Headphone listening and teens' hearing

Introduction: Hearing can be damaged when loud sound harms the tiny hair cells in the inner ear that turn sound vibrations into neural signals. Researchers studied whether the amount of time teenagers spend listening through headphones or earbuds is related to how well they hear high-pitched sounds.

Participants: 412 students aged 14 to 18 (52% girls, 47% boys and 1% another gender) at four public high schools in Ohio were invited through their health classes. Parents reported their race/ethnicity as 64% White, 18% Black, 9% Hispanic or Latino, 5% Asian and 4% multiracial. Students with an ear infection on the day of testing, or with a hearing condition diagnosed at birth, did not take part.

Method: An institutional review board approved the study. Parents gave written informed consent, and students agreed to take part. With permission, the researchers installed an app on each student's phone that recorded how many minutes per day the phone played audio through headphones or earbuds. The app ran for 14 days, and each student's daily listening time was the average of those 14 days. Nothing else was changed in the students' lives.

At the end of the 14 days, an audiologist measured each student's hearing threshold for a high-pitched 4,000 Hz tone: the softest level, in decibels (dB), at which the student could detect the tone, averaged across both ears. A higher threshold means a sound has to be louder before the student can hear it. Data were stored under code numbers, not names, and were not shared with the schools. Each student received their own results privately, and students with thresholds above 20 dB were referred to a hearing clinic for a follow-up check.

Results and Discussion: Students listened through headphones or earbuds for an average of 2.4 hours per day (range: 0 to 7.5 hours). Daily listening time was positively correlated with the 4,000 Hz hearing threshold (r = +0.37), a statistically significant relationship. The table compares students by listening time. The researchers noted that students who listen for many hours may also be exposed to other loud sounds, such as concerts or noisy jobs, more often.