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Biomedical subjects

K Begall

Publications and source records attributed to K Begall.

33 records · Page 2Linked to original sources
PubMed1993

[Functional and morphologic results of pedicled and microvascular anastomosis in tissue transfer].

UNLABELLED: From 1982 to 1992, large intraoral and pharyngeal soft-tissue defects were reconstructed using myocutaneous island flaps in 95 patients, free jejunal interpositions in 10 patients and forearm flaps in 18 patients at the Magdeburg School of Medicine, Department and Clinic of Otorhinolaryngology. Sixty-five patients were followed up after various time periods in order to assess the functional results. Investigation and evaluation of the individual patients' resultant quality of life were based on a specifically prepared examination questionnaire. In particular, the evaluation included: the mouth opening gap, motility of the tongue, sufficient masticatory area, adequate provision to fit artificial teeth, malocclusion, the extent of mandibular deviation, assessment of the swallowing act, articulation disturbances, paraesthesia, function accessory nerve, atrophy of the trapezius muscle, motility of the cervical spine, flexibility in the shoulder girdle, as well as subjective information obtained from the patients (pain, feeling of dryness, increased salivation, occupational rehabilitation, organisation of leisure time). In 45 patients, biopsy material from the transferred tissue was examined at varied time intervals after primary therapy. IN CONCLUSION: The functional results obtained for the myocutaneous island flaps, the forearm flap and the free jejunal interposition were satisfactory, and only minor differences were noted. From the morphological point of view, all the three types of tissue transfer were found to have adapted adequately to the recipient site.

Anastomosis, Surgical↗
PubMed1993

[Diagnosis of hearing disorders in premature infants].

In cases of severe hearing loss in babies an early rehabilitation should prevent a delay in development. More than a half of all hearing disorders in children are acquired; to a large extend these hearing disorders are caused by premature birth and can be detected by suitable screening. Two methods are used for testing: (1) reflex audiometry with a standardized stimulus generator; and (2) bedside recording of brainstem potentials. Having tested the method of bedside recording of brainstem potentials a group of 60 premature infants of varied body weights and no additional diseases was examined as "normal" control group. Only premature birth with all signs of maturation adequate for gestational age is not a greater risk for hearing disorders. In premature infants with birth weights less than 1500 g, having marked hyperbilirubinemia and extensive intracranial bleeding always increased wave V latencies has been observed. In about 10% of these children severe hearing disorders were diagnosed and after leaving the premature department were sent to a paedaudiological dispensaire.

Audiometry, Evoked Response↗
PubMed1993

[Acceptance and hearing aid use by patients of retirement age (in the Magdeburg clinical area)].

Providing patients with hearing aids in the former German Democratic Republic was carried out in audiological centers by otolaryngologists and authorized audiologic-phonatric assistants. The available selection of hearing aids was limited. A randomized group of 119 patients rehabilitated with hearing aids was examined. The current study includes persons older than 65 years. In 78.4% of the patients treated, the quality of life was improved with the hearing aids. In contrast, the other patients reported the aids to be useless. Nearly 90% of all patients had no problems in managing their hearing aids. About 75% of the patients used the hearing aid the whole day. In addition to the hearing aid prescribed, 33 patients also have had to read lips and only a combination of both allows these patients to have adequate communication. Patients reported that 80% of the hearing aids worked well or were rarely out of order. Further, 68% of the people questioned reported a positive attitude of their fellow citizens. Only 6% mentioned that the use of hearing aids to treat presbycusis disturbed social communications. Since hearing loss can be progressive and to avoid interference in early rehabilitation, frequent follow-ups by otorhinolaryngologists are required. The evaluation of patients with hearing disorders requires the collaboration of physicians and hearing aid acousticians in order to give patients the most information and understanding of their deafness.

Aged↗
PubMed1992

[Systematic hearing diagnosis in the premature infant. The Magdeburg model].

Almost 50% of all hearing disorders found in children are acquired. To a large extent these hearing disorders are caused by premature birth and can be detected by suitable screening. Two methods have proved useful for such testing: (1) Reflex audiometry with a standardized stimulus generator; and (2) bedside recording of brainstem potentials. Having tested the method of bedside recording of brainstem potentials we examined a group of 60 infants of varied body weights and otherwise normal findings as a "normal" control group. At all click intensities measured, premature infants weighing from 1500 to 2000 g showed a latency increase by about 0.7 ms when compared to infants weighing in excess of 2000 g. Premature infants showing signs of maturation adequate for gestational age were not at greater risk for hearing disorders. In contrast, premature infants weighing less than 1500 g and having marked hyperbilirubinemia as week as extensive intracranial bleeding always showed increased wave V latencies. Ten percent of these infants had severe hearing disorders requiring special pecaudiological training. Overall findings showed the great usefulness of audiometric screening in a pediatric hospital center for detecting hearing disorders in premature infants.

Audiometry, Evoked Response↗
PubMed1990

[Meningitis and hearing damage in children].

1. Meningitis is a noteworthy cause of postnatal sensorineutral hearing disorders in children. 2. A monaural or binaural sensorineutral hearing disorder previously not noted was found in nine of fifty children with completely cured meningitis. 3. The influence of various clinical factors (age and sex of child; type of pathogen; time from occurrence of initial symptoms until admission to hospital; time of commencement of therapy; period of temperature and period of hospitalization; neurologic complications, and type of antibiotic therapy) on the audition was studied. A cerebral predisposition elevated by meningitis was found to enhance the risk of contracting a hearing disorder. 4. Damage to the hearing organ was attributed to meningitis rather than to gentamicin frequently used for therapy, as monoaural hearing disorders prevailed. 5. The high incidence rate of hearing disorders of unknown origin justifies the demand that children with meningitis be referred to otological diagnosis immediately after discharge from hospital even if their audition is apparently normal. 6. Feasible today, electrophysiological diagnosis provides unambiguous information on the function of the hearing organ.

