Relations among different measures of speech reception in subjects using a cochlear implant

Abstract

A comprehensive set of speech reception measures were obtained in a group of about 20 postlingually deafened adult users of the Ineraid multichannel cochlear implant. The measures included audio, visual, and audiovisual recognition of words embedded in two types of sentences (with differing degrees of difficulty) and audio-only recognition of isolated monosyllabic words, consonant identification (12 alternatives, /Ca/), and vowel identification (8 alternatives, /bVt/). For most implantees, the audiovisual gains in the sentence tests were very high. Quantitative relations among audio-only scores were assessed using power-law transformations suggested by Boothroyd and Nittrouer [J. Acoust. Soc. Am. 84, 101-114 (1988)] that can account for the benefit of sentence context (via a factor k) and the relation between word and phoneme recognition (via a factor j). Across the broad range of performance that existed among the subjects, substantial order was observed among measures of speech reception along the continuum from recognition of words in sentences, words in isolation, speech segments, and the retrieval of underlying phonetic features. Correlations exceeded 0.85 among direct and sentence-derived measures of isolated word recognition as well as among direct and word-derived measures of segmental recognition. Results from a variety of other studies involving presentation of limited auditory signals, single-channel and multichannel implants, and tactual systems revealed a similar pattern among word recognition, overall consonant identification performance, and consonantal feature recruitment. Finally, improving the reception of consonantal place cues was identified as key to producing the greatest potential gains in speech reception.

Comparison of vu-meter-based and rms-based calibration of speech levels

“…The peak vu-meter reading and rms value of each of those sentences was determined as described above. The presence of the four-talker babble on the QuickSIN sentences with 25 dB SNR was estimated to have a negligible effect (less than 0.02 dB) on the composite level, compared to the original recordings of Rabinowitz et al (1992).…”

“…Sixteen of the sentences recorded by Rabinowitz et al, (1992) were chosen for a second comparison of the vu and rms methods. The original recordings of IEEE sentences of Rabinowitz et al 1992 were made during their study of the contribution of visual cues to speech intelligibility.…”

“…The original recordings of IEEE sentences of Rabinowitz et al 1992 were made during their study of the contribution of visual cues to speech intelligibility. The audio recording of one of their female talkers was used, with permission, for the target speech in the "QuickSIN" speech-in-noise test later described by Killion et al (2004).…”

“…6.2.11 of the latter standard. The standard calibration method was employed in the classic NU-4 and NU-6 speech tests (Tillman et al 1963;Tillman and Carhart, 1966) and the more recent MIT female-talker recordings (Rabinowitz et al, 1992) used in the QuickSIN test (Killion et al, 2004).…”

Changes in voice-onset time in speakers with cochlear implants

“…FC was tested unaided using the NU-6 open set test and scored 0% and 2% correct on two administrations. Following activation of their implant processors, all subjects performed above chance on the NU-6 test; their final scores and the number of weeks that had elapsed between the activation of the implant processor and the test administration are shown in the last two rows of Rabinowitz et al, 1992). Briefly, each of twelve syllables (six plosives, four fricatives, and two nasals, followed by the vowel/a/) was uttered three times by one male speaker, digitized at a 10-kHz sampling rate, and presented over a loudspeaker in blocks of 72 trials in quasirandom sequences.…”