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Biomedical subjects

A F Snik

Publications and source records attributed to A F Snik.

At least 19 recordsLinked to original sources
PubMed2001

Vibrant semi-implantable hearing device with digital sound processing: effective gain and speech perception.

BACKGROUND: The Vibrant Soundbridge (Symphonix Devices, San Jose, Calif) is a semi-implantable hearing device. The transducer is attached directly to the incus and is linked by telemetry to the externally worn audioprocessor. A major advantage of this semi-implantable setup, especially during its experimental phase, is that the audioprocessor can be updated. Recently, we replaced the previous 2-channel analog audioprocessor in 14 patients with a 3-channel digital device. DESIGN: Prospective clinical study. Basic functions were measured, including gain as a function of input level and speech perception in quiet. PATIENTS: Patients (n = 14) had moderate to severe sensorineural hearing impairment (average hearing threshold at 0.5, 1.0, 2.0, and 4.0 kHz of 40- to 76-dB hearing level [HL]) and chronic external otitis, which contraindicated use of an ear mold. RESULTS: Gain of the 3-channel audioprocessor for comfortable listening levels and for conversational levels varied from approximately 15- to 30-dB HL, suggesting that the device is suitable for patients with hearing loss of up to 60- to 70-dB HL. In 5 patients, identical measurements were performed using their conventional hearing aids. The other 9 patients did not use a conventional hearing device because of severe external otitis. On average, results obtained with the Vibrant Soundbridge were not as good as those obtained with the conventional device. Nevertheless, patients were satisfied with the Vibrant Soundbridge because they could use it all day without pain or itching. CONCLUSIONS: The Vibrant Soundbridge is suitable for patients with hearing loss of up to 70-dB HL. Compared with conventional devices, in audiometric terms, a surplus value of the Vibrant Soundbridge was not found.

Adult↗
PubMed2001

The bone-anchored hearing aid: a solution for previously unresolved otologic problems.

A major challenge for otologists treating middle ear infection is to obtain a dry ear and optimal hearing. If the patient needs amplification and uses an air conduction hearing aid, the ear mold, occluding the ear canal, may provoke or aggravate the infection in the middle ear and thus cause otorrhoea. Continuous otorrhoea may cause cochlear damage in the long run. Bone conduction hearing aids offer an alternative for such patients.

Bone Conduction↗
PubMed2001

Multicenter audiometric results with the Vibrant Soundbridge, a semi-implantable hearing device for sensorineural hearing impairment.

The Vibrant Soundbridge, a semi-implantable hearing device for subjects with moderate to severe sensorineural hearing impairment was introduced commercially. First audiologic results are presented on 63 patients from 10 European implant centers. Hearing loss was at 0.5, 1, 2, and 4 kHz varying between 43 and 81 dB HL. The patients used the analogue audio processor, type 302. Measured sound-field gain was compared with NAL-R target values. For most patients an acceptable agreement was found. There was a subgroup of patients, however, with relatively low gain. The results suggest that this was related to the suboptimal positioning and fixation of the transducer to the incus.

Audiometry, Speech↗
PubMed2001

Speech-evoked cortical potentials and speech recognition in cochlear implant users.

Processing in the auditory cortex may play a role in the unexplained variability in cochlear implant benefit. P300 and N1/P2 were elicited in post-lingually deaf cochlear implant users wearing a Nucleus multichannel cochlear implant. Four sound contrasts were presented (500-1,000 Hz, /ba/-/da/, /ba/-/pa/ and /i/-/a/). N1 and P2 were present in all subjects for all conditions. Prolonged N1, P2 and P300 latencies were found in the cochlear implant group compared to a control group of subjects with normal hearing. Cochlear implant users show smaller amplitudes of N1 for all the speech signals as well as smaller amplitudes of P2 for the consonants compared to the controls. P300 results of the cochlear implant users were compared to behavioural results of speech recognition testing. A relation was found between P300 amplitude and magnitude for the 500-1,000 Hz and /i/-/a/ contrasts and behavioural speech recognition in cochlear implant users. The results suggest that P300 measurements are useful and have additional value to speech recognition evaluations in cochlear implant users.

Adolescent↗
PubMed2001

Auditory performance of young children with hearing aids: the Nijmegen experience.

