scholarly journals A Site-Selection Strategy based on Polarity Sensitivity for Cochlear Implants: Effects on Spectro-Temporal Resolution and Speech Perception

2019 ◽  
Author(s):  
Tobias Goehring ◽  
Alan Archer-Boyd ◽  
John M. Deeks ◽  
Julie G. Arenberg ◽  
Robert P. Carlyon
Keyword(s):  
Speech Perception ◽  
Temporal Resolution ◽  
Site Selection ◽  
Dynamic Range ◽  
High Amplitude ◽  
Selection Strategy ◽  
Noise Performance ◽  
Large Variability ◽  
Processing Strategies ◽  
A Site

Thresholds of asymmetric pulses presented to cochlear implant (CI) listeners depend on polarity in a way that differs across subjects and electrodes. It has been suggested that lower thresholds for cathodic-dominant compared to anodic-dominant pulses reflect good local neural survival. We evaluated the hypothesis that this polarity effect (PE) can be used in a site-selection strategy so as to improve speech perception and spectro-temporal resolution. Detection thresholds were measured in 8 users of Advanced Bionics CIs for 80-pps, tri-phasic, monopolar pulse trains where the central high-amplitude phase was either anodic or cathodic. Two experimental MAPs were then generated for each subject by deactivating the five electrodes with either the highest or the lowest PE magnitudes (cathodic minus anodic threshold). Performance with the two experimental MAPs was evaluated using two spectro-temporal tests (STRIPES, Archer-Boyd et al., 2018; and SMRT, Aronoff and Landsberger, 2013), and with speech recognition in quiet and in noise. Performance was also measured with an experimental MAP that used all electrodes, similar to the subjects’ clinical MAP. The PE varied strongly across subjects and electrodes, with substantial magnitudes relative to the electrical dynamic range. There were no significant differences in performance between the three MAPs at group level, but there were significant effects at subject level - consistent with previous reports of a large variability in CI users’ performance, and in the potential benefit of site-selection strategies. The STRIPES but not the SMRT test successfully predicted which strategy produced the best speech-in-noise performance on a subject-by-subject basis. The average PE across electrodes correlated significantly with subject age, duration of deafness and speech perception scores, consistent with a relationship between PE and neural health. These findings motivate further investigations into site-specific measures of neural health and their application to CI processing strategies.

Signal Coding in Cochlear Implants: Exploiting Stochastic Effects of Electrical Stimulation

2003 ◽  
Vol 112 (9_suppl) ◽  
pp. 14-19 ◽  
Author(s):  
Jay T. Rubinstein ◽  
Robert Hong
Keyword(s):  
Electrical Stimulation ◽  
Speech Perception ◽  
Cochlear Implants ◽  
Speech Processing ◽  
Music Perception ◽  
Dynamic Range ◽  
High Rate ◽  
Monosyllabic Word ◽  
Stochastic Effects ◽  
Processing Strategies

Speech perception in quiet with cochlear implants has increased substantially over the past 17 years. If current trends continue, average monosyllabic word scores will be nearly 80% by 2010. These improvements are due to enhancements in speech processing strategies, to the implantation of patients with more residual hearing and shorter durations of deafness, and to unknown causes. Despite these improvements, speech perception in noise and music perception are still poor in most implant patients. These deficits may be partly due to poor representation of temporal fine structure by current speech processing strategies. It may be possible to improve both this representation and the dynamic range of electrical stimulation through the exploitation of stochastic effects produced by high-rate (eg, 5-kilopulse-per-second) pulse trains. Both the loudness growth and the dynamic range of low-frequency sinusoids have been enhanced via this technique. A laboratory speech processor using this strategy is under development. Although the clinical programming for such an algorithm is likely to be complex, some guidelines for the psychophysical and electrophysiological techniques necessary can be described now.

Waste disposal site selection techniques in Quaternary terraine Ontario, Canada

1991 ◽  
Vol 7 (1) ◽  
pp. 211-217
Author(s):  
A. J. Cooper
Keyword(s):  
Site Selection ◽  
Waste Treatment ◽  
Careful Analysis ◽  
Quaternary Geology ◽  
Disposal Site ◽  
Geological Investigation ◽  
Fine Grained ◽  
Clayey Silt ◽  
Treatment And Disposal ◽  
A Site

AbstractThick and predictable deposits of fine grained Quaternary materials have been used for the siting of waste management facilities in Ontario. The search for such sites is founded on the application of techniques in Quaternary geology and hydrogeology. Two examples are presented. Oxford County is located southwest of Toronto in an area of parallel morainic ridges separated by flat till plains. Conventional wisdom would focus on the till plains for thick, consistent fine grained Quaternary Sediments. However, the careful analysis of the Quaternary stratigraphy and glacial history revealed that better sites are located along the moraines. A site on the Ingersoll Moraine was studied in detail and defended at a public hearing. Concerns about the geology of the materials were allayed by the confirmation of homogeneous clayey silt materials exposed when the site opened in late 1986. A much wider ranging search was undertaken for a major hazardous and liquid industrial waste treatment and disposal facility for the Province of Ontario. Progressively more detailed investigations of the Quaternary geology were used to assist a multi-disciplinary site selection team. Initial interpretations covered an area of 75 000 km2 at a scale of 1:250 000. Eight candidate sites were then selected for further investigation with five continuously sampled stratigraphic boreholes. The chosen site is located in a depression in the bedrock filled with 40 m of glaciolacustrine clayey silt. Site specific hydrogeological and geotechnical studies were integrated with a detailed geological investigation.

