PERCEPTION OF SPECTRO-TEMPORAL SPEECH INFORMATION

These closely related topics form the main line of investigation for the Laboratory. Frequency Resolution of Speech: In this work, the frequency resolution employed during the reception of everyday running speech is established. This is compared to traditional measures of frequency resolution (the CB) established using simple tone and noise stimuli. Temporal Speech Information: In this line of work, the ability of listeners to extract information from the temporal amplitude patterns of speech is examined. Various characteristics have been assessed, including the integration of patterns across various frequency separations, the ability to tolerate disruptions to exact across-frequency timing, and the influence of smoothing filter parameters. Across-Frequency Integration of Speech by Hearing-Impaired Listeners: In this work, the ability to integrate temporal speech patterns across various loci is examined in both normal-hearing (NH) and HI listeners. In sharp contrast to their intact ability to integrate simple tone and noise stimuli, an Across-Frequency Processing Deficitt has been observed in HI listeners, that appears specific to complex patterns of speech.

COCHLEAR IMPLANT SENSITIVITY TO CUES

In this line of work, a novel method has been employed to examine the availability of cues to cochlear implant (CI) users under natural listening conditions. Frequency and intensity cues are presented within synthesized speech syllables, and testing is performed in the free field of a calibrated loudspeaker. The results therefore reflect the everyday operation of the device, including the numerous interactions that exist between the various stages of CI processing -- from microphone to electrode array.

SPEECH AND AUDITORY RECEPTION IN MRI SCANNER NOISE

In this work, the influence of the intense noise accompanying MRI scanning on the reception of various auditory signals is assessed. The influence of this noise has been examined for both NH listeners and for those having a language deficit (aphasia) following stoke.

DETERMINANTS OF SENTENCE INTELLIGIBILITY

In this work, it is examined whether individual auditory sentences retain their particular level of difficulty relative to other sentences. It has been found that subjects generally agree on which sentences are easy or difficult to understand, and that sentences that are easy/difficult in one test condition are generally the same that are easy/difficult in another. However, this Sentence Effect is largely acoustic, rather than linguistic, as evidenced by the fact that it is strongest within particular types of signal distortion (e.g., filtering or the addition of noise).