reactivity was not detected in serum from 11 of 11 patients with otosclerosis, or in eight of eight with Cogan's syndrome. It was found in serum from one of 10 patients with a positive test for antinuclear antibody and in one of 53 normal controls. Antibody to the 68-kd protein was detected in serum from 89% of patients with actively progressing IPBSNHL and none of the 25 patients with inactive disease ( P P Conclusions. —These results indicate that the presence of circulating antibody to a 68-kd constituent of bovine inner ear extract serves as a marker for IPBSNHL and that its presence correlates with disease activity and responsiveness to corticosteroid treatment. ( JAMA . 1994;272:611-616)

The histopathology of the temporal bones of a patient who died of unrelated causes 10 weeks following cochlear implantation using a Richards Ineraid device is presented. Deafness was caused by a prolonged course of intravenous gentamycin therapy 5 years prior to implantation. The electrode array of the cochlear implant was left in situ throughout histologic preparation and sectioning. Despite displacement and disruption of supporting structures of the inner ear, particularly in the 6-to-15-mm range as measured from the round window, there was no significant difference in the mean densities of spiral ganglion cells in the implanted and unimplanted sides. This case is presented as evidence that despite significant disruption of supporting elements of the inner ear, which is common during cochlear implantation, there appears to be little effect on the residual spiral ganglion cell count, at least in the short term.

Three patients had a positive "fistula sign," or "Hennebert sign," with intact tympanic membranes. Two had symptoms typical of Meniere disease. All three were shown to be free of congenital syphilis. Labyrinthectomy was performed for one patient, and the extracted stapes sectioned. This revealed part of the membranous labyrinth firmly adherent to the medial surface of the footplate. This histopathological finding is herein named "vestibulofibrosis." Study of unrelated pathological specimens selected from the temporal bone collection of the Massachusetts Eye and Ear Infirmary revealed that vestibulofibrosis is a finding common to several postinflammatory or progressive inner ear disease processes, including congenital syphilis, viral labyrinthitis, and Meniere disease. Such fibrous adhesions between the footplate and membranous labyrinth are suggested as the pathological basis for the positive fistula sign in the presence of an intact tympanic membrane.

An entity of episodic true vertigo of delayed onset following sudden and profound sensorineural hearing loss is described. Data on 12 patients and three case reports are presented. The latency between sudden deafness and the onset of the vertigo varied from 1 to 68 years. The vestibular symptoms are identical to the vestibular symptoms of Ménière's disease, and there is some evidence that endolymphatic hydrops in the previously deafened ear represents at least part of the labyrinthine pathology. Labyrinthectomy in the deaf ear was curative. Tentatively, this entity is best considered a variant of Ménière's disease.

A retrospective analysis of 29 cases of squamous cell carcinoma of the external and middle ear and 15 cases of glomus jugulare tumors of the middle ear was performed to evaluate the incidence of osteoradionecrosis of the temporal bone following surgery and/or radiotherapy. Osteoradionecrosis occurred in 42% (8/19) of cases of squamous cell carcinoma which were treated with radical mastoidectomy, lateral or subtotal temporal bone resection leaving an open cavity and followed by an average of 5,840 rad postoperatively. No osteoradionecrosis, wound breakdown or otorrhea occurred in another group of six patients who were treated by surgical exenteration, total cavity obliteration, and an average of 5,700 rad of postoperative radiotherapy. Thus, cavity obliteration significantly decreased the incidence of these complications (p

The surgical results in 69 patients with unilateral tumors of the cerebellopontine angle or internal auditory canal in whom total tumor removal was accomplished, and in whom an attempt was made to preserve hearing, are presented. The success rate of preservation of hearing and facial nerve function was correlated with the size of the tumor. Useful hearing, as defined by speech reception threshold no poorer than 70 dB and a discrimination score of at least 15%, was preserved in 73% of cases in which the tumor extension to the posterior fossa was no greater than 0.5 cm. In contrast, useful hearing was preserved in 22% of cases in which posterior fossa extension was greater than 2.5 cm. No significant correlation was found between preoperative evoked responses and success in preservation of hearing. The techniques and value of intraoperative monitoring of electrocochleogram (ECoG) and brain stem evoked responses are discussed. A theory of pathogenesis of intraoperative hearing loss, based on correlation of changes in evoked responses and simultaneous surgical events, is presented.