scholarly journals Developmental Links Between Speech Perception in Noise, Singing, and Cortical Processing of Music in Children with Cochlear Implants

2018 ◽  
Vol 36 (2) ◽  
pp. 156-174 ◽  
Author(s):  
Ritva Torppa ◽  
Andrew Faulkner ◽  
Teija Kujala ◽  
Minna Huotilainen ◽  
Jari Lipsanen
Keyword(s):  
Speech Perception ◽  
Cochlear Implants ◽  
Musical Instrument ◽  
Noise Performance ◽  
Speech Perception In Noise ◽  
Speech In Noise ◽  
Brain Responses ◽  
Time Period ◽  
Musical Sounds ◽  
Auditory Skills

The perception of speech in noise is challenging for children with cochlear implants (CIs). Singing and musical instrument playing have been associated with improved auditory skills in normal-hearing (NH) children. Therefore, we assessed how children with CIs who sing informally develop in the perception of speech in noise compared to those who do not. We also sought evidence of links of speech perception in noise with MMN and P3a brain responses to musical sounds and studied effects of age and changes over a 14–17 month time period in the speech-in-noise performance of children with CIs. Compared to the NH group, the entire CI group was less tolerant of noise in speech perception, but both groups improved similarly. The CI singing group showed better speech-in-noise perception than the CI non-singing group. The perception of speech in noise in children with CIs was associated with the amplitude of MMN to a change of sound from piano to cymbal, and in the CI singing group only, with earlier P3a for changes in timbre. While our results cannot address causality, they suggest that singing and musical instrument playing may have a potential to enhance the perception of speech in noise in children with CIs.

scholarly journals Modulation depth discrimination by cochlear implant users

2021 ◽  
Author(s):  
Jessica Monaghan ◽  
Robert P. Carlyon ◽  
John M. Deeks
Keyword(s):  
Speech Processing ◽  
Dynamic Range ◽  
Modulation Depth ◽  
High Rate ◽  
Backward Masking ◽  
Pulse Trains ◽  
Processing Strategies ◽  
Depth Discrimination ◽  
Variable Point ◽  
Forced Choice Task

Cochlear implants (CIs) convey the amplitude envelope of speech by modulating high-rate pulse-trains. However, not all of the envelope may be necessary to perceive amplitude modulations (AM); the effective envelope depth may be limited by forward and backward masking from the envelope peaks. Three experiments used modulated pulse-trains to measure which portions of the envelope can be effectively processed by CI users as a function of AM frequency. Experiment 1 used a three-interval forced-choice task to test the ability of CI users to discriminate less-modulated pulse trains from a fully-modulated standard, without controlling for loudness. The stimuli in Experiment 2 were identical, but a two-interval task was used in which participants were required to choose the less-modulated interval, ignoring loudness. Catch trials, in which judgements based on level or modulation depth would give opposing answers were included. Experiment 3 employed novel stimuli whose modulation envelope could be modified below a variable point in the dynamic range, without changing the loudness of the stimulus. Overall, results showed that substantial portions of the envelope are not accurately encoded by CI users. Experiment 1, where loudness cues were available, participants on average were insensitive to changes in the bottom 30% of their dynamic range. In Experiment 2, where loudness was controlled, participants appeared insensitive to changes in the bottom 50% of the dynamic range. In Experiment 3, participants were insensitive to changes in the bottom 80% of the dynamic range. We discuss potential reasons for this insensitivity and implications for CI speech-processing strategies.

scholarly journals Site Selection for Joint Logistics over the Shore (JLOTS) Operations Using Multi- Objective Decision Analysis

2016 ◽  
Vol 4 (2) ◽  
pp. 88-95
Author(s):  
Mike Evans ◽  
Mike Lami ◽  
Brendan Madarasz ◽  
Benjamin Smith ◽  
Chris Green
Keyword(s):  
Decision Analysis ◽  
Site Selection ◽  
Decision Support Tool ◽  
Military Operations ◽  
Support Tool ◽  
Multi Objective ◽  
Selection Protocol ◽  
Operational Criteria ◽  
A Site ◽  
Development Center

As the U.S. military faces an increasing need to deploy across a range of military operations and environments, the ability to establish and sustain logistics support remains a major challenge. The Engineer Research and Development Center is currently developing the Planning Logistics Analysis Network System (PLANS), a decision support tool, to facilitate strategic and operational logistics planning. This paper describes a site selection protocol for logistics operations occurring without a suitable port, commonly referred to as Logistics over-the Shore (LOTS) operations. The model uses multi- objective decision analysis techniques to weight different operational criteria to determine the best overall site for logistics over the shore operations. This tool will enhance the time and accuracy in determining an optimal site that meets the decision maker’s specific operational needs.

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