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PubMed2005

Parental distress: the initial phase of hearing aid and cochlear implant fitting.

The results of previous cross-section studies suggest that childhood hearing impairment may lead to parental psychosocial stress. The present study investigated whether modifications in parental psychic state can be ascertained in connection with the child's treatment events and the child's hearing and speech status, in a prospective study design. Data were available on 116 fathers and mothers regarding the pre-cochlear implant examination or hearing aid fitting of their child. In the course of the child's treatment, parental quality of life improved from a low to a normal level. Among children who were at the stage of pre-examination for a cochlear implant, better hearing and speech capacity was linked to more severe impairment of the parental state. It is emphasized that the parents whose children showed comparatively good language development at the time of pre-examination for a cochlear implant were especially subjected to stress.

Child, Preschool↗

PubMed2000

Speech recognition by normal-hearing and cochlear implant listeners as a function of intensity resolution.

The importance of intensity resolution in terms of the number of intensity steps needed for speech recognition was assessed for normal-hearing and cochlear implant listeners. In experiment 1, the channel amplitudes extracted from a six-channel continuous interleaved sampling (CIS) processor were quantized into 2, 4, 8, 16, or 32 steps. Consonant recognition was assessed for five cochlear implant listeners, using the Med-El/CIS-link device, as a function of the number of steps in the electrical dynamic range. Results showed that eight steps within the dynamic range are sufficient for reaching asymptotic performance in consonant recognition. These results suggest that amplitude resolution is not a major factor in determining consonant identification. In experiment 2, the relationship between spectral resolution (number of channels) and intensity resolution (number of steps) in normal-hearing listeners was investigated. Speech was filtered through 4-20 frequency bands, synthesized as a linear combination of sine waves with amplitudes extracted from the envelopes of the bandpassed waveforms, and then quantized into 2-32 levels to produce stimuli with varying degrees of intensity resolution. Results showed that the number of steps needed to achieve asymptotic performance was a function of the number of channels and the speech material used. For vowels, asymptotic performance was obtained with four steps, while for consonants, eight steps were needed for most channel conditions, consistent with our findings in experiment 1. For sentences processed though 4 channels, 16 steps were needed to reach asymptotic performance, while for sentences processed through 16 channels, 4 steps were needed. The results with normal-hearing listeners on sentence recognition point to an inverse relationship between spectral resolution and intensity resolution. When spectral resolution is poor (i.e., a small number of channels is available) a relatively fine intensity resolution is needed to achieve high levels of understanding. Conversely, when the intensity resolution is poor, a high degree of spectral resolution is needed to achieve asymptotic performance. The results of this study, taken together with previous findings on the effect of reduced dynamic range, suggest that the performance of cochlear implant subjects is primarily limited by the small number (four to six) of channels received, and not by the small number of intensity steps or reduced dynamic range.

Acoustic Stimulation↗

PubMed2005

Latin American experience with the cochlear implant.

CONCLUSIONS: Complications such as migration, extrusion, skin inflammation by magnets and implant failures are mostly related to the type of device. Meticulous technique rather than specific surgical approaches seems to be the key in avoiding complications. The overall results of the Latin American experience are comparable with those reported recently in the literature. OBJECTIVE: To review the experience of Latin American groups with the cochlear implant. MATERIAL AND METHODS: A questionnaire was sent to all cochlear implant teams in Latin America. The main questions involved: (i) the type of device; (ii) the techniques used for placing and fixing the implant, surgical incision and closure; (iii) migration, exposure and failure of the implant; and (iv) skin erosion and infection. A total of 41 groups participated in the study. The total number of implanted patients involved was 3773, representing 92% of Latin American cases. RESULTS: Of the 3773 devices implanted, 5 were experimental prototypes and therefore 3768 were considered for calculations. The occurrence of complications was as follows. Migration: 13 cases (0.35%), mostly related to ceramic implants (p =0.016). Extrusion: 15 cases (0.4%), mostly related to large implants (p =0.0103). Implant failure secondary to trauma: 18 cases (0.48%) (9 in ceramic and 9 in soft implants). Spontaneous failure: 86 cases (2.28%), 74/1293 (5.72%) in ceramic and 11/2418 (0.45%) in soft implants (p = 0.0001). The most reliable implant was the Nucleus 24, with a failure rate of 0.3%. Skin inflammation by magnet: 35 cases (0.9%), mostly related to soft implants (p =0.0103). INFECTION: 26 cases (0.7%), with no significant relationship to device type.