Recent interest in cochlear implantation for children has made it important to understand how postnatal growth of the ear will affect such devices. In this study, the postnatal growth of the labyrinth, middle ear, and mastoid was measured in three dimensions using radiographic and temporal bone data. Measurements were made from histologic sections of 48 temporal bones from children and compared to adult temporal bones. Radiographic measurements were made from 253 sets of skull radiographs of children and compared to adult skull series. In the three dimensions measured, there was no postnatal growth of the labyrinth and little variation in size between individuals. Measurements of the middle ear showed greater variation between individuals than measurements of the inner ear, but growth only in the distance from stapes footplate to the tympanic membrane. The mastoid showed growth in all three dimensions: length, width, and depth. The pattern of growth for mastoid length and width appears to follow a double logistic model, with differences between males and females. The growth in mastoid depth is smaller and appears to follow a single exponential curve. The implications for cochlear implantation in children are discussed.

The innervation densities, i.e. the number of afferent endings per inner and outer hair cell, number of synaptic specializations per inner hair cell and the number of efferent endings per outer hair c

The ultrastructural pathology in an ear with long-standing profound deafness is presented. Endolymphatic hydrops was present, although there had been no vestibular symptoms. Although hair cells were absent, the intercellular junctional complex at the endolymphatic surface of the organ of Corti was maintained, suggesting “healing” by migration or proliferation of supporting cells to fill the empty spaces. Severe atrophy of the stria vascularis was present, and crystalline deposits were found within the strial remnant. An encapsulated tectorial membrane was interpreted in light of ultrastructural findings as either herniation of the fibrillar connective tissue of the spiral limbus into the scala media or alternatively demonstrating abnormal continuity between the connective tissue of the spiral limbus and the remnant of tectorial membrane. Neural degeneration was severe in all cochlear turns. However, more nerve fibers were seen in the proximal portion of Rosenthal's canal than at the habenula perforata or in the organ of Corti, and central processes from the ganglion area were more numerous than peripheral processes. The ganglion cell population was reduced to approximately 10% of normal, and only unmyelinated cell bodies were found. Few recognizable neural fibers were seen within the organ of Corti, although bizarre collections of apparent cellular debris and cell processes containing many mitochondria or vesicles were seen in regions normally containing neural fibers.

The intercellular junctions in the organ of Corti of cat and man were examined with the electron microscope. In contrast to the zone of tight junctions, or zonulae occludentes, which were present at the surface of cells lining the scala media, there was no tight junctional specialization among the cells of the tympanic lamina, perilymphatic lining cells of the scala vestibuli, basal processes of the supporting cells of the organ of Corti or cells of the spiral limbus and spiral ligament. These findings suggest the possibility of fluid continuity between the scala vestibuli and scala tympani all along the cochlear duct. Morphological evidence for an intercellular diffusion barrier was present only at the endolymphatic surfaces of the cochlear duct and between the processes of the basal cells of the stria vascularis in cat and man.

Twenty-nine patients with presumed syphilitic hearing loss, either congenital or acquired, were treated on one or more occasions according to a three-month protocol using penicillin and prednisone. Changes in hearing were carefully followed during treatment and for at least one year thereafter. Of 58 ears studied in 29 patients, 19 demonstrated significant partial improvement in hearing during treatment. However, 11 ears returned to pretreatment hearing levels after therapy, and only 8 ears, or 15%, maintained the hearing gains one year later. Enhanced discrimination occurred more commonly than gains in pure tone threshold. Long-term alternate day prednisone therapy was required to sustain hearing improvement in a small number of patients.

Spiral ganglion cell populations were determined for six normal adults using two methods, 1) graphic reconstruction to calculate total segmental spiral ganglion counts, and 2) measurement of spiral ganglion cell density for given cochlear segments. Such data can be used to evaluate possible loss of spiral ganglion cell populations in pathologic human specimens. The method of segmental density calculation will be particularly useful when serial sections of the entire spiral ganglion are not available.

The incidence of reciprocal synapses at the base of outer hair cells of the human organ of Corti was studied by electron-microscopic serial section reconstruction. Reciprocal synapses were found in each of six ears from five individuals. A total of 1,386 serial sections and the neural poles of 25 outer hair cells in two individuals were examined. Fourteen of the 25 outer hair cells (56 %) possessed reciprocal synapses. The incidence of reciprocal synapses increased from the first to the third rows of outer hair cells, as determined by the percentage of outer hair cells and afferent nerve terminals of each row demonstrating reciprocal synapses and the average number of reciprocal synapses per hair cell in each row. Hair cells with reciprocal synapses had more afferent and fewer efferent terminals per hair cell than hair cells without reciprocal synapses.

