Risk of sensorineural hearing loss in patients with vitiligo.

OBJECTIVE: The purpose of this study was to determine the prevalence of hearing loss and vestibular symptoms among Israeli vitiligo patients as compared with healthy controls. METHODS: 16 vitiligo patients and 16 healthy controls were enrolled in this prospective study. Vitiligo patients had undergone dermatologic evaluation and complete ENT evaluation. RESULTS: Vitiligo patients demonstrated a significantly higher prevalence of sensorineural hearing loss (SNHL) (p = 0.001). A 'notch'-shaped audiogram was the most frequent type of audiogram found among vitiligo patients (p = 0.021). Patients with mucosal involvement as the primary site of onset had a significantly more normal hearing level (p = 0.004). CONCLUSIONS: Due to the high prevalence of SNHL amongst vitiligo patients, it is recommended that these patients undergo a complete hearing evaluation, avoiding ototoxic hazards if possible.

The neural generators of the vestibular evoked response.

A new method for the induction and recording of a short-latency vestibular evoked response (VsER) to intense acceleration impulses with skin electrodes was studied in cats. The first two waves, P1 and P2, had latencies of 2.5 and 3.5 ms, respectively, and coincided with the recorded gross neural activity in the vestibular nerve and nuclei, respectively. Single second-order vestibular neurons with low and irregular activity responded to the same acceleration impulses with a latency as short as 3.5 ms.

Dorello's canal: a microanatomical study.

The microsurgical anatomy of Dorello's canal has been studied in 20 specimens obtained from 10 cadaver heads fixed in formalin. The bow-shaped canal through which courses the abducens nerve before reaching the cavernous sinus is located inside a venous confluence which occupies the space between the dural leaves of the petroclival area. The petrosphenoidal ligament (Gruber's ligament), which forms the posteromedial wall of the canal, appears as a fibrous trabecula surrounded by venous blood. Canal measurements were performed and its anatomical relationship with the sixth cranial nerve is described. Angulations of variable degrees were observed in the course of the nerve inside and outside the canal. The influence of this relatively tortuous course of the abducens nerve upon its vulnerability in some pathological conditions is discussed.

The superior wall of the cavernous sinus: a microanatomical study.

The superior wall of the cavernous sinus was studied in 30 specimens obtained from 15 cadaver heads fixed in formalin. Trapezoidal in shape, the superior wall of cavernous sinus is limited laterally by the anterior petroclinoid ligament, medially by the dura of the diaphragma sellae, anteriorly by the endosteal dura of the carotid canal, and posteriorly by the posterior petroclinoid ligament. An interclinoid ligament bisects the wall, dividing it into two triangles: the carotid trigone anteromedially and the oculomotor trigone posterolaterally. Similar to the lateral wall of the cavernous sinus, the superior wall is formed by two layers: a smooth superficial dural layer and a thin, less defined deep layer. In the area of the carotid trigone, both layers separate to wrap the anterior clinoid process. The removal of this process will reveal a "clinoid space" medial to which the internal carotid artery can be identified. This clinoid segment of the artery, still extracavernous, is surrounded by two fibrous rings: a distal ring formed by fibers of the superficial dural layer and a proximal ring related to the deep dural layer. Below the proximal ring, the internal carotid artery becomes intracavernous; above the distal ring, the artery is continuous with its supraclinoid segment. The complex dural anatomy of the superior wall, its fibrous rings, and the clinoid space in relation to a superior surgical approach to the cavernous sinus are discussed.

Development of short latency vestibular evoked potentials in the neonatal rat.

The development of short latency vestibular evoked potentials (VsEPs) was investigated in the neonatal rat. Using the appropriate stimulus (linear or angular acceleration impulses) and head orientation, responses elicited in various vestibular end-organs (utricle: x-VsEP; saccule: z-VsEP; lateral semi-circular canal: a-VsEP) were measured in rat pups at various ages between post-natal days (PND) 5 and 30, and compared to those recorded from adult animals. It was found that the VsEPs initially appeared on PND 6 (x-VsEPs and z-VsEPs) or 7 (a-VsEPs), and that by PND 8 the three responses could be recorded in all animals. The first wave of the responses, generated in the primary sensory nerve and reflecting end-organ activity, reached adult latencies and amplitudes by PND 10, showing rapid maturity of the responses. Auditory responses, on the other hand, develop at a later stage (from PND 11). The possible mechanisms involved in this differential maturation between vestibular and auditory activity are discussed.