Cochlear Implantation↗

PubMed2006

Combined electroacoustic stimulation in conventional candidates for cochlear implantation.

OBJECTIVE: To report on combined ipsilateral electrical and acoustic stimulation in a subset of conventional candidates for cochlear implantation where preoperative pure tone thresholds were </=60 dB HL for 250 and 500 Hz. METHODS: Subjects were 10 adults implanted with the Nucleus 24 Contour Advance perimodiolar electrode array. Soft surgical procedures were strictly observed: </=1.5-mm cochleostomy hole placed anterior and inferior to the round window, a Healon bubble placed over the opening to prevent entry of foreign bodies, and no suction applied. The electrode array was inserted 17 mm to the first marker rib using the recommended 'advance-off-stylet' technique. Pure tone hearing threshold levels were recorded pre-, and postoperatively at 1-2 and 6-12 months. Speech recognition was tested for cochlear implant (CI) alone and combined with ipsilateral hearing aid for 7 subjects who retained significant residual hearing in the implanted ear at 1-2 months after operation. RESULTS: There were 3/10 cases where 1-2 months after operation low-frequency responses were considered vibrotactile only (>85-110 dB HL, 250-500 Hz). In the remaining 7 cases, residual hearing was maintained up to at least 6 months after operation with minor changes. Insertion depth angles in these cases ranged from 285 to 420 degrees . For these subjects, the mean preoperative score for words presented at 65 dB SPL was 22%. Mean postoperative scores were 56% for CI alone, and 68% for CI plus ipsilateral hearing aid (p < 0.05, paired t). For sentences presented in multitalker babble noise at 5 dB SNR, mean scores were 61% CI alone, and 75% CI+IpsiHA (p < 0.01, paired t). CONCLUSIONS: Hearing was conserved during surgery and over time in 70% of conventional candidates implanted with the Nucleus 24 Contour Advance CI who had significant levels of preoperative low-frequency residual hearing (</=60 dB HL). These conventional candidates for CI also benefited from improved speech recognition in noise when using combined ipsilateral electrical and acoustic stimulation.

Acoustic Stimulation↗

PubMed2006

Longitudinal formant analysis after cochlear implantation in school-aged children.

INTRODUCTION: The purpose of this investigation was to describe the correlation between vocal and hearing development by longitudinal analysis of sound spectrograms, as a basic system for evaluating progress in vocal development. SUBJECTS AND METHODS: Two school-aged children with prelingual deafness were evaluated diachronically to assess speech perception and speech intelligibility after cochlear implantation. One child had non-syndromic hearing impairment without any known neurological deficit except for hearing loss, while the other had hearing impairment accompanied by mild mental retardation and attention deficit disorder. Their voices were recorded for monthly follow-up after cochlear implantation; these were used for formant analysis and compared with their mother's voice, and alteration of the formant data was also compared with monosyllable speech perception. RESULTS: Formant analysis demonstrated high concordance was observed between monosyllable speech perception and speech intelligibility. F1-F2 forms of the patients more closely resembled those of their mothers after 1 year's follow-up. The time point at which speech development altered was very similar in both cases although the final outcomes were different. CONCLUSION: Fair improvement of articulation after cochlear implant was demonstrated by the F1-F2 gram analysis. This procedure can be used for data sharing and cooperation between medical and educational specialists.

Child↗

PubMed2002

Electrical stimulation of the auditory nerve via cochlear implants in patients with auditory neuropathy.

Auditory neuropathy (AN) is a term used to describe an auditory disorder in which there is evidence of normal outer hair cell function (otoacoustic emissions and/or cochlear microphonics) and poor function of the auditory nerve (absent or highly distorted auditory brain stem response starting with wave I). Many of these patients have evidence of generalized peripheral nerve disease, leading to an assumption that the peripheral portion of the auditory nerve is the most likely site of lesion. A small group of these patients has received cochlear implants, and the majority of them achieve average to above-average performance. Although this outcome may seem incongruous with neural disease, average performance by patients with AN may be a result of the reintroduction of neural synchrony by electrical stimulation and/or the fact that most deaf patients have poor nerve survival. Although cochlear implants are promising for deaf patients with AN, more study of the disorder is needed.

Adult↗

PubMed1990

The prognostic value of round window electrical stimulation in cochlear implant patients.