During recent years, significant progress has been made in the development of methods for screening hearing sensitivity in toddlers. Nowadays, in several countries, nationwide screening programmes are carried out. Much less attention has been paid to the next step, namely treatment of very young hearing-impaired children with hearing devices. A review of published data indicate that the DSL (Desired Sensation Level) hearing aid prescription method, developed especially for young children, is at least a good point to begin hearing aid fitting. DSL target values for gain and output seems to be adequate for young children. Documenting the benefit for hearing aid use in young children is still cumbersome. One option is to measure the development of basal auditory functions. A review of available data showed that for this purpose, speech material can only be used in children of 3 years and older. For children of 1 year and older, tests with environmental sounds can be applied. It is concluded that, although growing, there is a lack of tests and limited knowledge on how to optimize hearing aid fittings and how to document hearing aid benefit in toddlers.

Adolescent↗
PubMed2001

Reliability of manometric eustachian tube function tests in children.

OBJECTIVE: To assess the reliability of manometric eustachian tube function tests in children with ventilation tubes in situ. STUDY DESIGN: Repeated manometric eustachian tube function tests during one session. SETTING: The study took place at a secondary referral hospital and a tertiary referral hospital. PATIENTS: Ninety-nine children with ventilation tubes in situ because of persistent otitis media with effusion. MAIN OUTCOME MEASURES: Opening pressure (Po), closing pressure (Pc), and tubal function group. RESULTS: Analysis of Po and Pc showed a decrease with repeated measurement (p = 0.0001 and p = 0.001, respectively). The effect of repeated measurement on Po was more pronounced than the effect on Pc. The results of the first and second pressure equilibration tests showed 99% agreement. CONCLUSIONS: This study showed good reproducibility of the categorized results of the pressure equilibration test, whereas the results of the forced-response test seemed to be less reproducible and showed a downward shift with repeated measurement. A single measurement using wet swallowing and starting pressures of 100 and -100 daPa and the mean of the first three measurements of the Po and Pc are sufficient to determine tubal function. Further studies are needed to determine the discriminative power of these tests in children with different degrees of middle ear disease.

Child, Preschool↗
PubMed2001

Eustachian tube function in children after insertion of ventilation tubes.

This study was performed to assess the effect of the insertion of ventilation tubes and the subsequent aeration of the middle ear on eustachian tube (ET) function in children. Manometric ET function tests were performed repeatedly for 3 months after the placement of ventilation tubes in 83 children with otitis media with effusion (OME). Opening and closing pressures (passive tubal function) and active tubal function were measured. Analysis of the results showed a significant increase in opening pressure over time, whereas the closing pressure did not change. The active tubal function did not change and remained at the same poor level. Therefore, the opening pressure and closing pressure and, especially, the poor active tubal function, were more likely to be a causal factor of OME than a result. Certain children may have poor intrinsic ET function that makes them more susceptible to OME.

Child↗
PubMed1999

Auditory training in severely and profoundly hearing impaired toddlers: the development of auditory skills and verbal communication.

Three different tests are applied to evaluate the performance of very young hearing impaired children. Three subgroups were formed according to hearing loss. The sound identification test as well as the Reynell Developmental Scales proved to be useful but Early Scales of Communication did not differentiate well enough between the three subgroups.

Auditory Perception↗
PubMed1999

The BAHA HC200/300 in comparison with conventional bone conduction hearing aids.

A retrospective study was performed on 89 patients from a consecutive series who received a BAHA HC200/300 after having previously used conventional bone conduction hearing aids. The patients' performance with the BAHA HC 200/300 was compared to their performance with conventional bone conduction hearing aids. The patients were divided into two groups, depending on the time of implantation (before or after May 1992). The patients in group 1 (long-term users) were asked to fill in a questionnaire, the same one as they had filled in at the initial BAHA fitting more than 5 years previously. The answers were compared to their original opinions and difference scores were calculated. The long-term clinical results from group 1 are also presented. Although they are encouraging, the patients' opinion about the BAHA deteriorated somewhat over time. The audiometric results of group 2 were highly comparable with those of group 1. This confirms the positive results with the BAHA found in previous studies.

Acoustic Stimulation↗
PubMed1998

Short- and long-term results with implantable transcutaneous and percutaneous bone-conduction devices.

