Newborn hearing screening and cochlear implantation: impact on spoken language development.

OBJECTIVES: This study retrospectively evaluates the effect of newborn hearing screening on age at diagnosis, age at cochlear implantation and spoken language development in severely hearing-impaired children. METHODS: Age at diagnosis, age at cochlear implantation and language development were evaluated in a group of early screened (n = 149) and a group of late screened (n = 139) severely hearing-impaired children. Language outcomes were quantified as language quotients (LQs) on the Reynell Developmental Language Scales and Schlichting Expressive Language Test at 1,2, and 3 years after cochlear implantation. RESULTS: Early screened children were significantly younger than late screened children at the time of hearing loss diagnosis and cochlear implantation. Furthermore, early screening was associated with better receptive and expressive spoken language skills after cochlear implantation. CONCLUSION: The results of this retrospective study indicate that the newborn hearing screening program in Flanders and The Netherlands resulted in earlier intervention in deaf children, which beneficially influenced spoken language development.

Cochlear implantation in posttraumatic bilateral temporal bone fracture.

Temporal bone (TB) fractures can cause loss of audiovestibular function. Four cases of profound hearing impairment following bilateral TB fracture are presented in this report. All patients received a cochlear implant. All 4 patients became regular users of their implants. None of the patients experienced facial nerve stimulation. Implant-aided audiometry demonstrated a hearing threshold of 28 dB HL. The performance in speech understanding was comparable to standard postlingual adult patients implanted. We believe that cochlear implantation in patients suffering from profound sensorineural hearing losses secondary to TB fractures can be an effective tool for rehabilitation.

Therapeutic approach in managing patients with large vestibular aqueduct syndrome (LVAS).

OBJECTIVE: To discuss the clinical approach in managing patients with large vestibular aqueduct syndrome. METHODS: Over the period from November 1997 to March 2005, 106 children have been fitted with cochlear implants in Antwerp University Hospital (UZA). The Hospital University of Maastricht (azM) had implanted 36 children since 1999 to March 2005. The present study focuses on nine children and one adult patient with large vestibular aqueduct syndrome (LVAS). The medical, report and radiology report were retrospectively analysed. RESULTS: Eight out of nine children with LVAS had been implanted and one child was on the waiting list. One adult patient was implanted with Nucleus 24M at the age of 22 years old. Nine out of 10 patients had bilateral large vestibular aqueduct. There were no intraoperative or postoperative complications encountered. CONCLUSION: Cochlear implantation is a safe operation for patients with LVAS.

Good speech recognition and quality-of-life scores after cochlear implantation in patients with DFNA9.

OBJECTIVE: To compare audiometric and quality-of-life results in DFNA 9 patients who received a cochlear implant with cochlear implant patients with adult-onset progressive sensorineural hearing loss. STUDY DESIGN: Prospective comparative design; results were collected cross-sectionally. SETTING: Tertiary referral center. PATIENTS: Eleven DFNA 9 patients were included in the study as well as a comparative group of 39 post-lingually deafened cochlear implant subjects with adult-onset progressive sensorineural hearing loss. INTERVENTIONS: All patients received a cochlear implant. Subjects were implanted with either the Nucleus 24 M/RCS or Med-el Combi 40+ cochlear implant systems implementing the SPEAK, ACE, or CIS+ coding strategies. MEAN OUTCOME MEASURES: Speech recognition was determined by means of phonetically balanced monosyllabic word lists. The Hearing Handicap Inventory for Adults, the Glasgow Benefit Inventory, and the Scale for the Prediction of Hearing Disability in Sensorineural Hearing Loss were used to quantify the quality of life. RESULTS: The results show that the speech perception and the quality of life of the DFNA 9 patients do not differ significantly from the control group (p=0.179; p=0.56). CONCLUSION: In spite of the fact that DFNA 9 is a disease that is known to involve cochlear dendrites, cochlear implantation is a good option for treatment of deafness in DFNA 9.

Speech recognition tests in sensorineural hearing loss.

The ability to understand speech must be considered the most important measurable aspect of human auditory function. Due to the innovative developments in hearing aids and cochlear implants, there has been a renewed interest in speech recognition testing. During recent years, the start of several multi-centre studies have increased the urge to come to some consensus on the use of different speech materials. In this article a global overview of existing types of speech material in Dutch will be given. For each type, there is a reference to similar speech audiometric tests in French, English and German.

