Individual Variations in Effort: Assessing Pupillometry for the Hearing Impaired.

Assessing effort in speech comprehension for hearing-impaired (HI) listeners is important, as effortful processing of speech can limit their hearing rehabilitation. We examined the measure of pupil dilation in its capacity to accommodate the heterogeneity that is present within clinical populations by studying lexical access in users with sensorineural hearing loss, who perceive speech via cochlear implants (CIs). We compared the pupillary responses of 15 experienced CI users and 14 age-matched normal-hearing (NH) controls during auditory lexical decision.

Effects of electrode design and configuration on channel interactions.

A potential shortcoming of existing multichannel cochlear implants is electrical-field summation during simultaneous electrode stimulation. Electrical-field interactions can disrupt the stimulus waveform prior to neural activation. To test whether speech intelligibility can be degraded by electrical-field interaction, speech recognition performance and interaction were examined for three Clarion electrode arrays: the pre-curved, enhanced bipolar electrode array, the enhanced bipolar electrode with an electrode positioner, and the Hi-Focus electrode with a positioner.

Modulation detection interference in listeners with normal and impaired hearing.

Listeners were asked to detect amplitude modulation (AM) of a target (or signal) carrier that was presented in isolation or in the presence of an additional (masker) carrier. The signal was modulated at a rate of 10 Hz, and the masker was unmodulated or was modulated at a rate of 2, 10, or 40 Hz. Nine listeners had normal hearing, 4 had a bilateral hearing loss, and 4 had a unilateral hearing loss; those with a unilateral loss were tested in both ears.