OBJECTIVES: To compare the percutaneous bone-anchored hearing aid (BAHA; type NBC-HC-200, Nobel Biocare, Gothenburg, Sweden) and the transcutaneous temporal bone stimulator (TBS; Xomed-Treace, Jacksonville, Fla) with conventional hearing aids and to evaluate long-term results. DESIGN: In a prospective clinical study, the new implantable bone-conduction devices were compared with the patients' previous conventional hearing aids. Speech perception in quiet and in noise were studied, and a questionnaire concerning the actual use of the device and speech recognition was administered. During follow-up that exceeded 4 1/2 years, relevant technical and medical problems were documented. PATIENTS: Forty-one successive subjects who were fitted with a BAHA and 17 subjects who were fitted with a TBS. RESULTS: In most subjects who had previously used a bone-conduction device, the new BAHA and TBS devices led to improved or comparable results on speech recognition tests and the questionnaire. However, among the subjects who had previously used air-conduction hearing aids, the results were ambiguous. In the long-term, the percentage of nonusers in the BAHA group was 5% (2/39); in the TBS group, 65% (13/20). The main reasons for not using the TBS were insufficient gain and medical and technical problems. The vulnerability of the percutaneous coupling of the BAHA to trauma or inflammation was not a major issue; only 4 implants were lost during the total follow-up of more than 250 years. CONCLUSION: Results indicate that the BAHA is the better choice.

Adolescent↗
PubMed1998

Intraindividual comparison of the bone-anchored hearing aid and air-conduction hearing aids.

BACKGROUND: Some patients have to stop using their air-conduction hearing aid(s) because it causes or exacerbates chronic otitis. Then, a solution is the use of a bone-conduction hearing aid such as the percutaneous bone-anchored hearing aid (BAHA). OBJECTIVE: To compare patients' performance with their previous air-conduction hearing aid(s) and their BAHA using audiometric tests and a questionnaire. DESIGN: Prospective clinical evaluation in a single subject design. PATIENTS: The results of 34 consecutive patients from the Nijmegen, the Netherlands, BAHA series were included. The patients had bilateral conductive or mixed hearing loss and chronic ear problems. Before the BAHA was fitted, the patients used air-conduction hearing aids. RESULTS: The results of the speech recognition in noise test showed a small but significant improvement with the BAHA. This improvement was related to the size of the air-bone gap. The greater the air-bone gap, the poorer the results with the air-conduction hearing aid(s). The questionnaire demonstrated that the majority of patients preferred the BAHA; diminished occurrence of ear infections played a significant role. The patients did not express an evident preference concerning speech recognition. CONCLUSIONS: In patients with chronic ear problems a BAHA is an acceptable alternative if an air-conduction hearing aid is contraindicated. Preoperative assessment of the size of the air-bone gap is of some help to predict whether speech recognition may improve or deteriorate with the BAHA compared with the air-conduction hearing aid.

Adult↗
PubMed1998

Can event-related potentials be evoked by extra-cochlear stimulation and used for selection purposes in cochlear implantation?

To investigate whether electrically evoked event-related responses (P300) could be elicited by extra-cochlear stimulation, measurements were performed on a group of adults fitted with the single-channel extra-cochlear implant. To optimize measurement conditions, and because of the low number of subjects still using an extra-cochlear device in our cochlear implant programme, measurements were also performed on a group of experienced users fitted with the intra-cochlear Nucleus multichannel device. For reference purposes, subjects with normal hearing (control group) were also included in the study. Reproducible late latency responses (N1 and P2 peaks) were found in the five extra-cochlear implant users, while P300s were present in four out of these five subjects. The latencies were longer than those of the control group, but were similar to those obtained in the intra-cochlear implant group. Significant correlations were found for most N1, P2 and P300 measurements evoked by the tonal stimuli and by speech stimuli. The P300 amplitudes, evoked by either tonal or speech stimuli, appeared to be related to speech perception ability. This led to the conclusion that N1, P2 and P300 measurements may have potential as a clinical tool for preoperative prediction and postoperative evaluation of sound processing on a cortical level.

Adolescent↗
PubMed1998

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.

Audiometry, Pure-Tone↗
PubMed1998

Intra- and interindividual correlations between auditory evoked potentials and speech perception in cochlear implant users.

