This work is a part of the research on standardization of speech audiometry for hearingimpaired children. In the first phase, the experiment was made on children in nursery classes (aged 3-6 years) at a school for the deaf in order to evaluate a test word list and the procedure for word intelligibility test by picture identification. From the results of the experiment the following suggestions were made: 1) The test word list should be consisted of concrete nouns which can be pictorially presented. 2) A test sheet with 6 pictures is used for every test word. Therefore 25 test sheets are needed to 25 test words. 3) Before the test, it is necessary to ascertain whether each test word is within the recognition vocabulary of each subject. In the second phase, according to the first experiment a test word list was made, and the intelligibility test was carried out on 90 children, aged 3-15 years at a school for the deaf. The results were as followed: 1) Mean hearing loss more than 95dB (ASA-1951) was associated with lower score of this test. 2) This test was easier than the monosyllabic intelligibility test (67-list of Japan Audiological Society) which has been widely used in Japan, and the test scores distributed over the wider range than those of 67-list. Therefore this test can be utilized for evaluating the speech recognition ability of severely impaired hearing children.
In a series of the lesion experiments of the superior olivary nuclei and inferior colliculi, the changes of brain stem response (BSR) recorded from the vertex of adult cats were analyzed to determine the origin of each wave component. The results were as follows: 1) The typical wave from of BSR in anesthetized cat consists of five waves. The average latencies of these wave potentials were: 1.3±0.12; 2.3±0.18; 3.1±0.24; 4.3±0.43; and 5.6±0.52 msec. respectively. 2) Destruction of the bilateral reticular formation of the brain stem caused no change in either amplitude or latency of BSR. 3) Destruction of the bilateral superior olivary nuclei abolished the third to fifth waves completely, whereas the first two waves were not affected. 4) After destruction of the unilateral superior olivary nucleus (ipsilateral or contralateral), the third wave was not completely abolished and there was a slight change in amplitude and latency. 5) Following destruction of the unilateral superior olivary nucleus (ipsilateral or contralateral), or destruction of any combination of inferior colliculus and superior olivary nucleus, the fourth wave was not completely disappeared. 6) The fifth wave was almost completely abolished by destruction of the contralateral inferior colliculus or contralateral suporior olivary nucleus, but not by destruction of the ipsilateral one. The conclusions were as follows: 1) The bilateral superior olivary nuclei are the primary generator of the third wave. 2) The fourth wave is evoked at the both ipsilateral and contralateral inferior colliculi and is related to the ascending auditory pathways from the bilateral superior olivary nuclei. 3) The fifth wave is mainly evoked at the contralateral inferior colliculus and is related to the ascending auditory pathway from the contralateral superior olivary nucleus.
Extratympanic electrocochleography with Sanei Sokki 7S11 without anesthesia was performed on 14 normal-hearing subjects. As the active electrode a silver ball electrode was placed on the posteriorsuperior part of the tympanic annulus. As the reference electrode and the ground electrode EEG disc electrodes were placed on the ipsilateral ear lobe and the root of nose respectively. Click was delivered from TDH 49 ear phone. AP response threshold was 0dB to 10dB above the subjective threshold. Maximum of N1 amplitude was 2.7μV to 6.3μV. N1 amplitude-intensity function and N1 latency-intensity function were obtained. L curve and H curve were distinguished. Three kinds of AP wave (N1 only, N1N2, N1N2N3) were observed at high intensities. Wave form was deformed at 320Hz high pass filter, but was not changed at high pass filter lower than 80Hz. Clear response was recorded averaging 8 responses at high intensity and 32 responses at low intensity. Negative SP alone was recorded on all subjects. -SP visual detection threshold was 60dB to 80dB (above normal subjective threshold). -SP/AP ratio was 0.20 on the average and 0.053 on the standard deviation at 80dB. The results of extratympanic electrocochleography using silver ball electrode was compared with that of electrocochleography using other electrodes, and clinical usefulness of this method was discussed.
The present study was performed to evaluate the effect of adenosine triphosphate (ATP, ADEPHOS KOWA) on the peripheral vascular system of the inner ear in guinea pigs. ATP of 5mg/kg was administered to guinea pigs intraperitoneally. Some of the animals were also treated with Diphenidol of 5mg/kg intraperitoneally. The following conclusions were obtained. 1) Ten minutes after the single administration of ATP, the transient increase in diameter of the blood vessels was noted in the radiating arterioles and suprastrial capillaries and capillary network of the stria vascularis in every turn of the cochlea. The transient increase in diameter was also seen in the capillary networks of the maculae and cristae ampullares of the vestibule. 2) In the animals treated with Diphenidol, the transient increase in diameter was seen in similar fashion. There was no significant difference in the increase in diameter of the blood vessels. 3) The studies previously done by investigators on the effect of ATP on the cardiovascular system suggest that the transient increase in diameter of peripheral vascular system of the inner ear is attributed to the increase in the influx of arterial blood. From these data, the possible effect of ATP on metabolism of the inner ear was discussed.
Morphologic changes in the capillary network of the stria vascularis of guinea pigs were investigated on the surface specimens of the spiral ligaments after the superficial blood vessels of the scalas were stained with benzidine. It was demonstrated that multiple narrowing of the capillary lumen and occasional ischemia occurred in the capillary network of the stria vascularis immediately after intravenous administration of ethacrynic acid (80mg/kg) or furosemide (100mg/kg). These changes were recovered rapidly in guinea pigs receiving furosemide, but slowly in the animals treated with ethacrynic acid. On the other hand, intracochlear perfusion with histochemical reaction solution containing Nitro-blue tetrazolium (Nitro-BT, 0.05%) and phosphate buffer (pH7.4) was carried out immediately after decapitation to demonstrate the alterations in supravital reduction at the CoQ-level of the electron transfer system of the surviving hair cells of the spiral organ. Microscopic observation in the surface specimens of the spiral organ revealed that supravital reduction of Nitro-BT occurred prominently in the inner hair cells, but was impaired considerably in the outer hair cells immediately after intravenous injection of ethacrynic acid (80mg/kg) or furosemide (100mg/kg). However, the impaired reduction in the outer hair cells recovered almost completely 3 hours later in guinea pigs receiving furosemide. On these surface specimens, the body of the outer hair cells became swollen in association with disturbance of the supravital reduction of the Nitro-BT. These findings suggest that these damages in the outer hair cells may be caused by primary injury of the membrane ATPase by the diuretics, and these damages were independent of intercellular edema of the stria vascularis. The latter change may be responsible for the narrowing and compression of the capillary lumen in the stria vascularis and ischemia.
The brain stem responses were studied in 13 patients with confirmed various lesions of the brain stem. Abnormalities in response appeared with shorter interstimulus intervals with clicks delivered monoaurally to the involved side in the patients with brain stem vascular lesion. One out of 4 cases of pinealoma showed abnormally greater variability of the response on the affected side. Auditory brain stem responses recorded from the patients with other brain stem lesions showed prolongation in latency and/or reduction in amplitude of the components originating in the site central to the lesion. Reviewing reports of animal experiments, the authors discussed the difference of site of origin of the 4th component which appeared prominently in those cases with the lesions at the middle, upper pons or the midbrain in human.