No abstract

The audibility curve of the chinchilla was measured on 76 animals using the auditory evoked response (AER). The standard behavioral measures of sensitivity and the AER measures are shown to agree within an average of 5 dB through the 0.25 to 8 kHz range. Furthermore, the AER is shown to reflect temporary and permanent partial losses of hearing due to noise exposure. It is concluded that the AER is a useful index of auditory sensitivity for the brief tones of the order of 20-msec duration.

No abstract

Data were collected on sound levels in public school shops, the policies regarding hearing protection and sound level monitoring in shops in a four-state area, and hearing levels of students with varying histories of noise exposure. Results of this study warrant three conclusions: (a) Sound levels in most school shops are sufficient to constitute a hazard to hearing. (b) A very small percentage of the shop programs surveyed furnish hearing protection or monitor sound levels. (c) Students involved in shop activities and/or use firearms are more apt to have high-frequency loss of hearing than those not participating in these activities. These findings are discussed in terms of implications for the involved students and the role of audiology as a profession in the public schools.

Threshold of audibility, loudness discomfort level (LDL), and acoustic reflex threshold (ART) were obtained by the tracking method on 51 cars of 34 children enrolled in a residential school for the deaf. Stimuli consisted of broad-band noise and pure-tone frequencies of 0.5, 1, 2, and 4 kHz. Stimulus duration was 500 msec, with approximately 30-msec rise time and approximately 50-msec fall time and 500-msec interstimulus interval. Relationships between loudness discomfort level (LDL) and acoustic reflex threshold (ART) fell into four distinct categories. That is, those subjects without loudness discomfort level and acoustic reflex threshold, those with LDL present and ART absent, those with ART present and LDL absent, and those with LDL and ART present. The results of this study will be discussed in terms of its relationship to the fitting of hearing aids on deaf children.