The use of preoperative round window stimulation has been advocated for its possible predictive value in cochlear implant patients. We have attempted to correlate cause of deafness, preoperative radiologic study, and postoperative stimulability and performance with preoperative stimulation. Round window stimulation procedures consisted of measurements of electrical thresholds and comfort levels, gap detection, and temporal difference limen. Radiologic studies were performed using high-resolution computerized semi-axial and coronal tomography with 1.5-millimeter overlapping cuts. Patient performance was measured using a standard audiologic test battery. Sixteen postlingually, profoundly deaf adults who received the Nucleus multichannel cochlear implant were studied. All 16 patients who responded to preoperative stimulation had acceptable CT scans for the ear operated on and stimulated postoperatively with the prosthesis. The lowest level at which a patient could reliably detect a gap between two signals ranged from 10 to 150 milliseconds, which was not predictive. For the temporal difference limen task, the patients who could reliably identify the longer of two pulses when the difference was less than 100 milliseconds did achieve varying amounts of open-set speech discrimination postoperatively. In summary, results indicate that the preoperative psychoacoustic electrical stimulation test battery provides useful information in predicting postoperative performance.

Cochlea↗

PubMed1997

Electrode discrimination and speech recognition in postlingually deafened adult cochlear implant subjects.

This study investigated the relationship between electrode discrimination and speech recognition in 11 postlingually deafened adult cochlear implant subjects who were implanted with the Nucleus/Cochlear Corporation multichannel device. The discriminability of each electrode included in a subject's clinical map was measured using adaptive and fixed-level discrimination tasks. Considerable variability in electrode discriminability was observed across subjects. Two subjects could discriminate all electrodes, and discrimination performance by the remaining nine subjects varied from near perfect to very poor. In these nine subjects, the results obtained from the discrimination tasks were used to create a map that contained only discriminable electrodes, and subjects' performance on speech recognition tasks using this experimental map was measured. Four different speech recognition tests were administered: a nine-choice closed-set medial vowel recognition task, a 14-choice closed-set medial consonant recognition task, the NU6 Monosyllabic Words Test [T. W. Tillman and T. Carhart, Tech. Rep. No. SAM-TR-66-55, USAF School of Aerospace Medicine, Brooks Air Force Base, Texas (1966)] scored for both words and phonemes correct, and the Central Institute for the Deaf (CID) Everyday Sentences test [H. Davis and S. R. Silverman, Hearing and Deafness (Holt, Rinehart, and Winston, New York, 1978)]. Seven of the nine subjects tested with the experimental map showed significant improvement on at least one speech recognition measure, even though the experimental map contained fewer electrodes than the original map. Three subjects' scores improved significantly on the CID Everyday Sentences test, three subjects' scores improved significantly on the NU6 Monosyllabic Words test, and five subjects' scores improved significantly on the NU6 Monosyllabic Words test scored for phonemes correct. None of the subjects' scores improved significantly on either the vowel or consonant tests. No significant correlation was observed between electrode discrimination ability and speech recognition scores or between electrode discrimination ability and improvement in speech recognition scores when programmed with the experimental map. The results of this study suggest that electrode discrimination tasks may be used to improve speech recognition of some cochlear implant subjects, and that each electrode site does not necessarily provide perceptually distinct information.

Adult↗

PubMed1987

The UCSF/Storz cochlear implant: patient performance.

Clinical trials of the UCSF/Storz multichannel cochlear implant were initiated in February 1985, under the sponsorship of Storz Instrument Company. This four-channel device uses simultaneous bipolar, radial stimulation and a vocoder-based speech processing scheme. To date, eighteen patients have been implanted with the UCSF/Storz implant at four clinical centers in the United States. Based on data accumulated through June 1986, fifteen of these patients had received their speech processors and were given at least an initial evaluation of their performance with the implant. Results have been very encouraging, with all but two of these patients obtaining some degree of open-set auditory-only speech recognition. Most patients have demonstrated improvement over time without extensive rehabilitative intervention and all patients have attained an enhancement in lip-reading ability, as measured with a tracking procedure. According to a self-rated performance scale, all patients have experienced improvement in general communicative function since receiving the implant.

Adult↗

PubMed1997

Are spiral ganglion cell numbers important for speech perception with a cochlear implant?

