1aSC1 – Untangling the link between working memory and understanding speech

Adam Bosen – adam.bosen@boystwon.org
Boys Town National Research Hospital
555 N. 30th St
Omaha, NE 68131

Popular version of paper 1aSC1 Reconsidering reading span as the sole measure of working memory in speech recognition research
Presented Tuesday morning, June 8th, 2021
180th ASA Meeting, Acoustics in Focus

Many patients with cochlear implants have difficulty understanding speech. Cochlear implants often do not convey all of the pieces of speech, so the patient often has to use their memory of what they heard to fill in the missing pieces. As a result, their ability to understand speech is correlated with their performance on working memory tests (O’Neill et al., 2019). Working memory is our ability to simultaneously remember some information while working on other information. For example, if you want to add 57 and 38 in your head you need to sum 7+8 and then hold the result in memory while you work on summing 50+30.

The reading span test is a common tool for measuring working memory. In this test, people see lists of alternating sentences and letters and must decide whether each sentence makes sense while simultaneously remembering the letters. The reading span test is important because it often predicts how well people with hearing loss can understand speech.

We do not know is why the reading span test is related to speech understanding. One idea is that the ability to simultaneously remember and work on interpreting what you heard is essential for understanding unclear speech. To test this idea, our lab asked young adults with normal hearing to try to understand unclear sentences. These sentences were mixed with two other people talking in the background and then processed to mimic the limited signal a cochlear implant provides.

[Vocoded Speech in Babble.mp3, An unclear recording of someone saying “If the farm is rented, the rent must be paid” with other people talking in the background.]

They also completed memory tests which do not require them to work on anything, such as remembering lists of spoken numbers (example) or words on a screen (example). These tests were as good as reading span at predicting how well these participants could understand unclear speech. This finding indicates that the reading span test is just one way to assess the parts of memory that relate to understanding speech. We conclude that the ability to simultaneously remember and work on information is not the only part of memory that helps us understand unclear speech.

We also tested older adults with cochlear implants on their ability to understand sentences and their ability to remember lists of numbers. Surprisingly, we did not find a relationship between remembering lists of numbers and understanding speech like we did in young adults with normal hearing. This finding indicates that age and/or hearing loss change which parts of working memory relate to understanding speech. Previous work suggests that some parts of working memory tend to decline with age, while others do not (Bopp & Verhaeghen, 2005; Oberauer, 2005). We conclude that further untangling the link between working memory and understanding speech requires measuring different parts of memory using multiple tests.

Bopp, K. L., & Verhaeghen, P. (2005). Aging and Verbal Memory Span: A Meta-Analysis. Journal of Gerontology, 60B(5), 223–233. https://doi.org/https://doi.org/10.1093/geronb/60.5.P223

O’Neill, E. R., Kreft, H. A., & Oxenham, A. J. (2019). Cognitive factors contribute to speech perception in cochlear-implant users and age-matched normal-hearing listeners under vocoded conditions. The Journal of the Acoustical Society of America, 146(1), 195–210. https://doi.org/10.1121/1.5116009

Oberauer, K. (2005). Control of the contents of working memory – A comparison of two paradigms and two age groups. Journal of Experimental Psychology: Learning Memory and Cognition, 31(4), 714–728. https://doi.org/10.1037/0278-7393.31.4.714

 

1aMU4 – In search of huge sound… or huge strings, at least

Pawel Bielski – pawbiels@pg.edu.pl
Hanna Pruszko – hanprus1@pg.edu.pl
Tomasz Mikulski – tomi@pg.edu.pl
Gdansk University of Technology
Narutowicza 11/12, 80-233 Gdansk
Poland

Popular version of paper 1aMU4 Numerical and experimental assessment of string gauge influence on guitar tone
Presented Tuesday morning, June 08, 2021
180th ASA Meeting, Acoustics in Focus

Meet Adam. Adam loves the nines (that is, 0.09-inch gauge, or 9’s, named by the diameter of the high E string). When he touches a guitar stringed with the 9’s, it seems soft and responsive under his fingers. This phenomenon is called “feel”. Adam picks a guitar with a proper feel and unites with the instrument. Suddenly physical bounds disappear. Adam believes in supernatural traits of the 9’s and no research can change his mind.

But we can still try.

Guitar players are obsessed with string gauges. From the super slinky 7’s of Billy Gibbons, through the agile 8’s and 9’s of Jimi Hendrix and Jimmy Page, massive sound of Joe Bonamassa (11) and Stevie Ray Vaughan (13), to Pat Martino’s super fat 15’s and extreme twang of Dick Dale (16’s). A wide selection of string gauges covers a variety of guitar playing styles.

