Management of hearing loss in infants: the UTD/Callier Center position statement.

As infants are being identified earlier and earlier by universal newborn hearing screening programs, there is a need to establish principles for professionals involved in habilitative processes. Recently, a panel of experts was convened for a 2-day conference entitled "Habilitative Issues for Infants with Hearing Loss," the Bruton Conference on Audiology/Communication Sciences, UTD/Callier Center for Communication Disorders. The purpose of this document was to summarize the panel's discussions on habilitative principles, state-of-the-art practices, and future needs for infants with hearing loss.

Preoperative functional assessment of auditory cortex in adult cochlear implant users.

OBJECTIVES: To explore functional neuroanatomical responses to auditory stimulation before and after implantation. STUDY DESIGN: A prospective study of three cochlear implant candidates (pure-tone averages of 90 dB HL or greater bilaterally and hearing in noise test [HINT] performances of <40%) in which regional cerebral blood flow (rCBF) was assessed using single photon emission computed tomography (SPECT). METHODS: Candidates watched a 15-minute videotaped story under four conditions: audio presented monaurally in the right and left ears (aided), audio presented binaurally (aided), and visual-only presentation of the story. Five minutes into each story, 20 to 25 mCi of technetium 99m (99mTc) hexamethyl-propyleneamine-oxime (HMPAO) (Ceratec; Nycomed Amersham, Princeton, NJ, U.SA) was injected over a 30-second period to ensure that subjects were unaware of tracer administration. Subjects were scanned for 20 minutes using a PRISM 3000 gamma camera (Picker International, Cleveland, OH, U.S.A.). Data were normalized and co-registered, and subtraction images were compiled. Subtraction images contrasted activation patterns generated under the visual-only control condition to the auditory activation states acquired monaurally and binaurally. RESULTS: Right and left ear monaural stimulation in normal hearing subjects resulted in significant bilateral activation of Brodmann areas 41, 42, 21, 22, and 38. Although substantial intersubject response variability was noted, subjects generally failed to bilaterally activate these areas under monaural hearing aid presentations; however, bilateral activation of areas 41 and 22 was noted under binaural presentations. CONCLUSIONS: Despite relatively similar hearing losses in each ear, significant differences in preoperative auditory cortex activation were observed between ears. These data suggest that functional brain imaging provides a useful tool for exploring the responsiveness of the auditory cortex in cochlear implant candidates.

Speech-perception performance in prelingually deafened French children using the nucleus multichannel cochlear implant.

PURPOSE: The speech-perception abilities of 36 French children, whose onset of deafness occurred before 2 years of age, was longitudinally examined after they received a Nucleus multichannel cochlear implant. METHODS: Speech perception was assessed in four areas: phoneme detection, closed-set word and sentence recognition; and modified open-set recognition. RESULTS: All children achieved phoneme detection by 3 months after implantation. Closed-set word and sentence recognition appeared initially less accurate in children with congenital deafness than in the prelingually deafened children; however, these differences disappeared by 18 months after implantation. Some modified open-set recognition was evident by 12 months after implantation and continued to improve 3 years after implantation. CONCLUSIONS: Data demonstrate significant improvements in speech perception with implant experience: 15 (60%) of 25 of the children identified sentences in closed sets, 22 (88%) of 25 identified words in closed sets after 12 months' experience, and 13 (81%) of 16 demonstrated open-set recognition after 24 months of implant use.

A clinical report on speech production of cochlear implant users.

OBJECTIVE: The aim was to assess articulation and speech intelligibility over time in a group of cochlear implant users implanted at 8 yr or over. The hypothesis was that the postoperative speech production performance would be greater than the preoperative performance. DESIGN: A test of intelligibility using sentences and an articulation test measuring non-imitative elicited speech were administered to 11 and 10 subjects, respectively, who were implanted with the 22-electrode cochlear implant. Nine subjects received both tests. Age at implantation ranged from 8 yr to 20 yr and implant use ranged from 1 yr to 4 yr 5 mo. RESULTS: For both the intelligibility and articulation tests roughly half of the subjects showed significant improvements over time and group mean postoperative performance significantly exceeded preoperative performance. Improvements occurred for front, middle, and back consonants; for stops, fricatives, and glides and for voiceless and voiced consonants. CONCLUSIONS: Despite being deprived of acoustic speech information for many childhood years, roughly half of the patients assessed showed significant gains in speech intelligibility and articulation postimplantation. The lack of a control group of non-implanted patients means that we cannot separate out the influence of the implant on speech production from other influences such as training and tactile-kinaesthetic feedback.

Articulation accuracy of children using an electrotactile speech processor.

OBJECTIVE: Use of wearable tactile speech perception devices is suggested to help overcome the difficulties in speech production resulting from severe and profound hearing impairment in children. This suggestion is based on the assumption that subjects can use tactile input in isolation, or in combination with information from residual aided hearing, to monitor and modify their speech. The present study evaluated the benefits to articulation provided through use of a multichannel electrotactile device ("Tickle Talker"). DESIGN: Six profoundly hearing-impaired children were videotaped speaking with the Tickle Talker on and with the Tickle Talker off during conversations with their audiologist. Five of the subjects also wore their binaural hearing aids during all recorded conversations. The number of vowels, consonants, and overall phonemes correctly articulated by each child in the two conditions were compared. RESULTS: One subject improved articulation of initial consonants and initial phonemes; one subject improved articulation of total vowels, total consonants, initial consonants, total phonemes, and initial phonemes; and a third subject improved articulation of total vowels and medial phonemes. CONCLUSIONS: Use of on-line tactile feedback from the Tickle Talker may benefit the articulation accuracy of some children, and the device may therefore be suitable to use with children who have not responded to more traditional speech training techniques.

