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Making Sense of What We Hear

By studying speech perception, Lauren Calandruccio seeks to advance optimal communication for all

By Alexander Gelfand

Fall | Winter 2017

Lauren Calandruccio, an associate professor in the Department of Psychological Sciences, established the Speech and Auditory Research Laboratory when she joined the college faculty in 2015. Photo by Mike Sands.

Picture this: You’re at a cocktail party, chatting with a friend over drinks and canapés. In the background, glasses clink, music plays—and a myriad of other voices babble away. Chances are, you’ve never paused to consider how you’re able to follow a single speaker’s voice in such a situation.

Experts in speech perception, however, have devoted considerable thought to this phenomenon, which they call “the cocktail party effect.” Lauren Calandruccio, an audiologist and hearing scientist, began exploring it while she was in graduate school. By studying how people understand speech in noisy environments, she hopes to bring about improvements in the design of hearing aids. She is also developing cognitive strategies to help those with hearing loss—and even those without it—communicate better in challenging surroundings.

In 2015, Calandruccio brought her research to Case Western Reserve, where she is now an associate professor in the Communications Sciences Program in the Department of Psychological Sciences. She conducts her experiments in the Speech and Auditory Research (SpAR) Laboratory, a space she created in the Cleveland Hearing & Speech Center.

To understand Calandruccio’s fascination with speech and noise, it helps to know a bit about hearing and sound perception in general—activities performed so effortlessly by people with normal hearing that they are usually taken for granted.

Competing Sounds

According to the standard textbook model, the process of hearing begins when sound waves are collected by the outer and middle ear and transferred as mechanical vibrations to the inner ear. Tiny structures called hair cells, contained within a spiral cavity known as the cochlea, transform these physical vibrations into neural impulses in the auditory nerve. Those impulses are then carried into the brain, which interprets them as intelligible sounds.

So far, so good. But as Calandruccio explains, making sense of what we hear in the real world is rarely so straightforward.

Take that cocktail party, for example. The barrage of sounds entering your ears and stimulating your cochlea comes from all kinds of sources. Many of these sounds occur at overlapping frequencies, exciting your hair cells and auditory nerve fibers in similar ways. Some contain linguistic content that competes for your brain’s attention, further complicating matters.

Such physical and perceptual interference is known as “masking,” and it raises important questions. How, for instance, does the auditory system distinguish the speech of one person—the “target speaker,” in the parlance of speech perception—from all the other aural stimuli swirling around it? And how does the brain perceive that speech as a single coherent stream even as it is crosscut, overlaid and otherwise jumbled by a cacophony of unrelated sounds?

The answer appears to be: with varying degrees of success.

In clinical settings, audiologists test our hearing using pure tones made up of specific frequencies, which they occasionally mask with simple, steady noise. Calandruccio herself performed such tests as a clinician at Riley Hospital for Children at Indiana University Medical Center just after earning her master’s degree in audiology. In the SpAR Lab, however, she investigates our ability to perceive speech under more realistic conditions, using a specially designed sound suite and experimental software.

The suite is essentially a large, sound-attenuating box with heavy doors and double walls. (Once inside, Calandruccio says, “you might not hear your heartbeat, but you will hear your stomach gurgle.”) It contains two sections: a control room for researchers and a test room for study participants. Researchers play recorded speech through headphones worn by the participants, who identify what they have heard. By adding extra voices to the mix and otherwise manipulating the sounds—degrading the audio quality, say, or obscuring certain audio frequencies—Calandruccio and her students try to mimic the complex masking that occurs in daily life.

From left: In the sound suite of Calandruccio’s lab, Gabrielle Miller, a doctoral student in the Communication Sciences Program, participates in a study of the link between hearing and memory in older adults. Master’s student Brandi Jett (CWR ’17) is running the experiment. Photo by Mike Sands.

Such experiments reveal that even people with normal hearing can have trouble perceiving speech in real-world conditions. But people with hearing loss—even mild hearing loss—have a much harder time. Put them in a restaurant with horrible acoustics, Calandruccio says, and “they just can’t communicate. They literally can’t understand the speech that somebody’s saying when there are so many competing sounds.”

This can be true even if these people wear hearing aids, which amplify selected audio frequencies. Unfortunately, making sounds louder doesn’t necessarily make them clearer. As a result, trying to use a hearing aid in a noisy environment can be an exercise in frustration.

Multiple Languages

Calandruccio has witnessed the effects of diminished hearing firsthand, and not just in her clinical practice. Her husband incurred permanent hearing loss as a child, and several other family members, including her grandfather, developed severe age-related hearing loss.

Her grandfather’s experience, in particular, helped shape Calandruccio’s research agenda. Born in Calabria, Italy, he arrived at Ellis Island by boat in 1925. He learned English but “spoke with a thick Italian accent until the day he died,” Calandruccio says. He also had a terrible time communicating in noisy environments, but he kept his hearing aid in a drawer because it was so ineffective.

Much of Calandruccio’s early research was in fact focused on hearing aids; her dissertation explored strategies for weighting frequencies in ways that could help people cope with the cocktail party effect.

Yet most of that early work—like the majority of speech-perception research—involved monolingual English speakers. At least, that was the case until Calandruccio came across a study participant whose performance gave her pause. He had grown up in Brazil, and though he had learned English at a very young age, his experience with the language was much different from that of his monolingual peers. Calandruccio found that the features of spoken English he relied on to understand another person’s speech weren’t the same ones that monolingual speakers attended to.

