Algorithm for multi-curve-fitting with shared parameters and a possible application in evoked compound action potential measurements

BACKGROUND: Experimental results are commonly fitted by determining parameter values of suitable mathematical expressions. In case a relation exists between different data sets, the accuracy of the parameters obtained can be increased by incorporating this relationship in the fitting process instead of fitting the recordings separately. METHODS: An algorithm to fit multiple measured curves simultaneously was developed. The method accounts for parameters that are shared by some curves. It can be applied to either linear or nonlinear equations. Simulated noisy "measurement results" were created to compare the introduced method to the "straight forward" way of fitting the curves separately. RESULTS: The analysis of the simulated measurements confirm, that the introduced method yields more accurate parameters compared to the ones gained by fitting the measurements separately. Therefore it needs more computer time. As an example, the new fitting algorithm is applied to the measurements of the evoked compound action potentials (ECAP) of the auditory nerve: This leads to promising ideas to reduce artefacts generated by the measuring process. CONCLUSION: The introduced fitting algorithm uses the relationship between multiple measurement results to increase the accuracy of the parameters. Its application in the field of ECAP measurements is promising and should be further investigated

Systematic Review on Surgical Outcomes and Hearing Preservation for Cochlear Implantation in Children and Adults

OBJECTIVE: The mastoidectomy with facial recess approach (MFRA) is considered the reference standard for cochlear implantation. The suprameatal approach (SMA) was developed more recently and does not require mastoidectomy, which could influence postoperative outcomes. We aim to identify the optimal operative approach for cochlear implantation based on postoperative complications and hearing preservation in children and adults. DATA SOURCES: PubMed, EMBASE, Scopus, and Google Scholar. REVIEW METHODS: Studies comparing MFRA and SMA in children and adults were eligible for inclusion. Original reports with moderate relevance and validity were included. Relevance and validity were assessed with a self-modified critical appraisal tool. This review was reported in accordance to PRISMA guidelines. RESULTS: We retrieved 294 citations. Only retrospective nonrandomized studies were identified (level III evidence). Six articles were selected for full-text inclusion and 4 articles for data extraction. No article found a significant difference between MFRA and SMA with respect to postoperative complications in children and adults. One study found a significantly (P < .023) higher pediatric MFRA mastoiditis rate; however, meta-analysis did not indicate an overall effect. Hearing preservation was reported only in adults, and outcomes between techniques did not differ. CONCLUSION: No evidence was noted for lower complication rates or improved hearing preservation between the MFRA and SMA for cochlear implantation in children and adults. Pediatric data were available for children implanted above the age of 24 months only. Level I evidence is needed to resolve the uncertainty regarding differences in postoperative outcomes of pediatric and adult MFRA and SMA