To clarify, the woman can only hear voices belonging to other women.
At the hospital, Chen was treated by Dr. Lin Xiaoqing - a woman - who noted that while Chen was able to hear Xiaoqing's voice, she couldn't hear the voice of a nearby male patient "at all", according to Newsweek. And it's rare: According to Tennessee's Thigpen Hearing Center, "for every 12,000 cases of hearing loss, only one person has RSHL".
Ms Chen, from the Chinese city of Xiamen, on the east coast of China, went straight to the hospital when she woke up, and her condition left doctors confused.
After Chen went to a specialist ear, nose and throat doctor (ENT) she was diagnosed with a condition called "reverse-slope hearing loss". She chalked it up to being overworked and stressed, and didn't think much of it before going to sleep, hoping that a peaceful slumber would fix the problem.
After diagnosis it was found that Chen was suffering from reverse-slope hearing loss, in which she could only hear high frequencies.More news: Rohit Sharma says nobody’s guaranteed a ticket to England
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As well as struggling to hear low-frequency voices, those with the condition can find it tough to make out voices on the phone, as well as noises like the hum of the fridge or thunder.
"She was able to hear me when I spoke to her, but when a young male patient walked in, she couldn't hear him at all".
According to local reports, Doctors tried to figure out her freaky symptoms, which were the opposite to more common forms of hearing loss.
It was possible that stress may have contributed to the condition, the doctors said. It is hard to detect, as both patients and medical professionals are often unaware of the condition. The term describes the shape of a hearing test audiogram of those who can't hear low frequencies. In the days before she woke up with hearing loss, Chen reportedly had been working long days and not getting a sufficient amount of sleep.
Only around 3,000 people in north America are affected by the rare condition.