Reevaluating Traditional International Service-Learning during a Global Pandemic

Engineers in Action (EIA) Bridge Program provides engineering students with international service-learning opportunities through design-build footbridge projects. The conventional project model relies on an implementation trip as a primary learning activity. Prior to the pandemiccaused cancellations of all implementation trips in 2020, EIA resources were already being allocated to increase on-campus learning activities in an effort to improve the inclusivity of the program to students without the financial means to travel and forego paid internships. Online courses were developed using Open edX (https://eiaeducation.org) and the focus of students was shifted from preparing themselves to implement the bridge projects in person, to aiding local staff and communities to implement the projects without EIA students onsite. All student chapters remained actively engaged in their projects through the adapted project preparations and online courses. The successful adaptation of a service-learning project to an online format suggests that students still highly value these educational experiences. In the future, servicelearningprojects should consider offering online formats to engage more engineering studentsacross a wider range of institutions.</p

Social Emotional Development in Children who are Deaf or Hard of Hearing

Purpose: The purpose of this study was to assess social emotional development (SED) in children who are deaf or hard of hearing (HOH). This research focused on three questions: 1) Do children who are deaf or HOH demonstrate delay in SED compared to typically hearing children; 2) Are there certain social emotional skills that the children have difficulty with; and 3) Are there differences in social emotional ability percentile ranks for children who are approximately 15 months versus when they are 31 months of age? Methods: The Greenspan Social Emotional Growth Chart (GSEGC) was used to quantify SED in children who are deaf or HOH. 78 participants, ages 9 to 39 months, had completed GSEGCs. Of those participants, 55 completed the GSEGC at two different times, allowing for comparison between a mean age of 14.5 months and 31.5 months. Results: In the younger group 28.2% and in the older group 21.1% of participants fell below the 10th percentile on the GSEGC; however, over an approximate 1-year time span, SED percentile ranks improved within this sample. Conclusions: Children with hearing loss showed a delay in SED, although delays were less apparent over time. Social emotional skills that were most difficult were related to sound, attention getting, and the use/comprehension of language.</p

The Acoustic and Peceptual Effects of Series and Parallel Processing

Temporal envelope (TE) cues provide a great deal of speech information. This paper explores how spectral subtraction and dynamic-range compression gain modifications affect TE fluctuations for parallel and series configurations. In parallel processing, algorithms compute gains based on the same input signal, and the gains in dB are summed. In series processing, output from the first algorithm forms the input to the second algorithm. Acoustic measurements show that the parallel arrangement produces more gain fluctuations, introducing more changes to the TE than the series configurations. Intelligibility tests for normal-hearing (NH) and hearing-impaired (HI) listeners show (1) parallel processing gives significantly poorer speech understanding than an unprocessed (UNP) signal and the series arrangement and (2) series processing and UNP yield similar results. Speech quality tests show that UNP is preferred to both parallel and series arrangements, although spectral subtraction is the most preferred. No significant differences exist in sound quality between the series and parallel arrangements, or between the NH group and the HI group. These results indicate that gain modifications affect intelligibility and sound quality differently. Listeners appear to have a higher tolerance for gain modifications with regard to intelligibility, while judgments for sound quality appear to be more affected by smaller amounts of gain modification

Application of Auditory Models to Discrimination Thresholds of Voicing Parameters

Abstract: A recent study(1) reported discrimination thresholds for synthesized complex tones emulating glottal flow waveforms and output pressure waveforms for the vowel /#. Each signal type was varied along both an open quotient and a speed quotient continuum. Whereas Ns for open quotient were not significantly different for glottal flow and output pressure waveforms, JNDs for speed quotient were significantly larger for output pressure. The current experiment compared differences in the amplitude spectra and various auditory-perceptud representations of each standard-JND pair. Two center of gravity measures were relatively constant across signtis, suggesting a basis for the discriminations of these signals

Working memory and intelligibility of hearing-aid processed speech

Previous work suggested that individuals with low working memory capacity may be at a disadvantage in adverse listening environments, including situations with background noise or substantial modification of the acoustic signal. This study explored the relationship between patient factors (including working memory capacity) and intelligibility and quality of modified speech for older individuals with sensorineural hearing loss. The modification was created using a combination of hearing aid processing (wide-dynamic range compression and frequency compression) applied to sentences in multitalker babble. The extent of signal modification was quantified via an envelope fidelity index. We also explored the contribution of components of working memory by including measures of processing speed and executive function. We hypothesized that listeners with low working memory capacity would perform more poorly than those with high working memory capacity across all situations, and would also be differentially affected by high amounts of signal modification. Results showed a significant effect of working memory capacity for speech intelligibility, and an interaction between working memory, amount of hearing loss and signal modification. Signal modification was the major predictor of quality ratings. These data add to the literature on hearing-aid processing and working memory by suggesting that the working memory-intelligibility effects may be related to aggregate signal fidelity, rather than on the specific signal manipulation. They also suggest that for individuals with low working memory capacity, sensorineural loss may be most appropriately addressed with wide-dynamic range compression and/or frequency compression parameters that maintain the fidelity of the signal envelope