In a sample of 80 persons in the 60–79-year age range, threshold shifts suggestive of collapsible car canals were found in over one third of the subjects. A very conservative interpretation of the data suggests that at least 10–16% of these 60–79-year old elderly subjects have collapsible, ear canals. Neither sex nor age was related significantly to prevalence. Results of this study indicate in testing elderly persons there are threshold inaccuracies, relating possibly to collapsible ear canals, which, if not taken into account, may cause unacceptably large errors in both clinical and research applications.

No abstract

Different sound processing strategies are used in the various cochlear implant designs. This report presents auditory data on 35 patients implanted at the University of Utah from April 1984 to April 1989. A multichannel monopolar electrode system is inserted intracochlearly. During daily use and auditory performance testing, four electrodes receive simultaneous input. The incoming acoustic signal is amplified and routed to the different electrodes through a band‐pass filter system. Mean pure‐tone performances were: 500 Hz−29.6 ± 9.4 dB; 1000 Hz−23.5 ± 13.2 dB; 2000 Hz−25.4 ± 9.6 dB; 4000 Hz−32.1 ± 11.5 dB; and 6000 Hz−42.2 ± 7.7 dB. Audio‐only CID sentence testing showed 51.4% of patients scoring better than 60% and 40% scoring better than 80%. The percutaneous pedestal is well tolerated; patients have had the systems in place for 13 and 15 years.

appearing loudness function. CVC words (MRT) were processed under three conditions: (a) only levels between Lr -25 dB and Lr -13 dB (L• is the average maximal rms levels of the test words' vowels) were compressed (LLC) with a compression ratio CR = 4:1; (b) only levels above L• -13 dB were compressed (HLC) with CR = 4:1; and (c) only levels above L• -25 dB were compressed with the average compression ratio between L• and L r -25 dB in conditions "a" and "b" equal to 1.7. All three conditions had attack and release times of 1.5 and 30 ms, respectively. The performance of nine sensori-neural hearing-impaired subjects did not significantly differ among the three conditions investigated; this confirms Lippmann's (1978) findings with the compression system restoring normal equal loudness contours. [Work supported by NIH NS 12946.] DD6. Speech perception for various time constants of amplitude compression. Igor V. N fib•lek, W.Modified rhyme test words and CVC nonsense syllables were processed without or with background pink noise through a wideband amplitude compressor set for a 2.5:1 compression ratio and various attack (Tn = 1 through 42 ms) and release (TR = 10 through 370 ms) times. These stimuli were presented to nine subjects with sensori-neural hearing impairment. The compression threshold was set 25 dB below the average maximal rms level of the vowels in the test words or CVC syllables. The compressed signal was amplified with individually adjusted frequency responses and delivered to the listeners via a circumaural earphone. The presentation of speech was always at the same, comfortable level for each individual listener. The signal compressed without noise was sometimes mixed with a masking pink noise at -10, -5, and 0 dB re speech. There were no significant differences in mean performances for different time constants, or between compressed and noncompressed stimuli. Performance slightly increased with compression, only when masking noise was added to the signal after processing (Ls -L N =< 5 dB) and the attack and release times were shorter than 3 and 90 ms, respectively. [Work supported by NIH NS 12946.]

No abstract