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Biomedical subjects

A F Snik

Publications and source records attributed to A F Snik.

At least 55 records · Page 3Linked to original sources
PubMed1995

The bone-anchored hearing aid compared with conventional hearing aids. Audiologic results and the patients' opinions.

The bone-anchored hearing aid (BAHA) was evaluated in 65 patients by comparing speech recognition and questionnaire results with those obtained with the patients' own previous hearing aids. In the majority of patients who previously used a conventional bone conductor, significantly improved speech recognition scores were found with the BAHA. The majority preferred the BAHA to their previous bone conductors. For the patients who previously used air conduction hearing aids but had to stop because of chronic draining ears, the results were ambiguous. Nevertheless, the BAHA seems to be the best solution for this subgroup as well. It is concluded that the BAHA is a valuable addition to the audiologists' tools.

Adult↗
PubMed1995

Air-bone gap in patients with X-linked stapes gusher syndrome.

It is often possible to elicit the stapedius reflex in patients suffering from recessive X-linked progressive mixed deafness syndrome with stapes gusher. The presence of an air-bone gap in the audiogram and the ability to elicit the stapedius reflex are conflicting. Measurements were performed on two patients who were suffering from this syndrome, to establish whether the hearing loss was of the mixed or purely sensorineural type. It was argued that, owing to congenital malformations, the audiovestibular system might act as a more than normally efficient transducer, to convert skull vibrations into inner ear fluid motions, leading to bone conduction thresholds that are better than expected. The results of tone and speech audiometry, stapedius reflex measurements, and brainstem evoked response audiometry in this study showed a pattern similar to that generally seen in patients with purely sensorineural hearing loss. This supports the hypothesis that the air-bone gap in the audiogram does not have the usual significance of a conductive hearing loss component.

Adult↗
PubMed1994

Clinical results of percutaneous implants in the temporal bone.

The bone-anchored hearing aid is an alternative to the conventional bone-conduction hearing aid, without the disadvantages of pressure pain or skin irritation and with direct sound transmission to the skull. The bone-anchored hearing aid is coupled to a percutaneous titanium implant, which is placed in the mastoid process in two surgical stages. We analyzed the clinical results of 68 percutaneous implants in 65 patients. After a follow-up period of 8 to 45 months, 97% of the implants were anchored in the bone. In 86% of the implants, no potentially dangerous skin reactions occurred. The occurrence of skin reactions was not time dependent. Movement of the skin, thick skin, and poor skin condition around the implant were related to the onset of skin reactions. This study showed that the percutaneous titanium implant forms a stable link between the bone-anchored hearing aid and the skull.

Adolescent↗
PubMed1994

Aided free-field thresholds in children with conductive hearing loss fitted with air- or bone-conduction hearing aids.

Although conductive hearing loss is often found in children, few reports have appeared on the fitting of hearing aids in these children. In the present study, aided thresholds were determined in 40 children and 30 adults with pure conductive hearing loss (bone-conduction thresholds of 20 dB HL or less) who were successfully fitted with hearing aids. The patient group was split into subgroups according to the type of hearing aid used (bone-conduction hearing aid, binaural or monaural air-conduction hearing aids). Within each subgroup, the aided thresholds proved to be comparable between the adults and children and were nonconsistently related to the degree of (air-conduction) hearing loss. In the patients with a bone-conduction hearing aid, the aided free-field thresholds at the most important frequencies for speech perception (1, 2 and 4 kHz) were found to be between 20 and 30 dB HL, while in the patients with an air-conduction hearing aid, irrespective of whether it was applied monaurally or binaurally, these thresholds were between 15 and 20 dB HL. It is suggested that these values should be considered as target thresholds when fitting hearing aids in children with conductive hearing loss.

Adolescent↗
PubMed1994

Audiologic results for the bone-anchored hearing aid HC220.