Adolescent↗
PubMedDate not supplied

Observation of eardrum movements during quasi-static pressure changes by high-speed digital imaging.

Under specific quasi-static pressure conditions during the Valsalva manoeuvre, high-speed digital video pictures of eardrum displacements were recorded using an endoscope and a Kodak Image Ektapro 1000 Motion Analyzer. A new type of data interface enabled the complete videoclip to be saved and processed digitally, and, with special mathematical algorithms, it is possible to generate three-dimensional computer animations of eardrum movements under quasi-static pressure. The present study describes patterns of eardrum movements under static pressure changes (Valsalva manoeuvre). These patterns were consistent with the results of finite-element simulations of highly similar eardrum displacements reported by other workers.

Adult↗
PubMedDate not supplied

High-speed digital videoimaging of fast eardrum motions during Valsalva maneuver.

Digital high-speed camera systems are used to record high-frequency video-clips. After adapting this technology to the analysis of eardrum motions, fast motions of the eardrum can be recorded using an endoscope. Under specific static pressure conditions during the Valsalva maneuver, recordings of eardrum motions were made. The use of a Kodak Image Ektapro 1000 Motion Analyzer allowed only conventional videosignal processing and storage. A new type of data interface made it possible to save and process the complete video-clip digitally. Using an image-processing workstation and special mathematical algorithms, three-dimensional computer animations of fast eardrum motions under static pressure can be generated. In the present study, several animations of fast eardrum movements are described. High-speed digital videoimaging is an adequate method to describe fast eardrum displacements under static pressure (Valsalva maneuver). It is possible to create visible timeshift images of separate eardrum parts during the fast Valsalva maneuver.

Adult↗
PubMedDate not supplied

Artificial petrous bone produced by stereolithography for microsurgical dissecting exercises.

Training in microsurgery of the middle ear requires dissecting to be carried out on petrous bone. Human petrous bone structures are not available in adequate quantity to permit extensive practicing. Using synthetic resins, true reproductions of petrous bone can be obtained by means of a stereolithographic method, yielding structures of the petrous part which are highly similar to human bone. Digital data sets are obtained from spiral CT scans, and transferred to CAD systems such that, using stereolithography, petrous bone facsimiles are produced on the parametric model. Any number of such models of an original can be produced. Thus, identical structures can be made available for a wide range of uses. Exercises conducted on artificial petrous bone so produced are equivalent to those carried out on human structures, in terms of material properties and visualisation of anatomic details.

Anatomy↗
PubMedDate not supplied

Speech understanding with the CIS and the n-of-m strategy in the MED-EL COMBI 40+ system.

Speech tests have been performed on 6 subjects for comparing the standard 12-channel continuous interleaved sampling (CIS) strategy (CIS12), the 7-channel CIS strategy (CIS7) and the 7-of-12 strategy in the MED-EL COMBI 40+ system. An ABAB experimental design was used whereby each strategy was reversed and replicated. Speech tests were performed in quiet (vowels, consonants, monosyllables, sentences) and noise (sentences). Results showed that for vowels, CIS12 is significantly superior to CIS7, for consonants and sentences CIS12, CIS7 and 7-of-12 performed equally well, and that for monosyllables 7-of-12 is significantly superior to both CIS12 and CIS7. In addition, 7-of-12 is superior to CIS7 by almost the same amount as CIS12, but in this case the difference is not significant. Further, all strategies have been found to be equally robust in noise with respect to sentence understanding. The differences between CIS12 and 7-of-12 on the one hand and CIS7 on the other hand may be attributed to decreased spectral resolution of the latter. The fact that - in contrast to what has been reported for the SPEAK strategy - 7-of-12 is equally robust in noise as the CIS strategies is explained by the use of higher stimulation rates, wider frequency bands and a higher percentage of channels stimulated in each cycle.

Adult↗
PubMedDate not supplied

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.

Adult↗
PubMedDate not supplied

Selective chemical vestibulectomy. Preliminary results.

In an attempt to destroy the peripheral vestibular labyrinth selectively in patients suffering from intractable vertigo as a result of end-stage Ménière's disease, 25 patients underwent selective chemical vestibulectomy between 1989 and 1994. As part of the procedure a certain quantity of streptomycin was placed between the bony and the membranous part of the lateral semicircular canal. The dosage of streptomycin used for successful ablation of vertigo varied between 250 and 100 micrograms. Within 12 months following the procedure all patients experienced a tremendous improvement in their overall condition. In spite of the fact that some patients noted an overall hearing improvement, increased cochlear thresholds were observed in a number of patients, which could not be ignored. The aim of this report is to detail the reliability of control of vertigo, conservation of hearing, and change in disability 12 months after surgery in the 23 patients (of 25) available for follow-up.

Administration, Topical↗
PubMedDate not supplied

Resonant frequency pattern in multifrequency tympanograms: results in normally-hearing subjects.

This paper presents experimental data on the evaluation of middle ear resonances by multifrequency tympanometry. Multifrequency tympanograms (MFTs) of 18 normally-hearing subjects were recorded with a frequency resolution of 15 Hz. The fine structure found in the MFT patterns was compared with findings in literature. A first approach for the evaluation of this fine structure was made explaining the great variability of the main ossicular resonance frequencies described in previous publications. The consequence of the present investigation is that the concept of the main ossicular resonance has to be revised critically.

Acoustic Impedance Tests↗