• The selection of patients for cochlear implantation requires consideration of a variety of anatomical and histological facts. Mechanical impediments to cochlear implantation, including the consequences of chronic otitis media, bony obliteration of the membranous labyrinth, or labyrinthitis ossificans, following bacterial labyrinthitis or vascular compromise of the inner ear, obliterative otosclerosis, and middle-ear dysplasias may present difficulties in access to the inner ear and placement of electrodes. Consideration of the histopathlogical features of known causes of profound deafness will help predict the presence or absence of inner ear structures essential for successful implantation. The identity of these critical structures and the histopathologic characteristics of bacterial labyrinthitis, fungal meningitis, syphilis of the inner ear, otosclerosis, presbycusis, genetically determined degenerations, trauma, intoxications, inflammatory, autoimmune and idiopathic disorders are presented in terms of their relevance for cochlear implantation. ( Arch Otolaryngol 1984;110:160-163)

We report 21 cases of invasive external otitis and review 130 cases from the English literature. Invasive external otitis is the term that most appropriately describes the locally invasive Pseudomonas infection that begins in the external ear canal, breaches the epithelial barrier and results in signs of local subcutaneous tissue invasion. Nineteen patients were diabetic. Fifteen of these 19 had pre-existent, long-standing diabetes (average 15.8 years) and 10 had microvascular disease. Studies of the skin of the temporal bone in two patients provided evidence of diabetic microangiopathy of the dermal capillaries. Pseudomonas aeruginosa was isolated from the involved area in all cases. All patients without neurologic deficits survived, compared with six of nine with deficits of the central nervous system. All 13 patients in whom initial therapy was successful received a combination of an aminoglycoside and a semisynthetic penicillin, whereas all six episodes of recurrent disease occurred when only one antibiotic was used. The overall mortality was 15 percent (three of 20 in whom the long-term outcome is known). We propose that diabetic microangiopathy of the skin of the temporal bone results in poor local perfusion and creates an environment well suited for invasion by Pseudomonas aeruginosa. There is a good correlation between the extent of disease clinically and prognosis. Effective treatment requires early diagnosis and combination therapy with an aminoglycoside and a semisynthetic penicillin.

Syphilis, both congenital and acquired, may cause sensori-neural hearing loss. Congenital syphilis presents in two forms: early (infantile), and late (tardive). Acquired syphilis, both secondary and tertiary, may cause deafness. The clinical course of the acquired and congenital forms are similar. Sensori-neural hearing loss with low discrimination scores may affect both ears simultaneously or sequentially, and vestibular complaints are common. A clinical diagnosis can be made on the basis of history, the presence of other stigmata of syphilis, and serological tests, including the FTA-ABS. The histopathology of acquired and congenital forms is indistinguishable and is essentially twofold: first, syphilis may cause a miningo-neurolabyrinthitis with round cell infiltration of the labyrinth and VIIIth nerve as the predominant lesion in early congenital syphilis and the acute meningitides of secondary and tertiary acquired syphilis. Second, syphilis may cause a perivascular round cell osteitis of the temporal bone with secondary involvement of the membranous labyrinth in both late congenital and acquired late latent or tertiary syphilis. Endolymphatic hydrops may be seen in both the congenital and acquired forms. A case of bilateral sequential sudden deafness due to acquired syphilis is presented. A histological diagnosis of syphilitic involvement of the temporal bone was made by incudectomy. Treatment with prednisone and penicillin over a three-month period resulted in return of good cochlear function in one ear.

Cochlear implantation, a form of neural prosthesis, is now being employed for some profoundly deaf individuals. The pathophysiology of profound deafness, the strategies inherent in cochlear implantation, the differences between various cochlear implant strategies and designs, medical and otologic evaluation of implant candidates, and the surgical procedure are each discussed. The results in speech recognition and speech reading that have been obtained with four commonly used cochlear implant systems are also presented.

Tuberculosis of the middle ear is currently a rare disease in developed countries but one that still occurs and typically causes significant morbidity manifested by profound and permanent hearing loss. Diagnosis is difficult since most physicians are unfamiliar with the typical presenting features; in addition, special cultural and pathologic studies are required for diagnosis. A case report and review of the literature are presented to delineate typical clinical, epidemiologic, and laboratory features of tuberculous otitis media and associated tuberculous disease. A diagnostic and therapeutic plan is outlined that would allow early therapy and preservation of hearing.

