Most people believe that natural sounds are harmless to human health, but a recently reported incident proves that there are some exceptions. An 18-year-old boy surnamed Wang went camping in a forest in Ningbo, Zhejiang province, where he was exposed to the clicking sounds of hundreds of cicadas for several hours, which affected his hearing.
Wang noticed that the cicada noises became noticeably louder around noon, but he remained in the forest until evening, when he began experiencing tinnitus and a sensation of fullness in his ears. As the cicadas started going silent, he noticed that he couldn’t hear the chirping of birds, or even the notification sounds of his phone.
Terrified that he could lose his hearing completely, Wang went straight to the hospital, where a quick checkup revealed that both his ears were swollen. He was prescribed medicine to bring down the swelling and advised to avoid loud noises for at least 14 days. Luckily, after two weeks, the teenage boy healed completely.
“Many people mistakenly think that the sounds of nature are harmless to the ears,” Li Ji, a senior doctor in the otorhinolaryngology (Ear, Nose and Throat) department of Ningbo University No 1 Affiliated Hospital, explained.
Cicadas are recognized as the world’s loudest insects, but one single cicada can’t really cause and hearing damage, as its clicking rarely surpassed 70 decibels. The problem is that a choir of cicadas can exceed 85 decibels, the threshold past which hearing damage occurs.
“The hair cells in the cochlea can develop oedema due to the irritation from loud noises for a relatively short duration. They typically recover after avoiding the noisy environment and resting for 1-2 weeks,” Dr. Li explained. “However, if the hair cells become necrotic, they cannot regenerate. The resulting hearing impairment is permanent and irreversible, forcing the patient to rely on hearing aids for auditory assistance.”
