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Volume 40 (1997)
- Issue 6 Pages 701-
- Issue 5 Pages 257-
- Issue 4 Pages 201-
- Issue 3 Pages 153-
- Issue 2 Pages 87-
- Issue 1 Pages 1-
Predecessor
Volume 40, Issue 3
Displaying 1-7 of 7 articles from this issue
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Kazuo Sato, Hiromichi Kuriyama, Toshio Yamashita1997 Volume 40 Issue 3 Pages 153-157
Published: June 30, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSThe changes distribution NMDA receptor subunit mRNAs after Unilateral deafness was observed in the rat superior olivary complex (SOC) using in situ hybridization histochemistry. Silver grains density of NMDAR1 subunit mRNA was decreased in the lateral superior olive (LSO), medial superior olive (MSO) and lateral nucleus of the trapezoid body (LNTB). These changes were transient, and showed the peak after 5 days. No significant changes of NMDAR2 subunits was seen in all SOC unclei.View full abstractDownload PDF (680K) -
Seiichi Nakata1997 Volume 40 Issue 3 Pages 158-163
Published: June 30, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSA tungsten-wire microelectrode with a tip diameter of 6-8μm was inserted into the AI posterior (AIp) of the unanesthetized mustuched bat for extracellular recording of action potentials from single neurons. Constant-frequency (CF) tone bursts with 30ms duration and 0.5ms risefall time were delivered to the bat at a rate of 5.0/s. Neurons studied were classified as single-peaked or multipeaked neurons according to the shape of their frequency-tuning curves. The great majority (90%) of AIp neurons showed multipeaked frequency-tuning curves. In 60% of these multipeaked neurons, two peaks (i.e., two best frequencies) of a tuning curve were harmonically related to each other in a ono-to-two ratio. I speculate that those functions of the AIp are important for communication calls.View full abstractDownload PDF (1221K) -
Nobuyoshi Kawashima, Yuji Ase, Jun Kusakari1997 Volume 40 Issue 3 Pages 164-172
Published: June 30, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSWhen we hear two tones of different frequencies (f1<f2), the additional tones called combination tones (e.g. 2f1-f2, 3f1-2f1…) are audible in addition to these primary tones. These combination tones are considered to be generated by the nonlinear responses of the basilar membrane to the primary tones. Distortion product otoacoustic emissions (DPOAEs) are the phenomena reflecting these response. It is well known that the amplitude of DPOAEs and the intensity of combination tones are far larger at 2f1-f2 than at 2f2-f1. The present study was designed to explain the generation mechanism of DPOAEs and the difference in amplitude between 2f1-f2 and 2f2-f1 using a mathematical model of the cochlea based on the current theory in cochlear physiology.
When two primary tones are input to the cochlea, the movement of the basilar membrane is suppressed in the area between the displacement maxima for f1 and f2 so as to obtain better discrimination. Since the tuning curve of the basilar membrane movement is asymmetrical (sharper at the apex side), this suppression effect is larger on the lower frequency tone (f1) than on the higher one (f2). It was theoretically explained using a mathematical model how this difference in suppression effect makes the 2f1-f2 amplitude higher than of 2f2-f1.View full abstractDownload PDF (1125K) -
Nonlinear Stimuli and Linear StimuliMichiko Saitoh, Hiromi Ueda, Noriyuki Yanagita1997 Volume 40 Issue 3 Pages 173-177
Published: June 30, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSWe measured the evoked otoacoustic emissions (EOAEs) to nonlinear stimuli and linear stimuli with an ILO88 device in 22 ears of 13 subjects with normal hearing. The input-output curves and minimal detectable levels were measured.
We used two different methods to evaluate whether EOAEs were present. In method 1, responses were accepted as positive when reproducibility was above 40%. In method 2, responses were accepted as positive when we could visually detect fast and slow components.
There were no significant differences in the total echo power (TEP) or highest peak power (HPP) in response to the two different stimuli above an intensity of 24dBnHL. In a representative case, the inputoutput curves for the responses of both fast and slow components to nonlinear stimuli corresponded with these for the responses to linear stimuli above the minimal detectable levels. The minimal detectable levels of the responses to nonlinear stimuli were significantly higher than those to linear stimuli. The difference between these minimal detectable levels may be related to the linearity of the EOAEs in the range of weak stimuli, which cancelled responses to nonlinear stimuli.View full abstractDownload PDF (577K) -
Hirofumi Harada, Kimio Shiraishi, Yo-ichi Eura, Kensuke Shibata, Toshi ...1997 Volume 40 Issue 3 Pages 178-182
Published: June 30, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSSelf-assessment using HEARING DISABILITIES AND HANDICAP SCALE (HDHS) and pure tone audiometric testing were carried out in 114 retired Japanese self defense force officials (51-54-year-old). There were 20% of subjects with normal hearing and 80% with hearing impairment. Hearing impaired group showed a significantly high value of HDHS score (p<0.05) than the normal group. But the degree of correlation between the pure tone average and the HDHS score was low (r=0.31).
The subjects complained of the hearing disabilities (especially in speech), but denied of their handicaps.View full abstractDownload PDF (519K) -
K. Takahashi, Y. Asaka, S. Kimura, T. Wada, A. Hara, J. Kusakari1997 Volume 40 Issue 3 Pages 183-188
Published: June 30, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSTo investigate the therapeutic effect of retinoic acid (RA) upon acoustic trauma, albino guinea pigs were exposed to 2kHz pure tone of 110 or 115dB SPL for 10minutes and then given 200mg/kg RA i. p. daily for following one week. The threshold of the compound action potential (CAP) was examined at the 7th day and the results were compared with those in the control group given methanol instead of RA. The CAP threshold shift due to acoustic overstimulation in cases which were exposured to 115dB SPL sound was not significantly different from that in the control animals. In cases received 110dB SPL exposure, however, the CAP threshold shift in the RA given animals was significantly smaller than that in the control.
These results indicated that RA is effective in case of milder acoustic overstimulation.View full abstractDownload PDF (647K) -
Kazuoki Kodera, Mitsutoshi Hiraishi, Masayoshi Miura1997 Volume 40 Issue 3 Pages 189-194
Published: June 30, 1997
Released on J-STAGE: April 30, 2010
JOURNAL FREE ACCESSEffects of co-articulation on the speech discrimination scores of the Japanese consonants were studied in 8 normally hearing subjects and 12 patients with sensorineural hearing loss. Speech discrimination scores using nonsense bi-syllable lists with and without co-articulation were analyzed from the view points of articulation manner. Results and conclusions were as follows. 1) Speech discrimination scores of the first mono-syllables are higher than those of the second mono-syllables in fricative consonants and plossive consonants, for the word lists with co-articulation. 2) For the word lists without co-articulation, speech discrimination scores of the second cono-syllables decreased markedly, in the patients with sensorineural hearing loss. Masking by the vowels of the first mono-syllables reduced the speech discrimination scores of the second mono-syllables. 3) Acoustic information caused by co-articulation contributes to improve the speech discrimination scores of the second mono-syllables in the patients with sensorineural hearing loss.View full abstractDownload PDF (696K)
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