Vestibular ototoxicity of gentamicin assessed by the recording of a short-latency vestibular-evoked response in cats.

The short-latency vestibular-evoked response (VsER) and the auditory brain stem response (ABR) were recorded with scalp electrodes in four cats before, during, and after systemic administration of gentamicin. The VsER was altered and later disappeared in three cats, and in one cat it became asymmetric, typical of a unilateral vestibular lesion. In all cats the ABR was unaffected and remained normal through the end of the experiment 4 months later. Histopathological examination of the temporal bones of three cats showed severe damage to the vestibular end-organ, particularly in the summit of the cristae, but in lesser amounts in the hair cells on the slopes of the cristae and in the maculae. In one cat, the pathological condition was greater in one ear, corresponding to the asymmetry in the VsER records. This new method of inducing and recording the VsER has been demonstrated by the present study to be an effective tool for experimentally assessing vestibular end-organ and nerve function in animal models. Furthermore, these results indicate that the VsER is generated in the vestibular labyrinth, most probably by the cristae of the semicircular canals.

The firing properties of second-order vestibular neurons in correlation with the far-field recorded vestibular-evoked response.

Action potentials of the second-order vestibular neurons of ten cats were recorded, both in rest and responding to sinusoidal and intense impulse acceleration stimuli. The data were compared with the far-field recorded vestibular-evoked response induced by the same impulse stimuli. It was found that the irregular (kinetic) neurons, which had a phase lead relative to head velocity, were capable of responding to these impulses with a latency as short as 3.5 msec after the start of head acceleration. It is assumed, therefore, that these neurons are the generators of the second wave of the vestibular-evoked response, having a similar latency. A high correlation was found between the latency of the first peak in the poststimulus time histogram in response to acceleration impulses and the phase of the response to sinusoidal rotations. The regular (tonic) vestibular neurons did not respond to acceleration impulses and probably did not contribute to the vestibular-evoked response.

The microsurgical anatomy of the abducens nerve in its intracranial course.

The microsurgical anatomy of the abducens nerve through its intracranial course was studied in 20 specimens obtained from 10 cadaver heads fixed in formalin. Another 20 specimens were used to study the pattern of branching of the nerve trunk. The following intracranial segments were studied: subarachnoid or intracisternal, petroclival, and intracavernous. Angulations, neurovascular relationships, and branching patterns of the nerve are described. The long intracranial course of the abducens nerve, its tortuosity, and its tight attachment to the skull base at the level of the petrous apex may influence its vulnerability in some pathological conditions.

Nd:YAG laser turbinate surgery animal experimental study: preliminary report.

The chronically hypertrophic nasal turbinate is a challenging problem for otolaryngologists. Although some success has been achieved with a number of medical and surgical methods, other forms of treatment are still needed. In this study, encouraging results were achieved using the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser on canine turbinates. Clinical and histological results showed that with Nd:YAG laser surgery, coagulation occurs in the deep cavernous vessels and submucosal glands of the turbinate, while the overlying mucosa remains intact.

The effect of loop diuretics on the vestibular system. Assessment by recording the vestibular evoked response.

Whether or to what extent loop diuretics, e.g., ethacrynic acid and furosemide, affect the vestibular system is controversial. We studied this problem by recording in cats the short-latency vestibular evoked response (VsER) to acceleration stimuli by skin electrodes before and after local or systemic administration of loop diuretics. The effect on the VsER was minimal in contrast to the major changes that appeared in the auditory evoked response, in which, among the waves known to originate from the brain stem, the most affected was N1. These findings suggest that the vestibular end-organ function is minimally affected by loop diuretics and that the changes in the vestibulo-ocular reflex reported by several authors might be due to the effect of the drugs on the central nervous system. Thus, recording of the VsER in experimental animal models might serve as a useful tool for direct evaluation of the effect of certain drugs and conditions on the vestibular system.

Peripheral generators of the vestibular evoked potentials in the cat.

