These and more new research studies will be addressed at the 141st Meeting of the Acoustical Society of America (ASA), to be held June 4-8 at the Palmer House Hilton Hotel in Chicago, Illinois.

Over 1,000 papers will be presented at the meeting of the largest scientific organization in the United States devoted to acoustics, with over 7,000 members worldwide.

Here are some highlights from among the many papers being given at the meeting. Full abstracts of the papers mentioned below can be viewed by typing in the last name of the author or the appropriate paper code at the ASA Meeting Abstracts database. (The first number of the paper code indicates the day of the talk, with "1" denoting Monday, "2" denoting Tuesday, and so on, up to "5" for Friday.)

Neurology Research, Hearing Disorders and Learning Problems

For the first time, researchers from Northwestern University have identified neural timing deficits in the auditory pathway of children with learning problems. In their talk (2pAB6) Tuesday afternoon, researchers Nina Kraus and Cynthia King will present evidence that these timing deficits can affect children's ability to perceive fundamental differences in certain basic acoustic features of speech.

The researchers studied normal and learning-impaired groups of children and observed that the learning-impaired children had measurable deficiencies in neural synchrony (a neurobiologic process involving neural responses that depend on synchronous activity across a population of neurons).

The researchers found that these timing deficits are related to performance on speech-sound perception and learning measures, and suggest that this research could significantly impact the diagnosis of auditory-based learning disorders in children.

In their talk, Kraus and King will also discuss first evidence of brain/behavior changes associated with commercially available auditory training regimens in children with learning problems.

Lithotripter Shock Plus IL-12 Promising Against Cancer

Researchers at the University of Michigan, Washington State University and Southern Illinois University including Douglas Miller, University of Michigan, will present their findings on Friday afternoon (5pBB4), showing that mice with melanoma cancer lived longer after being treated with a combination of lithotripter shock waves (SWs) and the drug interleukin-12 than with either treatment alone -- or no treatment at all.

Lithotripter shock waves (SWs) are very high pressure ultrasonic pulses which can be generated outside the body and focused on a target inside the body. SWs are currently used in medicine to treat kidney stones without surgery.

This group presents results that show mice with a combination of shock wave and drug treatment had significantly prolonged survival, and one mouse had complete tumor remission. The American Cancer Society says melanoma, while only accounting for 4% of all skin cancers, is the most deadly, causing 79% of skin cancer deaths.

Microphone Necklace for Hearing Aids

Researchers have just created useful jewelry for hearing-impaired persons. Bernard Widrow of Stanford has designed a necklace of microphones that is supported on the user's chest by a conducting loop that encircles the user's neck.

Electronic components on the necklace receive and combine the microphone signals so as to provide an amplified signal emphasizing sounds of interest originating in front of the user. A small coil in the ear picks up the signal.

Widrow says this system is "comfortable, inconspicuous, and convenient to use" and it provides a significant improvement in speech perception over existing hearing aids, especially in the presence of echoes and background noise. (3pSP1)

In separate attempts to make telephone speech easier to discern with hearing aids, Peter Nordqvist of the Royal University of Sweden will discuss the creation of a mathematical algorithm for a smart hearing aid which could automatically recognize telephone speech and change its settings (such as reducing its volume) to make the telephone speech easier to hear. (5aSCb2)

Detecting The Gender of A Speaker

Alireza Afshordi Dibazar of the University of Southern California will present a new automatic voice identication system which has demonstrated 99.2% accuracy in classifying the gender of the speaker. The researchers, including Theodore Berger, say that their method is easy to implement into voice recognition systems (1pSC30).

Taking Pictures of Tinnitus

One of the most widespread and frustrating hearing diseases is subjective tinnitus, in which the listener experiences what can be an unrelenting noise inside the head, such as ringing or buzzing. It has been a mystery as to exactly what creates these noises even when no external sound produces them.

Alan Lockwood of VA Healthcare Upstate New York and the University at Buffalo will present new medical studies of tinnitus that employ positron emission tomography, a medical technique for lighting up active regions of the brain as it performs various tasks.

Two studies of human subjects suggest that tinnitus does not originate in the cochlea, the inner ear where sound waves from the outside world are converted into electrical signals which travel to the brain. Instead, evidence suggests that tinnitus originates farther along the auditory pathway, closer to brain processing centers.

In fact, other sensory or motor systems may interact with these aberrant pathways, and this might explain how subjects can sometimes move their jaw or perform other actions to vary the volume and pitch of the sounds they are hearing.

Such interactions with the motor and neural pathways are complex and may explain why tinnitus is unresponsive to many drugs. This work may help assist efforts to design effective drugs for treating tinnitus. (1pPP5) Other talks at session 1pPP describe cutting-edge neuroimaging of auditory processes.

You Can Play That?

Percussion instruments built of wood, metal, glass and stone; ceramic flutes and sound sculptures inspired by ancient wind instruments; unusual tunings and scales; and a numerical model duplicating the sounds of the Woodstock Gamelan tubular chimes. These are just a few of the subjects addressed in session 2pMU dedicated to experimental musical instruments.

The session begins with an overview of recent trends in musical instrument making (2pMU1) by Bart Hopkin of Experimental Musical Instruments, who will describe numerous unusual instruments including Richard Water's Waterphone and Ellen Fullman's renowned Long String Instrument.

Subsequent talks address novel percussion instruments Thomas D. Rossing, Northern Illinois University (2pMU2), 21st century acoustic and orchestral instruments Patrick Ozzard-Low, London Guildhall University (2pMU4), and new woodwinds Lewis Jones, London Guildhall University (2pMU6), among others.

What Whales Hear

Australian researchers have found that the rapid change of noise levels produced by whale-watching boats that maneuver constantly may be more offensive to humpback whales than the noise levels themselves.

In a talk Thursday afternoon (4pAB6), Robert McCauley from Curtin University and Douglas Cato from the Defence Science and Technology Organisation will present their research on humpback whales in Hervey Sound (Queensland).

McCauley and Cato found that the whales responded more adversely to the rate of change of underwater noise produced from the design of various types of whale-watching vessels than to the steady level of noise. The researchers also suggest some important design criteria that impact underwater noise, that they recommend be taken into account when designing whale-watching vessels.

(Editor's Note: These descriptions were prepared by Ben Stein, Rory McGee and James Riordon of the American Institute of Physics in cooperation with the Acoustical Society of America.)

[Contact: Ben Stein]

23-May-2001