Species diversity can be inferred using multiple data types, however, results based on genetic data can be at odds with patterns of phenotypic variation. Tiger beetles of the Cicindelidia politula (LeConte, 1875) species complex have been taxonomically problematic due to extreme phenotypic variation within and between populations. To better understand the biology and taxonomy of this group, we used mtDNA genealogies and multilocus nuclear analyses of 34,921 SNPs to elucidate its evolutionary history and evaluate the validity of phenotypically circumscribed species and subspecies. Genetic analyses recovered two divergent species that are also ecologically distinct, based on adult life history. These patterns are incongruous with the phenotypic variation that informed prior taxonomy, and most subspecies were not supported as distinct evolutionary lineages. One of the nominal subspecies was found to be a cryptic species; consequently, we elevate C. p. laetipennis (Horn, 1913) to a full species. Although nuclear and mtDNA datasets recovered broadly similar evolutionary units, mito-nuclear discordance was more common than expected, being observed between nearly all geographically overlapping taxonomic pairs. Additionally, a pattern of ‘mitochondrial displacement’ was observed, where mitochondria from one species unidirectionally displace others. Overall, we found that geographically associated life history factors better predict genomic divergence than phenotype and mitochondrial genealogies, and consequently taxon identifications based on mtDNA (e.g., DNA barcodes) may be misleading.
Purpose:
The Vibrant Soundbridge (VSB) active middle ear implant can be used to treat adults and children with hearing loss. Intraoperative measurements based on auditory brainstem response (ABR) allow the determination of the implant's performance. Two methods for stimulus presentation during ABR measurements via VSB will be compared.
Method:
ABRs were measured in patients implanted with a VSB using a standard ABR system. The stimulus was transmitted directly to the VSB using a new transmission unit (AcoustiAP, MED-EL) and for comparison via a standard audio processor coupled to a wireless streaming device. The study included 10 subjects with mild-to-profound sensorineural, conductive, or mixed hearing loss.
Results:
As opposed to the wireless method, the AcoustiAP transmits the ABR stimulus without additional signal processing. Therefore, only minor distortions of the transmitted signal are to be expected. There was no significant difference between the performance of the two methods (mean wave V amplitudes 313 [75.2] vs. 301 [88.2] nVpp). In addition, the new system allowed for a more stable connection to the implant system.
Conclusion:
The AcoustiAP is a valuable tool for performing ABR measurements in patients during VSB implantation using standard equipment, as it allows for easier and more controlled measurements of the coupling efficiency of the implant.
Fitting cochlear implant (CI) users can be challenging. Anatomy-based fitting (ABF) maps may have the potential to lead to better objective and subjective outcomes than conventional clinically based fitting (CBF) methods. ABF maps were created via information derived from exact electrode contact positions, which were determined via post-operative high-resolution flat panel volume computer tomography and clinical fitting software. The outcome measures were speech understanding in quiet and noise and self-perceived sound quality with the CBF map and with the ABF map. Participants were 10 experienced bilateral CI users. The ABF map provided better speech understanding in quiet and noisy environments compared to the CBF map. Additionally, two approaches of reducing the frequency-to-place mismatch revealed that participants are more likely to accept the ABF map if their electrode array is inserted deep enough to stimulate the apical region of their cochlea. This suggests an Angular Insertion Depth of the most apical contact of around 720°–620°. Participants had better speech understanding in quiet and noise with the ABF map. The maps’ self-perceived sound quality was similar. ABF mapping may be an effective tool for compensating the frequency-to-place mismatch in experienced bilateral CI users.
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