List Equivalency of PRESTO for the Evaluation of Speech Recognition.

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.

Influence of early linguistic experience on regional dialect categorization by an adult cochlear implant user: a case study.

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.

Some factors underlying individual differences in speech recognition on PRESTO: a first report.

BACKGROUND: Previous studies investigating speech recognition in adverse listening conditions have found extensive variability among individual listeners. However, little is currently known about the core underlying factors that influence speech recognition abilities. PURPOSE: To investigate sensory, perceptual, and neurocognitive differences between good and poor listeners on the Perceptually Robust English Sentence Test Open-set (PRESTO), a new high-variability sentence recognition test under adverse listening conditions. RESEARCH DESIGN: Participants who fell in the upper quartile (HiPRESTO listeners) or lower quartile (LoPRESTO listeners) on key word recognition on sentences from PRESTO in multitalker babble completed a battery of behavioral tasks and self-report questionnaires designed to investigate real-world hearing difficulties, indexical processing skills, and neurocognitive abilities. STUDY SAMPLE: Young, normal-hearing adults (N = 40) from the Indiana University community participated in the current study. DATA COLLECTION AND ANALYSIS: Participants' assessment of their own real-world hearing difficulties was measured with a self-report questionnaire on situational hearing and hearing health history. Indexical processing skills were assessed using a talker discrimination task, a gender discrimination task, and a forced-choice regional dialect categorization task. Neurocognitive abilities were measured with the Auditory Digit Span Forward (verbal short-term memory) and Digit Span Backward (verbal working memory) tests, the Stroop Color and Word Test (attention/inhibition), the WordFam word familiarity test (vocabulary size), the Behavioral Rating Inventory of Executive Function-Adult Version (BRIEF-A) self-report questionnaire on executive function, and two performance subtests of the Wechsler Abbreviated Scale of Intelligence (WASI) Performance Intelligence Quotient (IQ; nonverbal intelligence). Scores on self-report questionnaires and behavioral tasks were tallied and analyzed by listener group (HiPRESTO and LoPRESTO). RESULTS: The extreme groups did not differ overall on self-reported hearing difficulties in real-world listening environments. However, an item-by-item analysis of questions revealed that LoPRESTO listeners reported significantly greater difficulty understanding speakers in a public place. HiPRESTO listeners were significantly more accurate than LoPRESTO listeners at gender discrimination and regional dialect categorization, but they did not differ on talker discrimination accuracy or response time, or gender discrimination response time. HiPRESTO listeners also had longer forward and backward digit spans, higher word familiarity ratings on the WordFam test, and lower (better) scores for three individual items on the BRIEF-A questionnaire related to cognitive load. The two groups did not differ on the Stroop Color and Word Test or either of the WASI performance IQ subtests. CONCLUSIONS: HiPRESTO listeners and LoPRESTO listeners differed in indexical processing abilities, short-term and working memory capacity, vocabulary size, and some domains of executive functioning. These findings suggest that individual differences in the ability to encode and maintain highly detailed episodic information in speech may underlie the variability observed in speech recognition performance in adverse listening conditions using high-variability PRESTO sentences in multitalker babble.

Development, reliability, and validity of PRESTO: a new high-variability sentence recognition test.