Twenty-six patients with severe mixed hearing loss (PTA range 57 to 108 dB HL) were fitted with the "super-bass" bone-anchored hearing aid (BAHA) HC220 and divided into two groups. Group I contained 19 patients who previously used a conventional bone conduction hearing aid that had resulted in serious complaints. Group II contained 7 patients who had previously used an air conduction hearing aid that could no longer be used because of recurrent otorrhoea. Sound field speech audiometry for the patients in Group I revealed that for 7 patients the maximum phoneme score did not change, but that it improved for 12 patients with the HC220, compared with their conventional bone conduction hearing aid. In Group II, the maximum phoneme score improved for 3 patients, worsened for 3 patients and did not change for 1 patient with the HC220, compared with their air conduction hearing aid. Speech recognition in noise was difficult for most of the patients regardless of group. However, results were obtained from 10 patients, and 7 improved significantly with the HC220 compared with their previous aid. Overall, speech recognition with the HC220 was comparable with or better than a conventional bone conduction hearing aid; however, compared with an air conduction hearing aid the results were ambiguous.

Adult↗
PubMed1994

The effect of otitis media with effusion at preschool age on some aspects of auditory perception at school age.

The relationship between otitis media with effusion (OME) at preschool age and performance on five tests of auditory perception was studied in 89 school-age children who had OME histories well documented from participation in serial screening for OME at 2-4 yr of age. The tests used at 7.5-8 yr of age were: speech-in-noise, filtered speech, binaural fusion, dichotic speech, and auditory memory. A significant effect of OME was found on the speech-in-noise test. No additional effects were demonstrated by this particular group of children.

Audiometry, Pure-Tone↗
PubMed1994

Stapedius reflex and EABR thresholds in experienced users of the Nucleus cochlear implant.

Evoked auditory brainstem responses (EABR) and stapedius reflex thresholds were established in 7 experienced users of the Nucleus cochlear implant. Even using biphasic 400 microseconds/phase clicks for the EABR, responses were observed in only 5 patients; no stapedius reflex (SR) was seen in 3 patients, 2 of whom had a history of middle-ear disorder. The EABR threshold varied widely between subjective threshold and uncomfortable loudness level (ULL) for the same stimulus. The average SR threshold was found somewhat more consistently at 66% of the dynamic range between threshold and ULL, but grossly overestimated the most comfortable level (MCL) in most cases. To obtain equal loudness at the same current level we suggest that broad clicks (300 microseconds/phase) be used for EABR measurements, thus compensating for the lower repetition rate of EABR stimulus compared with the device fitting stimulus.

Acoustic Stimulation↗
PubMed1994

Influence of the thickness of the skin and subcutaneous tissue covering the mastoid on bone-conduction thresholds obtained transcutaneously versus percutaneously.

Percutaneous and transcutaneous bone-conduction thresholds were obtained at 0.25, 0.5, 1, 2, and 4 kHz in 57 patients who were fitted with the Bone Anchored Hearing Aid (BAHA). Additionally, the thickness of the skin and subcutaneous tissue covering the mastoid was determined. No relation was found between the thickness of the skin and subcutaneous tissue, and the improvement in bone-conduction thresholds at any of the frequencies, i.e. thresholds obtained percutaneously minus transcutaneously. The improvement (or deterioration) in speech recognition with the BAHA in a subgroup of patients who had previously used a (conventional) transcutaneous bone-conduction hearing aid was not related to the thickness of the skin and subcutaneous tissue layers. Therefore, the thickness of the skin and subcutaneous tissue layers measured pre-operatively cannot be used as a predictor of successful fitting with a BAHA.

Adolescent↗
PubMed1994

Speech recognition with the bone-anchored hearing aid determined objectively and subjectively.

Some patients with a bone-conduction hearing aid experience serious problems such as skin irritation or headaches and inconsistency in the sound quality due to shifting of the transducer over the mastoid. The Bone Anchored Hearing Aid (BAHA) provides direct bone-conduction and therefore evades these problems. Results of 58 patients fitted with either the head level BAHA HC200 or the more powerful HC220 were available for evaluation. Speech recognition-in-quite and in-noise tests were performed in order to make a comparison between the patients' performance with their individually adapted BAHA and their previous hearing aid. Furthermore, all the patients filled out a questionnaire, involving questions on speech recognition-in-quite and in-noisy surroundings. Individual comparisons of the audiological and questionnaire results in the subgroup of patients who had used a bone-conduction hearing aid showed that the results with the BAHA were comparable with or significantly better than those with the previous bone-conduction hearing aid. The results in the patients who had previously used an air-conduction hearing aid were ambiguous.

