The objective and subjective evaluation of multichannel expansion in wide dynamic range compression hearing instruments.

Purpose: The effects of multichannel expansion on the objective and subjective evaluation of 20 listeners fitted binaurally with 4-channel, digital in-the-ear hearing instruments were investigated.

Method: Objective evaluations were conducted in quiet using the Connected Speech Test (CST) and in noise using the Hearing in Noise Test (HINT) at 40, 50, and 60 dB SPL. Subjective evaluations were conducted by having each participant (a) rate their satisfaction regarding the amount of noise reduction they perceived daily and (b) indicate which expansion condition they preferred overall after a 2-week trial.

SII and fit-to-target analysis of compression system performance as a function of number of compression channels.

This work was undertaken to answer the question, 'How does the speech audibility/fit-to-gain-target provided by compression change with number of channels?' For each of 957 audiograms and a given number of compression channels, the channel crossover frequencies were set either to maximize the SII (speech intelligibility index) for low- and high-level speech spectra, or to optimize the fit-to-gain targets from the Cambridge method for loudness equalization (CAMEQ). The audiograms comprised all common configurations, and losses ranged from mild to severe. Use of these computational procedures allowed the predicted, channel-number-based performance to be determined separately from the effects of other compression parameters.

The subjective evaluation of the expansion time constant in single-channel wide dynamic range compression hearing instruments.

The present study investigated the subjective evaluation of expansion time constants in single-channel wide dynamic range compression (WDRC) hearing instruments. Thirty participants utilized binaural WDRC hearing instruments for a two-week trial. Subjective evaluations were conducted by having each participant rate their satisfaction with the expansion time constant on a daily basis and by having each participant indicate their preferred expansion time constant following the completion of the two-week trial.

The effects of expansion time constants on the objective performance of hearing instrument users.

The present study investigated the effects of expansion time constants on the objective performance of 20 hearing instrument users fitted binaurally with digital in-the-ear products. Objective performance was evaluated in quiet using the Connected Speech Test and in noise using the Hearing in Noise Test. Results indicated that objective performance in quiet and in noise decreased as the expansion time constant increased.

The effects of high presentation levels on consonant feature transmission.

The effect of high speech presentation levels on consonant recognition and feature transmission was assessed in eight participants with normal hearing. Consonant recognition in noise (0 dB signal-to-noise ratio) was measured at five overall speech levels ranging from 65 to 100 dB SPL. Consistent with the work of others, overall percent correct performance decreased as the presentation level of speech increased [e.

The effects of expansion on the objective and subjective performance of hearing instrument users.

The present study investigated the effects of expansion on the objective and subjective performance of 20 hearing instrument users fitted binaurally with digital ITE products. Objective performance was evaluated in quiet using the Connected Speech Test and in noise using the Hearing in Noise Test. Subjective performance was evaluated in two ways: (a) by having each participant rate their satisfaction regarding the amount of noise reduction they perceived in each expansion condition on a daily basis and (b) by having each participant indicate which expansion condition they preferred following the completion of a two-week trial.