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Biomedical subjects

N Y Kiang

Publications and source records attributed to N Y Kiang.

44 records · Page 3Linked to original sources

Recording auditory-nerve potentials as an office procedure.

Recording auditory-nerve potentials from human subjects is already a routine procedure in the laboratory. In order to bring such recording capabilities into the office of practicing otologists, a number of difficulties had to be overcome. First, a small signal averager was built and incorporated into a stimulus generating and response recording system. The entire system was made portable and self-sufficient. The effects of electrical interference and background acoustic noise were shown to be tolerable. After studies of how responses vary with electrode location, electrodes were designed to be placed on the ear canal so that no invasive procedures were necessary. Methods were found to simplify the procedure so that recordings can be made in a matter of minutes by one person working alone.

Acoustic Stimulation↗

Auditory-nerve activity in cats exposed to ototoxic drugs and high-intensity sounds.

The response characteristics of auditory-nerve fibers in normal cats are compared with those in cats exposed to kanamycin and high-intensity sounds. The pathophysiology is characterized by an elevation of the tuning-curve "tips," which is sometimes associated with hypersensitivity of the "tails". Plots of unit thresholds are correlated with patterns of sensory-cell losses in the cochlea. There can be significant shifts in unit threshold without significant loss of hair cells; however, significant hair cell loss is always accompanied by highly abnormal unit thresholds. The presence of inner hair cells seems to be essential for the long-term survival of spiral ganglion cells. An incidental observation is that in the "normal" animal there is almost always a prominent "notch" at 3-4 kHz in the plots of threshold at characteristic frequency, which may have been produced by environmental noise.

Animals↗

Click-evoked gross potentials and single-unit thresholds in acoustically traumatized cats.

Click-evoked gross potentials were recorded from the round windows of 29 cats previously exposed to high-level sounds. The latency and amplitude of the gross neural components of these responses were determined and compared with the patterns of threshold shift measured in single auditory nerve fibers from the same 29 animals. Both of these electrophysiological measures were compared with the patterns of hair cell loss as seen in celloidin sections through the temporal bone. The correlations between single-unit abnormalities and cochlear pathology in these cases have been documented elsewhere. In this report, the correlations between gross-potential abnormalities and cochlear pathology are examined. The diagnostic potential of these correlations is discussed.

Acoustic Stimulation↗

Fundamental considerations in designing auditory implants.

The usual premise underlying developmental work on cochlear prostheses as prospective cures for profound deafness is that the auditory nerve can be electrically stimulated in such a manner that communicative skills can be developed or maintained. Physiologic recordings from single fibers in the cat's auditory nerve and attempts to model these responses have generated a description of how the auditory nerve codes complex sounds such as speech. This work suggests that certain minimal cues might have to be present at the level of the auditory nerve in order that adequate discrimination of specific speech signals can take place. The prospects for achieving a useful prosthesis in the near future will be evaluated in terms of what can be expected from current attempts to code the artificial stimulation properly.

Acoustic Stimulation↗