LINGUIST List 15.2084

Fri Jul 16 2004

Diss: Phonetics: Lowenstein: 'Artificial hearing...'

Editor for this issue: Takako Matsui <takolinguistlist.org>

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1. jhlowens, Artificial Hearing, Natural Speech...

Institution: University of Chicago
Program: Department of Linguistics
Dissertation Status: Completed
Degree Date: 2003

Author: Joanna Lowenstein

Dissertation Title: Artificial Hearing, Natural Speech: Cochlear
implants, speech production, and the expectations of a high-tech
society

Linguistic Field: Phonetics 

Dissertation Director 1: Karen Landahl
Dissertation Director 2: Bill Darden
Dissertation Director 3: Sean Fulop

Dissertation Abstract:

Modern society desires a technological solution for every problem,
even the physical; from human interest articles to science fiction
television series, technology is presented as a way to overcome the
frailties of the human body. Cochlear implants (CIs), electrode and
hearing-aid-sized computer prostheses for the inner ear in cases of
nerve deafness - even called "bionic ears" by one manufacturer - are
hailed as a cure for deafness. Several dramatic and documentary
presentations featuring cochlear implants have aired on
U.S. television in the past five years; though they generally present
accurate factual information about cochlear implants, they also
transmit footage of highly skilled CI users that can lead to
unrealistic expectations about the speech and hearing skills of
ordinary cochlear implantees.

Acoustic studies of the speech of one class of "ordinary" implantees,
postlingually deaf adults (who lost their hearing after they learned
to speak), were primarily conducted in the mid to late 1990s with less
technologically sophisticated analog cochlear implants. These studies
revealed that analog CIs provided a sufficient degree of auditory
feedback to affect vowel and consonant articulation and voice pitch,
generally resulting in more "normal" speech.

This study analyzes the speech of three postlingually deaf adults with
modern digital CIs (which provide a more sophisticated signal),
focusing on vowel formants and duration, voice onset time and syllable
duration, and fundamental frequency. The speech of one subject
generally changes in ways comparable to subjects in previous studies;
another subject exhibits a pattern of change and return, where speech
changes at one and three months after the implant was activated, but
returns to pre-implant articulations at six months. This pattern was
confirmed by results from a naive listener perceptual study. The third
subject exhibits change and return for some measures, and normative
changes for others.

The results from this study are discussed in light of previous
studies, for what they reveal about the role of auditory feedback in
speech production, and for how they compare to expectations induced by
televised dramas and documentaries.