• A patient had fetal cellular rhabdomyoma of the larynx confirmed histologically and by electron microscopy. The literature on laryngeal rhabdomyomas is reviewed. Adult and fetal rhabdomyomas demonstrate no clinical differences in the larynx, unlike rhabdomyomas described elsewhere in the body. Most patients are middle-aged men with less than three years' history of hoarseness. The diagnosis is established pathologically by using routine histologic criteria, special stains, and electron microscopy. Treatment consists of local surgical excision. The tumors rarely recur. (Arch Otolaryngol1983;109:821-826)

One hundred five cases of primary squamous cell carcinoma of the epiglottis were reviewed and the results of treatment compared. The cure rate by radiation therapy for epiglottic carcinomas, both suprahyoid and infrahyoid, was poorer than previously reported cure rates for all supraglottic carcinomas (p

An adepithelial basement lamella of 8–10 layers of apparently orthogonally arrayed collagen fibrils develops in the skin of Fundulus heteroclitus between the fifth and twelfth days after fertilization. Subsequent thickening of the lamella with growth until posthatching stages is the result of an increase in the number of rows of fibrils per layer, not in the number of layers. In contrast to the admuscular lamella, which forms in posthatching stages, the adepithelial lamella is acellular except in the sublamellar region. A morphological study of the skin of developing stages of Fundulus places the present “plywood” theory of basement lamella structure and development in doubt and supports a new “scindulene (shingle)” theory. Collagen fibril layers are observed to descend at a slight angle from the basement membrane, rather than to lie parallel to it as proposed by the plywood theory. Deposition of collagen in the basement lamella appears not to result from sequential switching and layering of collagen fibrils parallel to the basement membrane, as suggested by the plywood theory. Rather it appears that the collagen fibrils are inserted at end points into the basement membrane and are polymerized in one orientation only in any given area of the basement membrane and that adjacent areas are oriented at 105–110° to each other. Morphological changes with growth are accounted for by expansion of these “areas of insertion” in the basement membrane. Problems of variation in lamella thickness, crossover fibrils between different collagen layers, and the possible role of the basement membrane in the deposition of collagen into the lamellar structure are discussed.

Histochemical techniques with the electron microscope for the localization of specific acetylcholinesterase and non-specific cholinesterases have been applied to preparations of the abdominal muscle receptor organ, or stretch receptor, of the lobster. Reaction product specific for AChE was found to be localized in a discrete but interrupted fashion on the external surface of the cell membranes of both the fast and slow sensory neurons at the levels of axon, cell body, large and small dendritic processes, and fine dendritic terminations. Reaction product specific for AChE was also found on the external surface of the limiting membranes of motor axons, but not at neuromuscular endings. Non-specific ChE was limited to cytoplasmic vacuoles and cisternae of the Schwann cells of the neural sheaths. These findings lend support to the hypothesis that in the lobster the ACh system may mediate membrane excitability of nerve fibers. Furthermore, at the level of dendritic terminations this system may mediate the transduction of mechanical into electrical energy via reversible permeability changes.

The dendritic processes and terminals of the abdominal muscle receptor organ of the lobster have been studied with the electron microscope. In both the “fast” and “slow” adapting components of the muscle receptor organ, dendritic processes ramify within the body of the stretch muscle in a zone of “relative muscle exclusion,” where the continuity of the muscle bundle is interrupted by a zone of connective tissue. The cell bodies and larger dendritic processes are ensheathed in alternate layers of connective tissue and Schwann cells, but the smallest dendritic twigs are entirely divested of their Schwann cell envelope. The membrane of the dendritic terminations is intimately applied to either connective tissue of the zone of relative muscle exclusion or to the sarcolemma of the stretch muscle. This apposition is interpreted as morphological specialization for transduction or mechanoelectric conversion. It is suggested that these two types of dendritic terminals may represent two distinct sites for transduction and may also mediate different modalities of input. The distribution of dendritic processes and terminals differs in the fast and slow systems. In the fast system the dendrites quickly ramify into a glomerular burst of processes near the junction of stretch muscle and connective tissue. In the slow system, the dendrites ramify more gradually and lie more nearly parallel to the long axis of the stretch muscle. In both the fast and slow systems, but especially in the dendritic terminals of the fast neuron, collections of vesicles 400–2000 A in diameter have been observed. These vesicles are clearly different in fine structure from those found in the neuromuscular junction or axo-dendritic synapses. An effort is made to relate neurophysiological characteristics of this system with the fine structural observations, with particular attention to the mechanism of transduction, or mechanoelectric conversion.

