Betty P-K Luk

The Chinese University of Hong Kong, Hong Kong, Hong Kong

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Publications (2)3.03 Total impact

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    ABSTRACT: This study aimed at developing a theoretically driven open-set speech recognition test for pediatric clinical population of cochlear implant and/or hearing aid users, with Cantonese Chinese as their first language, to track progress in speech recognition performance as an outcome measurement of their rehabilitation. Six monosyllabic and six disyllabic word lists were generated from the Cantonese CHILDES language database, constructed according to the Neighborhood Activation Model. There were three lexically "easy" and three lexically "hard" word lists in each sub-test, with 25 items in each list. Four pediatric cochlear implant users and 10 hearing aid users, with bilateral congenital severe to profound sensorineural hearing impairment and below the age of 10, participated in the study. Their performances on word recognition and phoneme recognition with the new test lists, as well as the inter-list equivalency, inter-rater reliability, and face validity of the new materials, were investigated. Word recognition was higher among disyllables than monosyllables. Lexically "easy" disyllabic words were better recognized than their "hard" counterparts and the monosyllables. No significant difference was noted among the three lists in each combination of syllable structure and lexical property. High inter-rater reliability, as well as high correlation between Cantonese LNT score and a receptive vocabulary test score, were revealed. These newly developed test lists provided reliable information on spoken word recognition of pediatric hearing prosthesis users with severe to profound hearing impairment. Inter-list equivalency and inter-rater reliability allowed monitoring of rehabilitation progress on such specific pediatric clinical population with this new test. (255).
    International Journal of Pediatric Otorhinolaryngology 08/2008; 72(7):1121-9. DOI:10.1016/j.ijporl.2008.03.025 · 1.19 Impact Factor
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    ABSTRACT: Accurate pitch perception on the basis of fundamental frequency patterns is essential for the processing of lexical tones in tonal languages such as Cantonese. Speech intelligibility in Cantonese-speaking CI recipients was compared using current signal processing strategies, which typically result in poor pitch perception, and a new strategy, known as the multi-channel envelope modulation (MEM) strategy, was designed to enhance temporal periodicity cues to the fundamental frequency. Performance of nine postlingually hearing-impaired adult cochlear implant users was measured twice using each strategy, initially after a four week trial, and again after two weeks of use with each strategy. Speech intelligibility in speech-spectrum shaped noise was measured using the Cantonese hearing in noise test. A fixed noise level of 65 dB A was used and the signal-to-noise ratios were fixed at either +10, +15, or +20 dB, depending on the baseline performance of individual subjects using the clinical processor. Self-reported benefit in 18 listening situations and overall preference for strategies were obtained at the end of these trial periods. Results showed poorer speech intelligibility with CIS while results obtained using ACE and MEM were comparable. Unfamiliar place coding might have contributed to poorer performance using CIS. Self-reported benefit across strategies did not differ in most listening situations. Participants preferred ACE for listening overall in daily situations, and a few preferred MEM in noise. Whilst the results did not demonstrate any advantages for speech recognition in noise when using MEM compared to ACE, no degradation in performance was observed. This implies that the form of processing employed by MEM retains similar segmental information to that provided by ACE and that potentially, future variations/optimizations of MEM may lead to some improvement in tone perception.
    International journal of audiology 07/2008; 47(6):337-47. DOI:10.1080/14992020802070788 · 1.84 Impact Factor