Thicker strings are harder to bend but carry more force. Vibration is essentially very fast bending in different modes (shapes) – 1st harmonic (fundamental) and upper harmonics (overtones). Harmonic composition is called the brightness of the string. Higher harmonics create a sharp and open sound. Lower harmonics help to beef up the tone. Definition of chords also benefits from profound fundamentals.

strings

Fundamental mode and upper harmonics of a vibrating string [Source image: Harmonics.png]

Depending on the gauge, the total force carried by electric guitar strings ranges from the weight equivalent of a ten-year-old child to an adult man. It makes nearly triple the difference. Acoustic guitars offer a more humble selection of 10’s – 13’s string gauges, but the choice might be even more critical. The acoustic sound is raw and less processed. It depends on the physical features of the instrument. Fiddling with the pulling force and vibrating mass on a resonant guitar body must make a difference. The body gets tenser and stiffer. It is driven hard and significantly deformed. Will it be able to breathe freely?

Imagine borrowing your general practitioner’s stethoscope and listening to the acoustic guitar’s soundboard while it plays. This is roughly how we used accelerometers. Low E strings of different gauges were repeatedly tested for their volume, sustain (duration of sound), and harmonic composition. The samples were recorded with a microphone too. We analyzed the sound spectrum during different stages of the sound.

Setup of accelerometers [Source image: AccSetup.png]

Most findings agree with the general beliefs regarding string gauges besides one major exception. The weak sustain of heavy strings might be a surprise to many guitar players. Thick strings have a rich and loud attack yet immediately lose their superb qualities. They seem to excel at quick, punchy notes, but struggle with slow-paced singing solos. In the long run, light strings were more sustainable, retaining their harmonics in time.

[Recording of 13’s string: E6nr13.mp3]

[Recording of 10’s string: E6nr10.mp3]

Recordings of heavy and light strings (flanger effect caused by averaging from multiple samples

Advantages of the different gauges shown at two scales [Source image: Signals.png]

Other than that, heavy strings are generally louder and more substantial, while light strings seem brighter and more open. Thick strings excite the body modes (structural vibration) more, while light ones favor air resonance.

Adam will probably not readjust his beliefs, but maybe you will?

Summary of the findings

3pSCb1 – Sound Teaching Online During COVID19

Anne C. Balant – balanta@newpaltz.edu
State University of New York at New Paltz
1 Hawk Dr.
New Paltz, NY 12561

Popular version of lightening round talk 3pSCb1 “Lab kits for remote and socially distanced instruction in a GE Acoustics Course“
Presented Thursday afternoon, June 10, 2021
180th ASA Meeting, Acoustics in Focus
Read the article in Proceedings of Meetings on Acoustics

How do you give students in an online acoustics course a hands-on lab experience?

kit

At the State University of New York (SUNY) at New Paltz, students in the online sections of “The World of Sound” use a lab kit that was designed by the instructor. Students pay for shipment of the kits to their homes at the start of the course and return them at the end. They submit photos or videos of their activities along with their completed lab reports.

These kits had been in use for several years in an online post-baccalaureate program that prepares students for graduate study in speech-language pathology when the COVID19 pandemic radically changed the undergraduate on-campus version the course.

“The World of Sound” is a four-credit general education lab science course. Undergraduates typically work in groups of three and share equipment within and across lab sections. By summer of 2020, it was clear that on-campus labs in the upcoming fall semester would have to meet social distancing requirements, with no sharing of materials, and that there could be a pivot to fully remote instruction at any time. The cost of the needed individual instructional materials was a consideration due to the fiscal impact of COVID19. A revised lab kit was developed that contains everything needed for seven labs, costs under $30.00, and has a shipping weight of less than two pounds.

kit

About one-fourth of the undergraduates in the course chose to study fully remotely during fall 2020. These students had their kits shipped to them and they attended a weekly virtual lab session. Each student in the seated course was issued an individual lab kit in a shipping box that was addressed to the department for ease of return shipment. Seated labs were conducted with all required precautions including face coverings and social distancing. The kits contained everything needed for each lab, including basic supplies, so no equipment had to be shared.

Although the college was able to keep COVID19 rates low enough to stay open for the entire semester, about 15% of the students in the course transitioned to remote learning at least briefly for reasons such as illness or quarantine, missing a required covid test date, financial issues, or COVID19-related family responsibilities or crises. Having their lab kits in their possession allowed these students to move seamlessly between seated and virtual lab sessions without falling behind. Every undergraduate who studied remotely for part or all of the semester completed the course successfully.

3aBA9 – Ultrasound mediated thermal stress augments mass and drug transport in brain tumors

Costas Arvanitis
Georgia Institute of Technology
costas.arvanitis@gatech.edu

Popular version of paper 3aBA9 The role of U.S. thermal stress in modulating the vascular transport dynamics in the brain tumors
Presented Thursday morning, June 10, 2021
180th ASA Meeting, Acoustics in Focus

Local hyperthermia and stimuli-responsive delivery systems, such as thermosensitive liposomes, represent promising strategies to locally enhance drug delivery in brain tumors and improve treatment outcomes. However, a critical obstacle towards exploring their therapeutic potential in brain tumors is the limited ability to attain reliably and reproducibly the desired temperature in the brain.