OBJECTIVE: Studies of factors affecting the survival of ganglion cells in adults with profound hearing loss and speech perception in cochlear implant users are reviewed in order to assess the hypothesis that ganglion cell numbers have a strong influence on the level of speech perception achieved by adult implant users. DATA SOURCES: All histopathologic data have been published as tables or figures in refereed papers. Speech perception data were collected from published papers and directly from clinics and from Cochlear Corporation's database. STUDY SELECTION: Histopathologic studies with reasonably large groups of patients were selected. The speech perception data were from the largest study available. DATA EXTRACTION: All data used have been published in refereed journals of high repute. No other assessment of quality or validity was available to the author. DATA SYNTHESIS: Trends in the speech perception data were compared qualitatively and quantitatively with trends in the histopathologic ganglion cell data. CONCLUSIONS: The analysis found no strong evidence that spiral ganglion cell numbers have a strong influence on the level of speech perception achieved with a cochlear implant. A possible explanation for this surprising result may be that the minimum number of cells required for good speech perception is quite low, and the majority of implant users exceed this minimum requirement.

Adolescent↗

PubMed1997

Temporal representations with cochlear implants.

OBJECTIVE: To record and characterize intracochlear evoked potentials (EPs) for a variety of electrical stimuli in studies with cochlear implant patients. METHODS: Recordings were made with patients having direct percutaneous access to their implanted electrodes. Intracochlear voltages were recorded via unstimulated electrodes. The stimuli included trains of identical pulses, with pulse rates ranging from 100 to 4065/s, and a modulated pulse train produced by a single-channel speech processor, with the pulse rate of 824/s. RESULTS: Magnitudes of EPs for each pulse in trains of identical pulses were uniform for pulse rates below about 200/s. For rates between about 400 and 1000/s, an alternating pattern of EP magnitudes was observed, with relatively large EPs following the odd-numbered pulses. For rates between about 1000 and 3000/s, more complex patterns were observed. After the first millisecond of each train at even higher rates, uniform EPs again were observed across pulses, although the absolute magnitude of the EPs was much lower than that observed for low rates of stimulation. The approximate rates corresponding to boundaries between these different regions varied among subjects and among electrodes within subjects. EP magnitudes for the modulated pulse train reflected the gross periodicity of the modulation waveform but did not reflect temporal details within the periods. CONCLUSIONS: Population responses of the human auditory nerve, as indicated by EP magnitudes, reflect the amplitudes of electrical pulses for pulse rates below about 200/s and above about 3000/s. Use of intermediate rates may introduce distortions in the transmission of stimulus information with cochlear implants.

Cochlear Implantation↗

PubMed2003

Spatial spread of neural excitation in cochlear implant recipients: comparison of improved ECAP method and psychophysical forward masking.

This study introduces and evaluates a method for measurement of the longitudinal spread of electrically evoked neural excitation in the cochlea, using the Neural Response Telemetry system (NRT) available with the Nucleus((R)) 24 cochlear implant system. The recently released version of the NRT software (version 3.0) enables presentation of the 'masker' and 'probe' on different electrodes. In the present method the probe position was fixed, while the masker position was varied across the electrode array. The amplitude of the response to the partially masked probe provides a measure of the amount of masking, which is dependent on the extent of overlap of the excitation regions of the masker and probe. These measurements were performed in seven subjects implanted with the Nucleus 24 cochlear implant system (four with straight and three with Contour electrode arrays), for basal, middle and apical probe electrodes. Similar excitation profiles were obtained using either the standard NRT subtraction paradigm or an alternative 'Miller' method. The excitation profiles were compared with those obtained from psychophysical forward masking and good agreement was found. The widths of electrically evoked compound action potential (ECAP) and forward masking profiles did not differ significantly. Whereas the width of the ECAP measure was significantly correlated with both the maximum comfortable level and the distance of the electrode band from the modiolus, the width of the forward masking profile was not.

Adult↗

PubMed1984

Tone decay in subjects with the single-channel cochlear implant.

Tone decay was studied in a group of 17 profoundly deaf adults who have a single-channel cochlear implant. With direct electrical input through the subject's induction coil system, tone decay was evaluated at 125, 250, 500, 2 000, 4 000, and 16 000 Hz. Results indicated that as the intensity of electrical stimulation increased, the ability to perceive a continuous signal also increased for the majority of the subjects. All but 3 of the subjects were able to perceive the electrical signal at suprathresholds for 2 min. The 3 subjects who exhibited tone decay differed from the rest of the sample in several ways: (1) they became deaf at an earlier age; (2) they had more years of profound deafness, and (3) they had fewer years of cochlear implant and hearing aid use.

