Imagine waking up one morning to find that you could no longer hear your partner's voice, while still perceiving all the other sounds in the house. Some people might see this as a relief and adjust easily, but for most of us, it would be quite baffling upsetting. How can hearing loss only apply to male voices? The answer can be found through this surprising clinical case.

That morning in Xiamen, a city located on the southeast coast of China, Mrs. Chen, a young woman, woke up and realized she couldn’t hear what her boyfriend was telling her. Listening to surrounding sounds, she discovered that only part of her hearing has been affected, and apparently it was her boyfriend that she could longer hear! The night before, she had gone to bed with ringing in the ears and nausea.

The young woman went to the hospital. The patient had no trouble hearing Dr. Lin Xiaoging (a female doctor) as she examined her. But when a male patient arrived for a consultation and began talking, Mrs. Chen couldn’t hear him. The ENT doctor made the following diagnosis: reverse-slope hearing loss, a rare type of low-frequency hearing loss. Indeed, the tone of someone's voice depends on the frequency with which the vocal chords vibrate. This frequency is measured in oscillations per second and expressed in Hertz. The average frequency is 125 Hz for men and 210 Hz for women. In the same speaker, this frequency can vary significantly depending on their emotional state and what they are saying.

Generally, when a person loses their hearing, the audiogram follows a downward slope, meaning patients are unable to hear higher frequencies. In the case at hand, the opposite was true (a much rarer phenomenon), and the audiogram shows an ascending curve. This is why we call it "reverse-slope hearing loss,” which can impair the ability to hear low male voices.

But what caused this sudden hearing loss? Mrs. Chen reported a lack of sleep due to her work during the period leading up to the appearance of symptoms. This fatigue, along with stress, may have contributed to the development of this auditory disorder. Other causes may also be involved, including Meniere's disease (which affects the inner ear and causes tinnitus, vertigo, and hearing problems), and genetic mutations.

The disorder can however often be reversed if detected early.