A holistic model for matching high-tech hearing aid features to elderly patients.

Successful hearing aid fittings using high-technology features for elderly patients require consideration of factors beyond results obtained from routine audiologic evaluations. A holistic hearing aid selection, fitting, and evaluation approach that considers patient characteristics from communication, physical, psychological, and social assessment domains is presented here along with a checklist and flowcharts for matching high-tech hearing aid features to older persons who are hearing aid candidates.

Clinical use of otoacoustic emissions in children with autism.

Transient-evoked otoacoustic emissions (TEOAEs) may offer an objective way of evaluating the peripheral auditory systems of difficult-to-test patients. Children with autism are often suspected of hearing loss, but frequently will not respond on traditional behavior auditory tests. The clinical feasibility of obtaining TEOAEs on children with autism was evaluated here. The use of TEOAEs for 6 children (12 ears) with autism is described here regarding the acquisition of data, the presence of emissions, and their amplitudes and reproducibility. Emissions were recorded for 9 of the 12 ears; the lack of emissions for the remaining 3 ears was due to lack of patient cooperation. The results suggest that TEOAEs may be a valuable part of the audiologic test battery for children with autistic behavior. The ease of obtaining emissions for these children with autism is discussed.

Effects of listeners' and talkers' linguistic backgrounds on W-22 test performance.

The effects of listeners' linguistic backgrounds on their word recognition performance were investigated. Equivalent 50-item CID W-22 word lists were recorded in English by three (Turkish, East Indian, and American) talkers and presented to 27 normal-hearing listeners representing each of these language groups. The listeners' word recognition results were compared within and across groups. A linguistic analysis of the subjects' errors indicated that only the Turkish listeners' word recognition scores were influenced by the talkers' or their own linguistic background. The Turkish listeners performed best with the Turkish talker, while the East Indian and American listeners' scores were not significantly affected by the talkers' linguistic backgrounds. Generally, the findings were not clinically significant and indicate that linguistic background should not be problematic in the clinical evaluation of these subjects' word recognition abilities. However, because some listeners' perceptions of some consonants and vowels showed language background effects, listeners having less experience with English may not perform as well as these subjects, and precautions should be taken in scoring non-native English listeners' responses to word recognition tests.

Real ear unaided responses in ears with tympanic membrane perforations.

This study evaluated 13 adult patients with tympanic membrane (TM) perforations in one or both ears. Probe microphone real ear unaided responses (REURs) for mean peak frequency and peak dB gain showed no substantial differences among patients, across ears with intact TMs, ears with TM perforations (regardless of size), or between measures taken before and after closure of the perforations. Inspection of individual differences in the patients' REURs, however, produced an interesting finding. The REURs of ears having small TM perforations did not differ from those with intact TMs, but the REURs for ears having larger perforations consistently revealed bimodal responses (two prominent peaks separated by a valley of at least 10 dB lower gain). Thus, size of the perforation affected the REURs.

Stimulus presentation level and speech perception through a single-channel cochlear implant.

This study evaluated the effects of stimulus presentation level on 12 adult 3M/House single-channel cochlear implant users' speech perception performance. Dynamic ranges and loudness growth functions were measured for meaningful speech, and performance-intensity functions were plotted for VCV and CVC nonsense stimuli to determine the presentation level(s) that produced maximum speech perception performance for each subject. Considerable variability was found in the subjects' dynamic ranges. Generally, loudness growth functions were steep for subjects having restricted dynamic ranges and more gradual for those having wide dynamic ranges. No single optimal presentation level was determined; instead, a range of levels produced maximum performance for each subject. Mean levels producing peak scores in equivalent dB SPL were 80 for VCVs and 72 for CVCs. Presentation levels producing optimal performance varied with type of speech stimulus.

Perceptual features for normal listeners' phoneme recognition in a reverberant lecture hall.

Johnson et al (1988) found that normal-hearing listeners' consonant recognition scores on a nonsense syllable test were significantly better when they were seated within versus beyond the critical distance of a typical lecture hall. The present study used a Sequential Information Analysis (SINFA) to document a priori perceptual features for Johnson et al's subjects' confusion errors to the initial and medial consonant portions of the stimuli. The features and the percent of information transmitted for them differed as a function of consonant position in the stimulus and whether the subjects were seated within or beyond the critical distance of the room. Generally, more information was transmitted within rather than beyond the critical distance for both initial and medial consonants. However, less information was transmitted for features for the medial than for the initial consonant position. Beyond the critical distance, high-frequency features (e.g., sibilant) were transmitted somewhat better than those based more on low-frequency energy (e.g., voicing). Place of articulation features were not transmitted as well for the initial as for the medial position and they suffered in both positions as distance increased. The effects of reverberation on the subjects' perception are discussed and compared to results of other studies.

