Biomedical subjects

K Gyo

Publications and source records attributed to K Gyo.

93 records · Page 6Linked to original sources

PubMedDate not supplied

Histological study of chronic electrode implantation through the round window of the guinea pig.

A platinum-iridium electrode with a Teflon cover tube was chronically implanted through the round window into the scala tympani of the guinea pig. Animals were sacrificed at 30 to 40 weeks after electrode implantation, and the cochleae were observed by scanning electron microscopy or with light microscopy. The results revealed that the electrode was firmly enclosed with fibrous tissue on the inside of the round window and with epithelial tissue on the outside. These tissues were considered to act as a barrier to the entry of infection while preventing leakage of the perilymph.

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PubMedDate not supplied

Healing of experimentally produced round window membrane rupture.

The healing mechanism of experimentally produced ruptures of the round window was histologically studied in guinea pigs. Surgically created rupture of the round window resulted in spontaneous closure within 2 weeks. Light microscopical examination indicated that the rupture closed with proliferation of connective tissue which usually appeared to protrude into the middle ear cavity, each case showing a unique shape. In one case, the wound was covered with granulation tissue at the site of closure on the middle ear surface. Although the rupture was closed by connective tissue, the elastic fibres of the middle layer remained disrupted at the early stage of healing.

Animals↗

PubMedDate not supplied

Implantable hearing aid using a piezoelectric ossicular vibrator: a speech audiometric study.

The speech discrimination provided by a piezoelectric implantable hearing aid (IHA) was compared to that by a conventional hearing aid (CHA) using speech audiometric studies in seven patients. Recognition of monosyllabic and bisyllabic words was measured using word lists recorded on a compact disc with and without background noise. the intensity of speech sound was 65 dB SPL, while that of background noises varied from 65 to 75 dB SPL. The ear canal opposite the test ear was closed with a clay mold to avoid perception of the test sound through the contralateral ear. On monosyllabic test without noise, speech discrimination scores by the IHA and the CHA showed no significant difference. However, with noise of 65 dB SPL, the IHA outperformed the CHA. When the intensity of the noise increased to 70 or 75 dB SPL, the scores by both devices decreased, but a significant difference was noted between the two. On the bisyllabic test, the results were almost identical with those on the monosyllabic test. These findings indicate that speech recognition by the IHA was superior to that by CHA under noisy circumstances.

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