Mutsumi Kenmochi

Hearing Impairment and Tinnitus Pitch in Patients With Unilateral Tinnitus: Comparison of Sudden Hearing Loss and Chronic Tinnitus

Objectives The objectives were to analyze the results of pitch‐matching and loudness‐balance testing in patients with unilateral tinnitus and to evaluate the relationship between audiological findings based on the tinnitus‐affected and tinnitus‐unaffected threshold differences and tinnitus pitch by using linear interpolation methods. In addition, the effects of the duration of the tinnitus on this relationship were investigated. Sudden sensorineural hearing loss with tinnitus was selected for the “acute tinnitus” group, and unilateral tinnitus with unknown disease and a duration of more than 3 months was selected for the “chronic tinnitus” group.

Recovery of human compound action potential using a paired-click stimulation paradigm

The recovery process from adaptation of the compound action potential (CAP) was studied using an equilevel paired click stimulation paradigm in humans with normal hearing. The CAP amplitude to the second click of paired clicks was normalized to the amplitude to the first click. The second-click CAP amplitude recovered as a function of interclick interval (ICI) between the first and the second click of a pair. A regression line fitted to the recovered amplitude data demonstrated the logarithmic function of the ICI. Full recovery times changed from 118 to 278 ms with increasing click intensity. The regression lines for higher click intensities exhibited two different slopes in two ICI ranges: from 3 to 100 and 120 to 300 ms. We suppose that the CAP recovery for ICI <100 ms is attributable to both the relative refractoriness of auditory nerve and the short-term adaptation mechanisms, while, for ICI >100 ms chiefly to the short-term adaptation mechanisms. The recovery process of the second-click CAP slowed with increasing intensity, which is a similar result to that obtained in the animal experiments by Parham et al. The input-output (I-O) curve of the second-click CAP amplitudes exhibited a different slopes above and below 60 dB normal hearing level (nHL). We assume that the mechanisms underlying this characteristic curve pattern differ from those for the I-O curve of the CAP in response to single-click stimuli. We expect that investigating the CAP recovery in pathological ears will provide clinically useful information on cochlear synaptic function.

Zinc deficiency and tinnitus

OBJECTIVE To determine if there is a correlation between serum zinc levels and audiometric performance in tinnitus patients. METHODS Seventy-three patients participated in this study. Patients age was restricted to 20-59 years. All patients were examined at the otolaryngology outpatient clinic of the St. Marianna University Toyoko Hospital. The control group consisted of 38 age- and sex-matched healthy volunteers. A blood sample was taken to measure serum zinc levels. Hypozincemia was set at a level of the mean minus one S.D. in the control group. An average hearing sensitivity was calculated as the mean value of hearing thresholds at five frequencies: 250, 500, 1000, 2000, and 4000 Hz. Normal hearing was indicated when the hearing threshold at each of these frequencies was within 20 dB of normal thresholds. RESULTS There was no significant difference in serum zinc levels between patients with tinnitus and controls. However, patients with tinnitus who had normal hearing had significantly lower serum zinc levels compared to controls. In contrast, no significant difference in serum zinc levels was found between patients with tinnitus who had hearing loss, and controls. A significant correlation between average hearing sensitivity and serum zinc level was observed. CONCLUSIONS These findings suggest that zinc is involved in the generation of tinnitus, especially in patients whose hearing is relatively normal.

Two cases of Aspergillus sinusitis with bone destruction.

We experienced the clinical courses of two cases of destructive Aspergillus in paranasal sinuses in which an Aspergillus fungus ball was formed, and which caused bony destruction are described. The case in which a nidus could not be completely surgically removed and with intervening diabetes had an unfavorable prognosis. It is recommend to perform an early expanded operation as well as to administer a sufficient amount of antifungal drugs for the treatment of destructive Aspergillus in paranasal sinuses.

Subcutaneous emphysema secondary to tonsillectomy: a case report

We report a patient in whom subcutaneous emphysema developed shortly after a tonsillectomy. A 55-year-old female with a chronic tonsillitis underwent a tonsillectomy, and about 8 h after surgery complained of swelling to the left side of the face and neck. There was crepitus and local tenderness in the left side of the neck. A CT scan revealed subcutaneous emphysema. The mechanisms underlying emphysema after tonsillectomy are discussed.

