Some hearing-aid users experience listening difficulty in certain environments, e. g., related to reverberation, but no standard way currently exists to evaluate hearing-aid fit adversely affected by reverberation.
We produced speech materials with different reverberation times that mimicked the actual listening environment. Those with normal hearing and with impaired hearing took listening tests using these materials wearing a hearing aid in a sound-proof booth. Listening tests were also done in an actual environment.
Results showed that increasing reverberation times of two-syllable words decreased in the percentages of correct answers in the hearing-impaired, as also occurred in a real environment.
These findings suggest that using speech materials with different reverberation times enables hearing-aid to be evaluated in relation to reverberation.

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Spontaneous intracranial hypotension (SIH) is a syndrome accompanied by orthostatic headache, low cerebrospinal fluid (CSF) pressure without apparent cause, and diffuse pachymeningeal gadolinium enhancement on MRI. Hearing impairment, tinnitus, and vertigo are also associated with SIH. We report a case of a 46-year-old woman with low-tone sensorineural hearing loss (SNHL), tinnitus, vertigo, and orthostatic headache. Audiometry showed bilateral fluctuating low-tone SNHL. She evidenced enhanced meningeal thickening in MRI and extradural leakage in the cervical vertebrae in isotope cisternography using indium-111-labeled DTPA. She underwent epidural blood patch with autologous blood at C6-7 once (8ml), 5days after which her hearing recovered completely and symptoms disappeared.

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Sensorineural hearing loss is commonly accompanied by reduced frequency selectivity and temporal resolution. The reduction of frequency selectivity engenders marked disadvantages through masking, particularly masking of middle and high frequency components by intense low frequency components: the so-called upward spread of masking. To reduce masking between contiguous frequency bands, we propose dichotic listening, in which frequency spectra are split into two complementary parts and presented dichotically. This way improve speech intelligibility. We studied the effect of dichotic listening on speech intelligibility in both quiet and noisy environments. Tests used vowel /u/-consonant-vowel nonsense syllables presented to four subjects with mild to moderate sensorineural hearing loss. In dichotic listening speech signals were divided into two frequency bands based on 5 the formant frequencies of Japanese vowels. (1) Results of speech intelligibility tests showed that speech intelligibility improved when the dividing frequency was 0, 8kHz (between F1 and F2 of Japanese vowel/u/). (2) The improvement in intelligility tends to increase with increasing speech-to-noise ratio.

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Hearing aids must be evaluated both at fitting and after prolonged use. We fitted hearing aids in 26 subjects, and evaluated their efficacy subjectively and objectively at fitting and after 3 months of use. We also evaluated satisfaction with the hearing aid using a visual analog scale. After 3 months, no significant difference was found in usefulness, except in conversation under noisy conditions and listening to TV. Satisfaction, however, decreased significantly. Although the decrese in satisfaction was studied comparing those with increased and decreased satisfaction, this was independent of observed usefulness. Results showed that satisfaction is affected by usefulness and other factors such as wear, howling, and hardware problems. Since some occur after long use, follow-up is clearly required after fitting. Evaluating both usefulness and other problems may increase satisfaction.

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Because most cochlear implants (CI) are designed and adjusted to enable phonemes in speech to be most efficiently perceived, prosody is perceived poorly and may even interfere with phonemic perception. We studied the effects of (1) Japanese-language pitch accent on phonemic perception and (2) the presentation level on the perception of phonemes and pitch accents, with word intelligibility tests in three postlingually deaf CI patients (N24, SPEAK). Two-syllabic Japanese words were presented with either low-high or high-low pitch accent at +10, 0, -10, and -15/-20dB relative to the most comfortable level (MCL). Results showed that the same phonemes were heard differently depending on the accent type or the presentation level, suggesting an interaction between phonemic and prosodic perception. Different types of pitch accent were found to affect phoneme perception differentially at MCL or higher. Phonemic perception improved as the presentation level increased, whereas the performance of pitch accent identification was similar across all levels. These results suggest that postimplantation training should explicitly incorporate prosodic factors to improve overall speech intelligibility.

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Two types of binaural testing {Binaural Interaction component of auditory brainstem response (BI component of ABR) and interaural discrimination test: Just Noticeable Difference (JND)} with interaural intensity difference were tested in 9 normal hearing young adults. We used two stimulus levels for measuring the BI component of ABR: 1.70-70dBnHL 2.68-72dBnHL (left ear-right ear). We defined the difference in latency and amplitude between stimulus 1 and 2 for relative BI. Two stimulus levels —50dBSL and 20dBSL— used for the interaural intensity discrimination test clearly differed. We found an obvious correlation between the latency of relative BI and JND, suggesting that the BI component of ABR may be of clinical use.

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The purpose of this study was reproducibility, and the sound source normal position of COR minimum response levels (MRLs) were considered based on movement and language development in 303 children with multiple disabilities and motor disorders. They were less than 6 years old (average: 2 years and 5 months), had less than motor development age (DA) at 12 months, and MRLs were less than 35dBHLs. Reproducibility exists in language development positive in the group of 10 months or more in 90% or more of cases, and the sound source normal position to one direction was accepted in 50% or more of cases.
The positive sound source normal position to right-and-left 2 direction was possible for 2% of all cases. For less than motor DA 7 months and less than language DA 4 months, the sound source normal position was difficult and influenced by condition such as awakening and epilepsy. In physiologically stable subjects, reflecting, inquiry, and emotion reactions were accepted as hearing behavior, especially the eye reaction. We surmised that the reaction to hearing behavior according to motor and language development became the index of evaluation. A setup of the stable seating position in which the head is easy to control is importnat during behavioral hearing testing.

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