Biomedical subjects
W Shehata-Dieler
Publications and source records attributed to W Shehata-Dieler.
[Development of a new test for speech audiometry in children and results in CI children].
BACKGROUND: Speech audiometry plays an important role for hearing evaluation in children. Hearing impaired children, such as those with cochlear implant (CI) who frequently undergo testing, learn the test words by heart. Furthermore, the standard tests use words of former time. PATIENTS AND METHODS: Using the most frequently words of modern children's literature a speech assessment test was developed for children between 1 to 8 years. The material was first evaluated on normal hearing children. In a second step the phoneme and word perception scores of 35 CI children were measured using 60 - 100 dB SPL according to the most comfortable level (MCL) in free sound field. RESULTS: The performance-intensity function for the single words were highly comparable with those of the Freiburger or Göttinger speech perception test. The average speech reception threshold in CI children was 44 % (test I), 36 % (test II), 63 % (test III) and 69 % (test IV), respectively. Compared to the Mainzer and Göttinger speech perception test the new words were more difficult to understand than those of the known tests. However, a statistically significant difference could be noted only for test II. CONCLUSIONS: The new developed "Würzburger speech perception test" appears to be a useful additional tool for the evaluation of hearing impaired children in addition to the standard test procedures.
Bilateral cochlear implants: a way to optimize auditory perception abilities in deaf children?
OBJECTIVES: The Würzburg bilateral cochlear implant (CI) program was started with the aim to improve the patients' communicative abilities in complex listening situations. In this study, the auditory skills of children using bilateral cochlear implants were evaluated. STUDY DESIGN AND SETTINGS: Qualitative data based on free observations in the rehabilitation setup were collected in 39 bilaterally implanted children. A speech discrimination in noise test was performed in 18 of these children; lists of bisyllabic words were presented in noise at a signal to noise ratio (SNR) of +15 dB. RESULTS: Qualitative and quantitative data show clearly that bilateral CI improves the children's communicative behaviour, especially in complex listening situations. Children examined with the speech in noise test scored significantly better under the bilateral condition compared to the unilateral condition. Integration of the second implanted side and use of binaural information was observed to be easier and faster in children with a short time lag between both implants. CONCLUSIONS: To be able to obtain optimal benefit from bilateral cochlear implants, an intensive rehabilitation program is necessary. The important aspects of such a program are creating realistic expectations in older children before implantation; performing the first processor fitting of the second side with the first side switched on; and separate intensive training with the new system in order to balance out the hearing competence of the second CI with that of the first.
[Detection of loudness recruitment in patients with retrocochlear lesions using the "Würzburger Hörfeld" loudness scaling].
BACKGROUND: The pathogenesis of hearing loss caused by cerebellopontine angle tumors such as acoustic neuromas is unknown. The lack of loudness recruitment is thought to be one of the features of retrocochlear hearing impairment. In contrast to conventional suprathreshold tests, the categorial loudness scaling using the "Würzburger Hörfeld" is a valuable tool to describe the individual perception of sound. The aim of the present study was to analyze the loudness growth rate in patients with acoustic neuroma. PATIENTS AND METHOD: Pure tone and speech audiometry as well as auditory brainstem response and bilateral categorial loudness scaling were performed preoperatively in 54 patients with acoustic neuroma. Loudness scaling was done in free field switching off the contralateral ear by using an ear-plug. RESULTS: An abnormal rapid loudness growth function was found in 38 of the 54 patients (70.4%) at least at one frequency on the tumor side. The contralateral side was effected only in 57.4% of the patients. The incidence of a recruitment depended on the frequency with a maximum at 4 kHz. The slope of the loudness function showed a tendency to increase with increasing hearing loss. CONCLUSIONS: Loudness recruitment is not a rare phenomenon in patients with acoustic neuroma. The underlying cause (a preexisting hair cell damage, hair cell changes resulting from an obstruction of the cochlear blood supply or a disruption of the cochlear efferents) still remains unclear.
Middle latency auditory evoked potentials in temporal lobe disorders.
Middle latency auditory evoked potentials (MAEP) were recorded in 30 normal subjects and in 19 age-matched patients with temporal lobe lesions. MAEP appeared to be differentially affected by the specific structures involved within the temporal lobe. In the majority of patients with lesions involving the auditory area and/or auditory radiation, Na-Pa amplitude was significantly reduced over the involved hemisphere. No similar reduction in amplitude was noted in subjects with lesions not involving the auditory structures within the temporal lobe. We also observed a shift in a Pa latency over the involved hemisphere in patients with temporal lobe lesions involving the auditory structures. This latency shift was less pronounced than the amplitude reduction. The generators of MAEP in humans are discussed according to these findings and to the available literature. Normal intersubject variability of the conventional amplitude measures, and the occasional myogenic contamination of the response, limits establishing reliable criteria for abnormality that can be applied clinically for the diagnosis of patients with temporal lobe disorders.
Comparison of the TEMPO+ ear-level speech processor and the cis pro+ body-worn processor in adult MED-EL cochlear implant users.
A study was conducted to compare the new MED-EL TEMPO+ ear-level speech processor with the CIS PRO+ body-worn processor in the COMBI 40/COMBI 40+ implant system. Speech tests were performed in 46 experienced subjects in two test sessions approximately 4 weeks apart. Subjects were switched over from the CIS PRO+ to the TEMPO+ in the first session and used only the TEMPO+ in the time between the two sessions. Speech tests included monosyllabic word tests and sentence tests via the telephone. An adaptive noise method was used to adjust each subject's scores to approximately 50%. Additionally, subjects had to complete a questionnaire based on their 4 weeks of experience with the TEMPO+. The speech test results showed a statistically significant improvement in the monosyllabic word scores with the TEMPO+. In addition, in the second session, subjects showed a significant improvement when using the telephone with the TEMPO+, indicating some learning in this task. In the questionnaire, the vast majority of subjects found that the TEMPO+ allows equal or better speech understanding and rated the sound quality of the TEMPO+ higher. All these objective and subjective results indicate the superiority of the TEMPO+ and are mainly attributed to a new coding strategy called CIS+ and its implementation in the TEMPO+. In other words, based on the results of this study, it appears that after switching over from the CIS PRO+ to the TEMPO+, subjects are able to maintain or even improve their own speech understanding capability.