OBJECTIVES: The contributions of each of the vertical semicircular canals (SCCs) and otoliths to the short-latency vestibular evoked potentials in response to angular acceleration impulses were studied in the cat. DESIGN: The experiments were conducted on unilateral labyrinthectomized cats. Vestibular activation was achieved by delivering angular acceleration impulses to the animal's head, held in the position presumed to be optimal for maximal stimulation of either the anterior or the posterior SCCs before and after obliteration of the SCC studied, and before and after obliteration of the other SCCs and ablation of the maculae. INTERVENTIONS: Unilateral labyrinthectomy, obliteration of the SCCs, and ablation of the otoliths and section of the commissural vestibular fibers in the brain stem with histologic confirmation were carried out in the experiments. RESULTS: Following selective obliteration of either the anterior or the posterior SCC of the remaining ear and stimulation in the presumed optimal plane of the obliterated canal, the early prominent waves (P1 and P2) disappeared, leaving only much smaller-amplitude waves. These were severely depressed after ablation of the maculae. On the other hand, the vestibular evoked potentials in response to excitatory stimuli were not affected by obliteration of the other two SCCs and ablation of the maculae. CONCLUSION: These results indicate that when the head is stimulated in the optimal plane of each of the SCCs, the vestibular evoked potentials are generated mainly by the cristae ampullaris being stimulated, while the otoliths contribute smaller responses.

Manometry and electromyography of the pharyngeal muscles in patients with dysphagia.

Simultaneous recording of the electromyographic activity of the pharyngeal muscles and the intraluminal pressure in the upper sphincter zone was performed routinely in patients with swallowing problems for the first time, to our knowledge. This technique was found to be very useful for the localization of the "site of lesion." The procedure is safe, easy to master, and causes minimal inconvenience. It can reveal, in the most direct way, whether the disturbance is in the hypopharyngeal musculature (represented by the inferior constrictor muscle), in the cricopharyngeal muscle (spasm or lack of relaxation), or in the synchronization between them. Simultaneous recording of intraluminal pressure adds valuable information about the mechanical events associated with electromyographic activity. It was found that in pathologic cases there is quite often no correlation between the electrical and mechanical events. Thus, simultaneous recording of both electrical and mechanical events is essential for the understanding of the pathophysiology of disturbances of deglutition.

Audiovestibular findings in patients with deafness caused by a mitochondrial susceptibility mutation and precipitated by an inherited nuclear mutation or aminoglycosides.

OBJECTIVE: To characterize the audiological and vestibular changes associated with a mitochondrial DNA mutation in an Arab-Israeli family and in other families with mitochondrial predisposition to aminoglycoside-induced hearing loss. DESIGN: Evaluation of audiological (pure tone thresholds, speech reception thresholds, speech discrimination, tympanometry, acoustic reflex thresholds, tone decay, and auditory brain-stem evoked response recording) and vestibular (complete history, physical examination, and 2-channel electronystagmography) systems. In 5 patients, structural evaluation of the inner ear was done by magnetic resonance imaging. PATIENTS: Fifteen members of an Arab-Israeli family, and 1 Chinese woman with the same mitochondrial DNA mutation who experienced hearing loss after short-term exposure to streptomycin. RESULTS: Most of the patients had a profound hearing loss due to cochlear involvement. The hearing loss usually was not accompanied by notable peripheral vestibular dysfunction. In the patient with severe hearing loss after exposure to aminoglycoside, the vestibular function was completely normal. CONCLUSIONS: In most of the Arab-Israeli patients with congenital deafness, the vestibular system function was normal, in contrast to the frequency of vestibular abnormality among deaf children, which was described in the literature. This may be related to genetic predisposition to aminoglycoside-induced deafness.

Transverse ligament rupture and atlanto-axial subluxation in children.

We report four children aged two to nine years with traumatic tears of the transverse ligament of the atlas and atlanto-axial subluxation. This is extremely rare in this age group since trauma usually causes a skeletal rather than a ligamentous injury. The injuries resulted from falls or motor vehicle accidents, with considerable delay in diagnosis. Flexion radiographs showed atlas-dens intervals (ADI) of 6, 7, 8 and 13 mm; all four patients were treated by posterior fusion at C1-C2 after the failure of conservative treatment. In one child with quadriparesis and a fixed ADI of 13 mm, transoral anterior resection of the odontoid was performed before the fusion. Diagnosis of this traumatic lesion requires a high level of suspicion. Conservative treatment is likely to fail; surgical stabilisation is indicated.