Dr Costas Arvanitis at the Georgia Institute of Technology and Emory University, and his graduate student, Chulyong Kim, hypothesized that trans-skull focused ultrasound combined with closed-loop controlled methods can achieve this goal.

brain tumors
Figure 1. Graphical representation of  US mediated  thermal stress drug release and delivery from  thermosensitive drugs in brain tumors.

Almost!
Attaining controlled thermal stress through the skull is not a trivial problem, especially in mice where every new treatment is tested for safety and efficacy. For example, although at low frequencies (< 1 MHz) most of the energy is transmitted through the skull, the resulting large focal region overlaps substantially with the skull, which due to its higher absorption leads to disproportionally high skull heating. On the other hand, at higher frequencies (> 2 MHz) skull reflections and aberrations become significant, and thus limit our ability to focus the beam in the brain through the skull. Using a physically accurate mathematical modeling, the investigations revealed that an optimal frequency (≈ 1.7 MHz) does exist for applying localized thermal stress in mice brain without overheating the skull.

Based on this knowledge, the investigators built a closed-loop trans-skull magnetic resonance imaging guided focused ultrasound (MRgFUS) prototype and demonstrated that it can attain reproducible experimentation and heating of the entire tumor at the desired temperature. Next, using semi-quantitative imaging, they revealed that localized thermal stress (41.5 oC for 10 minutes) in brain tumors in rodents promotes acute changes in the cerebrovascular transport dynamics in the brain tumor microenvironment. These changes can be important, as they can increase the amount of drug that reaches the tumor.

Subsequently, by combining the abilities of this system with those of thermosensitive liposomes loaded with doxorubicin, the most common chemotherapeutic agent, they were able to achieve a marked improvement in doxorubicin accumulation and uptake in preclinical glioma tumor models. Crucially, survival studies indicated that the proposed two-pronged strategy could lead to substantial improvement in the survival.

Overall, this work, in addition to refining our understanding on the role of thermal stress in modulating the transport dynamics in the brain tumor microenvironment, allowed to establish a new paradigm for noninvasive targeted drug delivery in glioblastomas. It may, thus, create new opportunities towards attaining clinically effective drug delivery in patients with aggressive brain tumors, such as glioblastoma, that currently have limited treatment options.

Acknowledgments: This study was supported by the National Institutes of Health grants R00 EB016971.

Links: https://arvanitis.gatech.edu/

2pMU3 – Why do harpists still prefer gut strings?

Jim Woodhouse — jw12@cam.ac.uk
Cambridge University Engineering Department
Trumpington St
Cambridge CB2 1PZ, U.K.

Nicolas Lynch-Aird — lynchaird@yahoo.co.uk
The Old Forge
Burnt House Lane
Battisford
Suffolk IP14 2ND, U.K.

Popular version of paper ‘2pMU3’ String choice: Why do harpists still prefer gut?
Presented Wednesday afternoon, June 9, 2021
180th ASA Meeting, Acoustics in Focus

Classical guitarists have all abandoned traditional gut strings in favour of nylon, but harpists still prefer gut.  Why is this? A study of the various limits on string choice for musical instruments has shown that the answer lies in a difference of “damping” in the strings, which is responsible for a difference in brightness of the sound.

When choosing a string for an instrument, the player knows the string length and the frequency it will be tuned to: their task is to choose the material and the diameter. The various different constraints on that choice can be summarised in a chart: a schematic version is shown here.

strings

Schematic chart for choosing strings for musical instruments

The length and the frequency multiplied together defines the position on the horizontal axis. The player’s choice then consists of moving along a vertical line through that point, to choose a string diameter. They need to make a choice within the blue region, otherwise something will go wrong.  The exact shape and position of this blue region depends on the choice of string material.

Obviously the string must not break. There are also upper and lower limits on the tension: if a string is too slack or too tight, it feels wrong to the player.  Less obviously, the choice must lie beneath the dashed line labelled “damping too high”, otherwise the sound will become a dull thud rather than a ringing musical tone. This is where the harp differs from the guitar.  Guitar strings stay well clear of the dashed line, but for the longer, lower-pitched strings of a harp, players want to use strings with very high tension so that the “feel” is right. But that pushes them towards the dashed line, and it is this damping limit that defines the practical limit on string choice. When the detailed charts are compared for nylon and  gut strings, the dashed line is higher for gut. That gives a bit more “headroom” for the player’s choice, and allows them to choose a string that feels good under the fingers, while still having a satisfyingly bright and ringing tone.