Chen “was able to hear me when I spoke to her,” treating provider Dr. Lin Xiaoqing, a woman, told the Daily Mail. “But when a young male patient walked in, she couldn’t hear him at all.”
Xiaoqing told local media she believes fatigue and stress played a role in Chen’s condition and expects her patient will make a full recovery.
When humans hear sounds, the tiny hairs inside the ear vibrate. But genetic conditions, injuries or types of drug use may make the hairs "brittle and prone to breakage," affecting one's ability to hear higher-pitched sounds, Dr. Michelle Kraskin, an audiologist at New York-Presbyterian Hospital who was not involved in Chen's case, told Live Science. But hearing loss of low-pitched sounds like Chen experienced is less common because the ear's cochlea, responsible for the lower frequencies, is usually highly protected.
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In fact, RSHL only affects an estimated 3,000 people in the United States and Canada. For every 12,000 people with some type of hearing loss, Audiology HEARS states on its website, only one individual has RSHL.
It’s most often caused by genetics, and many people with the condition might not even know they have it. Those with Wolfram syndrome, Mondini dysplasia and inheritance through a dominant gene are at increased risk, according to the clinic.
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Other causes of RSHL may include diseases like sudden hearing loss, viral infections or Ménière’s disease, all of which affect the hair cells. Autoimmune disorders that affect the inner ear, also rare, are another potential source. These conditions could also lead to dizziness, nausea and vomiting.
Any procedures or conditions that cause a change in pressure of inner ear fluid (or the endolymph) may also cause RSHL. These conditions include spinal or general anesthesia, intracranial hypertension or a perilymphatic fistula.
Some symptoms of RSHL may include difficulty comprehending speech over phones, which largely deliver low and middle frequencies; an inability to hear low-frequency sounds like a running refrigerator or thunder and, as Chen displayed, a difficulty hearing male voices compared to higher-frequency speech of women and children.
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It’s best to catch the condition within 48 hours for the best chance of recovery, Kraskin said. Once diagnosed, treatment may involve high doses of steroids.
Though RSHL may go away without any treatment at all, the condition can potentially worsen and become problematic in terms of safety.
“If you can’t hear a car coming, you can’t avoid it. If someone some distance from you is trying to warn you away from something, you might not hear it, because volume is a product of the lower frequencies,” according to Audiology HEARS.
Because general industry standards cater to high-frequency hearing loss, which is much more common, treating worsening RSHL can be quite difficult. Audiologists are encouraged to listen to the patient’s concerns and customize hearing aids and should take the time to determine “channel by channel, frequency by frequency” what patients finds “comfortable, audible, and helpful.”
Approximately 25 percent of people in the United States between ages 55 and 64 have some degree of hearing loss, according to the Mayo Clinic. It becomes increasingly common as you age. In fact, hearing loss affects 1 in 2 people older than age 65. Anyone who experiences sudden hearing loss, particularly in one ear, should seek medical attention immediately.