Interpretation of pure-tone thresholds in sensorineural hearing loss (SNHL): a review of measurement variability and age-specific references.

When assessing a patient with a sensorineural hearing impairment, the most simple and most widely available technical investigation is pure-tone audiometry. Although it is a subjective measure, the test is very reliable if the patient is cooperative. In this paper we review standards and test-retest reliability for pure-tone audiometry. A pure-tone threshold measurement at a single frequency has a chance of 90% to be repeated between -10 dB and +10 dB compared to the first measurement, assuming no real change in hearing thresholds has occurred. It is also of great importance to use correct gender- and age-specific reference values when interpreting pure-tone threshold measurements. Several large-scale epidemiological studies have been conducted during recent years, and have provided us with reliable gender- and age-specific references. A method to take into account the age-related deterioration is presented. In this method, Z-score audiograms represent traditional thresholds in an age- and gender-independent way. At each frequency, the Z-score value is the number of standard deviation units that the threshold differs from the median value for the otologically normal population (ISO 7029).

Oral language acquisition in children assessed with the Reynell Developmental Language Scales.

Oral language development of ten children, prelingually deafened by meningitis, was assessed with a Dutch version of the Reynell Developmental Language Scales. The test was administered pre-operatively and at regular intervals after implantation. The average rate of language development between two consecutive evaluations was computed. This rate was defined as the quotient of the increase of the language age and the increase of the chronological age between the evaluations. A normal language development has a rate of 1; this means 12 months language development in 12 months time. In case of language retardation the rate of language development is less than 1. The rate of receptive language development showed a gradual increase. In the interval between 12 and 24 months of implant use the ratio was 0.9. This implies a language development that is quite similar with the development in normal hearing children. The rate of expressive language development showed a fast improvement in the period between 6 and 12 months after implantation, up to 1.4. If this rate of development continues the children with C.I. will catch up with their normal hearing peers.

Predictors of cochlear implant performance.

Open set speech understanding with cochlear implants, without speechreading, is nowadays a common finding. However, there is a large variation in speech understanding between cochlear implant users. We tried to find pre-operative parameters which predicted the post-operative results. Thirty-seven adult post-lingually deafened Nucleus cochlear implant users with a mean age of 46 years (range 16 68) and a mean duration of deafness of 15 years (range 1.5-47) were studied. Pre-operatively, we performed pure-tone audiometry, round window and ear canal electrical stimulation, psychological tests and imaging. Additionally, we measured pre-operatively speech understanding in the auditory, the visual and the audiovisual conditions with several tests which were also administered after 6 and 12 months' implant experience. Correlation analysis between the pre-operative variables and the post-operative factors showed that duration of deafness and residual hearing are the most important predictors. The temporal difference limen in pre-operative round window electrical stimulation is a secondary predictor.

Assessment of basal sound identification skills and communication abilities in profoundly deaf children fitted with hearing aids or a cochlear implant.

Basal auditory functions and early verbal communication skills were examined in young, profoundly deaf children with hearing aids or a cochlear implant. The hearing aid users (n = 23) were subdivided on the basis of their (unaided) hearing thresholds into: group A (pure tone average (PTA) at 0.5, 1 and 2 kHz: 90-100 dB HL); group B (PTA: 100-110 dB HL); and group C (PTA > 110 dB HL). All the children with a cochlear implant (n = 20) had a profound sensorineural hearing loss with a PTA that exceeded 120 dB HL. Functional hearing was evaluated by means of basal sound identification. The child's communication abilities with hearing aids or a cochlear implant were assessed using structured observations on the Scales of Early Communication Skills for Hearing Impaired Children. The basal auditory functions on a sound identification level improved over time in the cochlear implant users and groups A and B. Hardly any improvement was seen in group C. The performance of all the groups (either hearing aid or cochlear implant) on the Scales of Early Communication Skills for Hearing Impaired Children at 6 months after fitting the device and at later evaluations, was close to the average level for their age.

[Cochlear implantation in deaf children]. / Cochleaire implantatie bij dove kinderen.

