Year of publication
- 2009 (2) (remove)
- Site of cochlear stimulation and its effect on electrically evoked compound action potentials using the MED-EL standard electrode array (2009)
- Background: The standard electrode array for the MED-EL MAESTRO cochlear implant system is 31 mm in length which allows an insertion angle of approximately 720°. When fully inserted, this long electrode array is capable of stimulating the most apical region of the cochlea. No investigation has explored Electrically Evoked Compound Action Potential (ECAP) recordings in this region with a large number of subjects using a commercially available cochlear implant system. The aim of this study is to determine if certain properties of ECAP recordings vary, depending on the stimulation site in the cochlea. Methods: Recordings of auditory nerve responses were conducted in 67 subjects to demonstrate the feasibility of ECAP recordings using the Auditory Nerve Response Telemetry (ART™) feature of the MED-EL MAESTRO system software. These recordings were then analyzed based on the site of cochlear stimulation defined as basal, middle and apical to determine if the amplitude, threshold and slope of the amplitude growth function and the refractory time differs depending on the region of stimulation. Results: Findings show significant differences in the ECAP recordings depending on the stimulation site. Comparing the apical with the basal region, on average higher amplitudes, lower thresholds and steeper slopes of the amplitude growth function have been observed. The refractory time shows an overall dependence on cochlear region; however post-hoc tests showed no significant effect between individual regions. Conclusions :Obtaining ECAP recordings is also possible in the most apical region of the cochlea. However, differences can be observed depending on the region of the cochlea stimulated. Specifically, significant higher ECAP amplitude, lower thresholds and steeper amplitude growth function slopes have been observed in the apical region. These differences could be explained by the location of the stimulating electrode with respect to the neural tissue in the cochlea, a higher density, or an increased neural survival rate of neural tissue in the apex. Trial registration: The Clinical Investigation has the Competent Authority registration number DE/CA126/AP4/3332/18/05.
- Quality management: reduction of waiting time and efficiency enhancement in an ENT-university outpatients' department (2009)
- Background Public health systems are confronted with constantly rising costs. Furthermore, diagnostic as well as treatment services become more and more specialized. These are the reasons for an interdisciplinary project on the one hand aiming at simplification of planning and scheduling patient appointments, on the other hand at fulfilling all requirements of efficiency and treatment quality. Methods As to understanding procedure and problem solving activities, the responsible project group strictly proceeded with four methodical steps: actual state analysis, analysis of causes, correcting measures, and examination of effectiveness. Various methods of quality management, as for instance opinion polls, data collections, and several procedures of problem identification as well as of solution proposals were applied. All activities were realized according to the requirements of the clinic's ISO 9001:2000 certified quality management system. The development of this project is described step by step from planning phase to inauguration into the daily routine of the clinic and subsequent control of effectiveness. Results Five significant problem fields could be identified. After an analysis of causes the major remedial measures were: installation of a patient telephone hotline, standardization of appointment arrangements for all patients, modification of the appointments book considering the reason for coming in planning defined working periods for certain symptoms and treatments, improvement of telephonic counselling, and transition to flexible time planning by daily updates of the appointments book. After implementation of these changes into the clinic's routine success could be demonstrated by significantly reduced waiting times and resulting increased patient satisfaction. Conclusion Systematic scrutiny of the existing organizational structures of the outpatients' department of our clinic by means of actual state analysis and analysis of causes revealed the necessity of improvement. According to rules of quality management correcting measures and subsequent examination of effectiveness were performed. These changes resulted in higher satisfaction of patients, referring colleagues and clinic staff the like. Additionally the clinic is able to cope with an increasing demand for appointments in outpatients' departments, and the clinic's human resources are employed more effectively.