Cochlear Function of Guinea Pigs with Experimental Chronic Renal Failure

This study aimed to evaluate electrophysiologically the cochlear function of guinea pigs that underwent a five-sixths nephrectomy and, additionally, to explore the synergistic action between chronic renal failure (CRF) and noise. Cochlear potentials were recorded at 1, 2, and 3 months postoperatively. Slight changes in compound action potential and cochlear microphonics were seen at 1 month postoperative, while moderate and profound changes were seen at 2 and 3 months. Endocochlear potential showed no significant reduction. The results indicate that CRF may be an etiologic factor for cochlear dysfunction and that the hair cells seem likely to be a main site of the lesion. One-month-postoperative animals were exposed to a broadband noise. In contrast to control animals, the test animals demonstrated no recovery from the decrease in compound action potential and cochlear microphonics that occurred immediately after noise exposure. This suggests a synergistic interaction between CRF and noise.

A case report of difficult diagnosis in the patient with advanced laryngeal tuberculosis.

We report a patient with severe laryngeal tuberculosis (LTB) involving thyroid cartilage and combined with whole-bone metastasis. A 57-year-old male had presented only with hoarseness. Radiological findings were indicative of suspected metastasis from a malignant tumor. However, tuberculosis was considered by histopathological findings, and so sputum samples were tested for acid-fast bacilli and purified protein derivatives of tuberculin in order to detect the presence of LTB. A polymerase chain reaction confirmed the diagnosis. Anti-tuberculous medications were effective in resolving the hoarseness, and the removal of the mass in the right wing of thyroid cartilage was confirmed by computed tomography (CT).

Electrocochleogram after transection of vestibulo-cochlear nerve in a patient with a large acoustic neurinoma

This study reports pre- and post-operative compound action potentials (CAPs) that were recorded from a 27-year-old woman with an acoustic neurinoma. During surgery it was necessary to totally sever her vestibulo-cochlear nerve to excise a large tumor. A pure tone audiogram changed to the scale-out pattern immediately after operation. However, CAP, the waveform of which was broadened, has been recorded 3 years post-operatively with a threshold elevation of 10 dB over the pre-operative threshold. This phenomenon suggests that CAP may originate from the extreme periphery of the auditory nerve within the cochlea. The broadening of the CAP was assumed to result from enhancement of the negative summating potential included in the CAP. We studied the effect of preceding stimulus on CAP using paired click stimuli pre- and post-operatively. A reduction of CAP amplitude in response to the second click of paired clicks was markedly suppressed in the inter-click interval between 3 and 80 ms post-operatively. We speculate that depletion of adaptation induced the abnormal CAP recovery described above and that the lateral efferent nerve system was involved in abnormal CAP adaptation with transection of the vestibulo-cochlear nerve in this case.

A case of meningoencephalic herniation of the temporal bone.

A case of cerebrospinal fluid leakage from a meningoencephalic herniation of the temporal bone is presented. Computed tomography and magnetic resonance imaging were useful for a diagnosis of meningoencephalic herniation. After surgical treatment, no recurrence was observed during a 6-month follow-up period.

Effects of nimodipine on salicylate ototoxicity

The purpose of this study was to examine the effects of nimodipine on salicylate ototoxicity in guinea pigs. The compound action potential (CAP) was recorded at the round window, and the cochlear blood flow (CBF) was measured simultaneously from the lateral wall of the basal turn of the cochlea by laser Doppler flowmetry. After administration of salicylate (100 mg/kg), the CAP thresholds were significantly elevated, by 5 to 20 dB (p < .05), and the CBF was significantly decreased (p < .05). After administration of nimodipine (2 mg/kg), the CAP thresholds were unchanged, but the CBF had increased significantly (p < .05), while systemic blood pressure had decreased significantly (p < .05). Simultaneous administration of both salicylate (100 mg/kg) and nimodipine (2 mg/kg) resulted in significant elevation of the CAP thresholds (p < .05), while the CBF did not decrease. These results suggest that nimodipine prevents the decrease in CBF induced by salicylate, but that nimodipine does not prevent the deterioration in the CAP.