A sindscal analysis of perceptual features for consonants produced by esophageal and tracheoesophageal talkers.

This study was concerned with the perceptual responses of normal-hearing listeners to consonants produced by esophageal and tracheoesophageal (TE) talkers and a single talker who was proficient in both of these alaryngeal speech modes. The listeners' perceptual responses were analyzed using Symmetric Individual Differences Scaling (SINDSCAL) to determine whether distinctive feature differences existed between these two methods of alaryngeal speech. This a posteriori analysis revealed that primary features retrieved for both speech methods included sibilant, affricate, dental, nasal, and sonorant. Although greater perceptual weightings were observed for TE speech, these productive/perceptual features were weighted similarly for both speech methods. Some secondary group-specific feature differences were also observed, but these features did not contribute substantially to the total amount of variance accounted for in the analysis. Thus, the SINDSCAL results showed that the groups did not use different feature systems. These results are discussed in regard to the unique alaryngeal speech production methods employed by esophageal and TE talkers and the relative limitations of the alaryngeal (esophageal) voicing source they use. General clinical implications of the data are discussed.

Performance of 3M/house cochlear implant users on tests of speech perception.

This report documents both closed- and open-set speech recognition performance for 18 adult experienced users of the 3M/House single-channel cochlear implant. The stimuli included tape-recorded, standard word and sentence recognition tests, an environmental-sound test, nonsense syllables, and sentences presented in auditory (implant-only), visual, and auditory-visual modes. All subjects were tested individually in a single session using their own cochlear implants, set to typical comfort use settings for running speech. Subjects' oral responses to the stimuli were transcribed by the experimenters and scored for percent correct. The results revealed considerable individual differences among the subjects and their performance on different tests. All subjects scored better than chance on the closed-set tests. Although they performed considerably poorer on the open-set tests, approximately half of these subjects demonstrated at least some open-set word recognition, a finding not previously reported in the literature for this device. All subjects performed better on the auditory-visual sentences than on either the auditory or visual conditions alone. These results contribute to the database on speech perception by cochlear implant users and show that open-set word recognition performance was somewhat better for these subjects using this implant than would have been predicted from the literature.

A young meningitically deaf child with a cochlear implant: a case study.

This study describes the development of the auditory, cognitive, linguistic, and social domains of a child deafened by meningitis at 20 months of age. He received a 3M/House cochlear implant at 27 months and is believed to be the youngest child to receive a cochlear implant. He was seen for intervention emphasizing audiometric conditioning and testing and language (speech and sign) stimulation for a period of 2:9 years (6 months pre-implant to 2:3 years post-implant). Videotapes of intervention; interviews with parents, teachers, and clinicians; test results; and medical and clinical reports were documented from pre-implant to two years post-implantation. The child regressed in all areas evaluated following his illness and subsequent deafness and cochlear implantation. At about one year after implantation, his social and cognitive skills began to improve. By two years after implantation (chronological age (CA) = 4:6), his abilities in all areas except auditory reception and speech had progressed to about the 4:0 age level. He communicates primarily through signs and seems to derive environmental sound and speech duration cues from the implant. Although it is difficult to separate the effects of the implant from maturational factors, he now willingly uses the implant simultaneously with his hearing aid on the non-implanted ear every day and seems to be functioning well with them. He responds inconsistently to his name when called, and consistently provides appropriate signed responses to questions. His imitative skills are improving; he can discriminate one- vs two-syllable words; and produces limited spontaneous speech. His cognitive and social abilities are at least age-appropriate and he signs 3- and 4-word combinations.

Audio-visual consonant recognition with the 3M/House cochlear implant.

Eight experienced 3M/House cochlear implant users' consonant recognition was evaluated with videotaped vowel-consonant vowel lists presented in auditory implant only (A), visual (V), and auditory-visual (AV) conditions. All subjects' scores were better than chance. Results revealed that the AV scores were significantly better than the V scores, which were better than the A scores. Sequential Information Analysis of the consonant errors revealed that different features were transmitted better in each condition. Sonorant and voicing features were transmitted well for the A condition, but features related to high-frequency and place cues were not. Place features were transmitted best in the V condition, but acoustic features were not. Both place and acoustic features were transmitted in the AV condition, but they were influenced most by visual cues.

Listeners' perceptions of consonants produced by esophageal and tracheoesophageal talkers.