OBJECTIVE: To evaluate the results of cochlear implantation in deaf children. DESIGN: Descriptive. SETTING: Ear, nose and throat department, Academic Hospital, Nijmegen, and Institute for the Deaf St. Michielsgestel, the Netherlands. METHODS: The results in 29 totally deaf children implanted with a 22-channel Nucleus implant--partly in a project supported by the National Fund for Investigative Medicine--in the period 1990-1996 were determined. Six of the children had congenital deafness, the others were deaf as a sequel to meningitis. The operation had no serious complications. All children were followed for at least two years. Progress in auditory perception and speech-language development were measured with structured tests. RESULTS: There was a marked improvement in auditory performance, and language development (measured with Reynell test), although the level of normal hearing children was not reached by most of the operated children. The results were better for children with total insertion of the electrodes than for those with partial insertion (n = 4); of these last, one stopped using the implant. CONCLUSION: Cochlear implantation can limit the consequences of total deafness in children.

Long-term speech perception in children with cochlear implants compared with children with conventional hearing aids.

OBJECTIVE: To determine the speech perception of children with cochlear implants. SUBJECTS AND METHODS: Speech perception results of seven children with cochlear implants (excellent performers), who showed stable speech recognition scores in the long term, were compared with those of severely hearing-impaired children with conventional hearing aids (reference group). The groups of children were matched according to their mean free-field aided thresholds. RESULTS: The results of the open-set word recognition test were comparable in the two groups. CONCLUSION: If we consider the results of the hearing aid users as the gold standard, the results suggest that speech recognition in selected children with a cochlear implant is close to optimal.

Speech perception performance of congenitally deaf patients with a cochlear implant: the effect of age at implantation.

The relation between age at cochlear implantation and long-term open-set speech recognition was studied in a group of nine congenitally deaf children. The age at cochlear implant surgery ranged from 4 to 13 years. The results showed that there was a tendency toward poorer results in the children implanted at a relatively older age. However, the results also indicated that an upper limit for age at implantation cannot yet be defined in these children.

Cost analysis of cochlear implants in deaf children in The Netherlands.

OBJECTIVE: The purpose of the study was to determine the costs of cochlear implants in children regarding the phases of selection, implantation, rehabilitation, and aftercare. STUDY DESIGN: This study was a prospective cost analysis paralleling a noncomparative observational study. SETTING: This study was conducted at a university hospital to evaluate cost data on selection and implantation and at an institute for the deaf to evaluate cost data on rehabilitation and aftercare. PATIENTS: The study group consisted of prelingual deaf children (mean age, 7 years; range, 4-11 years). INTERVENTION: A total of 106 deaf children were screened, of whom 20 received a cochlear implant. MAIN OUTCOME MEASURES: This study concentrated on the cost of cochlear implants. Volumes of utilization of human resources and materials were registered during the 1-year follow-up. For the subsequent period, volumes were modeled on planned aftercare activities. RESULTS: Real total medical costs per implanted child were $63,922; selection phase, $7,747; implantation phase, $30,442; rehabilitation phase, $13,428; and aftercare, $12,305. Nonmedical costs were $1,839. Calculations were based on 1994 prices, and a time horizon of 5 years was used. The economic consequences of cochlear implants on educational needs were not taken into account because of the limited follow-up period. A sensitivity analysis of the rate of implanted children as part of the number of screened children showed a moderate impact on the total cost. CONCLUSIONS: Compared to the results of cost analysis in other countries, the costs of the pediatric cochlear implants program in The Netherlands are relatively high. Most discrepancies can be explained by methodologic differences in the cost analyses.

Speech perception performance of children with a cochlear implant compared to that of children with conventional hearing aids. I. The "equivalent hearing loss" concept.

A new measure has been developed to quantify the speech perception performance of children with a cochlear implant (CI). The method summarizes the speech perception scores obtained on a battery of tests that ranges from very basal tasks up to open speech recognition. The overall performance of a child with a CI on the test battery at a certain time during follow-up is matched to that of a reference group of severely and profoundly hearing-impaired children with conventional hearing aids. This matching procedure results in the expression of the speech perception scores of a child with a CI as an "equivalent hearing loss" value. The equivalent hearing loss concept deals adequately with floor and ceiling effects which inevitably occur when a battery with such a large range of tests is used. To illustrate this, application of the procedure to three children with a CI showed that before implantation, while they were using conventional hearing aids, the equivalent hearing loss was above 120 dB hearing level (HL). At 3 years' follow-up the equivalent hearing loss improved to 70 dB HL in the two children with an aetiology of meningitis. This means that these children were performing as well as children in the reference group with a hearing loss of 70 dB HL. The child with congenital deafness showed minor improvements over time.

Speech perception performance of children with a cochlear implant compared to that of children with conventional hearing aids. II. Results of prelingually deaf children.