Adult↗

PubMed2006

[Cochlear implantation in deaf adults: effect on quality of life].

INTRODUCTION: Our aim was to assess the effect of cochlear implant (CI) surgery on the mental quality of life in totally deaf adults using a generic type of questionnaire. MATERIALS AND METHODS: The survey comprised 40 adult CI users who answered a standard and a retrospective version of the Short Form 36 questionnaire (SF-36). In the questionnaires, specific questions focused on four dimensions of the mental quality of life: vitality, social functioning, and emotional and mental health. RESULTS: Due to qualitative and quantitative deficiencies, the emotional scale was omitted. A statistically significant improvement in the quality of life (p<05) was demonstrated in the three remaining subscales between pre-implant and post-implant scores. The greatest improvement was observed in the social functioning subscale. Pre-implant mean scores on all three subscales of the SF-36 were markedly below the mean scores of the equivalent subscales of the Danish population, whereas the post-implant mean scores in two out of three cases were above the mean scores of the Danish population. DISCUSSION: CI was shown to have a statistically significant positive impact on the quality of life of adult deaf patients. This is in accordance with other published studies.

Adult↗

PubMed1994

[Test results in European children with a Nucleus Mini System 22 cochlear implant].

Over 600 European children have been implanted with Nucleus Mini System 22 Cochlear Implant since 1985. As well as its proven safety und effectiveness it has become increasingly important to monitor the benefit provided postoperatively at regular intervals. The results from 144 European children randomly selected suggest that postlingually deafened children show rapid improvements in performance whilst children deafened before acquisition of speech and language progress at slower but a continuous rate in the first years of experience.

Child↗

PubMed1991

Cochlear implant histopathology.

Twenty-two temporal bones and one brain stem from 13 cochlear implant patients were examined histologically. Sixteen temporal bones had undergone one or more implant procedure. Results of analysis suggested that the ganglion cells were the responding elements to the implant and that useful auditory sensation could result from as few as 10 percent of the normal number of ganglion cells. All implanted bones exhibited varying amounts of fibrosis (some ossified) in the basal turn of the cochlea and beyond in some cases. Usually there was damage to the surviving elements of the organ of Corti and the dendrites throughout the extent of the electrode insertion. However, the ganglion cell population was not affected. Prolonged electrical stimulation (up to 14 years) did not affect ganglion cell survival in three cases, and had no effect on the cochlear nerves in two cases or on cochlear nuclei in one case.

Adult↗

PubMed1991

Effects of preoperative electrical stimulability and historical factors on performance with multichannel cochlear implant.

We investigated the relationship between results of preoperative transtympanic electrical promontory stimulation, duration of deafness, postoperative implanted psychophysical results, and postoperative speech and speech sound recognition as indicated by a battery of five tests. Our subjects were 10 patients implanted with the Cochlear Corporation multielectrode implant, 1 year postimplantation, with a minimum of 17 active electrodes programmed in the bipolar + 1 mode. The results indicated that preoperative promontory thresholds, the slope of the threshold function, and the duration of auditory deprivation are excellent predictors of postoperative speech and speech sound recognition in the auditory (processor alone) mode. These results have significant implications for patient selection and counseling.

Adolescent↗

PubMed1987

Relationships among selected measures of single-channel cochlear implant performance.

Relationships among a number of pre- and postimplant variables measured in 20 adults implanted with a single-channel cochlear implant were examined through a variety of univariate and multivariate statistical techniques. A large number of variables were analyzed to yield information on the relationships between pre- and postimplant performance, and among a variety of postimplant measures. Variables included: age; etiology and nature of deafness; type of implant worn; pre- and postimplant warble tone and speech detection thresholds; postimplant performance on the Monosyllable-Trochee-Spondee (MTS) and Environmental Sounds tests; postimplant electrical thresholds, uncomfortable loudness levels, and dynamic range; I.Q. scores; and postimplant discourse tracking performance with and without the implant. The difference score on the discourse tracking task, representing the auditory advantage over performance with lipreading alone, related substantively to a combination of variables including type of unit worn (Sigma versus Alpha), nature of deafness (progressive versus sudden), and etiology (meningitis versus nonmeningitis). Additionally, MTS and Environmental Sounds test scores were found to relate to one another and to etiology and nature of deafness.

Adolescent↗