The purpose of this study was to investigate the consonant intelligibility of 3 esophageal (E) and 3 tracheoesophageal (TE) talkers, and 1 dual-mode (DM) talker proficient in both E and TE speech modes. Audio recordings of 24 English consonants produced by each talker in a consonant-vowel-consonant-vowel-consonant (CVCVC) context were presented in the sound field to 15 normal-hearing, naïve, young adult listeners who phonetically transcribed their responses using an open-response paradigm. Listeners' pooled responses were converted to confusion matrices and analyzed for overall intelligibility, voicing and manner features, and consonant omissions. Ratings of speech proficiency were also obtained. Overall, the intelligibility of the TE talkers was significantly better than that of the E talkers. The DM talker was also more intelligible in the TE mode. Voiced consonants, plosives, fricatives, nasals, and liquid-glides were significantly more intelligible when produced by TE talkers. Affricates were also more intelligible for the DM talker in his TE mode. The different patterns of intelligibility observed between the E and TE talkers studied may be due to temporal speech distinctions evolving from the influence of dissimilar driving sources upon the vibratory characteristics of the pharyngoesophageal segment. Clinical implications are presented.

Perceptual features from normal-hearing and hearing-impaired children's errors on the NST.

Perceptual features for consonants contained in the nonsense syllable test, were evaluated from normal-hearing and hearing-impaired children's errors. One group consisted of 30 normal-hearing children between 6:0 and 12:8 years of age; the other group consisted of 7 hearing-impaired children between 8:0 and 14:8. The subjects provided verbal responses to list A of the nonsense syllable test which was presented at 25, 35, 45, and 55 dB sensation levels regarding each subject's speech reception threshold. Responses were phonetically transcribed, pooled across sensation levels, converted to confusion matrices, and submitted to Symmetric Individual Differences Scaling. Consonants were analyzed for pre- and inter-vocalic positions. Results revealed that features differed across subject groups and consonant positions. Salient features related to place of articulation, voicing, nasality, sonorancy, and sibilancy.

Auditory/visual speech perception by cochlear implant users and hearing aid wearers.

This study assessed the auditory/visual speech perception abilities of profoundly hearing-impaired subjects using the cochlear implant (CI) developed at the House Ear Institute with those of patients using traditional hearing aids (HA). Audio-video tape recordings of consonant-vowel-consonants (CVCs) consisting of: ten vowels in the context/mvm/, vowel-consonant-vowels (VCVs) consisting of twenty-four consonants in the context/ C /, and the CID Everyday Sentences were presented through auditory, visual, and auditory-visual modes. Subjects' verbal responses to the stimuli were transcribed by the experimenters. Statistical analyses of the data revealed significant differences for groups, stimuli, and conditions. Inspection of the subject's confusion matrices revealed that both groups used closed-bilabial, velar, dental, labial, and easy to see/hard to see features based on place of articulation in the visual mode. Salient features in the auditory mode for the CI group were duration, sonorancy, and some manner attributes, while the HA subjects used these features as well as sibilancy and voicing. Both groups integrated auditory and visual cues to improve scores in the auditory-visual condition. These findings have implications for future developments of auditory prostheses and auditory rehabilitation programs.

Statistical models for predicting Edgerton-Danhauer NST scores from pure-tone thresholds.

Pure-tone thresholds (PTTs) and phonemic-scored responses to the Edgerton and Danhauer (1979) Nonsense Syllable Test (NST) at 25, 35, 45, and 55 db SL re each S's SRT, were taken from 97 Ss of 4 earlier studies of Danhauer and colleagues. All studies had used the same stimuli and procedures. Among the 97 Ss were heterogeneous subpopulations of normally-hearing and sensorineural hearing-impaired Ss, aged 6-81 yrs. PTTs at octaves from .25-8 kc/s, singly and in various weighted combinations, were explored by step-wise multiple linear regression analyses for the best equation to predict an individual's NST score at each SL. Included were the two weighted PTT averages (over .5, 1, and 2 kc/s) proposed by Butts, Schoney and Ruth (Asha, 1984, 26, 64). PTT2 kc/s was the single most predictive datum. The most predictive equation at one NST SL was not necessarily the best at another SL. At each NST SL, the most predictive equation was always one or other of the equations of Butts et al, and at the higher levels the best equations incorporated in addition certain weighted PTTs at .5 and 1 kc/s. The results indicated that it is possible to predict a S's NST scores from PTTs with reasonable accuracy: from 86-91% of Ss' NST scores were predicted within +/- 10%. Further validation and refinement of these models on larger and different subject samples may result in equations predicting NST scores from PTTs with those difficult-to-test patients in whom speech recognition capacity cannot well be tested directly.

