Browsing by Author "Tamati, Terrin N."

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    Influence of early linguistic experience on regional dialect categorization by an adult cochlear implant user: a case study
    (Ovid Technologies (Wolters Kluwer) - Lippincott Williams & Wilkins, 2014-05) Tamati, Terrin N.; Gilbert, Jaimie L.; Pisoni, David B.; Department of Otolaryngology--Head & Neck Surgery, IU School of Medicine
    To investigate the ability of a cochlear implant user to categorize talkers by region of origin and examine the influence of prior linguistic experience on the perception of regional dialect variation. A postlingually deafened adult cochlear implant user from the Southern region of the United States completed a six-alternative forced-choice dialect categorization task. The cochlear implant user was most accurate at categorizing unfamiliar talkers from his own region and another familiar dialect region, and least accurate at categorizing talkers from less familiar regions. Although the dialect-specific information made available by a cochlear implant may be degraded compared with information available to normal-hearing listeners, this experienced cochlear implant user was able to reliably categorize unfamiliar talkers by region of origin. The participant made use of dialect-specific acoustic-phonetic information in the speech signal and previously stored knowledge of regional dialect differences from early exposure before implantation despite an early hearing loss.
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    List Equivalency of PRESTO for the Evaluation of Speech Recognition
    (American Academy of Audiology, 2015-06) Faulkner, Kathleen F.; Tamati, Terrin N.; Gilbert, Jaimie L.; Pisoni, David B.; Otolaryngology -- Head and Neck Surgery, School of Medicine
    BACKGROUND: There is a pressing clinical need for the development of ecologically valid and robust assessment measures of speech recognition. Perceptually Robust English Sentence Test Open-set (PRESTO) is a new high-variability sentence recognition test that is sensitive to individual differences and was designed for use with several different clinical populations. PRESTO differs from other sentence recognition tests because the target sentences differ in talker, gender, and regional dialect. Increasing interest in using PRESTO as a clinical test of spoken word recognition dictates the need to establish equivalence across test lists. PURPOSE: The purpose of this study was to establish list equivalency of PRESTO for clinical use. RESEARCH DESIGN: PRESTO sentence lists were presented to three groups of normal-hearing listeners in noise (multitalker babble [MTB] at 0 dB signal-to-noise ratio) or under eight-channel cochlear implant simulation (CI-Sim). STUDY SAMPLE: Ninety-one young native speakers of English who were undergraduate students from the Indiana University community participated in this study. DATA COLLECTION AND ANALYSIS: Participants completed a sentence recognition task using different PRESTO sentence lists. They listened to sentences presented over headphones and typed in the words they heard on a computer. Keyword scoring was completed offline. Equivalency for sentence lists was determined based on the list intelligibility (mean keyword accuracy for each list compared with all other lists) and listener consistency (the relation between mean keyword accuracy on each list for each listener). RESULTS: Based on measures of list equivalency and listener consistency, ten PRESTO lists were found to be equivalent in the MTB condition, nine lists were equivalent in the CI-Sim condition, and six PRESTO lists were equivalent in both conditions. CONCLUSIONS: PRESTO is a valuable addition to the clinical toolbox for assessing sentence recognition across different populations. Because the test condition influenced the overall intelligibility of lists, researchers and clinicians should take the presentation conditions into consideration when selecting the best PRESTO lists for their research or clinical protocols.