Short latency vestibular evoked response to angular acceleration impulse in human beings.

Vestibular evoked response (VsEP) to acceleration stimuli were recorded in experimental animals and in human beings by scalp electrodes. The stimuli are angular acceleration impulses (up to 30,000 deg/sec2) transmitted to the skull by special devices. The short latency vestibular evoked response consisted of several waves during the first 10 msec. The first two waves (P1 and P2), which are the most consistent, have been shown in cats to originate from the vestibular nerve and nucleus, respectively. The middle latency response is believed to be of myogenic origin. It is hoped that the recording of VsEP in human beings will enable the localization of the site of lesion in vertiginous patients.

Objective method for differentiating between drug-induced vestibulotoxicity and cochleotoxicity.

HYPOTHESIS: An objective direct method is proposed to differentiate between drug-induced functional vestibulotoxicity and cochleotoxicity. BACKGROUND: Many substances are ototoxic. Although there are objective methods to directly evaluate functional cochlear toxicity (auditory nerve brainstem responses [ABR]), it is more difficult to assess direct functional ototoxicity to the various vestibular end organs. METHODS: Short-latency vestibular evoked potentials (VsEP) from different vestibular end organs and ABR, were used to assess functional impairment of the vestibular and cochlear end organs caused by daily injections of the aminoglycoside amikacin (known to be preferentially cochleotoxic) in guinea pigs. RESULTS: There was no significant change in the various VsEPs. whereas ABR thresholds were elevated, confirming the selective functional cochleotoxicity previously reported, as evaluated by other (mainly nondirect) methods. CONCLUSION: This study demonstrates the feasibility in general of using short-latency evoked potentials to evaluate functional cochleotoxicity and vestibulotoxicity of ototoxic drugs and to differentiate between them.

Contribution of the eighth nerve and cranial nerve nuclei to the short-latency vestibular evoked potentials in cats.

The object of this study was to assess the contributions of the vestibular nerve and various cranial nerve nuclei to the short-latency vestibular evoked potentials in cat. The following nuclei were investigated: vestibular nuclei and the third, sixth, and tenth cranial nerve nuclei. In unilateral labyrinthectomized cats, we performed suboccipital craniectomy and partial cerebellectomy to place bipolar electrodes into the neural structures under investigation. The surface-recorded vestibular evoked potentials (far field) were compared with the potentials recorded intracranially in response to the same acceleration impulses. The exact locations were later confirmed histologically. Reversible lesions also were induced by injection of lidocaine 2%. The results indicate that the first wave of the vestibular evoked potentials originates in the vestibular nerve, and the second wave is mainly generated in the superior and medial vestibular nuclei. The third, sixth, and tenth cranial nerve nuclei apparently contribute to the later waves of the vestibular evoked potentials, particularly waves 3 and 4.

Dysphonia caused by Forestier's disease.

A case of diffuse idiopathic skeletal hyperostosis (Forestier's disease) causing dysphonia as the presenting and only symptom is reported. The dysphonia is attributed to the mass effect in the hypopharynx and the mild pressure on the larynx. The bony mass anterior to the vertebral body is demonstrated by CT scan for the first time in the literature on Forestier's disease.

Irrigation of the maxillary sinus by canine fossa puncture. Experience with 202 patients.

Maxillary sinus lavage through the canine fossa was performed on 202 patients. This procedure is relatively safe, easily learned and quickly performed, has minimal side effects and a very low percentage of failures, and is more acceptable to most patients. It should be used by otolaryngologists, at least as a useful alternative to the classical method.

Chondrosarcoma at the skull base.

A rare case of chondrosarcoma at the skull base is presented. Computerized tomography scan was very helpful in delineating the exact extent of the tumor. Chondrosarcoma is a slow growing malignant tumor which metastasizes very late. Usually it is radioresistant, but when surgery is not feasible, irradiation treatment is worth a trial.