“His performance was so unlike everyone else’s,” Calandruccio recalls. She began to wonder how speech perception in general might differ for monolingual and bilingual speakers, and what that might mean for audiologists who work with bilingual populations.

By the time Calandruccio landed her first faculty position, at Queens College in New York City, she was actively studying speech perception among bilingual individuals: Chinese immigrants who grew up speaking Mandarin and only learned English later on, for example, or the children of Greek immigrants who learned Greek and English simultaneously. Although the scope of her research has expanded since then, her fundamental concerns remain the same.

In one recent study, Calandruccio and Kristina Bowdrie (CWR ’17), who graduated in May with a double major in communication sciences and psychological sciences, demonstrated that linguistic differences among competing talkers affect comprehension.

Researchers already knew that people have an especially difficult time recognizing sentences uttered by a target speaker when two other people, known as maskers, are also talking. This new study, however, showed that when both maskers speak a language that is very different from the target speaker’s (Dutch versus English, for instance), the listener’s performance improves. On the other hand, if at least one of the maskers speaks a language that is the same as or similar to the target speaker’s, comprehension becomes much harder. These results could shed light on how the brain processes speech in environments where multiple languages are spoken simultaneously. Such environments are already common in many parts of the world, and increasingly so in the United States.

Calandruccio is currently working on a project funded by a five-year, $2 million grant from the National Institutes of Health (NIH) to develop a bilingual English-Spanish tool for testing the speech-perception abilities of children under noisy conditions. This tool could help clinical audiologists, most of whom are not qualified to provide bilingual services, address the needs of the burgeoning population of children in this country who speak Spanish at home.

Forms of Engagement

Calandruccio’s research also influences her teaching. In 2015, she developed a course that introduces students to the linguistic and cultural aspects of communication disorders. The goal, she explains, is to equip these students to evaluate and treat both non-native speakers and speakers of dialects such as African American English. “We want to make sure that everybody can achieve optimal communication, not just people who are monolingual speakers of standard American English,” she says.

Calandruccio enjoys a reputation as an engaging instructor—the kind who has students act out the parts of various structures in the ear and who sculpts those structures in Play-Doh.

Among the students conducting research with Lauren Calandruccio (third from left) in 2016-17 were Nardine Taleb and Kristina Bowdrie, who received their bachelor’s degrees in May, and doctoral student Silvia Rodriguez. Photo by Mike Sands.

“I fell in love with her teaching,” recalls Nardine Taleb (CWR ’17), who became involved in the SpAR Lab as a sophomore after taking Calandruccio’s course in multicultural communication. After graduating in May with majors in communication sciences and English, Taleb decided to spend a year as the lab’s manager and to begin graduate school next fall. Eventually, she hopes to work as a clinical speech-language pathologist and serve as a mentor and role model for others, just as Calandruccio has done for her. Among those considering careers in speech-language pathology and audiology, “there aren’t a lot of people who look like me,” says Taleb, who as a devout Muslim wears a traditional head covering, or hijab. But as Calandruccio has pointed out, people who do look like Taleb may regard her as a role model and feel that the profession is open to them.

Both Bowdrie and Taleb assisted Calandruccio in one of her first projects at Case Western Reserve: developing a corpus of sentences tailored to test the speech perception of children. Taleb eventually led an experiment that looked at the performance of children hearing these sentences under noisy conditions. Her presentation of her work at CWRU’s undergraduate research symposium in December 2016 won first place in the social sciences category. After making a second presentation at the annual conference of the American Speech-Hearing-Language Association, she accepted a Meritorious Poster Award on behalf of the entire SpAR Lab.

In addition to communication sciences majors like Bowdrie and Taleb, Calandruccio also mentors students from Case Western Reserve’s Psychology Program. Silvia Rodriguez, for instance, is a doctoral candidate in clinical psychology who studies healthy aging. Her research in the SpAR Lab examines the relationship between the clarity of speech and people’s ability to remember it; her goal is to develop strategies to help older adults with hearing loss better perceive (and therefore recall) instructions they are given in doctors’ offices. Anne Kotynski, a doctoral candidate in experimental psychology, is investigating whether listeners can use cognitive exercises to narrow their auditory focus when entering a noisy environment, priming themselves to home in on a target speaker’s words.

While their research interests vary, Calandruccio’s students all attest to the care and effort she has invested in them, taking the time to discuss their long-term goals, pushing them to their intellectual limits and helping them succeed both inside and outside the lab.

Bowdrie, who worked in the SpAR Lab for two years as an undergraduate, says that Calandruccio gave her opportunities to practice every task related to the study they recently published, from recruiting participants to running experiments, before having her assume responsibility for all of them. In addition, Calandruccio coached her on budgeting for graduate school and avoiding too much student debt. This fall, Bowdrie entered the doctoral program in audiology at The Ohio State University with a fellowship to support her work in another NIH-funded research lab.

“When I came to Case Western Reserve, I was scared. I didn’t know what to do or what to expect,” Bowdrie says. “Dr. Calandruccio guided me and helped me develop the skills I needed to be successful on my own.”

That kind of mentorship requires good listening skills and a knack for conveying information and advice in ways that students can understand. But it’s no surprise that Calandruccio should have those talents in abundance.

After all, communication is her specialty.

Alexander Gelfand is a freelance writer in New York City.

Page last modified: January 13, 2019