Several electrophysiological techniques have been used to supplement behavioural measurements in the evaluation of the benefit of cochlear implantation, namely the electrically evoked auditory brainstem response (EABR), electrically evoked middle latency response (EMLR) and electrically evoked late latency response (EALR). To study the interdependence of these responses, the present paper deals with a combination of EABR, EMLR and EALR measurements obtained from 15 postlingually deaf subjects implanted with the Nucleus multichannel device at the University Hospital Nijmegen. In particular, we investigated whether there were intercorrelations between amplitude and latencies of the evoked potential peaks and/or correlations with long-term speech perception scores. Significant correlations were found between the peak V amplitude of the EABR and the NaPa and NbPb amplitudes of the EMLR. No significant correlation was found between the EABR and EMLR amplitudes on the one hand and EALR peak amplitudes on the other. In addition, no significant correlations were found between any of the EABR or EMLR peak amplitudes and speech perception test results. A moderate but significant relation was found between the EALR peak amplitude and speech perception test results. Unlike latencies of earlier peaks, the latency of the EALR peak P2 was significantly related to the speech perception scores.

Adolescent↗
PubMed1998

A new more powerful bone-anchored hearing aid: first results.

In a pilot study seven subjects were asked to use a new more powerful bone-anchored hearing aid, the BAHA cordelle, for 5 days. All seven had a moderate or severe sensorineural component in their hearing loss and had been using a BAHA superbass on a daily basis for more than 2 years. Free-field thresholds and speech recognition were measured with the BAHA superbass and with the BAHA cordelle. A questionnaire was also filled in to obtain subjective information about speech recognition with the BAHA superbass compared to the BAHA cordelle. Aided thresholds in the high frequency range with the BAHA cordelle were better than with the BAHA superbass. In six of the seven subjects there was significant improvement in the speech recognition score with the BAHA cordelle. These six subjects expressed preference for the BAHA cordelle.

Adult↗
PubMed1998

Audiometric results of bilateral bone-anchored hearing aid application in patients with bilateral congenital aural atresia.

The effect of bilateral application of bone-anchored hearing aids (BAHAs) was examined in terms of directional hearing and speech recognition in quiet and in noise in four patients with bilateral congenital atresia who, out of pure necessity, had been using a unilateral bone-conduction hearing aid since early life. This study comprised a prospective clinical evaluation in a single subject design; four patients with bilateral congenital atresia originating from the Nijmegen BAHA series participated. Three patients had Treacher Collins syndrome. All four patients had conductive, most probably, symmetrical, hearing loss. Recently these patients had applied for a second BAHA and were subsequently fitted bilaterally. With two BAHAs, all four patients showed significant improvement in sound localization. Also, speech perception in quiet showed significant improvement with bilateral application, and a significant improvement was found in speech perception in noise in three patients. These results suggest that patients with congenital conductive, symmetrical hearing loss will benefit from bilateral BAHAs.

Adolescent↗
PubMed1998

Binaural application of the bone-anchored hearing aid.

Most, but not all, hearing-impaired patients with air conduction hearing aids prefer binaural amplification instead of monaural amplification. The binaural application of the bone conduction hearing aid is more disputable, because the attenuation (in decibels) of sound waves across the skull is so small ( 10 dB) that even one bone conduction hearing aid will stimulate both cochleas approximately to the same extent. Binaural fitting of the bone-anchored hearing aid was studied in three experienced bone-anchored hearing aid users. The experiments showed that sound localization, and speech recognition in quiet and also under certain noisy conditions improved significantly with binaural listening compared to the monaural listening condition. On the average, the percentage of correct identifications (within 45 degrees ) in the sound localization experiment improved by 53% with binaural listening; the speech reception threshold in quiet improved by 4.4 dB. The binaural advantage in the speech-in-noise test was comparable to that of a control group of subjects with normal hearing listening monaurally versus binaurally. The improvements in the scores were ascribed to diotic summation (improved speech recognition in quiet) and the ability to separate sounds in the binaural listening condition (improved sound localization and improved speech recognition in noise whenever the speech and noise signals came from different directions). All three patients preferred the binaural bone-anchored hearing aids and used them all day.

Adult↗