BACKGROUND: There is a pressing need for new clinically feasible speech recognition tests that are theoretically motivated, sensitive to individual differences, and access the core perceptual and neurocognitive processes used in speech perception. PRESTO (Perceptually Robust English Sentence Test Open-set) is a new high-variability sentence test designed to reflect current theories of exemplar-based learning, attention, and perception, including lexical organization and automatic encoding of indexical attributes. Using sentences selected from the TIMIT (Texas Instruments/Massachusetts Institute of Technology) speech corpus, PRESTO was developed to include talker and dialect variability. The test consists of lists balanced for talker gender, keywords, frequency, and familiarity. PURPOSE: To investigate the performance, reliability, and validity of PRESTO. RESEARCH DESIGN: In Phase I, PRESTO sentences were presented in multitalker babble at four signal-to-noise ratios (SNRs) to obtain a distribution of performance. In Phase II, participants returned and were tested on new PRESTO sentences and on HINT (Hearing In Noise Test) sentences presented in multitalker babble. STUDY SAMPLE: Young, normal-hearing adults (N = 121) were recruited from the Indiana University community for Phase I. Participants who scored within the upper and lower quartiles of performance in Phase I were asked to return for Phase II (N = 40). DATA COLLECTION AND ANALYSIS: In both Phase I and Phase II, participants listened to sentences presented diotically through headphones while seated in enclosed carrels at the Speech Research Laboratory at Indiana University. They were instructed to type in the sentence that they heard using keyboards interfaced to a computer. Scoring for keywords was completed offline following data collection. Phase I data were analyzed by determining the distribution of performance on PRESTO at each SNR and at the average performance across all SNRs. PRESTO reliability was analyzed by a correlational analysis of participant performance at test (Phase I) and retest (Phase II). PRESTO validity was analyzed by a correlational analysis of participant performance on PRESTO and HINT sentences tested in Phase II, and by an analysis of variance of within-subject factors of sentence test and SNR, and a between-subjects factor of group, based on level of Phase I performance. RESULTS: A wide range of performance on PRESTO was observed; averaged across all SNRs, keyword accuracy ranged from 40.26 to 76.18% correct. PRESTO accuracy at retest (Phase II) was highly correlated with Phase I accuracy (r = 0.92, p < 0.001). PRESTO scores were also correlated with scores on HINT sentences (r = 0.52, p < 0.001). Phase II results showed an interaction between sentence test type and SNR [F(3, 114) = 121.36, p < 0.001], with better performance on HINT sentences at more favorable SNRs and better performance on PRESTO sentences at poorer SNRs. CONCLUSIONS: PRESTO demonstrated excellent test/retest reliability. Although a moderate correlation was observed between PRESTO and HINT sentences, a different pattern of results occurred with the two types of sentences depending on the level of the competition, suggesting the use of different processing strategies. Findings from this study demonstrate the importance of high-variability materials for assessing and understanding individual differences in speech perception.

Seeing facial motion affects auditory processing in noise.

Speech perception, especially in noise, may be maximized if the perceiver observes the naturally occurring visual-plus-auditory cues inherent in the production of spoken language. Evidence is conflicting, however, about which aspects of visual information mediate enhanced speech perception in noise. For this reason, we investigated the relative contributions of audibility and the type of visual cue in three experiments in young adults with normal hearing and vision. Relative to static visual cues, access to the talker's phonetic gestures in speech production, especially in noise, was associated with (a) faster response times and sensitivity for speech understanding in noise, and (b) shorter latencies and reduced amplitudes of auditory N1 event-related potentials. Dynamic chewing facial motion also decreased the N1 latency, but only meaningful linguistic motions reduced the N1 amplitude. The hypothesis that auditory-visual facilitation is distinct to properties of natural, dynamic speech gestures was partially supported.

Cisplatin ototoxicity affecting cochlear implant benefit.

OBJECTIVE: Report a case of loss of cochlear implant benefit after cisplatin therapy to treat osteosarcoma. Examine the implications for the loci of cisplatin-associated cochleotoxicity. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Single case study. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Cochlear implant programming levels. RESULTS: Increase in cochlear implant programming T- and C-levels after cisplatin therapy. CONCLUSION: Cisplatin therapy likely affects spiral ganglion cells. It seems that auditory cells other than outer hair cells in the organ of Corti are affected by cisplatin because the hearing sensitivity of this patient with nonfunctioning outer hair cells declined after receiving chemotherapy. Implications of these findings are discussed.

Bimodal stimulus presentation and expanded auditory bandwidth improve older adults' speech perception.

OBJECTIVE: A pair of experiments investigated the hypothesis that bimodal (auditory-visual) speech presentation and expanded auditory bandwidth would improve speech intelligibility and increase working memory performance for older adults by reducing the cognitive effort needed for speech perception. BACKGROUND: Although telephone communication is important for helping older adults maintain social engagement, age-related sensory and working memory limits may make telephone conversations difficult. METHOD: Older adults with either age-normal hearing or mild-to-moderate sensorineural hearing loss performed a running memory task. Participants heard word strings of unpredictable length and at the end of each string were required to repeat back the final three words.Words were presented monaurally in telephone bandwidth (300 Hz to 3300 Hz) or expanded bandwidth (50 Hz to 7500 Hz), in quiet (65 dBZ SPL), or in white noise (65 dBZ SPL with noise at 60 dBZ SPL), with or without a visual display of the talker. RESULTS: In quiet listening conditions, bimodal presentation increased the number of words correctly reported per trial but only for listeners with hearing loss and with high lipreading proficiency. Stimulus bandwidth did not affect performance. In noise, bimodal presentation and expanded bandwidth improved performance for all participant groups but did so by improving speech intelligibility, not by improving working memory. CONCLUSION: Expanded bandwidth and bimodal presentation can improve speech perceptibility in difficult listening conditions but may not always improve working memory performance. APPLICATION: Results can inform the design of telephone features to improve ease of communication for older adults.