The abdominal stretch receptor of lobster has been examined. Fine structural details of the receptor nerves are presented and neurophysiological correlations are suggested. Both axo-dendritic synapses and neuromuscular junctions were examined. Axo-dendritic synapses are of one type only, possessing elongated, or flattened, presynaptic vesicles approximately 200 A in diameter and 400–600 A long. In contrast two distinct types of neuromuscular junctions were observed. The first possesses spherical synaptic vesicles 500–900 A in diameter. The second possesses synaptic vesicles of dimensions similar to those of axo-dendritic synapses. It is suggested that synapses, both axo-dendritic and neuromuscular, with elongated or flattened vesicles, are inhibitory, and that neuromuscular junctions with spherical vesicles are excitatory.

The variability of the dimensions of the facial recess and extended facial recess with age, sex, and degree of pneumatization was measured in 87 temporal bones serially sectioned in the horizontal plane. Although some statistically significant differences in dimensions were identified, the absolute differences were small compared to the range of measurements. The mean dimensions were very similar in all groups studied. The clinical relevance of the data to mastoid surgery and cochlear implantation is discussed.

The temporal bones of a patient who suffered sudden deafness and ataxia after administration of both furosemide and ethacrynic acid, were prepared for light and electron microscopy. There was no loss of hair or supporting cells. However, some hair cells, in both the vestibular neuroepithelium and the organ of Corti, particularly in the basal turn, were more densely staining and more granular than normal. Membrane whorls also were common within mitochondria of such cells. the endoplasmic reticulum of some spiral ganglion cells was dilated. the major cytologic changes were found in the stria vascularis of the cochlea and dark cell areas of the vestibular system. There was marked dilatation of the intercellular fluid spaces, consistent with the biochemical observation that loop diuretics interfere first with enzyme systems responsible for fluid transport within the inner ear.

A retrospective study of 547 cases of meningitis was performed. Of these, 236 were bacterial, 304 were viral, and 7 were fungal in etiology. Of 110 survivors of bacterial meningitis over the age of 2 1/2 years, 23 or 21% suffered partial or complete sensorineural hearing loss. The site of auditory injury in cases of partial loss was the cochlea by audiologic criteria. A positive correlation with hearing loss was found for the species of organism, delay before treatment, low CSF sugar, and CSF pleocytosis. Of 7 patients with fungal meningitis, 3 suffered hearing loss with signs of a retrocochlear site. Of 304 cases of aseptic meningitis, none developed a hearing loss. The pathophysiology of hearing loss as a sequela of meningitis and the possible explanations for absence of hearing loss in viral meningitis are discussed.

A case of Usher's syndrome, type 3, is described. Histologic study of the inner ear of the patient demonstrated hair cell loss in the basal turn, severe loss of spiral ganglion cells, widespread neural degeneration in the cochlea, and discrete collections of degenerating supporting cells in the organ of Corti. The pattern of neural degeneration bore some similarity to abnormalities in the retina in retinitis pigmentosa. However, the findings in the supporting cells had no obvious parallel to the findings in the retina in this disorder. The histopathology of Usher's syndrome has been equated with the Scheibe, or cochleosaccular, pattern of degeneration. However, the findings in the present case and a critical analysis of published data did not support this concept.

• Syphilis can cause sensorineural hearing loss that is potentially treatable. To determine the incidence of positive serological findings in patients with sensorineural hearing loss, the rapid plasma reagin card test (RPRCT) and the FTA-ABS test were performed in a study group composed of patients with sensorineural hearing loss of obscure origin. Of the 306 patients with sensorineural hearing loss, 20 (6.5%) demonstrated a positive FTA-ABS as compared with two of 100 (2%) of the control group. Considerable variation was found in the rate of the false-negative and the biological false-positive RPRCT as performed by our hospital and state laboratories when compared with the results of the FTA-ABS test. Syphilis should be considered in any patient with sensorineural hearing loss of obscure origin, despite a negative history for syphilis. The FTA-ABS is the preferred test to exclude hearing loss of syphilitic origin. ( Arch Otolaryngol 104:63-65, 1978)