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(CNN)The receptionist at the doctor's office asks a question from behind her double mask and face guard on the opposite side of a large, plastic partition.

"Excuse me, what was that again?" It's a phrase I repeat a lot these days.

Distorted by masks and myriad sound barriers, sounds in the world around me have become muffled, emerging as garbled as Marlon Brando's infamous whispers in "The Godfather."

My hearing isn't that bad. So if I'm struggling to understand others during the pandemic, how must it be for elderly grandparents and others with hearing loss, especially with so many people double masking?

"We have been concerned about this issue from the start of the pandemic as many with hearing loss struggle much more in conditions where others are wearing masks," said Dr. Debara Tucci, who directs the National Institute on Deafness and Other Communication Disorders, a part of the National Institutes of Health.

A new study published Wednesday in PLOS One has tackled the problem by comparing four ways of masking up: using two different kinds of cloth masks, a surgical mask and an N95 mask, which filters 95% of tiny virus particles. The study did not investigate double masking.

"In the context of the pandemic, we were motivated to look at this issue more closely, since there was little previous research on how different types of masks affect speech," said study author Joseph Toscano, an assistant professor of psychological and brain sciences who directs the cognitive science program at Villanova University in Pennsylvania.

"In high levels of background noise, the surgical mask was shown to least hinder speech recognition, said Dr. Jawad Fares, a postdoctoral research fellow in the department of neurological surgery at the Feinberg School of Medicine in Chicago's Northwestern University.

"The findings of the study are important in light of the current pandemic, as it acknowledges the communication challenges that we are facing," said Fares, who was not involved in the study.

Worldwide problem

Statistics have shown almost 25% of people ages 65 to 74 and 50% of people over 75 in the United States have disabling hearing loss -- where they wouldn't be able to hear a vacuum cleaner, barking dog or even a baby's cry.

And it's not just the elderly. Globally, some 466 million people have disabling hearing loss -- 34 million are children, according to the World Health Organization. One in eight people in the United States 12 years or older have some form of hearing loss in both ears.

Many people with hearing loss -- and even some who don't -- rely on lip reading to follow conversational speech. That tool, of course, is removed by the use of masks during the pandemic.

The good news is that when background noise was limited, as is typical of many everyday settings, the study found cloth, surgical and N95 masks allowed speech to be conveyed effectively, Toscano said.

When background noise was loud enough that it might interfere with understanding speech, "we found that a surgical mask worked better than other masks for communication," Toscano said.

"The finding that surgical masks cause less of a problem than cloth masks or N95 masks is interesting," said NIDCD's Tucci. "However, these (surgical masks) are not always available to the public, and certainly early on use of these masks was discouraged so as not to interfere with supply for use in medical facilities."

Surgical masks

Designed to be used by surgeons and other health care professionals, surgical-grade masks are loose-fitting, disposable devices meant to "help block large-particle droplets, splashes, sprays, or splatter that may contain germs (viruses and bacteria), keeping it from reaching your mouth and nose," according to the US Food and Drug Administration.

True medical-grade masks are made of three layers of nonwoven fabric typically made from plastic. The colored top layer of fabric is made of medical-grade spunbond polypropylene, which is a resin polymer heat-bonded into a weblike structure.

Surgical masks also have small, bendable wires to help the mask stay in place, and are often tied behind the head or secured with ear ties. Such masks are one-time use only. If they are soiled or breathing becomes difficult, the mask should be carefully discarded and replaced, the FDA said.

Clear masks are an option, too

The NIDCD and the US Centers for Disease Control and Prevention suggest teachers and caregivers wear clear masks or cloth masks with a see-through plastic panel when interacting with young children learning to read, students learning new languages or people with hearing loss or disabilities.

That would certainly apply to caregiving in hospitals, nursing homes and long-term care facilities, and within families of mixed generations. Now it appears that there could be a new option, Tucci said, because the study found that "intelligibility is better with surgical masks."

"It is worth emphasizing to the public that if they are struggling to communicate -- for example if they have a close family member or friend who struggles to hear -- it would be worthwhile to procure either surgical masks or masks with a transparent panel to see if that is helpful," she said.