Noise-canceling headphones: The hidden risks behind convenience

Our brains constantly decode hundreds of sounds every day. Many people choose to wear noise-canceling headphones to reduce noise interference. Using active or passive noise reduction technology, these headphones effectively block out external noise, providing a quiet listening environment. However, this convenience may also hide some potential risks to hearing health.

The BBC recently reported that Sophie, a 25-year-old administrative assistant in London, found it difficult to distinguish the source of sounds in noisy environments while attending university. She was often described as "inattentive," "distracted," or "a little confused." Although hearing tests showed normal hearing, further testing revealed she had been diagnosed with Auditory Processing Disorder (APD). APD is a neurodevelopmental condition that causes difficulty distinguishing sounds or understanding speech in noisy environments.

Her doctors believe her habit of wearing noise-canceling headphones for up to five hours a day may be contributing to the problem, a neurodevelopmental issue that isn't hearing loss in the traditional sense, but rather an impairment in the brain's ability to process sound information.

Prolonged use of noise-canceling headphones may cause the brain to "forget" how to filter out noise, especially during adolescence, when the brain's complex auditory processing capabilities have not yet fully matured. Claire Benton, vice president of the British Association of Audiology, pointed out that long-term exposure to this "false quiet environment" may delay the brain's ability to process speech and noise.

The profound impact of noise-canceling headphones on the auditory system

1. Decreased auditory processing ability

The brain continuously receives environmental sound stimulation to train complex functions like sound localization and speech separation. When noise-canceling headphones block mid- and low-frequency ambient sounds (such as traffic noise) for a long time, the superior temporal gyrus, the region responsible for sound processing, becomes less active. This can cause patients like Sophie to experience hearing sounds but being unable to interpret their meaning in noisy environments.

The State Administration for Market Regulation's monitoring found that 50% of noise-cancelling headphones are insufficient to reduce low-frequency noise, forcing users to turn up the volume to above 85dB, further increasing the burden on the auditory system.

2. Impaired neuroplasticity

The auditory center of the adolescent brain is still developing between the ages of 18 and 25. Long-term reliance on noise-canceling headphones reduces the input of binaural acoustic difference signals, impairing the brain's ability to establish spatial auditory models. A study by Fujian Medical University showed that those who wore noise-canceling headphones for more than four hours per day had a 37% higher rate of auditory spatial localization errors than the general population.

3. Safety and mental health risks

Noise-canceling headphones reduce ambient sound by an average of 15-20dB, but high-frequency warning sounds (such as car horns) may still be filtered out. A 2023 Japanese traffic accident survey showed that pedestrians wearing noise-canceling headphones had a 2.3 times higher accident rate than pedestrians without headphones. Furthermore, prolonged isolation can trigger social anxiety, with clinical data showing that 29% of people who overly rely on headphones experience a sense of alienation from reality.

Scientific protection advice

1. Follow the 60/60 rule

Keep the volume to 60% of the device's maximum output and use it for no more than 60 minutes at a time. If the ambient noise level exceeds 85dB (such as in a subway car), it is recommended that you suspend use of headphones.

2. Choose compliant and suitable products

Prioritize headphones certified to the EN 50332-2 standard, with active noise reduction of at least 10dB. Avoid "pseudo-noise reduction" products with noise reduction below 5dB. Also, prefer headphones over in-ear earbuds, as they exert less direct pressure on the ear canal. Choose headphones that are breathable and comfortable to minimize ear discomfort.

3. Scenario-based use

• In a steady-state noise environment such as an office, you can turn on the noise reduction mode;
• Switch to transparent mode when walking outdoors to retain ambient sound above 2000Hz;
• Avoid using earphones while sleeping and use bone conduction devices instead.

Current research shows that qualified noise-canceling headphones, combined with appropriate usage habits, can still protect hearing. However, we must be wary of the hidden impacts of technology dependence on neurodevelopment. As Sophie realized after her treatment, "Learning to coexist with moderate noise is the key to balanced hearing health."

Note: This article is reprinted from 21db Acoustics