Effects of a Nucleus multichannel cochlear implant upon speech production in children.

The purpose of this report is to describe the speech production of children participating in the Food and Drug Administration's approved clinical trials for the Nucleus multichannel cochlear implant. A significant increase in the ability to imitate nonsegmental aspects of speech was noted after using the implant; however, nonsegmental performance did not appear to increase significantly between 12, 18, or 24 mo postimplantation. Significant increases occurred in imitative and elicited segmental performance after implantation at all measurement points. Speech intelligibility was significantly higher postimplant than preimplant; however, no significant change in mean length of utterance was observed. Data from these studies suggest a multichannel cochlear implant may provide information that is useful for assisting in the development or refinement of some aspects of spoken communication.

Effect of different types of auditory stimulation on vowel formant frequencies in multichannel cochlear implant users.

Two experiments investigating the effects of auditory stimulation delivered via a Nucleus multichannel cochlear implant upon vowel production in adventitiously deafened adult speakers are reported. The first experiment contrasts vowel formant frequencies produced without auditory stimulation (implant processor OFF) to those produced with auditory stimulation (processor ON). Significant shifts in second formant frequencies were observed for intermediate vowels produced without auditory stimulation; however, no significant shifts were observed for the point vowels. Higher first formant frequencies occurred in five of eight vowels when the processor was turned ON versus OFF. A second experiment contrasted productions of the word "head" produced with a FULL map, OFF condition, and a SINGLE channel condition that restricted the amount of auditory information received by the subjects. This experiment revealed significant shifts in second formant frequencies between FULL map utterances and the other conditions. No significant differences in second formant frequencies were observed between SINGLE channel and OFF conditions. These data suggest auditory feedback information may be used to adjust the articulation of some speech sounds.

Consonant production in children receiving a multichannel cochlear implant.

Consonant production was investigated in 29 children participating in the federal Food and Drug Administration's clinical trials of the Nucleus WSP-III cochlear implant. Speech samples were collected preimplant and 1 year postimplant. A significantly greater number of children produced stop, nasal, fricative, and glide consonants postimplant. Voiced stop consonants were used by more children than the voiceless cognates; however, voiceless fricatives were used more than voiced fricatives. Visible places of articulation were used more frequently than less visible places of articulation. Comparisons to Smith's data (J Speech Hear Res 1975;18:795-811) revealed qualitative similarities but postimplant, quantitative differences were observed. Post hoc analyses of the data revealed some sounds were influenced more by an implant than other sounds and suggest the role of an implant upon spontaneous speech is complex.

Speech production performance in children with multichannel cochlear implants.

The purpose of this study is to report on five speech production protocols collected as part of the Food and Drug Administration's Clinical Trials for the Nucleus multichannel cochlear implant. Sixty-one children, ranging in age from 2.4 years to 17.8 years, participated. Speech measures included nonsegmental and segmental portions of the Phonetic Level Speech Evaluation, the Phonologic Level Speech Evaluation, speech intelligibility, and an experimental condition examining speech produced with the device turned on versus off. Seventy-seven percent of the children improved on at least one-third of the speech production measures. Significant improvements in the ability to imitate prosodic characteristics were observed for 31.1 percent of the children. Improvements in the ability to imitate speech sounds were found for 66.7 percent of the children. Examination of phonologic skills acquired during spontaneous speaking improved for 55.6 percent of the children. Speech intelligibility improved in 62.9 percent of the children after implantation. More centralized second formant frequencies were observed in vowels produced with the speech processor turned off, as opposed to on, in all 13 of the children tested on this protocol. Data from this study suggest a multichannel cochlear implant may assist many children in developing better speech.

Shadowed and simple reaction times in stutterers and nonstutterers.

Stutterers may experience difficulties in preparing and executing responses. This study investigated these possibilities as well as the possibility that stutterers may experience difficulty in the selection of responses. Two reaction-time tasks were investigated: a shadowing response in which speakers exactly repeated vowel sequences they heard, and a simple response in which speakers said [u] regardless of the identity of the vowel stimulus. Two groups of six adult male subjects, stutterers and nonstutterers, participated. Stimuli consisted of vowel-vowel "syllables" whose initial duration (response foreperiod) was randomly varied from 500 to 1500 ms. Electromyographic (EMG) and acoustic measures were obtained for each response condition. The EMG response latencies, acoustic response latencies, and execution times (EMG latency less the acoustic response latency) were examined for the fluent responses. Results indicated stutterers were, on average, 34 ms slower on acoustic responses than nonstutterers regardless of the task or foreperiod. However, stutterers' and nonstutterers' EMG latencies were not significantly different. Further analysis indicated that the overall slower acoustic responses of stutterers were accounted for almost entirely by longer execution times. Stutterers' difficulties thus appear to lie after response initiation suggesting they have problems in coordination of gestures during execution of fluent responses.

Acoustic analyses of speech changes after maxillectomy and prosthodontic management.

Acoustic speech patterns of five maxillofacial surgery patients were examined before and after prosthodontic reconstruction to determine the effectiveness of a maxillary prosthesis for eliminating (or reducing) nasal resonances. Vowel formant frequencies were measured for /i/ (as in seep) and /u/ (as in in soup). Within-subject, across test-session comparisons were made by using analysis of variance techniques. Prosthodontic restoration significantly reduced the nasal resonances in all patients by either (1) completely eliminating the resonances, (2) reducing the amplitude of the resonances, or (3) changing the frequency of the resonances to more nearby regions of the vowels.