Adolescent↗
PubMed1994

Performance of prelingually or postlingually deafened adults who were using a single or multichannel cochlear implant.

Long-term (two-year post-implantation) speech recognition was evaluated of prelingually and postlingually deafened adult cochlear implant users who had received either a single or a multichannel device. The patient group comprised 8 pairs of patients matched according to the onset and duration of deafness; in each pair one patient had an extra-cochlear single-channel implant and one had an intra-cochlear multichannel implant. A CDT (Continuous Discourse Tracking) test and a closed-set speech recognition test were used for speech recognition. The results of the postlingually deafened pairs of patients showed that the multichannel implant was superior to the single-channel implant, which is in agreement with other studies. In the pairs of prelingually deafened adult patients, the multichannel system was not found to be superior. This warrants further study and further application of single-channel implants in prelingually deafened patients.

Cochlear Implants↗
PubMed1993

Preoperative electrical stimulation for cochlear implant selection. The use of ear canal electrodes versus transtympanic electrodes.

Preoperative electrostimulation tests were performed on 43 postlingually deaf and 20 prelingually deaf cochlear implant (CI) candidates. The stimulating electrode was placed at three different locations, i.e. the round window, the promontory and the ear canal and the results were compared. The evoked sensations were reported to be of auditory origin by most of the postlingually deaf CI candidates. Prelingually deaf subjects could not always distinguish clearly and reliably between "hearing" and "feeling". The percentage of stimulated ears of postlingually deaf subjects in whom hearing sensations were evoked was almost identical for the three locations of the stimulating electrode. However, in 5 out of the 7 ears without hearing sensations during ear canal stimulation (ECS), hearing sensations could be evoked during either promontory stimulation (PS) or round window stimulation (RWS). The mean threshold level for "hearing" at a stimulation frequency of 62 Hz was lowest during RWS, 7.7 dB higher during PS and 35.8 dB higher during ECS. The mean electrical dynamic range at 62 Hz was most favourable during RWS (23.9 dB), smaller during PS (15.6 dB) and smallest during ECS (10.0 dB). All differences were statistically significant. Placement of the ear canal electrode was easier, less frightening for the patient and required less time than insertion of the needle electrode for PS or RWS. Therefore we recommend the use of ECS to examine whether the CI candidate can be stimulated, and of RWS if more detailed information is required.

Adolescent↗
PubMed1993

Hearing aid fitting of preschool and primary school children. An evaluation using the insertion gain measurement.

This report presents the results of a group comparison between insertion gain measurements and the calculated Articulation Index (AI) in preschool children (n = 35), primary school children (n = 60) and adults (n = 40). Only patients with bilateral sensorineural hearing loss, successfully fitted binaurally with hearing aids, were included. Patients with an asymmetrical hearing loss or an abrupt high frequency loss were excluded. No statistically significant differences were found between the group results of the preschool children and the primary school children. The results showed that the overall level of insertion gain was 7 dB higher in the total children group (primary school and preschool children) than in the adult group and the AI was approximately 0.1 higher in the children group. Additionally, the measured insertion gain was compared to the desired gain resulting from prescriptive rules: it is concluded that for children the so-called half gain rule is appropriate, while for the adults the measured insertion gain lies between the values prescribed by the half gain rule and the one-third gain rule.

Acoustic Stimulation↗
PubMed1993

The use of the startle reflex measurement in patients with various types of fixation of the ossicular chain.

The results of startle and acoustic stapedius reflex measurements can be used to subclassify various types of fixation of the ossicular chain. Reflex measurements were performed on a group of subjects with normal hearing and on a group of patients with surgically verified ossicular chain fixation. In 97% of the subjects with normal hearing (n = 30), reproducible impedance changes were observed as part of a startle reaction and four different reaction patterns could be distinguished. In a subgroup of subjects with normal hearing who had a relatively, statistically significant, high acoustic reflex threshold, a characteristic response was found which was most probably caused by contraction of the tensor tympani muscle only. The same response was detected in 77% of the patients (n = 22) with otosclerosis. In the remaining 23%, no middle ear impedance changes occurred as part of a startle reaction. In five out of six patients with fixation of the malleus, no response was observed. Although the startle reflex measurement is a valuable tool for distinguishing between stapes fixation and multiple ossicular chain fixations, the results are not conclusive.