In a previous paper, a method was introduced to transform the results obtained by children with a cochlear implant (CI) on a battery of speech perception tests into an overall value, the "equivalent hearing loss" value. This was achieved by matching the speech perception test scores with those of a reference group of children with conventional hearing aids and hearing loss ranging from 50 to 130 dB hearing level (HL). The equivalent hearing loss values of 16 prelingually deaf children with a CI were plotted as a function of time. There was considerable spread in the rate of progress made by the children in terms of the equivalent hearing loss values. The variables studied, age at onset of deafness/duration of deafness (in the present study, these two factors were indistinguishable) and the communication mode used at the children's school, accounted for 64% of the variance in speech perception performance. A plateau in the performance of the better performers was found which seemed to be caused by the level of hearing (the aided thresholds) with the CI.

The relation between age at the time of cochlear implantation and long-term speech perception abilities in congenitally deaf subjects.

The issue of whether an upper age limit should be set for cochlear implantation in congenitally deaf subjects has often been debated. To gain more insight, the speech perception abilities were analyzed of 12 congenitally deaf subjects whose age at the time of cochlear implantation ranged from 4 to 33 years. Subjects implanted during adulthood only showed progress during the first few months after the speech processor had been fitted and their long-term results were poor compared to those of children implanted early in life. This latter group showed steady improvement over the whole evaluation period. The present results support the notion that the earlier in life implantation is performed, the better the development of speech perception. Based on the progress-over-time profiles and data on actual daily use of the cochlear implant, it can be suggested that implantation of congenitally deaf subjects during or after puberty offers only limited benefit.

Fitting hearing aids in children with severe hearing loss.

Because of limited initial data about the hearing loss of children and the difficulties in getting an optimal prescription, every fitting has to incorporate a procedure verifying or validating the final fitting. Fitting hearing aids should be focused on optimal speech recognition, even in children with very severe or profound hearing loss. When the MTS test is used, it is possible to optimize the gain and frequency response that gives the best possible prospects for speech recognition. The abilities for speech perception are a function of the PTA. For a hearing loss exceeding about 110 dB there are hardly any possibilities for adequate speech perception with hearing aids. Also, training on basal sound identification abilities shows no improvements. This is in contrast to hearing aid users with PTA between 90 and 110 dB.

Stapedius reflex measurements during surgery for cochlear implantation in children.

Electrically evoked stapedius reflex measurements were obtained in 19 children during surgery for cochlear implantation. They all received the Nucleus device. Stapedius reflexes could be elicited in all the children with congenital deafness but not in all the children with an etiology of meningitis. The intraoperative stapedius reflex thresholds were compared with postoperative values obtained after fitting of the speech processor and with the children's long-term behavioral most comfortable levels (C-levels). The intraoperative reflex thresholds were considerably higher than the postoperative reflex thresholds (44 "stimulus level steps" on the average), which could in part be ascribed to the influence of anesthetics used during surgery. It was concluded that, especially in children with an etiology of meningitis, the intraoperative stapedius reflex threshold (even after corrections for the concentration of the volatile anesthetics used) was a weak predictor of the C-level.

Averaged electrode voltages: management of electrode failures in children, fluctuating threshold and comfort levels, and otosclerosis.

Implant-generated surface potentials, or averaged electrode voltages (AEVs), were collected by means of the electrode-by-electrode (E-E) mapping variable mode strategy. Three topics were investigated. 1) Eighteen children under the age of 7 were tested and the E-E map of 4 of them was found deviant; all 4 children were deaf owing to meningitis. Some electrodes marked as failing by E-E mapping did not cause problems during device fitting, and electrodes not usable in device fitting showed normal AEVs in 1 child. Overall, the AEVs agreed well with abnormalities in the behavioral threshold (T) and comfort (C) levels. The E-E maps provided useful clues for the audiologist in most cases. 2) Repeated E-E mapping in 2 children who displayed large fluctuations over time of T levels suggested a fluctuation in (neural) responsiveness in 1 child and new bone formation in the other. 3) Although massive phase reversals of AEVs in 2 patients deafened by otosclerosis seemed to indicate a very permeable cochlear bone, stimulation in the pseudomonopolar mode across the basal turn did not affect T levels, and affected pitch perception in only 1 patient. Deviant AEVs from abnormal cochleas should, therefore, not be interpreted too easily as an indication of an electrode failure, faulty electrode placement, or inadequate tonotopy.