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    Non-native listeners' recognition of high-variability speech using PRESTO
    (Ingenta, 2014-10) Tamati, Terrin N.; Pisoni, David B.; Department of Otolaryngology -- Head & Neck Surgery, IU School of Medicine
    BACKGROUND: Natural variability in speech is a significant challenge to robust successful spoken word recognition. In everyday listening environments, listeners must quickly adapt and adjust to multiple sources of variability in both the signal and listening environments. High-variability speech may be particularly difficult to understand for non-native listeners, who have less experience with the second language (L2) phonological system and less detailed knowledge of sociolinguistic variation of the L2. PURPOSE: The purpose of this study was to investigate the effects of high-variability sentences on non-native speech recognition and to explore the underlying sources of individual differences in speech recognition abilities of non-native listeners. RESEARCH DESIGN: Participants completed two sentence recognition tasks involving high-variability and low-variability sentences. They also completed a battery of behavioral tasks and self-report questionnaires designed to assess their indexical processing skills, vocabulary knowledge, and several core neurocognitive abilities. STUDY SAMPLE: Native speakers of Mandarin (n = 25) living in the United States recruited from the Indiana University community participated in the current study. A native comparison group consisted of scores obtained from native speakers of English (n = 21) in the Indiana University community taken from an earlier study. DATA COLLECTION AND ANALYSIS: Speech recognition in high-variability listening conditions was assessed with a sentence recognition task using sentences from PRESTO (Perceptually Robust English Sentence Test Open-Set) mixed in 6-talker multitalker babble. Speech recognition in low-variability listening conditions was assessed using sentences from HINT (Hearing In Noise Test) mixed in 6-talker multitalker babble. Indexical processing skills were measured using a talker discrimination task, a gender discrimination task, and a forced-choice regional dialect categorization task. Vocabulary knowledge was assessed with the WordFam word familiarity test, and executive functioning was assessed with the BRIEF-A (Behavioral Rating Inventory of Executive Function - Adult Version) self-report questionnaire. Scores from the non-native listeners on behavioral tasks and self-report questionnaires were compared with scores obtained from native listeners tested in a previous study and were examined for individual differences. RESULTS: Non-native keyword recognition scores were significantly lower on PRESTO sentences than on HINT sentences. Non-native listeners' keyword recognition scores were also lower than native listeners' scores on both sentence recognition tasks. Differences in performance on the sentence recognition tasks between non-native and native listeners were larger on PRESTO than on HINT, although group differences varied by signal-to-noise ratio. The non-native and native groups also differed in the ability to categorize talkers by region of origin and in vocabulary knowledge. Individual non-native word recognition accuracy on PRESTO sentences in multitalker babble at more favorable signal-to-noise ratios was found to be related to several BRIEF-A subscales and composite scores. However, non-native performance on PRESTO was not related to regional dialect categorization, talker and gender discrimination, or vocabulary knowledge. CONCLUSIONS: High-variability sentences in multitalker babble were particularly challenging for non-native listeners. Difficulty under high-variability testing conditions was related to lack of experience with the L2, especially L2 sociolinguistic information, compared with native listeners. Individual differences among the non-native listeners were related to weaknesses in core neurocognitive abilities affecting behavioral control in everyday life.
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    The Perception of Regional Dialects and Foreign Accents by Cochlear Implant Users
    (American Speech-Language-Hearing Association, 2021-02-17) Tamati, Terrin N.; Pisoni, David B.; Moberly, Aaron C.; Otolaryngology -- Head and Neck Surgery, School of Medicine
    Purpose: This preliminary research examined (a) the perception of two common sources of indexical variability in speech—regional dialects and foreign accents, and (b) the relation between indexical processing and sentence recognition among prelingually deaf, long-term cochlear implant (CI) users and normal-hearing (NH) peers. Method: Forty-three prelingually deaf adolescent and adult CI users and 44 NH peers completed a regional dialect categorization task, which consisted of identifying the region of origin of an unfamiliar talker from six dialect regions of the United States. They also completed an intelligibility rating task, which consisted of rating the intelligibility of short sentences produced by native and nonnative (foreign-accented) speakers of American English on a scale from 1 (not intelligible at all) to 7 (very intelligible). Individual performance was compared to demographic factors and sentence recognition scores. Results: Both CI and NH groups demonstrated difficulty with regional dialect categorization, but NH listeners significantly outperformed the CI users. In the intelligibility rating task, both CI and NH listeners rated foreign-accented sentences as less intelligible than native sentences; however, CI users perceived smaller differences in intelligibility between native and foreign-accented sentences. Sensitivity to accent differences was related to sentence recognition accuracy in CI users. Conclusions: Prelingually deaf, long-term CI users are sensitive to accent variability in speech, but less so than NH peers. Additionally, individual differences in CI users' sensitivity to indexical variability was related to sentence recognition abilities, suggesting a common source of difficulty in the perception and encoding of fine acoustic–phonetic details in speech.