Acoustic Impedance Tests↗
PubMed1992

[The provision of hearing aids to young children with congenital hearing impairment].

Early screening for hearing impairment in children is generally advised to prevent sensory deprivation and speech, language and learning problems. In the present study, the age at which 176 probably congenitally hearing impaired infants were referred to the Audiological Centre in Nijmegen between 1983 and 1990 was examined. The mean age of fitting the hearing aids was 35 months. This was about 2 years after the auditory screening test (Ewing test) as performed in most baby health care centres. In general, if a screening test is positive, the child will be referred to the general practitioner, who can refer the child to either a general otolaryngologist or a ENT clinic with a (paedo-) audiological centre. Hearing aids can only be provided by an audiological centre. On average, hearing-impaired children who were directly referred to our clinic/audiological centre were provided with hearing aids 13 months earlier than children initially referred to a general otolaryngologist. It is concluded that young children who fail an auditory screening test should be thoroughly tested audiometrically after an otoscopic examination.

Age Factors↗
PubMed1992

The super-bass bone-anchored hearing aid compared to conventional hearing aids. Audiological results and the patients' opinions.

Twelve patients with severe mixed hearing loss (PTA ranging from 70 to 108 dB HL) were provided with the percutaneous 'super-bass HC 220' bone-anchored hearing aid (BAHA) to replace their former hearing aid. Five had previously worn an air-conduction hearing aid (behind-the-ear type, BTE) which could no longer be used because of recurrent otorrhoea; the others had previously worn a conventional (transcutaneous) bone-conduction hearing aid (CBHA) which had caused serious complaints, such as headaches or skin irritation. Free-field speech audiometry in the subgroup of patients who used to wear a CBHA revealed that the maximum intelligibility score with the BAHA was equal to or better than that obtained with the CBHA (range from 0 to +27%). In three of the five patients who used to wear a BTE, the speech scores were poorer with the BAHA than with the BTE (range from -13 to -40%). For the remaining two patients, the difference in scores was 0 and +10%. In conclusion, speech recognition with the BAHA HC220 in the patients with severe mixed hearing loss was comparable to, or better than, that with a CBHA. Compared to an air-conduction hearing aid, the results may be considerably poorer. The results of the questionnaire were in good agreement with the measurements and support the conclusions.

Adolescent↗
PubMed1991

[A hearing aid anchored in the cranial bone for amplification of bone conduction].

The purpose of this study was to compare hearing and understanding with a bone conduction hearing aid of a new type and with conventional models. The new instrument, BAHA (bone anchored hearing aid) is connected with the skull percutaneously rather than transcutaneously as with the conventional instruments. In the ENT department of Nijmegen University Hospital the understanding of speech with both types of hearing aid was evaluated thoroughly. The patients had a middle-ear loss with in addition an inner-ear loss of 60 dBHL at most. A conventional air conduction hearing aid (behind or inside the ear) was unsuitable for them because of, for instance, chronic runny ears or anomalies of the auditory meatus. A conventional bone conduction hearing aid containing a transducer pressing on the skin was rejected because of poor understanding or serious side effects such as headache and pressure pains. At the first session a titanium screw was implanted in the skull behind the ear. The percutaneous superstructure was put into place a few months later at a second session. In none of the patients were there peroperative problems or postoperative infections of any importance. Understanding of speech in silence and in noise was evaluated with the BAHA and with the conventional aid. Differences in understanding of speech were regarded as significant if they amounted to more than twice the known intra-individual standard deviation. As to understanding of speech in silence, 7 of the 15 patients were found to understand significantly better with the BAHA than with a conventional aid. In the other patients no difference was found.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Conduction↗
PubMed1991

Frequency resolution after successful surgery in congenital ear anomalies.

Frequency resolution was studied in patients with a unilateral congenital ear defect (atresia), who were successfully operated on. Psychophysical tuning curve (PTCs) were obtained. A comparison of the shapes of the PTCs revealed that the average curve for all the patients was much alike for the operated and non-operated (normal) ear: broad tuning curves, as reported from animal studies, were not found. After appropriate corrections were made for the small remaining air-bone gaps, as seen in all patients, the PTCs of all the operated ears lay reasonably well within the 2 S.D. range of the average PTC obtained in subjects with normal hearing.

Adolescent↗