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A nonlinear frequency domain beamforming algorithm was evaluated as a noise reduction technique with eight cochlear implant patients, in a take‐home trial. The subjects wore the prototype device coupled to the Nucleus processor for 5–8 weeks. The subjects were tested both before and after the take‐home trial with a single noise source at 45 deg ipsilateral to the implant and with sentence type material. The results strongly favored the coupled device for noisy environments and indicated no additional benefits from a period of continued use. The subjective reports indicated that the two‐microphone coupled device had a more robust sound quality and is preferred in noisy environments to the stand alone device. Currently the performance measures are being extended to cover sentence scores in a diffuse noise field (four speakers at different locations) and the results for both noise jammer arrangements will be reported.

Temporary threshold shift (TTS) and acoustic reflex activity were observed in 20 normal hearing subjects under several different states of attention. The Zwislocki acoustic bridge (model 3) was used to monitor acoustic reflex activity. Compliance shifts (changes in relative compliance) were measured during exposure of the contralateral ear to a 1000 Hz narrow‐band noise presented at 105 dB SPL, and TTS was measured at 1000 Hz for the contralateral ear after approximately 412 min of noise exposure. These measures were taken under three different conditions or modes of attention as defined by task performance: reverie (no task performance, high auditory attention), intelligibility test, and high visual attention (visual‐motor task). Also, levels of attention, as operationally defined by levels of task performance, were considered. From the results of this and other investigations it was concluded that there is a so‐called central factor involved in acoustic reflex activity although task performance per se, ...

One might hypothesize that various subjects differ in the magnitude of changes in middle‐ear acoustic impedance resulting from noise stimulation. If these impedance changes are apparently different, this may indicate differential middle‐ear musculature strength among various subjects. Twenty young adults (10 females and 10 males) with normal hearing sensitivity served as subjects for the following experiment. Measures of acoustic impedance were obtained with the Zwislocki Acoustic Bridge (Grason‐Stadler, model 3) at 500 Hz under two conditions—no noise and 105 dB SPL of white noise in the contralateral ear. As might be expected, the noise resulted in easily detectable impedance changes, however, these changes were not significantly different between the subject groups. Acoustic reactance increased for both groups (females 330 Ω and males 350 Ω), while acoustic resistance decreased for both groups (females 88 Ω and males 90 Ω). Several subjects with the smallest and greatest impedance changes were later exposed to intense noise stimulation and auditory threshold shift was measured. The results of the findings regarding impedance change and temporary threshold shift will be discussed in the paper.