Vowel perception: experiments with a single-electrode cochlear implant.

We investigated vowel perception by 15 subjects using the single-electrode cochlear implant used at the House Ear Institute in Los Angeles. Subjects were postlingually deaf adults having histories of unsuccessful hearing aid use and a minimum of 6 to 12 months experience with the implant. Eleven American English vowels spoken by a male talker were tape recorded, digitized, analyzed, and controlled for the experiments. The stimuli were audio-recordings of both natural and loudness-matched vowels. Subjects rated the dissimilarity of both the naturally spoken and the loudness-matched vowels, and performed identification of the latter. Two normal-hearing subjects served as controls for the dissimilarity tasks. Multidimensional scaling, hierarchical clustering, and percent correct identification analyses were used to help determine the perceptual features used by the subjects in their judgments. Generally, the normal-hearing subjects took advantage of second formant (F2) frequency information. The cochlear-implant users relied primarily upon fundamental (F0) and first formant (F1) frequency information and demonstrated difficulty in vowel identification. No major differences were noted for the natural versus loudness-matched vowels. F2 information, requisite for accurate vowel recognition, did not correspond to any of the perceptual dimensions discerned in the results obtained from implant subjects.

A survey of speech and other auditory perception assessment materials used by cochlear implant centers.

A questionnaire assessing the various auditory perception materials used by cochlear implant centers in evaluating cochlear implant candidates and patients was developed, pilot tested, and mailed in August, 1985, to 135 cochlear implant centers. After a follow-up, there was a 45% return rate. The questionnaire sampled responses pertaining to the respondents' demographics, the types of assessment materials they used, and their opinions about speech and other auditory perception tests for evaluating cochlear implant patients. The data revealed that most centers use the same tests repeatedly for both pre- and post-implant assessments. Several factors relating to the tests and their administration were identified. Only 36% of the centers expressed satisfaction with the currently-used materials. The tests most frequently used were not necessarily considered to be the best or most appropriate for evaluating cochlear implants. Most respondents stated a need for the development of new test materials, and some suggestions were provided.

Use of the California Consonant Test in evaluating hearing aids.

The California Consonant Test (CCT) was used to evaluate different hearing aids for twelve listeners with mild to moderate sensorineural hearing losses. The CCT was mixed with white noise at signal-to-noise ratios (S/Ns) of +30 (quiet), +15, +5, and O dB and presented through hearing aids for each listener; the quiet condition was retested. Significant differences were found between mean test scores for the high and low S/Ns. Intralistener hearing aid differences were found most frequently in the quiet condition. Truncation errors were frequent for the low S/Ns. These findings indicate that the sensitivity of the CCT is decreased rather than increased by mixing it with noise. Critical differences of 5% or more between hearing aids were more frequent as the S/N improved; the greatest number of differences occurred for the quiet condition.

Effects of noise on NST and NU 6 stimuli.

This study determined how normal-hearing listeners' performance on a nonsense syllable test (NST) was affected by three noise competitors, and how these responses differed from those on the standard NU 6 meaningful word test. Twenty young adult listeners heard the stimuli via earphones and provided verbal responses to the NST and NU 6 items in competition with: white noise, multitalker noise, and white noise which was amplitude modulated by the multitalker noise, each at a 0 dB signal-to-noise ratio. Responses were scored on a whole-word (all-or-none) basis. Statistical analyses revealed that listeners' performance was always poorer on the NST than on the NU 6 regardless of competitor type; and that scores were better in the multitalker noise followed by white noise and amplitude modulated white noise. These data and those from earlier studies indicate that the NST is sufficiently difficult in quiet that it may not warrant testing in noise.

Part- vs full-list performance on the NST by normal-hearing and hearing-impaired adults.

Performance-Level functions were determined for part- and full-list Edgerton and Danhauer (1979) Nonsense Syllable Test (NST) mean scores of 15 normal-hearing (NH) and 15 mild-to-moderately hearing-impaired (HI) Ss. In the first part-list procedure S received 5 different items from the 25-item NST List A at each ascending SL (25, 35, 45, 55, and 65 db re: S's better-ear SRT), while in the second, full-list, procedure S received the full 25 items. As previous studies had shown, the NST could be used to distinguish the NH and HI groups. The P-L functions were not significantly different for the part- vs the full-list procedures except at the 35 and 55 db SLs in which the part-list scores tended to overestimate those from the full list for both groups, to a maximum difference in percent correct of about 7%. Clinical implications are presented.